Research Article
Omid Nasiri-Gheidari; Safar Marofi
Abstract
Introduction: Due to the rapid rate of population growth, water resource topics wasmainly affected by the economic and social components, however, the importance of environmental issues in such projects has gained more attention. As pollution loads are increasing, it has become more essential to incorporate ...
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Introduction: Due to the rapid rate of population growth, water resource topics wasmainly affected by the economic and social components, however, the importance of environmental issues in such projects has gained more attention. As pollution loads are increasing, it has become more essential to incorporate water quality in water resource management issues. Under this condition, optimal water allocation by considering multiple objectives of water quality and quantity issues can lead to sustainable and optimal benefit of stakeholders. This study was done in order to balance environmental and economic concerns in water resource allocation.
Materials and Methods: Based on game theory concepts and fuzzy programming procedure, two new methodologies were developed for sustainable water resource allocation in river systems. The proposed methods which include a multi-objective bargaining and fuzzy programming approaches were utilized to analysis strategies of interaction between environmental protection and economical income. Two groups of players, consists of player 1 for environmental and player 2 for economic issues were considered in order to apply the developed models. As players will not be satisfied with the outcome of each other, they will begin the bargaining process. Throughout the bargaining rounds, players will reduce their expectations. After several negotiations, the interval between the reset goal values and outcomes will be decreased. The bargaining process will be finished if final solutions reach to the determined goals. In the study, the Total Dissolved Solids (TDS) were considered as water quality indicators of environmental objective function, since salinity is the important problem of the study area. Using crop production function in economic income objective function makes it possible to incorporate deficit irrigation in different crop growth stages. Since allocation problems include many decision variables, conventional (non-linear) crop production function will have high computational costs and linear form of it can reduce the complexity of the optimization model. Therefore,additive (linear) form of crop production function was taken into consideration instead of multiplicative form. Total pollution load discharged into the river (ton per year) and economical income of the system (thousand dollars per year) wasconsidered as environmental and economic values, respectively. During the fuzzy programming procedure, the purpose is to achieve a compromise solution. In this approach, the individual maximum and minimum values of objectives is used to define the membership function. This procedure will maximize the satisfaction degree of the constructed membership functions of the objectives. The presented methodology was illustrated in a part of Karoon-Dez river system between Gotvand dam, Dez dam and Ahvaz city, as a case study. The area of Karoon-Dez river basin is about 67000 square kilometers and it is located in the southwestern part of Iran. The selected area includes 8 agro-industrial and 3 traditional agricultural sub-sectors.
Results and Discussion: Using a linear form of crop production function for calculating the total benefit of the system leads to significant reduction in run-time of the optimization model and make irrigation programming possible by regarding crop growth stages and the available water amount. The results of this study showed that Nash equilibrium, which provides a base for decision makers to choose a strategy, was reached at the fourth round of bargaining process. Moreover, balance between economic and environmental objectives is available by reducing economical expectation and environmental concerns from 553636 to 496216 thousand dollars per year and from 68264 to 87251 tons per year, respectively. In these cases, the annual allocated water to environmental and economical player will be 6123 MCM (5318 to agro-industrial sub-sectors and 805 to agricultural sub-sectors) and 6453 MCM (5730 to agro-industrial sub-sectors and 723 to agricultural sub-sectors) respectively. The results of the fuzzy programming approach demonstrated that at optimal condition, environmental and economic objective function was 85999 tons per year 500422 thousand dollars per year, respectively and allocated water to water users are 6354 MCM per year (agricultural and agro-industrial sub-sectors of the system will be (763 and 5591 MCM per year). Agro-Industrial sub-sector 3 will take the maximum allocated annual water (1789 MCM per year) and Agro-Industrial sub-sector 5 will receive the minimum annual allocated water (151 MCM per year). Comparison of two investigated approaches showed that their results are in agreement with each other.
Conclusions: Results of applying the developed methodology to the Karoon-Dez river system demonstrated that it is effective and applicable to determine sustainable water allocation policies. Finding of this study reveals that the proposed framework can facilitate decision-making process and optimize allocated water to different water users under conflicting objectives. Therefore, the developed procedure can be used as a managerial tool for optimal water allocation strategies, which is in accordance with sustainable development approach. It is easy to apply the presented methodology to other river systems with high pollution loads of agricultural return flows.
Research Article
Mohsen Soleimanzadeh; Hossein Khademi; mozhgan sepehri
Abstract
Introduction: Iron is one of the essential micronutrients for plant growth. The total amount of iron in soil is often more than plant iron requirement, but the low solubility of iron compounds in many of soils leads to low uptake of this element by plant and eventually, results in iron deficiency symptoms ...
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Introduction: Iron is one of the essential micronutrients for plant growth. The total amount of iron in soil is often more than plant iron requirement, but the low solubility of iron compounds in many of soils leads to low uptake of this element by plant and eventually, results in iron deficiency symptoms in plant. Iron is the structural component of cytochromes, leghemoglobines and ferredoxins. This element participates in many vital activities of plants, such as photosynthesis, respiration and fixation of molecular nitrogen. Some of micaceous minerals including muscovite and phlogopite which contain significant amounts of iron are plentiful in soils of arid and semiarid regions of Iran. The purpose of this study was to evaluate the ability of two plant species (alfalfa and barley) to uptake structural iron from muscovite and phlogopite.
Materials and Methods: The greenhouse experiment was conducted as factorial arrangement based on completely randomized design with three replicates. Treatments consisted of two plant species (alfalfa and barley), two types of micaceous minerals (phlogopite and muscovite) and two nutrient solutions (complete and iron-free).The experiment was done in 700 g pots containing a mixture of quartz sand (as the filling material), cocopeat and micaceous minerals (phlogopite and muscovite). Quartz sand and micaceous mineral were obtained from a mine near Hamadan City in Iran. For this purpose, X-ray elemental analysis fluorescence (XRF) was used to investigate the possibility of using quartz sand and micaceous mineral. Micaceous minerals were passed through a 140 mesh sieve and then, samples were saturated with Ca using a 0.5 M CaCl2 solution. To remove the excess Cl, saturated minerals were washed with distilled water several times and then samples were oven dried at 105 °C. Pots were filled with a mixture of 600 g quartz sand, micaceous mineral and cocopeat. The amount of mineral was added until there was 0.35% K2O in all pots. Two barley and alfalfa seeds were planted in each pot. During the growth period (150days), plants were irrigated and fed with distilled water and nutrient solutions, respectively. At the end of the growth period, shoots and roots of plants were harvested andiron contents of plants extracts were measured by atomic absorption.
Results and Discussion: For two plant species, the results showed that iron concentration in the pots containing phlogopite and fed with iron-free nutrient solution was in a sufficient range for both barley and alfalfa. The amount of iron uptake by alfalfa in both substrates and nutrition solutions was more than barely. It seems that alfalfa is able to uptake more amount of iron due to the abundant root exudates. The highest amount of iron uptake by root is related to alfalfa cultivated in substrates containing phlogopite and fed with iron-free nutrient solution. The highest barley shoots weight is related to substrates containing phlogopite and muscovite fed with complete (with iron) nutrient solution, whereas in alfalfa, the highest shoot weight is related to phlogopite-containing substrates fed with iron-free nutrient solution. Plants cultivated in two substrates containing phlogopite and muscovite did not show deficiency symptoms until late growth period and appearance of plants fed with iron-free nutrient solution was completely similar to those fed with complete nutrient solution. The amount of iron uptake by roots is several times higher than that of shoots. High uptake of iron by plant roots are affected by phytosiderophores produced by plant roots. Phytosiderophores produce chelate Fe (III) in the rhizosphere. These chelates are absorbed into the apoplast of roots and Fe (III) is separated from them as a result of certain reactions, and takes the path to xylem.
Conclusion: The results of this study indicate that iron structural phlogopite and muscovite minerals can provide iron requirement for plant during the growth season. Since phlogopiteis a tri-octahedral mineral, it has more Fe (II) and its structure is weaker than muscovite, and hence, is able to provide more iron for the plant during growth season. But muscovite is di-octahedral and its structure contains Al+3, so octahedral may not easily release its elements into the rhizosphere for the plants utilization. The factors influence the release of elements from micaceous minerals are structure and type of mineral. Alfalfa is able to release more iron from micaceous minerals thanks to its root systems and ability to produce more shoot. Since micaceous minerals have considerable amount of iron and are able to provide iron requirement for plant during growth season, it is recommended to investigate whether micaceous minerals are able to supply this element for longer growth periods.
Research Article
siros sadeghi; Shahin Ostan; Nosratollah Najafi; Mostafa Valizadeh; Hassan Monirifar
Abstract
Introduction: Heavy metal contamination not only adversely affects the chemical properties, availability of nutrients and biological activity of the soils, but also causes serious risk to the human health from entering the food chain. Cadmium as an unnecessary heavy metal is highly toxic to plants. Cadmium ...
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Introduction: Heavy metal contamination not only adversely affects the chemical properties, availability of nutrients and biological activity of the soils, but also causes serious risk to the human health from entering the food chain. Cadmium as an unnecessary heavy metal is highly toxic to plants. Cadmium toxicity inhibits plant growth and even death. Metabolic processes such as photosynthesis and cellular respiration are disturbed due to cadmium toxicity. Among the heavy metals, zinc is an important nutrient in many biological processes such as photosynthesis, activity of antioxidant enzymes, proteins, hormones and other activities. Because of the similar chemical behavior of cadmium and zinc, interaction between the two metals is of interest to many researchers.
Materials and Methods: In this study, to investigate the interaction effects of cadmium and zinc on shoot and root dry matter and chemical composition of corn (Zea mays cv. single cross 704), a factorial experiment as a randomized complete block design in triplicate with eight levels of cadmium (zero, 0.5, 2.5, 5, 10, 20, 40 and 80 mg Cd kg-1) and eight levels of zinc (zero, 5, 25, 50, 100, 200, 400 and 800 mg Zn kg-1) was conducted in a loamy sand soil under greenhouse conditions. After 60 days, the plants were harvested and dry weights of shoots and roots were determined. Moreover, after wet digestion, the concentrations of cadmium, zinc, iron, manganese and copper in these tissues were determined by flame atomic absorption spectrometry (Shimadzu-6300).
Results and Discussion: Treatments with 800 mg Cd kg-1 showed symptoms of cadmium and or zinc toxicity at early stages of the growth. These plants died after 10 to 20 days of germination. The results showed that the cadmium and zinc interactions on shoot and root dry weights were significant. At 0.5, 2.5, 20 and 80 mg Cd kg-1 (except for Cd0.5-Zn25), application of 5 to 50 mg Zn kg-1 increased shoot dry weight. Higher levels of zinc supplementation exhibited adverse effects. At 5 and 10 mg Cd kg-1, supply of 5 to 100 mg Zn kg-1 was associated with an increase in shoot dry weight, but shoot growth was reduced at higher zinc levels. At 40 mg Cd kg-1, application levels of 5 to 200 mg Zn kg-1 increased shoot dry weight, whereas 400 mg Zn kg-1 showed adverse effects. Moreover, the cadmium and zinc interactions on chemical composition of corn were significant. Based on the results, at low levels of cadmium, zinc supplementation at each level increased the shoot and root cadmium concentrations, while at high levels of cadmium, low and high zinc supply caused a decrease and increase in the shoot as well as root cadmium concentrations, respectively. The concentration of a particular trend was observed on the shoot and root. Supplementation of zinc at each level of cadmium (except for 80 mg Cd kg-1), first increased and then decreased the iron concentration of shoots and roots. Application of zinc at each level of cadmium decreased manganese and copper concentrations in shoots and roots.
Conclusions: According to the results, the ecological tolerance of corn to zinc was found to be 800 mg Zn kg-1. Also, the application level of zinc with positive effect on shoot dry weight increased with an increase in cadmium level. At all levels of cadmium, supplementation of zinc at medium levels prevented the accumulation of cadmium in shoots, while high and low levels of zinc intensified the cadmium accumulation. The highest accumulation of cadmium in roots was occurred at highest level of zinc. Zinc supplementation at each level of cadmium first increased and then decreased iron concentration in shoots and roots. However, zinc supply at each level of cadmium decreased copper and manganese concentrations in shoots and roots. As a conclusion, zinc at low levels diminished toxic effects and accumulation of cadmium, meanwhile high levels of zinc not only did not control cadmium but showed deleterious effects. The critical level of poisoning for cadmium in aerial parts of both plants in lower density in the soil (up to 90 mg kg-1 ) showed very little changes, but in higher density, it decreased in brassica napus and increased in zea mays. The critical level of poisoning on the aerial parts of both plants showed very little change with increasing the total density of cadmium in the soil.
Research Article
Mahmoud Enjavinejad; Hamidreza Owliaie; Ebrahim Adhami
Abstract
Introduction: Magnetic susceptibility measurements can serve a variety of applications including the determination of changes in soil-forming processes, the study of parent material effects, understanding sedimentation processes, soil drainage conditions, and even the separation and identification of ...
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Introduction: Magnetic susceptibility measurements can serve a variety of applications including the determination of changes in soil-forming processes, the study of parent material effects, understanding sedimentation processes, soil drainage conditions, and even the separation and identification of soil delineations. The technique is especially attractive since it is relatively rapid, non-destructive, and can be applied to both intact and disturbed samples of soils. Magnetic susceptibility is defined as the ratio of the total magnetization induced in a sample relative to the intensity of the magnetic field that produces the magnetization. Iron oxides are the most abundant of the metallic oxides in most soils; they are present in all climatic regions, in several mineral forms, and at variable concentrations. Typically, selective dissolution techniques are used to quantify the relative proportion of Fe oxides. Due to the large contribution of iron-bearing minerals to magnetic susceptibility, their presence in most soils, and the effects of the biophysical environment on them, pedologists have been paying growing attention to magnetic susceptibility as a means to understand soil and landscape processes. The effects of topography on χ were studied for example by many workers. They found that soil susceptibility changes with the position of a soil profile on a slope. Texture and drainage class assumed to be the main reasons. The soils of the Beshar Plain formed on the relatively same parent materials and are mainly affected by topography and land use. The objective of this study was to examine the role of topography and land use on pedogenic processes and their relation to soil χ, as well as, profile distribution of secondary Fe oxides, and the χ profiles.
Materials and Methods: This study was conducted on the Beshar Plain, Kohgilouye Province, in southwest of Iran. Physiographically this plain comprises hill, piedmont plain, river traces, and plateau. Eleven representative pedons were dug along a transect crossing the main physiographical units. Five pedons demonstrated aquic soil moisture regime. The mean annual temperature and precipitation at the site was 14.7°C and 800 mm, respectively. Soil moisture and temperature regimes of the study area were xeric and thermic, respectively. The soils were classified according to soil taxonomy and WRB. The soil pH was measured in a saturation paste and electrical conductivity (EC) in a saturation extract. Cation exchange capacity (CEC) was determined using sodium acetate (NaOAc) at a pH of 8.2. Soil texture was determined using the pipette method. Calcium carbonate equivalent (CCE) was measured by acid neutralization. Organic carbon was determined by wet oxidation method. Pedogenic Fe (Feo) and pseudo-total Fe (Fen) were extracted with the CBD method and HNO3, respectively.The magnetic susceptibility of bulk samples was determined using a Bartington MS2 meter equipped with the MS2B Dual Frequency sensor, capable of taking measurements at both low (χlf at 0.46 kHz) and high (χhf at 4.6 kHz) frequencies.
Results and Discussion: The soils were classified as taxonomic orders of Entisols, Mollisols, Inceptisols and Alfisols, according to the world reference base for soil resources (WRB) as reference soil groups of Kastanozems, Regosols, Gleysols, Luvisols, Fluvisols and cambisols. The dominant pedogenic processes in the soils were the accumulation of organic matter, the leaching of carbonates, and formation of calcic horizons, the mobilization of clay and development of argillic horizons. The results indicated that the soils are affected mainly by topography, drainage class and land use. Most pedons exhibited maximum of χ at the soil surface, suggesting preferential loss of diamagnetic components, as well as more pedogenic formation of antiferromagnetic minerals. Magnetic measurements showed that the χ values of aquic soils were much lower than those of non-aquic soils (43%). The highest value of χ was noted in pedons which are located on stable physiographic units and the lowest belong to those which are located on river lower terraces. Fed and fen was also positively correlated with χ in the soils studied. Aquic condition also decreased Fed and Fed/Fen, 44 and 65 percent, respectively with no clear effect on Fen. Low to medium amounts of χfd in the studied soils indicated that superparamagnetic gains are not too dominant in the soils. Higher values of χfd were typically observed in the A horizons than at depth, suggesting a greater proportion of ultrafine grains at soil surface. A positive correlation existed between χfd and χ in the soils.
Research Article
vali feiziasl
Abstract
Introduction: Nitrogen is the main component of fertilizer programs necessary for production of high quantity dryland barley. This element is the second limiting factor, after water in dryland areas. So for economic production of barley, the proper nitrogen fertilizer application is essential to increase ...
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Introduction: Nitrogen is the main component of fertilizer programs necessary for production of high quantity dryland barley. This element is the second limiting factor, after water in dryland areas. So for economic production of barley, the proper nitrogen fertilizer application is essential to increase seed quantity and quality in Iran dryland areas. Many researchers have been confirmed that dryland barley yield increased by nitrogen application management. Nitrogen fertilization in dryland areas can increase the use of soil moisture, and improve barley yields to some extent. Different studies have been confirmed interactions between water stress and nitrogen fertilizers on barley, especially under field conditions. From the nitrogen management factors, timing and amount of nitrogen application is known as the most important aspect. This project established in order to study nitrogen rates and nitrogen application time's effects on nitrogen requirement, nitrogen agronomy use efficiency (NUE) and crop characteristics of various dryland barley genotypes in cold and semi cold drylands of Iran.
Materials and Methods: This study was carried out in split-split plot in a RCBD in Dryland Agricultural Research Institute (DARI), Maragheh; where nitrogen application times (fall, 1/2 in fall and 1/2 in spring and 2/3 in fall and 1/3 in spring) were assigned to the main plots, nitrogen rates to sub plot (0, 30, 60, 90 and 120 kg/ha), and 5 dryland barley genotypes to sub-sub plots (Sahand, Abidar, Dayton/Ranny, Alpha/ Gumhuriyet/ Sonja and B-C-74-2)in 4 replications during 2007-2010 years. The Rainfall were 177-498 mm.yr-1 (long term mean is 365 mm.yr-1) in cropping years in DARI station. Soil samples were collected from 0-25 cm for determining total N, P-Olsen, K-Ammonium acetate, TNV, OC, Soil texture, pH, EC and Fe, Mn, Zn and Cu-DTPA before sowing and collected from 0-2, 20-40 and 40-60 cm depths in sub-sub plots in shooting stage (GS32) for determining NO3− andNH4+. Ammonium measurement in the soil KCl extracts were down by spectrophotometry method and colorimetric reaction at 655 nm. Also, Absorption spectrophotometry method was used for determination of nitrate in soil extract based on its UV absorbance at 210 nm. In this method two measurements were carried out; one before (by Zn coated by Cu) and second after reduction of nitrate). Using the difference between these two measurements, concentration of nitrate in the extracts was determined.
Results and Discussion: The results showed that nitrogen application rates significantly increased (p
Research Article
Sayyedeh Maryam Mirabolghasemi; Mahdi Ghobadi Nia; ahmad reza ghasemi; mohammad reza Nori Emamzadeie
Abstract
Introduction: Rice is one of the cereals that are widely used food in the world as staple.Rice is the largest consumer of water among agricultural products.At the field level, rice receives up to 2–3 times more water per hectare than other irrigated crop for producing of one kilogram of rice.Accordingto ...
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Introduction: Rice is one of the cereals that are widely used food in the world as staple.Rice is the largest consumer of water among agricultural products.At the field level, rice receives up to 2–3 times more water per hectare than other irrigated crop for producing of one kilogram of rice.Accordingto water resources limitation in Iran, According to water resources limitation in Iran, careful planning is essential to optimal use of water resources in agriculture as the largest consumer. One of the methods to reduce water consumption in rice cultivationis changing the traditional irrigation methods (flooding) to periodic irrigation. Change of management from traditional water-logging irrigation to unsaturated improves the irrigation water use efficiency. Due to water scarcity problems, the aim of this study was to evaluate controlled drainage and the impact of irrigation management on growth characteristics and yield components of rice in the arid and semi-arid.
Materials and Methods:To Considering the effect of water table level on water productivity in rice cultivation, the study was done in Shahrekord university. The experiments conducted in pots with 40 cm diameter and 45 cm hight. The experiment was arranged following a completely randomized design with four treatments (water table level) and five repetitions. The water table managements including: control water table 2 cm on the top of the soil (FI),the control water table 20 cm below the soil surface (CD20), control water table 36 cm below the soil surface (CD36) and Intermittent irrigation(AI). Tocontroll the water level, two tanks were used, one as stabilizer water table and another to measure the amount of water used. The Treatmentsares are completely water logging for a week, in second week treatments were applied. Sampled four times during the growing season was performed to determine the dry matter content of leaf, stem and leaf relative swelling and at the end of the growing season, the volume of water consumed, harvest index, the amount of grain produced and thousand grain weight was measured and recorded. The data obtained were analyzed using SAS software and LSD test was performed for comparison of means.
Results and Discussion:The results showed reduced yield treatments for CD20, CD36 and AI for each unit reduction in water consumption respectively as much 0.36, 0.46 and 0.38 units. Also results showed irrigation management caused significantly decrease in swelling relative only in the first and Second measuring stages respectively at the 5 percent level and in the fourth measuring stages at 1 percent level. Dry matter productive also was reduced under irrigation management in the Second and fourth measuring stages respectively in 1st and 3rd measuring stages at the 5 percent level. The impacts of irrigation management are no statistically significant on the rice harvest index and thousand grain weights but water consumption was reduced in CD20, CD36 and AI. Resulted to increment 5 percent water use efficiency based on performance and a significant increase 1 percent in the efficiency of water use was based on biomass. The highest and lowest harvses index belongs to FI (39.1) and CD36 (35.4) respectly. The highest and lowest thousand grain weights belong to FI (1247 kg/ha) and CD36 (1101 kg/ha) respectly.
Conclusions:High water Stress causes roots gone to sleep and their growth will slow after re-watering. Water scarcity is not only the hinder root growth but causes the root fuzzy and reduce its ability to absorb substances. The results showed that water reduction, a significant decrease in grain yield not occurred, Lack significant differences in grain yield mean that the water supply was adequate at all levels and in none of irrigation regimes, the plant was not affected by water stress and plant roots grown have enough at critical stages that needs greater water and has access to available water at greater depths. Results showed that T2 (control water table level at 20 cm below surface of soil) for each unit reduction in water consumption, 0.36 units reduces seed productionand 16% reduction in the amount of dry matter, That these lowest values are in the between treatments. With this irrigation management and reduce water consumption by 23% compared to control treatment area under cultivation can increased by as much as 30% and the grain production increase from 3424 to 4210 Kg per hectare.
Research Article
Hadi Ramezani Etedali; Alireza Shokoohi; S. Amin Mojtabavi
Abstract
Introduction: Qazvin plain is one of the most important agricultural regions in the central part of Iran. Because of recent continuous droughts and the increases in the demands of different sectors such as agriculture, industry, environment and domestic, the plain is faced witha severe shortage of water ...
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Introduction: Qazvin plain is one of the most important agricultural regions in the central part of Iran. Because of recent continuous droughts and the increases in the demands of different sectors such as agriculture, industry, environment and domestic, the plain is faced witha severe shortage of water resources. Due to the declining share of surface waters, farmers increased the using of groundwater. And the overusing of groundwater for irrigation has caused the severe drop in water level of the aquifer. The critical situations in the Qazvin plain have made the agricultural water management and crop pattern modification vital and necessary.Due to the population increase, concepts and theories such as food security, environmental protection and sustainable management of groundwater and surface water resources, virtual water footprint and virtual water trading are a dynamic concept for water resource management in all sectors that has considered more in recent years.
Materials and Methods: The green (effective precipitation), blue (net irrigation requirement), gray (for diluting chemical fertilizers) and white (irrigation water losses) water footprints (WF) of main crop production were estimated for Qazvin plain. The average yield and fertilizer application in irrigated and rainfed lands, for main crops wasobtained from Agricultural-Jihad Bureau of Qazvin Province in for 2003-2014. Pe values were calculated by USDA method and ETc was calculated by FAO-Penman-Montieth method using the model CROPWAT. Values of α under irrigation and rain-fed were considered 5 and 10%, respectively. In this study, WFGray has been calculated just for nitrogen fertilizers. The maximum nitrogen concentration in the receiving waters based on the US-EPA Standard is 10 mg/lit. Due to the differences in crop yield under rainfed and irrigation conditions, the WF components were calculated using crop yield for different conditions, separately.
Results and Discussion: Canola and maize with 4066 and 185 m3/ton have maximum and minimum WF in the irrigated lands, due to the yield of two crops. Canola and maize have maximum and minimum yield between the irrigated crops, respectively. The total wheat WF of was estimated 2673 m3/ton in the area. The total WF in the rainfed lands is much more than the total WF in irrigated lands that is due to the significant yield differences in the irrigated and rainfed lands, especially for wheat and barley. In recent years, because of the decrease in precipitation, the rainfed crop yields have decreased considerably. Between the irrigated crops, wheat, barley, tomato, and canola are the four crops which have similar white WF (about 50%) and gray WF (about 10%). Also there are the same shares between white and gray WFs of corn and maize. The shares of white and gray WF in corn and maize are 28 and 18, respectively. These results show that agricultural practices and managements are similar. In other words, the irrigation system efficiency and fertilizer application are similar in farms and for crops. Also there aren’t significant differences in the green and blue WFs of corn and maize. These similarities in WF components are the result of approximate equalities in the evapotranspiration, effective rainfall, fertilizer application, and depth of irrigation. In irrigated lands, white WF contains about 46% of the total water footprint in the production of main crops. In irrigated and rainfed lands, about 42% of the WF is related to white water. Thus, irrigation losses are about 864 MCM/year in the region, which is really considerable for a region that faced with water shortage crisis. In rainfed lands, the gray WF component is about 13. In total. If this gray WF which is the environmental need for protecting water quality doesn’t meet, contamination of surface and groundwater resources will be occurred. Wheat has the most consumed and exported virtual water volume with 652 and 343 MCM/year, respectively. The export of wheat includes 28.4% of the total exported virtual water volume and 20.2% of the exported water resources volume. Total consumed and exported virtual water volume from the region are 1031 and 1022 MCM/year. The exported volume of blue, gray and white WFs consists about 783 MCM/year. Therefore, considerable volumes of groundwater and surface water resources exported from the region by exporting main crops. The exported weight of maize, corn, alfalfa and tomato from the region is greater than the weight of consumption in the region. The total of blue, gray and white WFs is much higher than the green WF of these crops. The export of these crops imports the most pressure on groundwater and surface water resources of the region.
Conclusions: Qazvin Plain as one of the most important plains in the central part of Iran faces to water shortage crisis. The concept of virtual water and WF of agricultural production help to better agricultural water management in the region. The total share of gray and white WFs in the region is about 907.5 MCM/year and 44% of the total WF in the agricultural main crop production. Low efficiency of irrigation systems and excessive use of nitrogen fertilizers in farms are the most important causes of high shares of these two WF components. The planting and export of summer crops hasa considerable share of VW trade in the region. Due to the high water requirements, the total share of blue, gray and white WFs is high in these crops. These WF components are supplied from the limited surface and groundwater resources of the region. Also, WF in rainfed crops is much greater than the irrigated crops. Droughts and rain reduction are the main reasons of severe decreasing in the yield of rainfed lands. Supplementary irrigation is a management for reducing WF and improving yield in rainfed land. VW trade volume is about 1,022 MCM/year.
Research Article
Mohamad Rahmanian; AliReza Hosseinpour; Ebrahim Adhami; Hamidreza Motaghian
Abstract
Introduction: Rhizosphere is commonly defined as the zone where root activity significantly influences the biological and chemical properties of the soil. Biological, physical and chemical characteristics of rhizosphere, especially metal availability and metal chemical forms are different than the bulk ...
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Introduction: Rhizosphere is commonly defined as the zone where root activity significantly influences the biological and chemical properties of the soil. Biological, physical and chemical characteristics of rhizosphere, especially metal availability and metal chemical forms are different than the bulk soil. Plant roots continuously release compounds such as sugars, amino acids, and carboxylic acids. Plant roots have the ability to transform metal fractions for easier uptake through root exudation in the rhizosphere. This study was conducted to investigate change in availability and fractions of Copper in the rhizosphere of sunflower (Helianthus annuus L.) in a sandy contaminated soil treated with chelators (EDTA, citric acid and poultry manure extract (PME)) in greenhouse condition.
Materials and Methods: In this study, EDTA and citric acid were used at concentrations of 0, 0.5 and 1 mmol kg-1 soil and PME was used at concentrations of0, 0.5 and 1 g kg-1 soil. Three seeds of sunflower were planted in the rhizobox. After 10 weeks, plants were harvested and rhizosphere and bulk soils were separated. Dissolved organic carbon (DOC), microbial biomass carbon (MBC), available Cu (by using 7 chemical procedures including DTPA-TEA,AB-DTPA, Mehlich1, Mehlich3, CaCl2 0.01 M, rhizosphere-based method and distilled water) and Cu-fractions were determined in the rhizosphere and bulk soils.
Results and Discussion: Rhizosphere soils properties were different with bulk soils. The results showed that the mean of DOC and MBC in the rhizosphere soils were higher than the bulk soils, but this difference was significant in some treatments. The mean value of pH in the rhizosphere soils was significantly (p
Research Article
Yaser Safari; Mohammad Amir Delavar; Zahra Noori
Abstract
Introduction: Land suitability evaluation (LSE) may be considered as a worldwide accepted procedure to achieve optimum utilization of the available land resources for sustainable agriculture. The common LSE procedures, like the widely accepted “A framework for land evaluation” presented by FAO, however, ...
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Introduction: Land suitability evaluation (LSE) may be considered as a worldwide accepted procedure to achieve optimum utilization of the available land resources for sustainable agriculture. The common LSE procedures, like the widely accepted “A framework for land evaluation” presented by FAO, however, do not consider variability of soil quality parameters; whereas, the soil quality and its suitability for different uses are influenced by highly variable land management strategies. Therefore, assessing the spatial variability pattern of environmental variables and their accumulative effects on land suitability for specific crops, is the key for achieving to thoughtful land use planning for sustainable use. The present study was done aimed to evaluation of spatial variability of land suitability for irrigated wheat in Zanjan plain using accumulated limitation scores and geostatistics.
Materials and Methods: The study area is located in the southern part of Zanjan city, northwestern Iran, between the latitudes 36° 33′ and 36° 40′ N and the longitudes 48° 23′ and 48° 37′ E, covering an area of about 7000 ha. A total of 85 sampling locations were designed using a systematic sampling grid with an interval of 1000 m and consequently, soil samples at all sampling sites were collected from the depths of 0–25, 25-50, 50–75 and 75–100 cm. The soil samples were taken to the laboratory, where they were air-dried and then passed through a 2 mm sieve. Prepared samples were subsequently analyzed for required soil properties in LSE (Sys et al., 1993) using standard methods. Besides, required climatic data for LSE were obtained from Znajan Synoptic Meteorological Station for a 50 years period (1961– 2011). Then, the limitation degrees for all of the important properties for wheat cropping were determined (Sys et al., 1993). Afterwards, the determined limitation degrees were converted to limitation scores using standard tables presented by Zhang (1989). Then, accumulated limitation scores were calculated for all locations and using an exponential equation, land-suitability membership scores were achieved. Finally, these scores were interpolated using ordinary kriging method in ArcGIS software (ver. 10.2; ESRI) and the final suitability map was produced.
Results and Discussion: The results showed that the climatic conditions for irrigated wheat was relatively good; so that the region received just 1 limitation score arisen from the mean temperature of the growing cycle. On the other hand, among the studied soil properties, the content of coarse fragments made some serious limitations for wheat farming in the studied area; so that more than half of sampling points showed moderate to very severe limitations in respect of this property. This high observed limitation of coarse fragments may be attributed to the youthfulness of studied soils; because according to Soil Taxonomy, the studied soils are mainly classified as Entisols, which are poorly developed and immature soils maintaining their rock structure to some extent. Other studied soil properties, like soil texture and calcium carbonate equivalent content, made no or slight limitations for wheat farming in the studied soils. Accumulated effects of limiting properties led to elevated limitation scores in some sampling locations, especially in northwestern parts of the area and consequently, their suitability classes were decreased. Attributing the specific land suitability classes to each sampling location based on the calculated limitation scores revealed some sharp variability in suitability classes thorough the relatively small distances, which seems to be less compatible with the widely accepted generality of soil continuity. Totally, the spatial distribution map of land-suitability membership scores showed appreciable variability thorough the area. This may suggest that the studied soil properties have relatively high short-range variations, which is originated from the soil substantial characteristics or management practices. Comparison of the interpolated suitability map with the point map revealed that the spatial variability pattern of land suitability for irrigated wheat was more gradual and more obvious in interpolated map.
Conclusions: Compared with common conventional land suitability procedures, continuous pattern of land suitability variation based on the fuzzy viewpoint to the soil variability, lead to more compatible results with the continuous nature of environmental variables. However, due to the long and short-range variations of various soil properties thorough the studied area, appreciable variations in land suitability for wheat farming was observed. Controlling this highly variable suitability of studied lands for irrigated wheat farming needs precise and thoughtful management strategies.
Research Article
mehdi zangiabadi; manoochehr gorji; Mehdi Shorafa; Payman Keshavarz; Saeed Saadat
Abstract
Introduction: Soil physical quality isone of the most important factors affects plants water use efficiency in agricultural land uses. In the literature, some soil physical properties and indices such as S-index, Pore Size Distribution (PSD), porosity, Air Capacity (AC), Plant Available Water (PAW) content, ...
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Introduction: Soil physical quality isone of the most important factors affects plants water use efficiency in agricultural land uses. In the literature, some soil physical properties and indices such as S-index, Pore Size Distribution (PSD), porosity, Air Capacity (AC), Plant Available Water (PAW) content, Least Limiting Water Range (LLWR) and Integral Water Capacity (IWC) were mentioned as the soil physical quality indicators. It has been reported that the soils with the same PAW, LLWR and IWC may have different physical qualities. The index of Integral Energy (EI) of the soil moistureranges may differ between the soils with equal soilmoistureover a defined water content range. This index is defined as the required energy to uptake the unit mass of soil moistureby plants. According to this definition, the soils with low EI would have better physical quality for plants roots growth. In this research, we hypothesized that EI of different soil moistureranges were negatively related to S-index which means the plants required energy to uptake the soil water in the soils with high S-index, is lower than the soils with poor physical quality (less S-index). So we examined our hypothesis in medium to coarse-textured soils of Khorasan-Razavi province (Iran).
Materials and Methods:This research was conducted in Torogh Agricultural and Natural Resources Research and Education Station in Khorasan-Razavi province, north-eastern Iran (59° 37' 33"-59° 39' 10" E, 36° 12' 31"-36° 13' 56" N). Soil textures of this research station, are classified into loam, silt loam, silty clay loam, clay loam, and sandy loam which is as the same in more than 90% of agricultural soils in Khorasan-Razavi province. Thirty points with different soil textures and organic carbon contents were selected. In order to measure different properties of the soil, two soil samples (5 cm diameter × 5.3 cm length core sample and a disturbed soil sample) were collected from 0-30 cm depth of each point. After conducting required laboratory and field measurements using standard methods, the Soil Moisture Release Curve (SMRC) parameters (RETC program), S-index, PAW and LLWR (measured in matric heads of 100 and 330 cm for the field capacity), IWC and EI of mentioned soil moisture ranges were calculated. In this regard, integration calculations were done by Mathcad Prime 3 software. Finally, the relationships between the measured properties and EI values (for PAW100, PAW330, LLWR100, LLWR330 and IWC) were analyzed using Pearson correlation coefficient and stepwise multivariate linear regression by JMP (9.02) statistical software.
Results and Discussion: The S-index of 30 soil samples were between 0.029-0.070 with average of 0.046. These results showed that 90% of studied soil samples had good and very good and 10% had poor physical quality. The lowest average EI values of different soil moisture ranges were observed in sandy loam and silt loam and the highest was observed in silty clay loam soil textures. The EI(IWC) mean value was lower than EI(PAW) and EI(LLWR) mean values which indicated that calculating the EI values based on continuous effects of water uptake physical limitations, resulted in lower required energy for plants to uptake the unit mass of soil moisture . Statistical analysis resulted in significantly negative relations between S-index and two indices of EI(PAW100) and EI(IWC). Multivariate regression analysis showed that EI(PAW100) and EI(LLWR100) could be estimated by shape parameter (n) of SMRC by regression coefficients of 0.95 and 0.22, respectively and the value of EI(IWC) could be estimated by S-index and organic carbon content by regression coefficient of 0.57. The parameter of saturated volumetric water content (θvs) of SMRC and sand percentage were determining factors of EI(PAW330). In this research, it was not obtained the significant relationship between EI(LLWR330) values and measured soil physical properties. According to the results, increment of the shape parameter (n) of SMRC and S-index led to reducing the plants required energy to uptake the unit mass of soil moisture in PAW100 and IWC ranges. We found that EI of different soil moisture ranges could be used to evaluate the soil physical quality between the soils with equal soilmoisture contents.
Conclusion: This Research investigated the relationship of PAW, LLWR and IWC EI values with soil physical properties and S-Index in medium to coarse-textured soils. The results indicated that increment of S-index led to decreasing EI(PAW100) and EI(IWC) indices. According to the results, the shape parameter of SMRC and S-index could be accounted for determining factors of EI(PAW100) and EI(IWC) indices values.
Research Article
sonia zebardast; Seyed Hassan Tabatabaei; Fariborz Abbasi; Manouchehr Heidarpour; Carlo Gualtieri
Abstract
Introduction: It is important to understand the processes of diffusion and transporting solute in the furrow irrigation system, because of their role in diffusion of pollutants in the environment. Movement pattern of fertilizer from the source ofplants is usually under the effect of advection and turbulent ...
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Introduction: It is important to understand the processes of diffusion and transporting solute in the furrow irrigation system, because of their role in diffusion of pollutants in the environment. Movement pattern of fertilizer from the source ofplants is usually under the effect of advection and turbulent diffusion processes. Maximum solute diffusion length (SDL) is the minimum distance which materials such as a fertilizer, could uniformly spread in the whole flow cross section. The SDL depends on hydraulic properties, condition of vegetation and channel specifications. Velocity profile of furrows as a result of parabolic shape of the cross-section is different thanthe rivers and rectangular channels. The main objectives of this study were to investigate SDL in a permeable parabolic channel and evaluate the effect of different discharges and bed roughness on diffusion length in a parabolic cross-section of a furrow.
Materials and Methods: In this research, the effect of different levels of discharge and the bed roughness coefficient was studied on transverse diffusion coefficient (TDC) and the maximum solute diffusion length (SDL) in a parabolic channel with permeable and impermeable beds. The channel had a 10 m length, 0.5 m width and 0.3 m depth with a parabolic shape (similar tothefurrow irrigation system). Before entering the channel, the water flow passed the lattice filters to slow the flow. To increase the rate of flow development, the first half meter of the channel’s bed covered with gravels (maximum 5 cm thickness) and non-submerged woods. Three levels of discharge about were conducted including 5, 10 and 15 L/s as well as three levels of bed roughness coefficient including 0.2, 0.04 and 0.06. Different rates of roughness were created using various thickness of net and vegetation cover on the furrow’s bed and wall. This research was conducted in channels with beds of permeable and impermeable. In bed of with permeability, 15 holes with a diameter of 1.5 mm construct along the bed of channel. In this experiment, Sodium chloride as a tracer was injected to the water at the upstream cross section. The place of injection was 2.5 meters far from the channel inlet where flow was completely developed and water surface swings were constant. The tracer concentration in the water and the velocity profile were measured at eight cross sections along the channel including 3, 4, 5, 6, 7, 8, 9 and 9.5 m from upstream. The velocity profile was measured using Pitot tube. No specific equation is introduced to calculate the SDL. For this reason, dimensional analysis was used in this study.
Results and Discussion: The results show that, the values of TDC for different treatments ranged between 0.23 to 0.56 cm2/s in impermeable channel where it is 0.30 to 0.58 cm2/s in the permeable channel. Also the values of SDL ranged 108-170 m in impermeable channel and 91 -129 m in the permeable channel for different treatments. TDC has direct relation todischarge and bed roughness. In stationary bed roughness with increased discharge, and in stationary discharge with increasing bed roughness, TDC increased. Also In stationary bed roughness, discharge has positive and direct relation with SDL. However, in stationary discharge, roughness value has the negative relation with SDL. A statistical analysis of T-test indicated that the difference between the values of TDC and SDL in permeable and impermeable beds in the 1% level is significant. The Darcy Weisbach coefficient is the most important parameter in justifyingchanges SDL that this parameter depends on the velocity of flow, and the velocity of flow depends on discharge and shape of channel too. According to the results of the experiments and the regular values of discharge, infiltration and roughness coefficient in furrows, it was shown that the maximum solute diffusion length of furrows would be less than 70 meters.
Conclusions: The objective of this research was to develop an approach for the determination of solute diffusion in afurrow irrigation system where the cross section is parabolic. For this reason, solute diffusion length, in different bed roughness and inflow rate was studied. Eventually, an equation was developed to explain SDL in a permeable parabolic channel andthese experimental results could prove useful to predict the fertilizer transport in furrow irrigation method as well as other areas where mixing and contaminant decay is of interest.
Research Article
Saeideh Bardsirizadeh; Isa Esfandiarpour Borujeni; Ali Asghar Besalatpour; Peyman Abbaszadeh Dahaji
Abstract
Introduction: Aggregate, as the basic unit of soil structure,represents a collection of primary particles which their adherence to each other is more than their connection to environ soilparticles. Aggregate stability is a highly complex parameter influencing a wide range of soil properties, including ...
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Introduction: Aggregate, as the basic unit of soil structure,represents a collection of primary particles which their adherence to each other is more than their connection to environ soilparticles. Aggregate stability is a highly complex parameter influencing a wide range of soil properties, including carbon stabilization, soil porosity, water infiltration, aeration, compatibility, water retention, hydraulic conductivity andresistance to erosion by water and overland flows. Maintaining high stability of soil aggregate is essential for preserving soil productivity, minimizing soil erosion and degradation and thus minimizing environmental pollution as well. Nevertheless, aggregate stability is described as one of the soil properties that can serve as an indicator of soil quality.The main purpose of this study is to determine the most important component of soil aggregate (macro and/ormicro) in estimating the soil structural stability in the Rabor region, Kerman province, using geostatistical method.
Materials and Methods: Ninetysurface soil samples (0 to 10 cm) were taken on a 200 m square sampling grid in the study area for the geostatistical studies.After air drying the soil samples and passing them through a 4 mm sieve, the percentage of aggregates belong tothree parts of total, macro, and micro classes and aggregate staility were calculated in both dry and wet conditions.Some stability indices were calculated and their spatial variabilities were investigated using two variography and estimation stages methods. Finally, the kriged map of each aggregate stability indicator was produced. To determine the compatibility of kriged maps of the soil aggregates stability indices calculated for the macro and micro aggregates with aggregates stability index (i.e., AS index) calculated forthe total aggregates, the overall accuracy related to each aggregate component (i.e., macro and micro) was calculatedafter creating an error matrix.
Results and Discussion: The results showed that total aggregate stability in the dry condition and macro aggregate stability in the wet condition had the lowest and highest coefficients of variability,respectively. The highest percentage of total aggregate stability (i.e., 89.90 %)was observed in the north and southeast positions of the study areain the dryconditionwhich had the highest amount of organic matter(i.e., 2.30 %). Also, the variograms of all investigated variables were exponentially and their ranges were varied between 380 to 450 m. Although the obtainedranges were different, a sampling distance more or less equal to 420 m is reasonable to study the most of the variables in the area. This can be a good indicator to decrease the sampling tasks for monitoring of these parameters in future.An overall look at the obtained root mean square standardized error (RMSSE) values indicated a high correlation between the measured and estimated values of all investigatedvariables (except for macro aggregate stability in the wet condition). However, all variables had a strong spatial correlation class. The percentage of overall accuracy obtained from crossing the total and macro aggregate kriged maps in the dry condition (i.e., 51.75 %), was more than its percentage for similar maps in the wet condition (i.e., 32.17 %). In return, the percentage of overall accuracy obtained from crossing the total and micro aggregate kriged maps in the wet condition (i.e., 17.31 %)was greater than its percentage for the mentioned maps in the dry condition (i.e., 10.93 %). Because of macro aggregate sensitivities to the amount of pressure imposed on them (as in the wet sieving method, the aggregates are under pressure caused by water energyin addition to tensions related to mechanical motion of sieving), the conformities of above two mentioned maps were less than those in the dry sieving method.
Conclusions: In general, the soil aggregates stability depends strongly on the amount of pressure imposed on them. Besides, the study of spatial variability of macro and micro aggregate stabilities and relative effects of each on the soil structure stability can be useful for choosing proper land management activities in future studies. According to theeffect of aggregation on nutrient cycling, capture, storage and water movement, and also other soil characteristics affecting plant growth and sustainable agriculture on one hand, and the effect of organic matter on aggregation on the other hand, it can be concluded thatall human activities that have a role in reducing or removing organic matter from the soil (e.g., grazing, deforestation, and intensive cultivation etc.) may reduce soil aggregate stability and finally can jeopardize human life in a near future.
Research Article
Hossein Kheirfam; Mehdi Homaee; Seyed Hamidreza Sadeghi; Behrouz Zarei Darki
Abstract
Introduction: Land degradation and soil losses are common and universal problems which is a pose threat to food security, ecosystem health and consequently sustainable development and human well-being. Meanwhile, improving the chemical and physical properties of biological soil crusts is an effective ...
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Introduction: Land degradation and soil losses are common and universal problems which is a pose threat to food security, ecosystem health and consequently sustainable development and human well-being. Meanwhile, improving the chemical and physical properties of biological soil crusts is an effective factor in soil loss controlling. Also, the chemical properties specially soil nitrogen are the important factors for soil quality determination. To this end, various strategies on techniques of amendments have been implemented to improve soil properties and quality. Although the application of most strategieshave been verified to soil quality,but their application in real conditions is restricted due to detrimental environmental effects, instability, cost and time-consuming and less accessibility. Recently, biological soil crusts enrichment based on soil microorganism inoculation and stimulation has been raised as a biological and useful strategy in soil conservation sciences. Accordingly, the present study aimed to investigate the role of individual and combined inoculation of bacteria and stimulant nutrient material into small-scale plots on soil nitrogen variation as one of the important soil chemical component.
Material and Methods: The study soil was collected from the erosion-prone and poor biological crust of a sub-watershed from Chalusrood watershed located in Mazandaran Province. The soil sampling was carried out from the upper of the soil surface using a 5cm-diameter coring polyvinyl chloride. The sampled soils were air-dried and sieved by a 2 mm-sized mesh. The Nutrient Agar and Tryptic Soy Agar general were used to bacteria isolation. The identification of isolated bacteria was carried out based on available protocols. Effective nitrogen-fixing bacteria were selected and then purified by selective Azotobacter Agar, Modified II and DSMZ1media. The purified bacteria proliferated by LB Broth medium and then inoculated into soil small sized-plots simultaneously with stimulant nutrient material throught spraying technique. The study was conducted at plot scale with 0.5×0.05×0.5 m dimensions and the plots filled by study soil based on standard protocols. The soil samples were taken at once the 7-8 days from surface of soil plots and the amounts of soil nitrogen were measured by using Kjeldahl method. As well as, experiment period was planned about 60 days. The one-way ANOVA and Tukey HSD test were subjected to statistically analyses.
Results and discussion: The results indicated that the Azotobacter sp. and Bacillussubtilis strain were selected as the most appropriate bacteria to be applied for nitrogen fixing in soil. Also, the results showed that the average total organic nitrogen in control plots ranged from 0.082 to 0.136%, which implies the soil limitation of total nitrogen. However, the measured total organic nitrogen in the bacteria, stimulant nutrient, and combined inoculation plots varied from 0.11 to 0.241%, 0.117 to 0.204%, and 0.124 to 0.374%, respectively. These results demonstrated the positive role of inoculated treatments on fixing nitrogen in the soil. Therefore, the population of Azotobacter sp., the Bacillussubtilis strain, was considerably increased after the inoculation process, and this led to converted and fixed atmospheric nitrogen (N2) into utilizable nitrogen (NH4 or NO3) in soil by using the enzyme nitrogenase as a catalyst. The statistical analyses and evaluation results were indicative of a significant (p
Research Article
majid janfada; D. Shahsavani
Abstract
Introduction: The nitrogen cycle may be affected by chemical fertilization and industrial waste water. Nitrate can affect the human body through water and food, which can be transformed into nitrate and nitrosamine as a threat for humans and aquatic life. Therefore, detecting the influential elements ...
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Introduction: The nitrogen cycle may be affected by chemical fertilization and industrial waste water. Nitrate can affect the human body through water and food, which can be transformed into nitrate and nitrosamine as a threat for humans and aquatic life. Therefore, detecting the influential elements and factors on this cycle, are essential from the environmental protection point of view. Many of scientists utilize mathematical models for these kind of problems. These models encompass linear and nonlinear differential equations that aresolved by numerical computer cods. The numerical codes are called “Deteministic computer models”, and running the model with different input values is called a computer experiment. One of the most famous models for the estimation of nitrogen river load is INCA-N (Integrated Nitrogen in Catchments).
Materials and Methods: INCA-N is a semi-distributed, process-based deterministic model of the flow of water and nitrogen through catchments. It simulates the key factors and processes that affect the amount of NO3 and NH4 stored in the soil and groundwater systems, and it feeds the outputs from these systems into a multi-reach river model. INCA-N has different input variables, thus detection of inactive variables of INCA-N is important. Because of reducing the input variables and simplifying of model, sensitivity analysis methods are used.
Sensitivity analysis involves sampling based, screening based and monte-carlo based and variance based method. Variance based method, which us used in this paper, detectsthe important variable and interaction effects. The main effect (first-order index) and total effect are most popular and important indices in variance based sensitivity analysis. These indices are multiple integrals based on the concepts of conditional mathematical expectation and conditional variance.The first-order index represents the main effect contribution of each input factor to the variance of the output. The total effect index accounts for the total contribution to the output variation due to factor Xi, i.e. its first-order effect plus all higher-order interaction effects. These indices are defined based on multidimensional integral which is estimated by simulation techniques.
In this paper, after introducing variance based approach and estimation of sensitivity indices with Monte Carlo and quasi random number, our attention is focused onsensitivity analysis of ofINCA-N model in the Tweed river. In this study the derived output is the average annual riverine load of inorganic nitrogen over a period of seven years.
Results and Discussion: The results of sensitivity analysis in optimized sample size showed that four variables, out of seven, of INCA-N are important:
1." Plant nitrate uptake." The average main effect and total effect of this variable are 0.44 and 0.49, respectively. The difference between the total effect and main effect, which is 0.051, indicates that this factor does not have any significant interaction with other input variables in the model.
2. "Denitrification rate". The mean and standard deviation for the main effect were 0.247 and 0.189, whereasthese two measures for the total effect are 0.248 and 0.366, respectively.
3. " Immobilization ". The mean and standard deviation of immobilization were 0.182 and 0.787 for the main effect, and they are 0.227 and 0.3736 for the total effect respectively.
4. "Mineralization rate". The mean and standard deviation of this variable were 0.072 and 0.268 for the main effect, and 0.106 and 0.391 for the total effect,respectively .
The main and total effect of thesefour variables are (0.44,0.49), (0.247,0.248), (0.182,0.227), (0.072,0.106). It can be mentioned that, the interaction between these variable are so weak (maximum= 0.059). Three other variables nitrogen fixation, ammonium planet uptake and maximum nitrogen uptake is not important. Thus the sensitivity analysis method has good efficiency in the reduction of variation.
Conclusions: To manage the riverine load of inorganic nitrogen in the Tweed River at least fourfactors, including nitrate uptake rate by plants, denitrification rates, immobilization and mineralization, should be controlled. The variance based method makes it possible to detect the important variables. In the other words, the sensitivity analysis lts of INCA-N model showed that for controlling the nitrogen entering the Tweed River, at least three factors of "plants nitrate uptake," "denitrification rate" and "immobilization" should be taken into consideration. In addition to these three factors, mineralization can be considered as the fourth factor affecting the nitrogen load.
Research Article
Hamid Reza Moradi; khalil Jalili; Omid Bozorg Hadad
Abstract
Introduction: The conflict between environmental protection and the economic development by different land uses within a watershed are challenges facing land use planners in many developing countries. Because of the growing demand for water, water resources optimization allocation management is at the ...
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Introduction: The conflict between environmental protection and the economic development by different land uses within a watershed are challenges facing land use planners in many developing countries. Because of the growing demand for water, water resources optimization allocation management is at the forefront in formulating sustainable development policies for many countries. Conjunctive use of surface water and groundwater is being practiced in many regions of the world to bring more areas under irrigation, increase agricultural production and productivity, and also maintain overall system balance. Successful agricultural water management policies put the physical, hydro-geological, and socio-economic constraints on these integrated water supplies. Application of optimization approaches has been started since the human faced a low efficiency production of the system. Optimization of resource allocation is one of the proper strategies to achieve sustainable development and to reduce resource dissipation. So land and irrigation water allocation based on water balance approach is the aim of this research and this paper proposed an optimal land and water resource allocation model based on linear programming to Islamabad plain’s irrigation areas.
Materials and Methods: The Islamabad plain aquifer is located in Seymareh watershed and 55 km of Kermanshah city in the Kermanshah Province; it comprises 19438 ha and extends between 33◦20 to 34◦24 N latitude and 46◦ 15to 46◦47 E longitude. Annual precipitation and annual temperature of study area are 445.1 mm and 12 ◦C respectively . The mean net benefit of irrigated wheat, sugar beet, corn, potato, irrigated chick-pea, alfalfa, vegetables, melon, tomato, fruit garden, dry wheat, dry barley, dry chick-pea and dry lentil were therefore calculated to be respectively some 38.21, 76.7, 34.39, 81.0, 16.98, 21.69, 47.2, 12.4, 61.4, 74.0, 7.26, 0.72, 17.1 and 10.9 Mir/ha and the objective functions of the benefit maximization problem in the Islamabad aquifer was formulated The problem was structuredin the study area to maximize economic return. The information and data required for defining constants and coefficients of objective Function and constraints, viz. Land availability, water availability/supply, present crop pattern, socio-economic conditions were extracted from the available comprehensive Hydrogeology, field studies and farmers viewpoints. A linear optimization problem has been formulated for the Islamabad plain to achieve sustainable development and optimal land allocation to crop pattern, then solved using the simplex method with the help of LINGO software packages and the optimal solution was ultimately determined. Three management scenarios and six action plan with resources accessibility, crop rotation, socio-economic constraints and nonnegative variables have analyzed and sensitivity analysis was done.
Results and Discussion: The results of the study verified that the linear optimization problem was successfully solved using the LINGO software program and the results led to maximize benefits in the Islamabad plain. The results also showed the successful linkage between economic aspects and environmental outcomes at an aquifer scale. Results show that in all scenarios sugar beet, corn, chick-pea, tomato and melon have been removed from the optimal cropping pattern. Wheat areas in two scenarios and five action plans have been increased. Benefit of optimization in management scenarios and in the entire optimal crop pattern was positive and increase from 19 to 55 percent. Sensitivity analysis showed that the change of some specific allocations would create much more impact on the final optimal solutions generated by the optimization programming.The results of sensitivity analyses also showed that the objective function was strongly susceptible to the constraint of water availability and total area of plain.
Conclusions: A benefit problem was formulated and then solved to maximize benefits using optimization of allocable land and irrigation water resources to 14 productions of present crop pattern within the Islamabad plain in Kermanshah province. The LINGO optimization software program was successfully applied and led to determine appropriate areas allotted to different crop. The results obtained during the study approved the applicability of optimization model in solving problems which sometimes conflicting each other. On the study plain there appears a significant augmentation in profit from allocating the optimal cultivated areas. The approach could provide better information on where changes are required, how large the changes need to be, and how much the changes will benefit the people when improving. The conjunction of optimization techniques with other tools like geographical information system, genetic algorithm, fuzzy logic, artificial neuron networks and applying different softwares and simulation techniques are also suggested to be taken into account in further studies to draw ultimate necessary conclusions.
Research Article
Hamed Rajabi; Sedigheh Safarzadeh Shirazi; abdolmajid ronaghi
Abstract
Introduction: Application of chemical fertilizer is one of the methods to supply nutrient elements for plants and it is an effective method to meet plants nutrients demands; but organic fertilizers such as biochar application can be used as a proper solution to decrease gases resulted from agricultural ...
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Introduction: Application of chemical fertilizer is one of the methods to supply nutrient elements for plants and it is an effective method to meet plants nutrients demands; but organic fertilizers such as biochar application can be used as a proper solution to decrease gases resulted from agricultural activities, increase soil's organic matters and to manage soil fertility. Biochar can increase soil fertility of some soils, increase agricultural productivity, and provide protection against some foliar and soil-borne diseases. Biochar is a high-carbon charcoal used as a soil amendment and it is made of plant biomass and produced during pyrolysis process in the absence of oxygen. The ability of biochar to store C and improve soil fertility will depend on its physical and chemical properties, which can be varied in the pyrolysis process (pyrolysis temperature) or through the choice of raw materials.
Materials and methods: In order to study the effect of pistachio residue biochar produced in two different temperatures and chemical fertilizer on macronutrients concentration and growth of spinach (viroflay) (Spinacia oleracea), a greenhouse experiment was conducted in a factorial (2×3×3) arranged in a completely randomized design with three replications. Treatments consisted of three biochar levels (0, 3, and 6% by weight) prepared at two temperatures (200 and 400 °C), and three fertilizers level [0 (blank), (Nitrogen=80 and Phosphorous=15 mg kg-1 soil) and (Nitrogen =150 and Phosphorous =30 mg kg-1 soil)]. Bulk soil sample was collected from the surface horizon (0–30 cm) in Bajgah Agricultural Station of Shiraz University, Iran. Pots contained 2 kg dry soil. Treatments were added to all pots uniformly and were mixed. Then soil samples incubated in 25 ̊C for 30 days; and soil moisture was kept at about field capacity (FC). Following incubation time, based on soil analysis nutrients were added to all pots uniformly. Ten seeds were sown in each pot, and soil moisture was kept at about field capacity. Spinach seedlings were thinned to five uniform plants per pot 15 days after emergence. The pots were then maintained under FC. Plants were harvested after 8 weeks after emergence. Aerial parts of spinach plants were separated and oven dried and were weighed and ground. Total nitrogen (N), phosphorous (P) and potassium (K) in plants were measured. Statistical analysis was performed using SAS and Excel statistical software packages.
Results and discussion: Results showed that biochar prepared at 200 and 400 ̊C had no significant effect on spinach dry weight (DW). Chemical fertilizer significantly increased average of spinach DW. Chemical fertilizers improved N and P concentration in plant, therefore increase growth of spinach than control. Biochar prepared at 200 and 400 ̊C significantly increased shoots N, P and K concentration of spinach compared to that of control; but biochar prepared at 400 ̊C had significant effect on shoots N and P concentration. Biochar might be direct nutrition resources for plant and supply many nutritional elements such as N, P and K for plant and increase concentration of these elements in plant. Application of chemical fertilizer significantly increased N and P and significantly decreased K concentration in spinach shoot. Several studies showed that application of biochar improved efficiency of nitrogen fertilizer in several soils and finally more nitrogen absorbed by plant. Biochar prepared at two temperatures had no significant effect on DW and shoot N concentration of spinach. However, addition of biochar prepared at 400 ̊C significantly decreased shoot P concentration and significantly increased shoot K concentration in spinach, as compared to biochar prepared at 200 ̊C.
Conclusion: Results indicated that application of biochar prepared at 200 and 400 ̊C improve composition of spinach but had no effect on its DW, probably because of short term of plant growth, kind of biochar, and biochor levels. Applications of biochar, increased shoot N and P concentration; it might be due to improving physical, chemical and biological properties of soil with addition of biochar. Also, biochar supplied nutritional elements and improve efficiency of chemical fertilizer; therefore it is appropriate that biochar applied with chemical fertilizers. Our results showed that 6% biochar level was the best suggested levels that in three chemical fertilizer levels increased shoot N and P concentration of spinach. With increasing temperature for preparing biochar, pH of biochar increased; so, it might be concluded that biochar prepared at low temperature was appropriate than biochar prepared at high temperature for application to calcareous soils.
Research Article
Salman Mirzaee; MirHassan Rasouli-Sadaghiani; Naser Miran
Abstract
Introduction: Citrus is an important fruit crop cultivated in tropical regions of the world with immense nutritional value and advised on daily basis in diet. In Iran, it is cultivated in high reaches of northern and southern regions. The low productivity has been ascribed mainly to the nutritional health ...
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Introduction: Citrus is an important fruit crop cultivated in tropical regions of the world with immense nutritional value and advised on daily basis in diet. In Iran, it is cultivated in high reaches of northern and southern regions. The low productivity has been ascribed mainly to the nutritional health of the plantations which is the most concern among farmers. To plan fertilization efficiently, it is necessary to know the desirable concentration of macro and micro nutrient in tissues that are representative of the plant’s nutritional status. Traditionally, to determine the optimum fertilizer doses the most appropriate method was to apply fertilizer on the basis of soil test and crop response studies (Regar and Singh, 2014) which defied the synergistic and antagonistic effects in relative availability of different essential nutrients from soil. The foliar nutrient concentration is considered most pertinent and reliable method to judge the well-being of a tree as it represents the in situ condition in a holistic way and is a very powerful tool for nutritional diagnosis to assess deficiency symptoms and make fertilizer recommendations (Filho, 2004). Because of the dynamic nature of the leaf tissue composition, strongly influenced by leaf age, maturation stage, and the interactions involving nutrient absorption and translocation, the tissue diagnosis may be a practice of difficult understanding and utilization (Walworth and Sumner, 1987). The Diagnosis and Recommendation Integrated System (DRIS) developed by Beaufils (1973), expresses the result of foliar analysis through indices, which represent in a continuous numeric scale, the effect of each nutrient in the nutritional balance of plant. DRIS is advantageous as it presents continuous scale and easy interpretation; allows nutrient classification (from the most deficient up to the most excessive); can detect cases of yield limiting due to nutrient imbalance, even when none of the nutrient is below the critical level; and finally, allows to diagnose the plant nutritional balance through an imbalance index (Baldock and Schulte, 1996). Nutritional balance is an important factor in increasing the yield and improving the quality of horticultural products especially Citrus. Hence, the objective of this study was to determining the optimum level of the macro and micro nutrient elements and evaluating the nutritional status of Lisbon lemon and Perl tangerine in Dezful.
Materials and Methods: For this purpose, 30 Lisbon lemon and 30 Perl tangerine gardens were selected randomly from citrus gardens in Dezful. Leaf samples were collected from middle of terminal shoots of current year growth in the periphery of tree from in late September. Leaf samples were washed in detergent followed by tap water and distilled water. Leaves dried under shade and then dried in hot air oven at 70ºC for 48 hours. The dried leaves were grounded to fine powder by using mixer and stored in air tight butter paper bags for nutrient analysis. Kjeldahl method was followed to measure total nitrogen, and phosphorus was measured by vanado-molybdophosphoric yellow colour method using spectronic, while potassium was measured by flame photometric method. Other elements content was determined by atomic absorption system. The gardens were divided into two groups of low and high yielding. All forms expression and their variance into two groups and variance ratio the group of low to high yielding in tow type gardens were calculated. Then using DRIS calibration formula, DRIS index for nutrient elements with low yielding were determined and nutrient balance index (NBI) were calculated.
Results and Discussion: The results showed that the optimum level in Lisbon lemon leaves were 2.97, 0.11, 1.85, 3.88 and 0.17% for N, P, K, Ca, Mg and 200.5, 24.9, 23.9, 68.8, 32.9 mg.kg-1 for Fe, Zn, Mn, Cu and B, respectively. In addition, the optimum level in Perl tangerine leaves were 2.97, 0.09, 1.57, 3.44 and 0.34% for N, P, K, Ca, Mg and 167.2, 32.7, 26.1, 28.0, 48.4 mg.kg-1 for Fe, Zn,Mn, Cu and B, respectively.
Conclusion: In general, based on DRIS indices priority on the macro and micro nutrients as Fe > N > B > K >Mn> Ca > Mg = P > Cu > Zn for Lisbon lemon and B > Fe > K > Cu > N > Ca > Mg >Mn> Zn > P for Perl tangerine were determined. The NBI of all gardens with low yielding was more than zero, indicating an imbalance nutritional in low yielding gardens.
Research Article
jalil javadi orte cheshme; mahmood kashefipoor
Abstract
Introduction: Nowadays, contamination of water is one of the problems that are more considered. Fecal Coliform (FC) is one of the most common indicator organisms for monitoring the quality of water. The problem that complicates the modeling of indicator organisms such as Fecal Coliform is determining ...
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Introduction: Nowadays, contamination of water is one of the problems that are more considered. Fecal Coliform (FC) is one of the most common indicator organisms for monitoring the quality of water. The problem that complicates the modeling of indicator organisms such as Fecal Coliform is determining the appropriate amount and an optimum rate of decay. It has been reported by many scientists that the decay coefficient or mortality rate is significantly affected by environmental elements. In this study, the effect of environmental parameters such as temperature, turbidity, radiation and suspended sediment concentration on the coliform decay coefficient hasbeen verified to have a dynamic and variable decay coefficient for better and reliable estimations of fecal coliform concentartion values.
Materials and Methods: Karun River is the longest and largest river in Iran. In this study, due to the accumulation of pollutants from industrial and agricultural wastes near Ahvaz city and for existence of quality measurement stations along the river, the Mollasani station to Farsiat station was selected to simulate and evaluate the hydrodynamic and quality of the river. The FASTER model has been used for modeling of the flow, sediment and water pollution. In this study, the dynamic roughness Manning coefficient has been used for more accurate simulate the flow, that had been added to the model by Mohammadi and Kashefipour. In Coliform bacteria and sediment modeling, some other dynamic parameters such as longitudinal dispersion coefficient are important and increasing or decreasing of these parameters are very significant and the accuracy of the Advection-Dispersion Equation (ADE) depends on the choice of the theoretical and/or experimental relations of these parameters. It was previously found that the Fisher equation performs the best for Karun river in modeling coliform, and this equation was therefore used in this study to calculate the dispersion coefficient. In order to investigate the effect of suspended sediment concentration on coliform decay rates, first this parameter must be modeled. In this research, the von Rijn method was used for modeling the suspended sediment load. In order to modeling the caliform, all dates of measuring were firstly determined in Zargan station; for each date the model was run for several times. For each run the decay coefficient was selected accordingly, until the predicted concentration by the model has the least difference inthe corresponding measured values. After that, the measured amount of environmental parameters such as Temperature, TUrbidity, RAdiation and also, the modeled values of suspended Sediment concentration wasdetermined for the same dates. Then, using a statistical software a relationship was developed to describe the decay coefficient as follows:
(1)
Results and Discussion: Using a statistical software, an equationfor decay coefficient was derived as follow:
(2)
Where K is decay coefficient (hr-1), T temperature (°C), TU turbidity (NTU), RA radiation(mmH2o-Vaporizeable) and Se suspended sedimentconcentration (kg/m3). Equation (2) was then added to the FASTER model, so the model was able to calculate the decay coefficient using the calculated suspended sediment at any time of simulation and this equation (dynamic decay coefficient). To be able to compare the dynamic decay coefficient and constant decay coefficient, the model was performed repeatedly for the whole calibration period and each time one constant K was given to the model. The best constant decay coefficient for the period of calibration and validation patterns was obtained to be K= 0.05 hr-1.Tables (1) and (2) show the amount of accuracy in predicting the suspended sediment concentration and coliform in both calibration and verification patterns, respectively. Table (1) shows that the FASTER model was able to estimate the suspended sediment concentration relatively accurate. Table (2) compares the effect of a constant decay coefficient versus the dynamic decay coefficient inaccurate estimation of fecal coliform concentrations.
Table 1- Comparison of the estimated error and correlation of suspended sediment
Pattern R2 a %E RMSE
Calibration 0.85 0.95 29.81 0.039
Verification 0.87 1.3 30.52 0.059
Table 2- Statistical parameters for coliform concentrations predicted and measured
Perioud k R2 a %E RMSE
Calibration Relation (2) 0.97 1.2 19 1906
0.05 0.92 2 50 4341
Verification Relation (2) 0.94 1.4 20 3860
0.05 0.77 1.5 44 7384
Conclusions: Comparison of the predicted fecal coliform concentrations with the corresponding measured values in the calibration and verification periodsshowed that the error estimate improved respectively about 31% and 24% when the dynamic decay coefficient was used instead of a constant value (the best constant value was obtained 0.05hr-1). The concentration of coliform bacteria in Zargan station during the total time of studying is more than 1000 CFU/100ml. Due to coliform bacteria concentrations and compared them with the levels allowed by the Standards, Karun river water is not suitable for human's drinking, confined livestock drink, food industry, oyster farming, irrigation products that are consumed raw and recreational uses (contact with water) like swimming.
Research Article
zeinab bigdeli; ahmad golchin; saeid shafiei
Abstract
Introduction: Dynamics of organic carbon and nitrogen are controlled by several factors, including physical, chemical and biological properties of soil. Heavy metals contaminate soils and change soil properties and affect organic carbon and nitrogen dynamics. Since toxicities of heavy metals are different ...
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Introduction: Dynamics of organic carbon and nitrogen are controlled by several factors, including physical, chemical and biological properties of soil. Heavy metals contaminate soils and change soil properties and affect organic carbon and nitrogen dynamics. Since toxicities of heavy metals are different and organic carbon and nitrogen dynamics are affected by available concentrations of these metals, the aims of this experiment were to assess the effects of different levels of soil cadmium on mineralization of organic carbon and nitrogen.
Materials and Methods: To assess the effects of different levels of soil cadmium on mineralization of organic carbon and nitrogen, a factorial pot experiment was conducted using litter bag method. The factors examined were different levels of soil cadmium (0, 10, 20, 40, and 80 mg kg -1soil) and incubation periods (1, 2, 3 and 4 months) that were applied in three replications. Soil samples were artificially contaminated with cadmium to desirable levels using cadmium sulfate and the samples were placed in plastic pots and the pots incubated at constant moisture and temperature for one month. Then litter bags containing 15 g wheat residues were buried in pots and incubated for different periods of time. At the end of incubation periods, the remaining amounts of plant residues were measured and analyzed for organic carbon and nitrogen concentrations using Walkley and Black and Kjeldahl methods respectively. The decomposition rate constants of organic carbon and nitrogen were calculated using Mt = M0 e –kt equation. Organic carbon and nitrogen losses were calculated by subtracting the remaining amounts of organic carbon and nitrogen in one incubation time interval from those of former one.
Results and Discussion: The results showed that the effects of soil cadmium levels and incubation periods were significant on organic carbon and nitrogen mineralization. The losses of organic carbon and nitrogen from wheat residues decreased as the levels of soil cadmium increased. The highest and the lowest organic carbon and nitrogen losses were measured in control and treatments with 80 mg Cd kg -1 soil respectively. Increase in soil cadmium levels decreased the losses of organic carbon and nitrogen from wheat residue. The losses of organic carbon for a period of four months were 37.54, 37.21, 36.11, 35.12 and 33.69 (%) in treatments with soil cadmium levels of 0, 10, 20, 40 and 80 mg kg -1 respectively. The loss of organic carbon in the first month of incubation was (30.78%) and in the other three months of incubation was (9.74%) with a sum of (40.52%) for a period of 4 months. Similarly, the loss of organic nitrogen in the first month of incubation was 23.69% and in the other three months of incubation was 8.56% with a sum of 32.25 (%) for a period of 4 months. The highest losses of organic nitrogen from wheat straw residue were measured in treatment of control cadmium (31.64 percent) and lowest losses of organic nitrogen (23.86percent) related to treatment with 80 mg of cadmium / kg of soil. The losses of organic nitrogen, after 4 months were 31.64, 30.69, 28.68, 26.25, and 23.86 (%) when treatment of cadmium contamination of soil was 0, 10, 20, 40 and 80, respectively. The decomposition rate constants for organic carbon were 0.0076, 0.0075, 0.0073, 0.0070 and 0.0066 day -1 when soil cadmium levels were 0, 10, 20, 40, and 80 mg kg -1 respectively. The rate constants for organic nitrogen at the mentioned soil cadmium levels were also 0.0061, 0.0059, 0.0054, 0.0048 and 0.0044 day -1 respectively.
Conclusions: The results of this research indicate that contamination of soils by heavy metals increases the residence time of organic carbon and nitrogen in soils and slows down the cycling of these elements. The mineralization rate of organic nitrogen was affected by soil cadmium levels more than that of organic carbon. The amounts of organic carbon and nitrogen losses are higher in the first month of incubation than those of other months and decomposition of wheat residue had a fast and a slow stage. The results of this study indicate that due to the adverse effects of heavy metals on soil organisms, mineralization rate of plant residue carbon is slower in polluted soils compared with non polluted soils.
Research Article
azadeh ehsaninezhad; ali abbaspour; hamidreza asghari; hamidreza samadlouie
Abstract
Introduction: Phosphor (P) is the second nutrient element after nitrogen mostly required by plant. P is the main component of nucleic acid, phospholipid, ATP and some coenzymes. The effectiveness of phosphate fertilizer application is only about 15% - 20% and 10 – 25%, based on the different references.Rock ...
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Introduction: Phosphor (P) is the second nutrient element after nitrogen mostly required by plant. P is the main component of nucleic acid, phospholipid, ATP and some coenzymes. The effectiveness of phosphate fertilizer application is only about 15% - 20% and 10 – 25%, based on the different references.Rock phosphate (RP) as a source of P is not expensive, but its availability of P is low. Solubility of RP can be increased by phosphate solubilizing microorganisms. Increasing RP solubility by microorganisms is due to the lowering of pH and/or organic acid excretion. Fungi have been reported to possess greater ability to solubilize insoluble phosphates than bacteria. Among the fungal genera with the phosphate solubilization ability, there are Aspergillus and Penicillium. Aspergillus Niger convert insoluble phosphates into soluble forms through the processes of acidification, production of organic acids, production of acid and alkaline phosphatases, and the release of H+ .These organic acids can either dissolve phosphates as a result of anion exchange or can chelate Ca, Fe or Al ions associated with the phosphates. The aim of this study was to investigate the effect of Aspergillus Niger and green manure on soil P solubility in the incubation conditions.
Materials and Methods: To investigate the effect of Aspergillus Niger and green manure on soil phosphorus availability, an experiment in a completely randomized design with three replications was conducted. The treatments were applied over a period of 70 days and were repeated at 3 incubations. The treatments were included C: control (50 g soil), As: Aspergillus Niger (50 ml/ kg), A: Green manure (1% weight of the soil), S: Sucrose (1 g/kg soil), P: Rock phosphate (150 kg/ha), As + A: Aspergillus niger + Green manure, As + S: Aspergillus Niger + Sucrose, As+P: Aspergillus niger + Rock phosphate, As + S + P: Aspergillus niger + Sucrose+ Rock phosphate , and As + A + P Aspergillus niger+ Green manure +Rock phosphate . Soils were air-dried and crushed to pass through a 2-mm sieve. Treatments were then applied to 50 g of soil and the treated samples were moistened to the field capacity (FC). The moisture of containers was kept near FC soil moisture content throughout the experiment by periodically weighing and replenishing evaporated water. At intervals of 7, 21, 35, 51 and 70 days, the samples were taken and after air drying, pH, EC, available soil phosphorus by Olsen method and soluble phosphorus were measured. The statistical analysis of all data obtained from the experiments was performed using the MSTAT-C software. The mean comparison was performed using Least Significant Difference (LSD) test at 5% level and drawing graphs using Excel software.
Results and Discussion: The results showed that all treatments had a significant effect on the measured parameters at 1% probability level. The effect of treatments and incubation Times on soil pH showed that all treatments were able to reduce soil pH. The greatest decrease was observed in Aspergillus Niger + Green manure (As + A) treatment that could reduce the pH by 0.59 unit. Usually, green manure decreases soil pH through decomposition and release carbon dioxide and organic acids. Aspergillus Niger also reduces pH and thus increases the solubility of soil phosphorus through the production of the metabolites and organic acids and microbial respiration. The effects of the treatments and incubation time on soil electrical conductivity showed that all treatments were able to increase soil electrical conductivity. Most of this increase was related to Aspergillus Niger+ Rock phosphate+ Green manure (As +P+ A) treatment .This increase was probably due to inorganic compounds found in green manure. The effects of the treatments and incubation time on soil available phosphorus and solube phosphorus showed that all treatments were able to increase them. Most of the soluble and available phosphorus amounts were observed in As +P+ A treatment and the amounts of increase resulting from this treatment for soluble and available phosphorus were 0/28 mg/l and 10/79 mg/kg, respectively. However, the green manure treatments and aspergillus alone increased soil soluble phosphorus, but with treatment of Aspergillus Niger (As) in green manure (A) observed that the amount of phosphorus in the soil solution was further enhanced. Organic acids resulting from the decomposition of organic matter by adsorption onto calcium phosphate surfaces and occupy the active sites such as nuclei for the formation of these deposits, prevent the growth of new crystals. These organic acids, in addition to the creation of the complex with calcium cations, reduce the activity.
Conclusions: The results of this study showed that use of phosphate solubilizing microorganisms and organic matter led to the significant decrease in pH and increase in electrical conductivity, dissolved phosphorus and available phosphorus in soil.. However, to obtain more accurate results, it is better to do a pot experiment as well.
Research Article
M. Biria; Abdulamir Moezzi; H. AmeriKhah
Abstract
Introduction: Among wide variety of soil pollutants including heavy metals, acidic precipitation and other toxicants, the importance of heavy metals due to their pollution capacity has received growing attention in recent years. These metals enters into soil through municipal and industrial sewage as ...
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Introduction: Among wide variety of soil pollutants including heavy metals, acidic precipitation and other toxicants, the importance of heavy metals due to their pollution capacity has received growing attention in recent years. These metals enters into soil through municipal and industrial sewage as well as direct application of fertilizer and pesticides. High cadmium and lead concentration in soil lead to severe environmental pollution. Such pollution not only has a destructive effect on crop yield but also endangers human being and other creatures’ health after entering in their food chain. Several physical, chemical and biological methods used to reduce the adverse effect of high concentration of heavy metals in soil. In spite of the hight cost, these methods are not always suitable for reclamation of small area and mostly have side effect on physico-chemical and biological characters of soil, after application. Biochar produced by thermal decomposition of biomass in the absence or presence of low oxygen. These material due to their high spacific surface area and high cation exchange capacity may have great ability to absorb charged material including heavy metals. Therefore in this study attempt is made to evaluate the effect of sugarcane bagasse –derived biochar in improving maize plant growth in cadmium and lead contaminated soils.
Material and methods: This study was carried out during the year 2014 in two separate experiments in Shahid Chamran university. The treatments in each case consisted of two levels of sugarcane bagasse made biochar (0 and 4 percent by weight) in combination with each soil, properly contaminated with 50 and 100 mg cadmium per kg soil in first experiment and 500 and 1000 mg lead per kg soil in the second. The treated soils were applied to pot and arranged in a complete randomized block designe and replicated 3 times. Prior to introduction of soil to pots, the heavy metal contaminated soils with moisture content around 70 percent of F.C. were incubated for 30 days. During incubation period sugarcane bagasse was dried, milled, sieved, compacted and subjected to traditional furnace at 550 oc for 3 hours on low pyrolysis. The furnace temperature was controlled manually using lesser thermometer. The furnace cooled down and the collected sugarcane bagasse made biochar sieved again. The incubated soil mixed with proper amount of sugarcane bagasse made biochar and incubated under previous condition for 45 days. The treated soils were poured to the labeled pots and 3 maize seeds were sown in each pot and two weeks after emergence thinned to one plant per pot. Nineteen days after sowing, the height of the plants and chlorophyll index were recorded and plants were harvested and leaf area of each plant was recorded, maize root content of each pot were carefully separated from soil and along with shoot property washed, dried, weighed and after milling subjected to chemical analysis. Prior to sowing maize seeds some of physic- chemical properties of untreated soil were estimated. Furthermore few charactoristics of sugarcane bagasse made biochar including pH and EC in 1 : 10 solution of biochar to water recorded. N, C, H, O concentration were estimated by elementary analyzer. Cation exchange capacity of sugarcane bagasse made biochar was measured by ammonium acetate method. Moreover its functional group determined by FT-IR method. Specific surface area estimated as per Branuar Emmet Teller (BET) method. Sugarcane bagasse made biochar image was obtained from scanning electron microscope. Cadmium and lead concentration in root and shoots were estimated by atomic absorption spectrometer after wet digestion. SAS software was used for statistical analysis data which fallowed by Duncan test to compare the mean values.
Results and discussion: The results showed that implementation of cadmium and lead led to decrease in chlorophyll index, leaf area, height of plant and root and shoot dry weight significantly. But the sharp decline in the concentration of cadmium and lead in root and shoot after sugarcane bagasse made biochar application improved chlorophyll index, leaf area, height of plant, root and shoot dry weight. Application of 4% Sugarcane bagasse made biochar, decreased transfer factor (TF) and bioaccumulation factor (BF) of these elements compared to control. The results showed high capability of sugarcane bagasse made biochar to absorb cadmuim and lead and reduce their availability to plant respectively. In fact application of sugarcane bagasse made biochar dwindled cadmium and lead absorption as well as their transfer factor and bioaccumulation factor, and hence improved plant growth.
Conclusion: The results obtained after sugarcane bagasse made biochar application mainly initiated due to high cation exchange capacity of which eventually was created by large number of functional groups in its high specific surface area (table 2) to stabilize cadmium and lead and render them unavailable to plant and hence improve its growth.
Research Article
tahereh mansouri; Ahmad Golchin; Mohammad Babaakbari
Abstract
Introduction: Arsenic (As) is the twentieth element in earth's crust and the contamination of soils and ground waters by it is common and disturbing. In addition to geological factors and soil parent material, human activities such as mining and smelting, coal combustion and the use of arsenic-containing ...
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Introduction: Arsenic (As) is the twentieth element in earth's crust and the contamination of soils and ground waters by it is common and disturbing. In addition to geological factors and soil parent material, human activities such as mining and smelting, coal combustion and the use of arsenic-containing compounds such as insecticides, pesticides, wood preservations and etc lead to the accumulation of high levels of this metal in the soils. Long-term exposure to As can lead to skin, bladder, lung, and prostate cancers.The presence of As in soil and water causes its transfer to different parts of the plant. Because of the crucial role of corn in human nutrition, investigation of the uptake, transport and accumulation of As in different parts of this plant is very important, thus this study was carried out with the aims of evaluating the response of corn to the presence of As in the environment and its impact on concentrations of phosphorus (P), iron (Fe), zinc (Zn) and manganese (Mn) in this plant.
Materials and Methods: Soil samples were collected and after air drying, passed through a 2 mm sieve and analyzed for some physico-chemical properties. The samples were then artificially contaminated by different levels of arsenic (0, 6, 12, 24, 48 and 96 mg/kg) using Na2HAsO4.7H2O salt and incubated for 6 months, and then planted to corn. Before planting, the concentration of available As was determined. At the end of growth period, mean height of plants was measured and then the above and below ground parts of plants were harvested, washed, dried and digested using a mixture of HNO3 and H2O2. The concentrations of As, P, Fe, Zn and Mn in plant extracts were measured. Statistical analyses of data were performed using SAS software and comparison of means carried out using Duncan's multiple range test.
Results and Discussion: The results indicated that As concentration increased both in root and in shoot with increasing As concentration. The highest As concentrations in corn root and shoot were 383.41 and 59.56 mg/kg, respectively. Arsenic accumulation in root was higher than the shoot, so that the concentrations of arsenic in the roots of plants grown at 6, 12, 24, 48 and 96 mg As/ kg of soil, were 1.88, 1.99, 3.13, 4.96 and 6.44 times higher than their concentrations in shoot, respectively. Corn was sensitive to As stress and growth of it reduced by increasing the level of soil As. Mean heights of plants grown in soils polluted with 6, 12, 24, 48 and 96 mg As/kg decreased compared to control by 10.74, 25.30, 38.99, 59.71 and 76.66%, respectively. The rate of reduction of dry weights of roots of plants grown in soils polluted with 6, 12, 24, 48 and 96 mg As/kg were 10.66, 30.20, 54.64, 81.65, 95.94 % and ones of shoot were 11.30, 27.25, 47.14, 77.66 and 95.22%, respectively, which showed corn root was more sensitive to As than shoot. Arsenic uptake by root and shoot increased with increasing the As levels to 48 and 24 mg/kg, respectively, but at higher levels of As it decreased, this showed that up to these levels, increasing arsenic concentrations in plant parts surpassed from the decreasing dry weights of them and the amount of uptake obtained by multiplying these two factors, increased. Phosphorus concentrations in root and shoot increased and decreased, respectively, with increasing soil As concentration, and this matter showed As reduced P translocation from the root to the shoot of plants. Iron and Zinc concentrations in root and shoot decreased but Manganese concentration increased with increasing soil As concentration.
Conclusions: The results of this study showed that the corn plant is very sensitive to arsenic and its growth decreased even in the presence of low concentrations of arsenic. Arsenic accumulation in root was higher than the shoot. Arsenic changed the concentration of nutrients in the soil and the corn, So that increased the available P concentration and reduced the available concentrations Fe, Zn and Mn. It also reduced the translocation of P, the concentration of Fe and Zn in the root and shoot. The statement that toxicity limits plant As uptake to safe levels was not confirmed in our study. If corn plants are exposed to a large concentration of As, they may accumulate residues which are unacceptable for animal and human consumption.
Research Article
Mohammad Nazeri Tahrudi; Farshad Ahmadi; Keivan Khalili
Abstract
Introduction: Given the fact that Iran is located in the center of the dryland of earth and is significantly influenced by the deserts of Central Asia and hot dry deserts of Arabia and Africa, is one of the most arid and low rainfall land areas.So is the proper management of water resources is of critical ...
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Introduction: Given the fact that Iran is located in the center of the dryland of earth and is significantly influenced by the deserts of Central Asia and hot dry deserts of Arabia and Africa, is one of the most arid and low rainfall land areas.So is the proper management of water resources is of critical importance. The first step in the proper management of water resources is studying the factors that affected these resources including climate change. In fact climate change is a dynamic process in terms of time and place. Large parts of the Earth's climate as part of their normal variability in short-term and long-term experience. Short-term climate changes due to the difference in terms of average annual values of specific climate variables in average periods such as 30 years. Causes and effects of regional climate change in several parts of the world have been widely studied from various aspects. Among hydrological parameters, precipitation is the most important parameter in the complex hydrologic cycle. Follow the phenomenon of global warming on the Earth's surface, the rainfall pattern has changed.Trends of rainfall in different parts of the world have been studied by many researchers. Due to climate change in Iran and climate change in the Basin of Urmia Lake it seems that evaluation the trend of monthly and annual precipitation and its time of change point in the basin of Urmia Lake changes is important. The goal of this study is evaluatingthe trend and time of the change point trend of monthly and annual precipitation of rain gage stations in Urmia Lake basin.
Material and methods: Lake Urmia is the focus of surplus accumulation of surface currents all the rivers of the basin, with an area of approximately 5750 square kilometers and the average elevation of 1276 m above sea level and is located in the middle of the northern basin. Around of Lake Urmia there are 16 wetlands with an area of 5 to 120 hectares (some have dried up) that mostly have sweet or salty and fresh water and a high value of ecosystems.Urmia Lake Basin is situated in eastern of 44-14 to 47-53 and north of 40-35 to 30-38 coordinates. Urmia Lake Basin rainfall changes is 220 to 900 mm and have mean precipitation about 263 mm that added in central parts of the basin to the highlands.
Trend analysis: The aim of process test is to specify whether an ascending or a descending trend exists in data series. Since parametric tests have some assumptions including normality, stability, and independence of variables, where most of these assumptions do not apply to hydrologic variables, the nonparametric methods are more preferred in meteorological and hydrological studies. The nonparametric methods are less sensitive to extreme values compared to parametric tests in the examination of trends. Nonparametric tests can also be utilized for data time series regardless of linearity or nonlinearity of the trend (Khalili et al. 2014). One of the most well-known nonparametric tests is Mann-Kendall test (Mann 1945; Kendall 1975).
The modified Mann-Kendall test (MMK): The main assumption of Mann-Kendall test is that the sample data has no significant autocorrelation. However, some hydrological series might have a significant autocorrelation coefficient. When a series has a positive autocorrelation coefficient, there is an increased chance for Mann-Kendall test to reveal the existence of a trend in this series. In this case, the null hypothesis i.e. lack of trend is rejected, yet this hypothesis should not actually be. The modified Mann-Kendall test was presented by Hamed and Rao (1998) and has been used by Kumar et al (2009) for the analysis of the trend of Indian rivers. In this method, the effect of all significant autocorrelation coefficients is removed from the time series and is appliesto a series whose autocorrelation coefficients are significant in one or more cases.
Change point test: Pettittest is a non-parametrictest that was developedin 1979byPettit. Themethod is used in order tofind change points ina time series(Salarijazi et al 2012).In this study,thestatisticwas usedtofind asudden change intemperaturedata.Thisstatistic isatest with rank basis and without a distributionin orderto detectsignificantchangesin the mean of the time seriesanditis importantwhenthereis noassumptionabout the change time.
Results and discussion: In this study the trend of monthly and annual precipitation of rain gage stations that located in Urmia Lake basin were investigated using modified Mann-Kendall test. Z values of case study were calculated in two monthly and annual scales. The results of evaluation the trend of precipitation of rain gage stations of Urmia Lake basin showed that in October, December, January, February and March (five months of the year) the trend of precipitation is decreasing and the mean of Z values showed the less than zero values. In April and May there is no sensible changing in precipitation trend. Also the results showed that the March, April and May have a low failure rate and February, December and July have a most of change point of monthly precipitation data. About 60 percentages of the time of change point in precipitation trend are between 1992 and 1998. Also the results showed that two months of May and November there is no changing point in west Urmia Lake rain gage stations. In annual scale the time of changing trend is between 1992 and 1998.
Conclusion: The results of evaluation the trend of Lake Urmia precipitations showed that the Urmia Lake basin has a combination of decreasing and increasing trend in studied time period. The decreasing trend in precipitation often seen in west stations of the basin and west and south-west of Urmia Lake. The increasing trend also seen in south and north-east of Urmia Lake basin. Also the results of zoning the Z values of Mann-Kendall test showed that in annual scale the regions that influenced by polar-continental air mass that they entered Iran have a decreasing trend.
Research Article
mozhdeh Jamei; mohammad mousavi; Amin Alizadeh; parviz irannejad
Abstract
Introduction: Surface soil moisture is one of the most important variables in the hydrological cycle, and plays a key role in scientific and practical applications such as hydrological modelling, weather forecasting, climate change studies and water resources managements. Microwave radiometry at low ...
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Introduction: Surface soil moisture is one of the most important variables in the hydrological cycle, and plays a key role in scientific and practical applications such as hydrological modelling, weather forecasting, climate change studies and water resources managements. Microwave radiometry at low frequencies (1.4GHz) is an established technique for estimating global surface soil moisture with a suitable accuracy. In recent years, soil moisture measurements have become increasingly available from satellite-based microwave sensors. The ESA’s Soil Moisture and Ocean Salinity (SMOS) satellite was launched in November 2009. It carries the first L-band 2-D synthetic aperture microwave radiometer to provide global estimates of soil moisture with an averaged ground resolution of 43 km over the field of view. The main objective of this research was to validateSMOS soil moisture retrievals over the west and south west of Iran.
Materials and Methods:The study area is located in the west and southwest of Iran which contains five areas belongingto the Ministry of Power. For the validation of SMOS dataover the study area, the SMOS soil moisture retrievals from MIR_SMUDP2 productswere compared with ground-based insitu measurements. The validation process was carried out using Collocation techniquefor the period 2012-2013. Collocation technique is a method used in the field of remote sensing to verify compliance measurements from two or more different instruments. In this study, the collocation codes were developed in Matlab Linux programming language. The ground-based in situ measurements included direct soil moisture measurements at the 5cm depth which were collected from five meteorological stations in the study area. We prepared a file for each station which contained daily soil moisture, date and time, geographical coordinates of metrological stations as input for validation model. The SMOS Level 2 Soil Moisture User Data Product (MIR_SMUDP2 files) version 551, which were provided through the ESA, contains the retrieved soil moisture and simulated TB, dielectric constants, etc. In this work, the ESA’s SMOS Matlab tool on RedHat Linux was used to read and derivesoil moisture data from MIR_SMUDP2 files.Four statistical metrics and Taylor diagram were used for the evaluation error of validation; the Root Mean Squared Difference (RMSD), the centered Root Mean Square Difference (cRMSD), the Mean Bias Error or bias and the correlation coefficient (R).
The Taylor diagrams wereused to represent three different statistical metrics (R, centered Root Mean Square Difference (cRMSD) and standard deviation) on two dimensional plots to graphically describe how closely SMOS dataset matched ground-based observations .
Results and Discussion: Based on the research algorithm and using MATLAB, the Validation model for SMOS soil moisture data was obtained. This model was appliedfor five metrological stations and the collocated soil moisture data from SMOS data and in situ data was saved as output of model to error evaluation. The results of validation errorshoweda good correlation between the SMOS soil moisture andin situ measurements. The highestand lowest correlation coefficientswere shown at Ahvaz (R=0.88) and Sarableh(R=0.75)stations, respectively.According to the bias values, the SMOS soil moisture retrievals had underestimation atAhvaz(MBE=0.04 m3m−3),Sararod(MBE=0.011 m3m−3), Sarableh(MBE=0.048 m3m−3) stations, whereas a slight overestimation of the SMOS product was detectedatthe Darab (MBE=-0.01 m3m−3) andEkbatan (MBE=-0.031 m3m−3) stations. In addition, the Root Mean Squared Difference (RMSD) values between the SMOS data and in situ data varied from 0.02 to 0.062 m3m−3 and at Ahvaz station withRMSD=0.048 m3m−3is close to the targeted SMOS accuracy of 0.04 m3m−3.Based on the Taylor diagrams, SMOS data had the highest correlation (R=0.88) with in situ measurements at Ahwaz stationand the lowest difference (cRMSD=0.008 m3m−3) between two data setswas found at Darab station.
Conclusions:The objective of this paper was to validateESA’s SMOS (Soil Moisture and Ocean Salinity) satellite products in the west and southwest of Iran for the period of 2012-2013. The validation of SMOS soil moisture retrievals from MIR_SMUDP2 products was done by using soil moisture measurements from five meteorological stations. The SMOS soil moisture retrievals showed underestimations at Ahvaz, Sararod andSarableh stations, whereas a slight overestimation werefound at Darab, Ekbatan stations. The validation results and Taylor diagrams showed thatthe SMOS soil moisture retrievals with R=0.88, RMSD=0.048 m3m−3, cRMSD=0.021 m3m−3at Ahvaz stationwasvery close to the targeted SMOS accuracy objectiveof 0.04 m3m−3 and then at Darab station SMOS data with R=0.82, RMSD=0.028 m3m−3,cRMSD=0.008 m3m−3indicateda good agreement with ground soil moisture measurements. Overall, the SMOS soil moisture data hadan acceptableaccuracy and agreement with in situ data at all stations. Therefore, we can use these data sets as a tool to derive soil moisture maps at study areas.
