Research Article
Irrigation
Z. Sojoodi; H. Shokati; Y. Sojoodi; M. Mashal
Abstract
IntroductionThe constructive effects of green spaces on the quality and livability of the urban environment have been reported in many studies. Therefore, using methods that can accurately estimate the evaporation of transpiration in green space can help to reduce water loss. The purpose of estimating ...
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IntroductionThe constructive effects of green spaces on the quality and livability of the urban environment have been reported in many studies. Therefore, using methods that can accurately estimate the evaporation of transpiration in green space can help to reduce water loss. The purpose of estimating water demand for urban green space is also different from the purpose of determining water demand for an agricultural farm. In urban green space, the goal is to maintain good growth, appearance and acceptable plant health, while biomass production is the main goal on agricultural farms. Therefore, urban green space can typically be managed using an irrigation area that is less than the amount of water needed to produce agricultural products. Due to the limited water resources in arid areas, the use of less irrigation in urban green space can be desirable to save water consumption.Materials and MethodsThe Wucols method for estimating Water requirements in green space was developed by Castello et al. (4). They developed the Wucols water taxonomy guidelines for planting green space in California. The Wucols method estimates evapotranspiration in green space using reference evapotranspiration and a set of coefficients (Species factor, density factor and microclimate factor). PF method is the minimum acceptable irrigation for green space plants that emphasizes maintaining the beauty of the plant. In this method, the water required by green space plants is considered as a percentage of ET0 so as not to reduce their appearance and performance. In this approach, PF is a regulatory factor that is actually considered instead of Kc and multiplied by ET0, except that the emphasis is on the appearance of the plant and not on its optimal growth and yield. The IPOS method has been developed by the Government of South Australia for planning and managing water needs in public open spaces, especially sports lawns and amusement parks. In this method, the water requirement of grass in urban open space is calculated. In this method, plant transpiration evaporation (ETL) is calculated by multiplying reference transpiration evaporation factors (ET0) by grass vegetation coefficient (Kc) by plant stress factor (Kst).Results and DiscussionThe results showed that the highest rate of evapotranspiration obtained by Wucols method was 83.38 mm during 21 Jun-21 Jul. Also, the rate of transpiration evaporation during one year of the experimental period was estimated to be 556.5 mm. The results of estimation of transpiration evaporation by PF method also show the maximum amount of transpiration evaporation during 21 Jun-21 Jul and is 75.55 mm. The evapotranspiration rate during one year was estimated to be 505.9 mm. For the Ipos method, the highest rate of transpiration evaporation was estimated to be 36.38 mm during 21 Jun-21 Jul and 242.9 mm during the experimental period. Gross irrigation requirement is estimated by considering 70% irrigation efficiency for each month using all three methods. For the Wucols method, the gross irrigation need during one year was estimated to be 794.8 mm. For the PF method was 722.7 mm and for the IPOS method was 346.9 mm. According to the reported irrigation records for the study area, which is 900 mm per year, the Wucols method has the closest result to the irrigation records.ConclusionThe results showed that the Wucols method has the best and closest estimate according to the irrigation records of the study area. The gross irrigation requirement calculated by the Wucols method during a year is 794.8 mm, which is 12% less than the gross annual irrigation requirement of the studied green space. While PF and IPOS methods determined the amount of gross demand 20 and 62% less than the annual irrigation rate in the region, respectively. The results of this study show that the Wucols method for estimating the water requirement of plants in urban green space where there is a combination of different plant species is more reliable than the PF and IPOS methods due to the diversity of species, vegetation density and different climates.
Research Article
Irrigation
M. Fouladi Nasrabad; M. Amirabadizadeh; M. Pourreza-Bilondi; M. Yaghoobzadeh
Abstract
IntroductionThe watershed acts as a hydrological unit regulating the quantity and quality of the water cycle, and human beings have incurred high costs due to ignorance of this complex cycle and lack of planning of projects in terms of the relationship between water management and community development.Knowledge ...
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IntroductionThe watershed acts as a hydrological unit regulating the quantity and quality of the water cycle, and human beings have incurred high costs due to ignorance of this complex cycle and lack of planning of projects in terms of the relationship between water management and community development.Knowledge of features such as maximum flood discharge is essential for the design of hydraulic structures, such as dams, spillways, bridges, and culverts, in order to reduce potential damages and predict when peak discharges will be reached in the downstream areas when discussing flood warning. Rainfall-runoff modeling is one of the key tools in hydrology to achieve flood characteristics, such as peak rate and peak time. In current research, the performance of IHACRES model using "Hydromad" R package has been implemented to simulate flow in the Shoor river basin in Ghaen on a monthly scale. The model simulation was done to investigate the effect of selecting "ARMAX" and "EXPUH" methods in the linear part of the target function. Also, the modeling process and the optimized values of the model parameters were investigated.Materials and MethodsThe Shoor river basin with an area of 2412.92 square kilometers located in Ghaen between 59 degrees and 12 minutes to 59 degrees and 14 minutes east longitude and 33 degrees and 42 minutes to 33 degrees and 45 minutes north latitude. The study catchment with an average altitude of 1420 m above sea level and an average long-term annual rainfall of 173 mm has a dry climate. This river is the largest river in Ghaenat city which flows into Khaf Salt field. In this research, the IHACRES model was implemented using the Hydromad R package. To perform the flow simulation, precipitation, flow rate and temperature data on a monthly scale during the years 1998 to 2017 were used. The IHACRES model has two parts: the first part, which converts precipitation into effective precipitation at each time stage and the second part, which converts effective precipitation into modeled flow. These sections are called nonlinear and linear modules, respectively. To implement each of the sections of nonlinear modules and linear modules according to the data and conditions in the study area, methods with different parameters can be used. In this research, in the non-linear module section, the "CWI" method and in the linear module section, "ARMAX" and "EXPUH" methods have been used for proper routing in the "reverse" calibration section. In the validation section of the "ls" method, the performance criteria of KGE, NS and R2 were used to evaluate the performance of the model in both calibration and validation process. Result and DiscussionComparison of obtained results in this study with previous studies showed that in terms of examining the performance of the model with the EXPUH linear method, the obtained results are consistent with the results of Sadeghi et al. (2015) and Lotfi Rad et al. (2015) and the model with the EXPUH linear method. The NS criteria has shown acceptable performance. According to the results of the model in the calibration section, in terms of evaluation criteria NS, KGE and , and in terms of simulation of peak flow values and the time to peak using EXPUH method in the linear part showed better performance than ARMAX method. The value of these criteria in EXPUH method is equal to 0.86, 0.93, and 0.86 and in ARMAX method are equal to 0.7, 0.85 and 0.73, respectively. In the validation section, the evaluation criteria in EXPUH method were equal to 0.51, 0.63, and 0.54 and in ARMAX method were equal to 0.55, 0.73 and 0.65, respectively, indicating better performance of the model by ARMAX method. Comparison of the EXPUH method, and also the model with ARMAX method showed more accurate performance in terms of peak discharges, quantity and time of occurrence. The values of NS, KGE and evaluation criteria in this section were 0.51, 0.63, and 0.54 using EXPUH method and 0.55, 0.73 and 0.65 with ARMAX method, respectively.ConclusionAccording to the results, the IHACRES model using ARMAX method in the linear section resulted in more accurate performance than EXPUH method in simulation of peak flow values and time to peak.
Research Article
Irrigation
O. Raja; M. Parsinejad; M. Tajrishi
Abstract
Introduction Surface and groundwater conjunctively interact at different spatial or temporal scales within a plain. In many plain, surface and groundwater resources are used in combination in agriculture. Therefore, it is important to accurately predict the components of groundwater and surface ...
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Introduction Surface and groundwater conjunctively interact at different spatial or temporal scales within a plain. In many plain, surface and groundwater resources are used in combination in agriculture. Therefore, it is important to accurately predict the components of groundwater and surface water balance. Despite the rapid expansion of numerical models over the past two decades, there is still a need for comprehensive and integrated assessment of surface and groundwater components. In particular, the interconnection of both surface and groundwater models is important to connect both surface and groundwater, especially the water balance in the unsaturated root zone. In this study the effect of water recharge due to deep percolation from simultaneous supply of irrigation water from surface and groundwater sources, and rainfall from the SWAT model were used to simulate groundwater balance using the combined MDOFLOW-NWT model.Materials and Methods In this study, the effect of recharge values obtained from the SWAT model was analyzed to simulate the fluctuation of water table, and groundwater balance components using the integrated model of MODFLOW-NWT model in the Mahabad plain. One of the important steps in quantifying the impact of irrigation management, and the change in land-use on the surface and groundwater balance was the simulated recharge due to the deep percolation of rainfall and irrigation water. This was done by the SWAT model, and was used as the boundary condition to the MODFLOW-NWT model. Calibration and validation of groundwater model were also done by trial-and-error and automatic PEST methods. The simulation period was performed for 10 years from the hydrological year of 2009-2010 to 2018-2019, from which 6 and 4 years were used as the period for calibration and validation were from 2009-2010 to 2014-2015 and 2015-2016 to 2018-2019, respectively. Groundwater balance components are naturally different for different years. Therefore, the study was conducted for dry, wet, and normal years. Hydraulic conductivity and specific yield were the used as initial calibration parameters in the MODFLOW-NWT model.Results and Discussion The results showed a higher hydraulic conductivity and specific yield values for the aquifer was in the southern, central, and northeastern areas of the plain, and the lowest values were in the northern and near the outlet of the plain. After the calibration process, the results showed that an average, 9% of rainfall, and 36% of irrigated water percolate to the aquifer. These observations were confirmed based on a satisfactory and acceptable estimate of the water table level of the model for both calibration and validation periods. The statistical RMSE criteria for calibration and validation periods were 0.35 and 0.34 m, respectively. Also, the results of R2 and NSE criteria were estimated as 0.94 and 0.91 for the calibration period, and 0.93 and 0.89 for the validation period, which indicates that the model was properly calibrated and was well able to simulate groundwater level. The groundwater hydrographs developed from piezometers’ readings, show that the recharge values estimated by the SWAT model, considering the change in land use and irrigation management across the plain, were able to properly simulate groundwater level across the aquifer. Specifically, the studies showed a continuous drop in groundwater level created in the southern and southwestern regions of the aquifer (piezometers of Fakhrighah, Gorg tapeh, and Serah Haji Khosh) due to the presence of high-consumption crops such as apple and alfalfa, and the higher number of operation wells.ConclusionThe results of this study showed that the recharge values obtained from the calibrated SWAT model was crucial parameters for proper simulation of groundwater, and can significantly improve the model results. The results of the main components of the groundwater balance for different years showed that the amount of recharge due to the infiltration of rainfall, and irrigation were different for each year. Also, interactions between surface and groundwater resources vary from about 30 to 50 million cubic meters between years, indicating a significant interaction between the water resources. In general, the SWAT-MODFLOW-NWT model can be used as a practical tool for proper management of surface and groundwater resources under different management scenarios.
Research Article
Soil science
S. Arabteymori; A. Halajnia; A. Lakzian; F. Nikbin
Abstract
Introduction Surfactants as surface-active substances with combined hydrophobic and hydrophilic properties are widely used in various fields. In soil remediation processes these substances can be used to increase the availability of organic and inorganic contaminants to improve microbial decomposition ...
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Introduction Surfactants as surface-active substances with combined hydrophobic and hydrophilic properties are widely used in various fields. In soil remediation processes these substances can be used to increase the availability of organic and inorganic contaminants to improve microbial decomposition of organic pollutants or heavy metals adsorption. In recent years, researchers have been seeking to produce and use surfactants that are more environment friendly. In this regard, produced biosurfactants by microorganisms are of special importance due to their environmental benefits. Microorganisms produce a wide range of biosurfactants. Biosurfactants are extracellular compounds that can combine with metals such as zinc, copper, and cadmium and can increase the solubility of these metals and reduce their toxicity. Negatively charged anionic biosurfactants such as rhamnolipids and lipopeptides can increase heavy metals availability by combining to metals and changing the properties of soil solution. In this study, the effect of surfactant application from Pseudomonas putida and Bacillus subtilis and some chelators include sodium citrate, humic acid and Na2-EDTA on soluble cadmium in a contaminated calcareous soil was investigated.Materials and MethodsThis study was conducted as factorial in a completely randomized design in laboratory conditions at several steps separately. A calcareous soil sample was contaminated with 15 mg kg-1 cadmium from the source of Cd (NO3)2. Contaminated soil incubated for 4 weeks at field capacity. Acid deposition method was used for surfactant extraction from culture medium of Pseudomonas putida KT-2440 and Bacillus subtilis 1795. The structure of extracted biosurfactants was investigated by FTIR. Equilibrium time was obtained by determining the amount of soluble cadmium at times 6, 12, 24, 36, 72 hours by adding 1mM sodium citrate, humic acid and Na2-EDTA to the contaminated soil (ratio of 1 to 5 soil to solution).The concentrations of 0, 0.1, 0.25, 0.5, 1 and 2 mM of humic acid, sodium citrate and Na2-EDTA were used to determine the appropriate concentration of each chelator. To investigate the interaction of chelators and biosurfactants on soluble cadmium, an experimental was conducted as a completely randomized design with factorial arrangement design. Experimental treatments consisted of three types of chelating agents (sodium citrate, humic acid, Na2-EDTA and control), two types of surfactants from Pseudomonas putida and Bacillus subtilis, and five concentration levels of the biosurfactants (0, 25, 50, 100 mg L-1).Results and DiscussionThe highest amount of soluble cadmium (11.59 mg L-1) was observed in Na2-EDTA treatment at 72 hours, which was significant compared to the other treatments. The lowest amount of soluble cadmium was obtained through application of sodium citrate (0.205 mg L-1) at 36 hours. In all studied concentrations, Na2-EDTA had the greatest effect and sodium citrate had the least effect on soluble cadmium. While the use of Na2-EDTA at all concentrations caused a significant increase in soluble cadmium, sodium citrate had no significant effect on soluble cadmium at studied concentrations. Humic acid at concentrations higher than 0.5 mM significantly increased the soluble cadmium. Increasing the concentration of humic acid and citrate from 1 to 2 mM did not show any significant impact on soluble cadmium. At all levels of biosurfactant application, Na2-EDTA and humic acid caused a significant increase in soluble cadmium concentration. In control and sodium citrate treatments, application of biosurfactants did not cause significant difference in the concentration of soluble cadmium. The highest amount of soluble cadmium was obtained as a result of the application of Bacillus subtilis surfactant and Na2-EDTA. However, increasing the concentration of Bacillus subtilis surfactant from 25 to 100 mg L-1 had no significant effect on increasing the efficiency of Na2-EDTA. Pseudomonas putida surfactant had no significant effect on soluble cadmium in Na2-EDTA application. While in humic acid treatment, the application of the Pseudomonas putida surfactant at the highest concentration (100 mg L-1) increased the concentration of soluble cadmium. Using Bacillus subtilis surfactant did not have effect on soluble cadmium in application of humic acid.ConclusionAmong the studied chelators (sodium citrate, humic acid and Na2-EDTA), Na2-EDTA had the greatest effect on soluble cadmium. While sodium citrate had no significant effect on soluble cadmium. Surfactants from Pseudomonas putida and Bacillus subtilis had different effects on increasing the efficiency of studied chelators and soluble cadmium in the studied soil. In Na2-EDTA and humic acid application, surfactant from Bacillus subtilis at a concentration of 25 mg L-1 and surfactant produced by Pseudomonas putida at a concentration of 100 mg L-1 had a significant effect on soluble cadmium, respectively. It seems using biosurfactants and chelators on increasing soluble cadmium in soil can be useful for phytoremediation purposes to increase its uptake by plant. However, further research is needed.
Research Article
Soil science
B. Rezaei; A. Amirinejad; M. Ghobadi
Abstract
IntroductionIndustrial development has resulted in higher soils pollution with heavy metals. Plants which are subjected to heavy metals may severely lose their yield capabilities. Applying improving compounds in the soil is a new method to reduce effects of heavy metals on plants growth. Biochar as a ...
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IntroductionIndustrial development has resulted in higher soils pollution with heavy metals. Plants which are subjected to heavy metals may severely lose their yield capabilities. Applying improving compounds in the soil is a new method to reduce effects of heavy metals on plants growth. Biochar as a carbon rich source and salicylic acid as an important plant hormone, are two main compounds to alleviate heavy metals stresses in plants. These are the cost-effective and environmentally friendly substances for increasing the resistance of plants. Lead (Pb), as a common and extremely poisonous element in polluted soils, can be accumulated due to its non-biodegradability nature. When Pb content in plants reaches a toxic level, it can inhibit plant growth by reducing enzyme activities and photosynthesis and changing mineral nutrients balance. However, with regard to the program of expanding the area under cultivation of medicinal plants, including thyme, there is a possibility of contamination of soils in the vicinity of industrial centers and roads with lead. Therefore, the present study was conducted to evaluate the effects of salicylic acid as a plant growth stimulant and biochar made of rapeseed wastes, as a stable organic compound, on alleviation of Pb-induced stress in thyme (Thymus vulgaris L.). Materials and MethodsIn order to investigate the effects of salicylic acid (SA) and biochar (BC) on reducing Pb stress in thyme (Thymus vulgaris L.), a factorial experiment was conducted based on a completely randomized design with three replications in the greenhouse of Razi University. The factors included Pb at three levels (0, 150, and 300 mg/kg as Pb(NO3)2), SA at three levels (0, 150, and 300 μM) and BC at three levels (0, 1 and 3% by weight). To apply the Pb treatments, the soil samples of each pot (8 kg) were sprayed with Pb(NO3)2 solutions, 4 weeks before planting, according to the contamination levels. Then, BC treatments were performed by mixing it with the soil samples. In each pot, four thyme seedlings were planted. At four-leaf stage, SA solutions were sprayed three times on foliage of the thyme plants , until the beginning of flowering. After harvesting, some characteristics of aerial and root parts of thyme, including soluble sugars and proline contents, plant height, dry weights of shoots and roots, root volume and root length were determined. All plant parameters were then averaged for each pot. Also, Pb concentrations in extracts obtained from digestion of leaf tissues, were measured by Varian AA220 atomic absorption spectrophotometer. The analysis of variance (ANOVA) and comparison of means (Duncan's multiple range test) were performed using SPSS-16 software.Results and DiscussionThe results revealed that Pb stress reduced all plant characteristics, such as plant height, root volume and root length, as well as, dry weights of shoots and roots, and elevated leaf Pb concentration, proline content and soluble sugars in thyme. However, BC application resulted in improvements in growth parameters. The positive effect of BC was further enhanced when SA was sprayed onto the foliage of the thyme plants. The interaction effects of SA, BC and Pb treatments on the growth parameters of thyme, i.e, shoot dry weight, root volume, Pb concentration, soluble sugars and proline contents were significant (P < 0.01). In other words, SA and BC treatments moderated the negative effects of Pb on the growth traits. The highest Pb concentration (4.83 mg) and proline content (37.8 μmol/g) were obtained in 300 μg/kg of Pb, and SA and BC controls. Also, the highest concentration of soluble sugars (0.46 mg/kg) was found at 300 mg/kg of Pb, 300 μM SA and BC control.ConclusionOur results indicated the positive effects of SA and BC treatments on the growth parameters, such as; shoot and root dry weights in thyme plants, especially under Pb stress. In other words, Pb stress, while reducing all growth characteristics, increased proline content and soluble sugars in thyme. In general, it seems that under Pb stress, treatment of thyme with SA (as a plant growth regulator) and BC (as an organic matter with high viability in the soil) is a simple and appropriate method in order to increase the plant's resistance and reduce the effects of Pb toxicity on the overall growth of thyme.
Research Article
Soil science
M. Mohammadi
Abstract
Introduction Almond (Prunusdulcis Mill.), native to West Asia to the Mediterranean, and Iran after the United States and Spain has a third rank in production of this product in the world. Drought stress is one of the most important factors limiting the yield and production of agricultural products. ...
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Introduction Almond (Prunusdulcis Mill.), native to West Asia to the Mediterranean, and Iran after the United States and Spain has a third rank in production of this product in the world. Drought stress is one of the most important factors limiting the yield and production of agricultural products. Many anatomical, physiological, enzymatic, nutritional, quantitative and qualitative characteristics of almonds are affected by drought stress. There are a lot of micro-organisms in soil can help plant nutrition and uptake of nutrient elements in different ways that can be mentioned by the dual symbiotic relation between micro-organism and plant. Mycorrhizae fungi are one of these microorganisms. The most important beneficial effects of mycorrhizal symbiosis is increasing the nutrient uptake, leaf gas exchange, photosynthesis, water use efficiency, productivity, improve plant nutrition and resistance to environmental stresses. Also, it helps the plant to absorb more water and nutrients by modification of rhizosphere environment, improvement of soil structure through formation of stable aggregates, expansion of external filaments and change of root morphology. The results of mycorrhizae symbiosis research in different plants show that the higher uptake of nitrogen (N), phosphorus (P), potassium (K), iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn). The aim of this study was to evaluate the ability of mycorrhizal fungi, a symbiotic and environmentally friendly agent, in drought stress condition on increasing growth and absorption of water and nutrient elements on almond rootstocks commonly consumed in Chaharmahal-va- Bakhtiari province.Material and Methods This field experiment was carried out as a factorial based on a randomized complete block design (RCBD) with three replications. The treatments consist of two level of mycorrhizal fungus (M0: without and M1 with using of mycorrhizal fungus), four kinds of rootstock (bitter, local Shorab 2, GF and GN) and four levels of drought stress (without stress as a control, slight, moderate and severe water stress which based on ratio of depletion of plant available water). Inoculation of mycorrhizal fungi at the rate of 100 g of a mixture of three species of mycorrhizal fungi (Clariodeoglumus etunicatum, Rhizophagus intraradices and Funneliformiss mosseae) was placed under the roots for each rootstock with a population of at least 100 active fungal organs including spores, vesicles, and hyphae per gram. The plants were exposed to drought stress for six weeks. Leaf samples were taken to measure the amount of nutrient elements. Nitrogen by Kjeldahl method, P by spectrophotometer, K by flame method with flame photometer and nutrients of iron, zinc, manganese, boron and copper were measured by atomic absorption spectrophotometry with an atomic absorption spectrometer (PerkinElmer Analyst 400, Waltham, United States of America). Statistical analysis was done with SAS 9.3 statistical software. Duncan’s multiple range test was used to separate means.Results and Discussion The results revealed that there were significant differences between four cultivars in terms of nutrient concentrations except B. The maximum amounts of the studied characteristics were obtained from GF rootstock. The GN rootstock was in the second ranking. Water deficient treatment showed a significant effect on the examined nutrient elements except Mn and Cu concentrations. The maximum amounts of measured nutrient elements, except K, were obtained from I1 treatment. The highest rate of K was obtained from I3 and I4 treatments. With increasing drought stress the decreasing trend of nutrient elements, except K was observed. Mycorrhizae fungi treatment caused increase of nutrient elements except B. The maximum amounts of N, P, Fe and Zn were obtained from GF +I1. Using of mycorrhizae fungi in drought treatments caused significant increase in N, K, Fe, Mn and B. The maximum amount of nutrients was obtained from GF + M1 treatment. The maximum amounts of N, Fe and B were obtained from I1 + M1 + GN. Inoculation of mycorrhizae fungi caused increase of rootstock growth under drought stress. The change in the shape, volume and number of root branches of the root caused by the consumption of mycorrhizae fungi was due to increased nutrient uptake and changes in the amount of plant hormones such as auxin. Growth and absorption of water and nutrients decreased under water deficient stress. Therefore, the effect of symbiosis with mycorrhizae fungi under water deficient stress conditions was more important than non-stress conditions. This has been reported in the research of various researchers.Conclusion The results of this study showed that with increasing water deficient stress, the amount of nutrient elements decreased except for K. The effectively of GF rootstock to mycorrhizae fungi inoculation was higher due to higher growth potential and root velocity. Nutrients that were measured in inoculated rootstocks were higher than those without inoculation. Under drought stress conditions, the amount of nutrients measured was higher in inoculated rootstocks. Inoculation of mycorrhizal fungi can lead to increase nutrients absorption with some mechanisms such as effective increase in root uptake, root length, number of lateral roots, proton production, and secretion of organic acids, siderophores, chelating compounds, and acid phosphates. Consumption of mycorrhizae fungi increased nutrient uptake and improved almond rootstock resistance to drought stress.
Research Article
Soil science
F. Maghami Moghim; A.R. Karimi; M. Bagheri Bodaghabadi; H. Emami
Abstract
Introduction The type of management operations and land use systems are the key parameters affecting the soil quality and sustainable land use. The exploitation systems by efficient use of soil and water recourse can decrease productions costs and increase the yield as well as conserve the ...
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Introduction The type of management operations and land use systems are the key parameters affecting the soil quality and sustainable land use. The exploitation systems by efficient use of soil and water recourse can decrease productions costs and increase the yield as well as conserve the natural resources. However, farmers and stakeholders need to be aware that through their management practices, they affect soil quality and, with the short-term goal of production and greater profitability, lead to soil degradation. They can both use the land economically and improve and maintain soil quality by balancing production inputs and refining their management approaches. There are different management systems of productivity in agricultural lands in Neyshabour plain in northeastern Iran. In addition to the water and soil limitations in the study area, the prevalence of the smallholder system and the unwillingness of farmers to integrate smallholder, has further increased the destruction of soils in the study area. The objective of this study was to assess the changes in soil quality index in surface soil and profile (0-100 cm) and calculate the correlation between soil quality index and alfalfa and rapeseed yield in rangeland and agricultural areas managed by smallholders, total owners, and Binalood Company in the study area.Materials and Methods A total of 21 soil profiles were described in the total owner, smallholder and Binalood company management system and sampled from the alfalfa and rapeseed lands. Questionnaires were prepared with the help of farmers and experts in the study area based on Analytic Hierarchical analysis (AHP) method. The physical and chemical characteristics of the soil samples were determined. The important soil characteristics affecting plant growth were determined by interviewing farmers and experts study area. Soil quality index in the minimum data set (MDS) was calculated by two methods of principal component analysis (PCA) and expert opinion (EO), by additive and weighted methods in surface soil and profile. To achieve a single value for each soil properties in the soil profile, two methods of weighted mean and weighted factor were used. To evaluate the accuracy of the assessment, the correlation between soil quality index and alfalfa and rapeseed yield was investigated of the various management system.Result and DiscussionThe results showed that the highest additive and weighted soil quality index at both surface and soil profile in both PCA and EO methods were in rangeland. It was due to lack of cultivation and maintaining organic matter comparing to agricultural land. The total owner management system due to its economic power and the use of appropriate and scientific methods comparing to smallholder management system, showed the highest additive and weighted soil quality index. In all management system, the EO-calculated weight index by weighted factor method had the highest value due to assigning the suitable weight for soil characteristics. The correlation analyses soil quality indices with canola and alfalfa indicated that the EO soil quality calculated by weighted factor for the soil profile were more correlated than surface soil in total owner system and the Binalood company. Weight coefficient method due to the application of different weights to each layer based on their importance, showed a higher soil quality index in both EO and PCA sets than the weighted average method. The reason for better EO performance probably is that the PCA is a reducing the dimensions, meanwhile, the minimum data selection in the EO method is based on regional experts which are familiar with cause-and-effect relationship of the soil properties. Due to the relatively good correlation of the yield of the studied products, with the soil quality index, an appropriate management needs to maintain and improve soil quality, especially in the smallholder system, as well as meeting the nutritional needs of these products.Conclusion Soil quality assessment in this study indicated that calculation of the soil quality index only considering the surface soil properties may not provide complete information for the farmers and land managers. Then inclusion of both surface and profile soil properties with farmers' knowledge and study area experts are essential for sustainable soil management. On the other hand, the differences in the management system also affected the soil quality index. Although the smallholder management system due to low input, especially chemical fertilizers, water and agricultural implements, had a high potential concerning environmental issues, but in terms of production, total owner and Binalood company management systems because of their high economic strength had the higher soil quality index. The farmers and stakeholders of the total owner management systems should be considered despite the proper management, however due to high inputs of fertilizer and water, especially in the Binalood company, the production may not be sustainable. Therefore, for further studies, calculating the water consumption in the desired management systems is recommended.
Research Article
Soil science
A. Nosrati Miandoab; H. Emami; A. Astaraei; M.R. Mosadeghi; H. Asgarzadeh
Abstract
IntroductionSoil salinity has a negative effect on physical, chemical and biological properties of soil. Salinity also affects the relationships between soil and plants, which in turn has a significant effect on plant growth. One of the solutions used to reduce the effects of salinity and improve the ...
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IntroductionSoil salinity has a negative effect on physical, chemical and biological properties of soil. Salinity also affects the relationships between soil and plants, which in turn has a significant effect on plant growth. One of the solutions used to reduce the effects of salinity and improve the physical properties of the soil is application of organic and chemical conditioners. Organic matter as well as calcium improve the structure and physical condition of the soil. Conditioners in saline soils include soluble calcium salts such as gypsum (CaSO4.2H2O), calcium chloride (CaCl2.2H2O) and phosphogypsum (phosphorous gypsum), and acids such as sulfuric acid, sulfur, pyrite, Aluminum sulfate and sulfur lime (calcium polysulfide). Strategies aimed at evaluating and ameliorating the structural quality of soils should be developed to ensure the sustainable use of lands. The least limiting water range (LLWR) attempts to incorporate crop-limiting values of soil strength, aeration, and water supply to plant roots into one effective parameter (on the basis of soil water content). The LLWR can be a useful indicator of soil quality and soil physical constraints on crop production. Therefore, the objective of this research was to study the effects of organic and inorganic conditioners on some structural and hydraulic indices of saline sodic soils.Material and MethodsIn this study, the effect of two types of organic and chemical conditioners and the simultaneous application of them on modifying the physical properties of 5 saline soils around the lake of Urmia were investigated. Treatments included algae, salfit and algae+salfit. The soil samples were transferred to culture boxes (40 × 40 × 40) according to the bulk density of the sampling site. The soil samples were wetted and dried several times. Conditioners treatments including application of calcium and organic compounds. After reaching the field capacity, wheat seeds were sown and irrigated with water (electrical conductivity 0.28 dS/m and pH= 7.78). It should be noted that irrigation was done at intervals of 8 days. Two months after the beginning the experiment, irrigation was stopped and soil moisture was allowed to reach a permanent wilting point. At this stage, undisturbed soil samples were prepared from the treated soil of each box and the mean weight‐diameter of dry (MWDdry) and wet (MWDwet) aggregates were measured. Then the values of least limiting water range in two suctions of 330 and 100 cm and water integral capacity of samples were measured.Results and DiscussionAccording to the initial analysis, all soils used were saline and the amount of calcium carbonate was high in two soils (number 3 and 5). Soil organic carbon content was also low. The results of salfit analysis also showed that the dissolved calcium and sulfur content were 8 and 3.9%, respectively. The results showed that soil 1 had the highest amount of MWDwet and soil 5 had the lowest amount of MWDwet. The highest and lowest aggregate stability values were obtained in soils 3 and 5, respectively, where soil 5 was very saline soil. The studied soils differed in terms of soil water relations. The highest amount of LLWR330 was found in soil 5, while the lowest amount of LLWR100 and IWC parameters was also obtained in same soil. The results of this study showed that salfit treatment caused the highest increase in aggregate stability (74.9%) LLWR330 (14.5%) and integral water capacity (26.2%) compared to the control and the highest mean weight‐diameter of aggregates in both wet and dry conditions was obtained in salfit-algae treatment (52.4% and 40.4% increase, respectively). The results of correlation analysis among the measured parameters showed that the highest correlation was found between aggregate stability and MWDwet. Among the measured parameters, aggregate stability had the highest correlation with other parameters and the correlation of this parameter with LLWR330, LLWR100, IWC and MWDwet were 0.36, 55, 75 and 88 %, respectively. Soil water integral capacity also had a significant correlation (p < 0.01) with LLWR330 (0.84) and MWDwet (0.7).ConclusionThe effect of initial soil properties on studied parameters was significant and the use of conditioners improved studied parameters, and use of conditioners increased indices structural and hydraulic of saline soils. In general, the results of this study showed the positive effect of conditioners on physical properties of the studied soils, in which salfit and salfit-algae have a better effect on studied parameter, and they could be useful to improve soil physical condition. It seems that the application of different rates of conditioners as well as their interaction with each other should be considered according to the basic properties of the soil.
Research Article
Agricultural Meteorology
S.M. Ebnehejazi; H. Yazdanpanah; S. Movahedi; M.A. Nasr-Esfahani; M. Moradizadeh
Abstract
Introduction Agricultural products frost in spring imposes heavy financial losses to agriculture particularly in northwest of Iran’s orchards. Not only temperature is one of the most important climate parameters but also it is a very crucial element in the agricultural sector. Untimely temperature ...
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Introduction Agricultural products frost in spring imposes heavy financial losses to agriculture particularly in northwest of Iran’s orchards. Not only temperature is one of the most important climate parameters but also it is a very crucial element in the agricultural sector. Untimely temperature fluctuations and rise and fall which are usually unexpected will cause shock and heavy damages. Therefore taking into consideration the agricultural products frost and offering an approach would be of great importance for reducing relevant damages. In studies carried out by Omidvar and Dehghan Banadoki (2012) and Hesari et al. (2015) characteristics and different types of frosts have been considered in relation to the agricultural products. Different models were introduced to predict flowering date in different investigated regions. In more studies, in addition to determining the best model for predicting the date of occurance of flowering stage, probable date of last frost has been estimated as well. Investigating long term temperature changes is a method which applied by Martínez-Lüscher (2017) and Vitasse et al. (2018) to find out about established changes in flowering date and also changes in the last frost date. Nasr Esfahani and Yazdanpanah (2019) realized that 48-hour early warning for frost occurrence can be performed with adequate precision. Despite all studies in the field of products frost particularly during flowering date, it seems a rapid frost warning system must be established and provided to make early warning for each orchard. In this essay, since our goal is to make such early warning three days before frosting, so we have to investigate accuracy and validity of 72-hour minimum temperature simulation using WRF model. On the other hand, we must know phonological stage of each product in each orchard to inform the farmer about frost hazards based on critical temperature, therefore the second goal of this research is to detect phonological stages through Landsat 7 and Landsat 8 images.Materials and MethodsIn order to achieve the aim of current study, 72-hour minimum temperature simulation through the Weather Research and Forecasting (WRF) model was investigated and values of vegetation index were derived for a 30 meters pixel at an experimental orchard in Kahriz, West Azerbaijan Province, in 2016-2107. Computational grid for 2 meters temperature simulation using WRF model contains of three nested grid with horizontal resolution of 27, 9 and 3 kilometers. Horizontal resolution of terrain height and land use data is equal to 30 second (about 1 km). The initial and 3-h boundary conditions with 0.5º horizontal resolution from the Global Forecast System (GFS) were obtained from National Centers for Environmental Information (NCEI). Based on the previous research KFMYJ physical scheme configuration for WRF model were used in this research. Model's hindcasts at 03:00 UTC hour for each of 51 synoptic weather stations of northwest of Iran in internal computational grid were interpolated by MATLAB software with interp 3 function using linear method, then the obtained values were compared to minimum temperature observed in the stations by using MAE, MSE, RMSE and MSSS indicators. Phenological statistics, the time of beginning and end of growth stages were obtained from Iran Meteorological Organization. Besides, 77 Landsat 7 satellite images of ETM+ sensor, and 41 Landsat 8 images of OLI sensor were downloaded from United States Geological Survey website from March to September 2007-2016 with a spatial resolution of 30 meters. In this research, atmospheric and radiometric correction were performed with the FLAASH method on the metadata file in the ENVI software environment and then vegetation index was calculated using NDVI index.Results and DiscussionExamining the evaluation indicators of the WRF model, results revealed a significant correlation and regression model between 2 meters temperature variable from WRF model output and minimum temperature variable observed in the entire stations for 72-hour simulation. As a result WRF model can be applied in 72-hour temperature simulation in the area of study. Another finding of this research indicated that in comparison to the field-recorded data, NDVI values gained from Landsat images properly indicates changes of phenology stages in the relevant apple orchard. In this study, the indicators used to evaluate the model error showed model hindcasts are more accurate for 24-hour and then 48-hour simulations than for 72-hour simulation, but the 72-hour simulation accuracy is not much different from 24-hour and 48-hour simulations. In northwestern Iran, which is a mountainous region, it is very difficult to simulate airflow in areas with complex topography, therefore the total correlation coefficient of all stations in all three simulations is in the range of 0.5, and the error rates of MAE and RMSE, respectively reaches about 2.8 and 3.8 Celsius. According to the second finding of this research, the NDVI indicator obtained from Landsat 7 and Landsat 8 satellite images can show the progress and changes in the phenological stages of apple trees.Conclusion This study showed the efficiency of the WRF model for 72-hour simulation of the minimum temperature as well as the potential of Landsat 7 and Landsat 8 images in detecting apple phenological stages in the study area. Therefore, by using the WRF model for 72-hour minimum temperature simulation and recognizing the phenological stages from Landsat images, if the temperature in any orchard reaches a critical level in the next 72 hours due to the phenological stage, frost warning can be announced and then frost mitigation should be done by the farmer.
Research Article
Irrigation
K. Raispour; B. Salahe; B. Abad
Abstract
Introduction Precipitation is the most important element of water level that recognizing its temporal-spatial characteristics at different scales is an important step towards better understanding and modeling of the hydrological cycle and related phenomena such as floods. Drought, landslides, snow ...
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Introduction Precipitation is the most important element of water level that recognizing its temporal-spatial characteristics at different scales is an important step towards better understanding and modeling of the hydrological cycle and related phenomena such as floods. Drought, landslides, snow and climate change are on a regional and global scale. Despite the large number of studies conducted in this field, there is still a lot of research need in many parts of the world for reasons such as lack of weather stations to access ground observation data and the non-uniform spatial distribution of these stations. Nowadays, with significant technological advances, including the advent of various satellites, access to a variety of precipitation data has been greatly facilitated. Among the latest precipitation products of various satellites, we can refer to the Global Precipitation Measurement (GPM) satellite data. Related to the subject of the present study, it is stated that most of the studies on rainfall in the Jazmourian catchment area have been based on station data, which due to the poor distribution of meteorological stations; it is not possible to estimate the temporal-spatial distribution of precipitation in the study basin. In this study, the temporal-spatial analysis of precipitation using GPM satellite precipitation products as one of the most important climatic parameters in the basin Due to the undeniable importance of rainfall in this basin, it seems that the analysis of variable rainfall can provide valuable climatic information to researchers and planners. To pave the way for new study platforms.Materials and Methods In this study, satellite data (GPM) with a spatial resolution of 0.1 × 0.1 degrees from January 2001 to December 2019 have been used for spatiotemporal analysis of precipitation in the Jazmourian catchment. The GPM satellite provides more accurate and realistic estimates than other TRMM satellites. In this study, a calibrated precipitation product of level 3 of 6 GPM satellite versions was used. Relevant data are in NCDF format and have UTM image system with WGS84 datum, which after quality control and preprocessing, by specialized software (ENVI, ArcGIS and EXCELL) is converted into network data and data tables and the necessary outputs based on the geographical boundary of the catchment was extracted. The average monthly rainfall was extracted from the average daily rainfall belonging to each month and the seasonal average was extracted from the average of three months related to each season. Spatially, the values of each pixel are the conditions of the average amount of precipitation related to each time series (monthly, seasonal and annual) during the statistical period.Results and Discussion Based on the results, the average rainfall in the Jazmourian catchment was estimated as 144 mm, the spatial distribution of which ranged from 83 to 232 mm. The maximum rainfall occurred in the northern and western parts and the minimum occurred in the central and eastern parts of the basin. Furthermore; based on the annual distribution of rainfall during the statistical period under study, the highest rainfall was in 2019 with 239 mm and the lowest with 53 mm in 2001. In terms of seasonal distribution, winter and spring with values of 118 and 88 mm, respectively, showed the highest and autumn and summer with values of 22 and 45 mm, showed the lowest values of precipitation. Also, during the statistical period under study, winter 2005 with 193 mm had the highest and autumn 2003 with 1 mm had the lowest seasonal rainfall in the basin. In addition, an interesting point is the spatial displacement of high-pressure nuclei in different seasons of the year; so that these nuclei are observed in the cold seasons of the year in the northern and western parts and in the warm seasons of the year in the southwestern and southeastern parts of the basin. The spatial distribution of monthly precipitation indicates the occurrence of the highest monthly precipitation in February and March and the lowest in May and September. Also, the monthly rainfall time series indicates the maximum incidence of precipitation in February 2001 (94 mm) and it’s minimum in January 2001 (no precipitation).Conclusion Precipitation as a source of fresh water on Earth is one of the most important hydrological parameters, the importance of which is undeniable in the survival of human communities and natural ecosystems. Due to the large temporal-spatial variations of precipitation, its study seems necessary. But one of the main challenges for studying this phenomenon is the lack of ground stations as well as their improper distribution. Today, with advancement of technology and remote sensing, a diverse range of satellite data has become available to environmental scientists. In this regard, in the present study, using GPM satellite data and in the statistical period 2001-2019, the temporal-spatial distribution of precipitation in the Jazmourian catchment area in southeastern Iran has been investigated. In general, the high variability of rainfall in Jazmourian catchment in different months and seasons of the year, shows the dominance of arid and low climate in this basin. Therefore, due to the rainfall situation and its high fluctuations under climate change conditions, in the near future, this basin will face serious challenges and crises in water resources management and the sustainability of natural ecosystems. The GPM satellite data used in this study showed appropriate and expected results from the spatial-temporal distribution of precipitation in the Jazmourian catchment and showed a good correlation with meteorological stations. In general, the use of GPM satellite data in the present study is appropriate, which due to its appropriate spatio-temporal separation, gives reliable and satisfactory results. On the other hand, inadequate spatial coverage of meteorological stations and their large statistical vacuum in such a relatively large basin justify the use of this valuable and useful satellite data.
