Soil science
M. Jafarian; A. Golkarian; H. Emami
Abstract
Introduction Changes in soil properties depend on factors such as climate, topography, landscape features, altitude, parent material, and vegetation. The quantity and quality of soils obtained from different rocks (igneous, sedimentary and metamorphic rocks) depend on the minerals that make up the ...
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Introduction Changes in soil properties depend on factors such as climate, topography, landscape features, altitude, parent material, and vegetation. The quantity and quality of soils obtained from different rocks (igneous, sedimentary and metamorphic rocks) depend on the minerals that make up the rock, as well as weather and other factors. Soil parent material is one of the primary and important issues in soil classification in terms of physical quality and also one of the most important effective factors in soil erodibility. The topographical factor of each region is one of the important and influential features on the soil quality of that region. The present research was conducted with the aim of understanding the spatial changes of soil properties in different slopes and different types of rocks. Material and Methods The studied area is located in Razavi Khorasan province in the cities of Mashhad, Chenaran, Sarakhs and Torbat-Haidarieh. The geographic location of the region ranges from 58 degrees and 52 minutes to 60 degrees and 40 minutes east longitude and 35 degrees and 38 minutes to 36 degrees and 25 minutes north latitude. This research was carried out on seven types of rocks: granite, Sarakhs paleogene limestone, Chenaran jurassic limestone, marl, shale, sandstone and ophiolite from relatively pure rocks of Razavi Khorasan province. In the present study, two factors of rock type and slope were investigated as effective factors of soil properties. Soil samples were taken from the surface layer (0-20 cm) and from three slope classes ie., less than 10%, 10-25% and more than 25%, as well as all soil samples from the southern slopes. Tree soil samples were taken from each slope and a total of 63 samples were taken and the samples were transfered to the laboratory for physical and chemical tests. In this study, the soil particle size distribution (texture) was measured by hydrometer method, organic carbon and calcium carbonate were determined by wet oxidation and titration with HCl 6 M, the mean weight diameter of soil aggregates and surface crust factor were calculated by related equations. To measure soil cohesion and penetration resistance were used pocket vane test and pocket penetrometer, respectively. Comparison of means was done through Duncan test in spss software. Results and Discussion The results showed that all the studied variables in different types of stones had a significant difference at the level of 1%. There was no significant difference in the variable of surface level in different slopes. Also, the variables of calcium carbonate percentage and saturated conductivity at 5% level had significant differences in different slopes. Other characteristics of soil, including percentage of organic matter, the mean weight diameter of soil aggregates, the number of drops impact, and soil cohesion and penetration resistance in different slopes had a significant difference at the level of 1%. Althoug the soil texture class was not significantly different in different slopes, the percentage changes of clay, silt and sand had a lot of difference along the slope. The highest and lowest parameters of organic matter percentage, Soil cohesion and penetration resistance were observed in granite and shale, respectively. The highest percentage of calcium carbonate was observed in Chenaran limestone (40.41%) and the lowest in granite (14.72 %). The mean weight diameter of soil aggregates was the highest in ophiolite (1.005 mm) and the lowest in marl (0.403 mm). The mean weight diameter of soil aggregates in the medium slope was significantly higher than the other two slopes. The parameter of the number of drops impact was the highest in granite (47.14 number) and the lowest in marl (27.70 number). The highest value of saturated conductivity variable was observed in marl rock and the lowest value was observed in Chenaran limestone. Conclusion The results showed that all the investigated variables had significant differences in different types of stones. Also, some of the investigated variables such as percentage of organic matter, percentage of equivalent calcium carbonate and the mean weight diameter of soil aggregates had significant changes along the hillside. As a general conclusion, given that the physical and chemical properties of the soil are partly under the influence of the parent material and the slope, and also with the presence of good geological information in the country, it can be suggested to provide suitable management solutions to prevent soil erosion and degradation by comprehensive examination of soil properties under different slope and types of stones.
Soil science
H. Emami; M. Memarzadeh
Abstract
Introduction
Wind Erosion is the natural process of transportation and deposition of soil by wind. It is a common phenomenon occurred mostly in dry, sandy soils or anywhere the soil is loose, dry, and finely granulated. Heavy metals are found in the environment and soils may become contaminated by accumulation ...
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Introduction
Wind Erosion is the natural process of transportation and deposition of soil by wind. It is a common phenomenon occurred mostly in dry, sandy soils or anywhere the soil is loose, dry, and finely granulated. Heavy metals are found in the environment and soils may become contaminated by accumulation of heavy metals through emissions from the rapidly expanding industrial areas, mine tailings, disposal of high metal wastes, leaded gasoline and paints, land application of fertilizers, animal manures, sewage sludge, pesticides, wastewater irrigation, coal combustion residues, spillage of petrochemicals, and atmospheric deposition. Soils are the major sink for heavy metals released into the environment by the aforementioned anthropogenic activities and their total concentration in soils persists for a long time after their introduction. The heavy metal contamination of soil and its potential risks to humans and the ecosystem is a significant concern. Windy deposition, which is the process of heavy metals being transported by erosive winds and deposited onto soil, is one of the sources of heavy metal contamination. Due to the geographical situation and climatic conditions such as arid soil, erosive winds are blown in periods of year in Tabas. Since wind are erosion is severe in this area, huge amounts of wind deposition accompanied with erosive winds entered into this town. Heavy metals through the windy deposition are suspended, translated and finally deposited in residential regions, which can create some problems for human health. Therefore, the knowledge of wind erosion and the human risk of these deposits is essential. The aim of this research was to determine the rate of wind erosion and the concentration of some heavy metals in these deposits.
Materials and Methods
For this purpose, the rate of suspended load was measured monthly from February 2021 to January 2022. Based on previous information from the erosive winds and storms, suspended depositions were gathered in some directions (north, northwest, northeast, west and southwest) of the Tabas entrance. In addition, the suspended load in the city center of Tabas was also measured. The cumulative load of suspended depositions was measured monthly and the concentration of some heavy metals such as manganese (Mn), iron (Fe), cupper (Cu), and zinc (Zn) were measured in these suspended particles. Soil digestion was made by Aqua regia (nitric acid and chloridric acid; ratio of 3:1), and after then atomic absorption was used to measure the total concentration of above heavy metals.
Results and Discussion
The results indicate that Tabas experiences significant wind deposition of suspended loads, with the highest rates entering from the northeast direction and the lowest rates from the southwest direction. This pattern aligns with the wind rose of Tabas, which illustrates the prevailing wind directions in the region. Additionally, substantial suspended loads are observed in the northwest and north directions. The variations in suspended load discharge reveal that the maximum discharge occurs in the city center of Tabas during the months of June and July 2021. This corresponds to the arid climate conditions of these months, where plant growth is limited, soil cohesion is low, and loose soil particles on the surface are susceptible to wind forces. As a result, these loose particles are easily detached by the wind, contributing to the high levels of suspended load. Regarding the spatial variation of heavy metals in suspended particles, the cumulative concentrations of Mn, Fe, Cu, and Zn are found to be higher in the west, northwest, north, and west directions, respectively. This suggests that these heavy metals are transported and deposited in specific areas within Tabas due to the prevailing wind patterns. In terms of temporal variation, the highest concentrations of Mn and Fe in suspended particles are observed in April 2021, predominantly in the northeast and west directions, respectively. On the other hand, the highest concentrations of Cu and Zn are found in May 2021, with the southwest and northeast directions being the primary deposition areas for each metal, respectively. These findings highlight the spatial and temporal dynamics of suspended load and heavy metal deposition in Tabas, emphasizing the influence of wind patterns and climatic conditions on these processes. Understanding these variations is crucial for assessing the potential risks associated with heavy metal contamination and implementing appropriate mitigation measures in the region.
Conclusion
The results of this research showed that most contents of the suspended load are entered from the northeast direction into Tabas. In addition, the spatial variation of heavy metals indicated that the concentrations of studied heavy metals (Mn, Fe, Cu, and Zn) in suspended particles, especially in the western, northwestern, and northern in spring, are very high and they can cause carcinogenic effects on human life. Therefore, the management practices should be mostly made in these directions to control or reduce soil erosion and reduce its damage effects.
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.
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.
Saman Hajinamaki; Hojat Emami; Amir Fotovat
Abstract
Introduction: Water scarcity is one of the important issues in agriculture, especially in arid and semi-arid regions of Iran. Therefore, the challenge for the agriculture in these areas is to find new sources of water for irrigation. One of the ways that has become more common in recent years is the ...
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Introduction: Water scarcity is one of the important issues in agriculture, especially in arid and semi-arid regions of Iran. Therefore, the challenge for the agriculture in these areas is to find new sources of water for irrigation. One of the ways that has become more common in recent years is the reuse of wastewater as a secondary source and replaces drinking water. The effects of irrigation with wastewater on physical, chemical and biological properties of soil have been studied by many researchers, which most of them are based on the direct use of untreated wastewater in agricultural land irrigation. In fact, a large amount of wastewater used in the agriculture is indirectly entered into the rivers, and used in the agriculture lands. Irrigation with wastewater may have effects on soil properties such as pH, EC, nutrient content, sodicity, pollutants and etc.
Materials and Methods: In order to determine the effect of irrigation by wastewater on soil properties in May 2015, several points of the Kashafrood River in the north of Mashhad were selected. The studied points were located between 59˚36ʹ- 59˚41ʹ E and 36˚19ʹ- 36˚22ʹ N geographical position. The wastewater is refined in Parkandabad station, and used for irrigation. The samples were taken from a depth of 0-30 cm in each point and three replications were regarded for them. Sampling distance was one kilometer from each other. In general, 15 points were irrigated with wastewater were selected. 12 physical, chemical and biological properties including pH, soil texture, bulk density (BD), dispersible clay (DC), mean weight diameter of aggregates (MWD), sodium adsorption ratio (SAR), organic carbon (OC), available phosphorous (P), available potassium (k), total nitrogen (TN), microbial biomass and base respiration (BR) were measured as a total data set (TDS). According to Liu and Chen the main component with an Eigen value greater than one using the PCA method were chosen as minimum data set (MDS). Within each PC, highly weighted properties were defined as those with absolute values within 10% of the highest weighted loading. When more than one variable was retained in a PC, each was considered important and was retained in the MDS if they were not correlated (r < 0.60). Among well-correlated variables within a PC, the variable having the highest correlation sum was selected for the MDS. Data analysis were performed using SPSS Statistics22 software.
Results and Discussion: The results showed that irrigation with wastewater increased biomass and BR, OC, SAR, K and stability index of soil structure. The parameters of K, TN, pH and MWD have been increased compared to the control, but were not statistically significant. Using PCA, five PCs were obtained, which PC1 and PC2 with Eigen value of 50.6 % were the most important components. The parameters of OC, SAR, TN, pH, BD, MWD, BR and K were chosen as MDS due to be changed as a result of irrigation with wastewater. Then, the correlations between these parameters in two groups of irrigated soils with wastewater and control were investigated. Organic carbon in both soil groups had the highest correlation with the SI. The SAR in both soil groups was negatively correlated with nitrogen and phosphorus. Nitrogen in irrigated soils with control was positively correlated with the SI and OC. The MWD was not correlated with any parameter. PH had shown positive correlation with microbial biomass and OC was positively correlated with BR, TN and SAR in soil controls. Potassium in the irrigated soils with wastewater had the negative and significant correlation with OC, SI, BD and MWD. Microbial respiration had a high positive correlation with SI, OC and TN in irrigated soils, which is due to carbon and nitrogen in the wastewater and causes an increase in its amount compared with the control.
Conclusion: The results showed that irrigation with wastewater caused a significant increase in parameters SI, SAR, P, BR, MBC and organic carbon in irrigated soil with wastewater and pH, MWD, TN and K had no a significant difference. On the other hand, the principal component analysis of the two groups of irrigated soils with wastewater and control had two distinct groups indicating that the irrigation with wastewater had a significant impact on the soil properties. According to the principal components analysis, eight parameters including OC, SAR, TN, MWD, BD, pH, BR and K were selected as the most important parameters to study the effects of irrigation by wastewater.
zahra sharifi; Alireza Astaraei; A Fotovat; mojtaba baranimotlagh; Hojat Emami
Abstract
Introduction: Zinc is one of the essential micronutrients for plants, mining and industrial activities leading to pollution of heavy metals, including zinc metal contamination in soils. In addition to the total concentration, knowledge of the Zinc fractions is necessary to assess the mobility of zinc ...
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Introduction: Zinc is one of the essential micronutrients for plants, mining and industrial activities leading to pollution of heavy metals, including zinc metal contamination in soils. In addition to the total concentration, knowledge of the Zinc fractions is necessary to assess the mobility of zinc in the soils. One of the sequential extraction methods is Tessier method. sequential extraction with plant cultivation simultaneously, is the appropriate approach for assessing the mobility of toxic metals. Therefore this study was conducted to evaluate the chemical forms and determine their relationship to the physical and chemical properties of soils in some fields under cultivation in Khorasan Razavi province.
Materials and Methods: The experiment was conducted in a completely randomized design with factorial arrangement includes 4 levels of contamination (0, 500, 1000 and 1500 (mg/kg)) and 10 soil types from different regions of Khorasan Razavi province of 0-30 cm depth in the range of electrical conductivity 1 up to 15 ds/m, with three replications at Research greenhouses of Ferdowsi University of Mashhad. An example of mining waste was prepared as a source of pollution. The soil samples were kept at field capacity moisture for 6 months. Then air-dried soil samples were used for planting borage and determine the Zinc fractions. Then soil samples were air dried and used for planting borage and determining the Zinc fractions. Texture, cation exchange capacity, organic carbon, electrical conductivity, pH and Available phosphorus and potassium were measured in the saturation extract. DTPA-extractable Zinc was measured by atomic absorption spectrometry. Borage was planted in greenhouses in 3 kg pots with three replications. During flowering, the plants were harvested and dry digestion method was used to measure the concentration of Zinc. Chemical forms and Pseudo total concentration of zinc in the samples were determined using Tessier and digestion by HCl and HNO3 acids (3:1) methods respectively. The concentration of the extracts was measured by atomic absorption spectrometry. Statistical analysis was done using Minitab and Excel softwares.
Results and Discussion: Chemical Forms Average of zinc in soils was as follows:
Exchangeable < iron and manganese oxides < organic < carbonate < residual
Despite the low percentage of organic matter in these soils, in high levels of Zinc contamination a large amount of zinc was saved. Lack of organic Zinc, in addition to the low amount of organic matter soil is related to the dominance of iron oxides. In high levels of soil contamination, increased concentrations of zinc in all fractions, especially organic and carbonate which leads to an increase in the availability of zinc, is a serious threat to environment. The amount of exchangeable zinc was insignificant. Also the exchangeable, forms a small part of total amount of metal in the soils. The correlation between the chemical forms with each other and with the pseudo total, absorbed by plant roots and shoots and extracted with DTPA together, was significant. Absence of correlation between the exchangeable and iron and manganese oxides is probably indicative of the fact that the main supplier of soluble and exchangeable zinc normally after carbonates are iron and manganese oxides, that have little role in these soils. There is a significant positive correlation between different fractions of zinc with each other and this indicate a dynamic relationship between the zinc chemical forms in the soil. Correlation coefficients between plant available and chemical forms of zinc showed that plant available zinc derived from all fractions. A higher correlation coefficient between the plant available with carbonate and organic zinc was obtained, which indicates that carbonate and organic are the major suppliers for available plants zinc.
Conclusion: In this study, the residual, carbonate and organic fractions are dominant form of zinc in soils, respectively. With increasing level of contamination, percentage of residual zinc decreased and percentage of other fractions increased, particularly organic and carbonate. Increasing the availability of zinc, is a threat to the environment. There is a high correlation coefficient between different fractions of Zinc with each other and with the pseudo total, amount of plant and available plant zinc showed that there is a dynamic relationship in the soil systems. There is a higher correlation coefficient between the available zinc and carbonate and organic fractions of soils, which indicate available plant zinc, are mainly derived from carbonate and organic fractions.
Seyyedeh Zohreh Taghdisi heydarian; Reza Khorassani; Hojat Emami
Abstract
Introduction: The amount of soil nutrients and their availability for plants are the important aspects of soil fertility. Although micronutrients are used by plants in very small amounts, they play an active role in many plant-based processes and reactions influencing the plant growth and yield. The ...
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Introduction: The amount of soil nutrients and their availability for plants are the important aspects of soil fertility. Although micronutrients are used by plants in very small amounts, they play an active role in many plant-based processes and reactions influencing the plant growth and yield. The efficiency of absorption of micronutrient can be increased by adding some organic and mineral materials to soil. Saha et al. (41) observed an increase in micronutrient concentration of corn grain by adding organic materials to soil. Zeolite is one of the most commonly minerals used to increase agricultural production (17). The zeolites, due to their structure and porosity, are well-suited for retaining the nutrients and gradually releasing them into the root zone (40).Despite the positive effects of zeolite on some physical and chemical properties of soil, its application at high levels may adversely affect the absorption of nutrients and plant growth. Hamidpour et al. (18) who used zeolite for Zinnia flower, reported that zeolite reduced the yield of Zinnia flower. Basari et al. (4) reported that zeolite application increased soil pH and electrical conductivity (EC). Therefore, this research was carried out with the aim of assessing the influence of zeolite application, type (i.e. vermicompost and cow manure) and organic matter levels on the growth and the micronutrients uptake and determining the appropriate composition for corn.
Materials and Methods: A factorial experiment was conducted in a completely randomized design with three replications in greenhouse under controlled condition.The treatments consisted of raw zeolite (natural) in three levels (0, 6, 12% by weight), organic matter including vermicompost in three levels (0, 0.125, 0.25% or 0, 5, 10 t ha-1) and cow manure at three levels (0, 0.5, 1% by weight or 0, 20, 40 t ha-1).The soil was collected at a depth of 0-30 cm from the Mashhad Soil and Water Research Center. General soil characteristics and micronutrients concentration (iron, zinc and manganese) were determined according to standard methods (14, 27). For vermicompost and cow manure, some parameters such as pH and EC, organic carbon (46), available phosphorus and potassium (21), total nitrogen (7) and micronutrient (iron, zinc and manganese) were also measured (21). Further, pH, EC and micronutrient (iron, zinc, and manganese) were measured for natural zeolite (27). The pots were prepared by mixing 5 kg soil and experimental materials. N, P, and K were added according to soil testing. Irrigation with distilled water at field capacity level was done during the growth period. The plants were harvested75 days after sowing and after separating shoot and root, the plant materials were transferred to laboratory. Root and shoot dry weight were determined and after dry digesting of plant materials, the concentration of micronutrient were quantified by Atomic Absorption (21). The soil samples were also analyzed in order to determine the chemical properties of the soil after harvesting. Statistical analysis of the data was performed using JMP software and the mean comparison was carried out based on LSD test at 5% probability level.
Results and Discussion: The results of the experiment showed that increasing zeolite levels reduced dry weight, decreased height and uptake of zinc, iron and manganese and increased soil pH and iron and manganese concentrations. In addition, it was observed that the zeolite application had a negative effect on the plant growth and micronutrients uptake. Burriesci et al. (8) concluded that the zeolite application without fertilizing seems not to considerably increase plant growth. According to Kimberly and Nelson (24), the use of natural zeolite, without adding nutrients, leads to a competition between plant roots and zeolite for the nutrients absorption. Sarmetzidis et al. (42) showed that zeolite had no effect on the growth and yield of roses. Kolar et al. (25) reported that increasing the amount of zeolite in the geranium cultivar increased pH and the plants growth. At lower levels of zeolite, shoot fresh and dry weight was larger than that in higher levels of zeolite. Our results also denoted that the maximum amount of plant dry weight, plant height, the micronutrient (zinc, iron and manganese) uptake and the lowest soil pH were observed for the treatment of cow manure (1 %) in the absence of zeolite which had a significant difference relative to other treatments and also control. Shirani et al. (44) reported that the application of cow manure significantly increased corn dry matter. Ortiz and Alkaniz (36) showed that using organic fertilizers enhances the amount of absorbent metals such as iron, zinc and manganese as these metals are in a soluble and exchangeable form in these fertilizers. By releasing organic acids, the organic fertilizers, especially cow manure, reduce the localized pH of soil and increase the iron uptake by plants during the mineralization process.
Conclusion: According to the results, the use of zeolite increased soil pH, decreased corn growth and micronutrient uptake. Applying organic materials with zeolite can reduce the mentioned negative effect of zeolite. Cow manure at lowest level was more efficient than vermicompost at all levels. Overall, adding cow manure can improve the plant growth and micronutrient uptake by plant when the zeolite is intended to be used to modify soil physical characteristic.
Hossain Shohab Arkhazloo; H. Emami; Gholam Hosain Haghnian; Abazar Esmali
Abstract
Introduction: Gully erosion is an important type of soil erosion in Iran and Ardebil province (Moghimi and Salami, 2011; Khatibi, 2006). Increasing the cross section of gullies is an indicator for gully developing (Deng et al, 2015). Topography and soil properties are two important factors in gully developing ...
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Introduction: Gully erosion is an important type of soil erosion in Iran and Ardebil province (Moghimi and Salami, 2011; Khatibi, 2006). Increasing the cross section of gullies is an indicator for gully developing (Deng et al, 2015). Topography and soil properties are two important factors in gully developing in various regions of worldwide (Poesena et al, 2003). Despite the importance of soil properties in gully erosion, the direct effect of these agents was less investigated and few researches have been carried out to the effect of physical and mechanical soil properties on gully erosion. Therefore, the objectives of this research were to determine 1) the effect of topography on gully erosion, 2) effect of surface and subsurface soil physical and mechanical properties on increasing the cross section of gullies and 3) to select the most important soil properties affect developing the cross section of gullies in three regions of Ardebil province (Ortadagh, Molla Ahmad, and Sarcham). In addition, the relationship between the most soil properties and topographic agents was investigated
Materials and Methods: The effect of topography on gully erosion was investigated by using of two methods i.e. topographic threshold of gully forming (as , where A and S is gully watershed cross section and slop, respectively, a and b is local coefficients) and the relationship between slope classes with gullies density. In regard to catchment characteristics, a set of similar gullies was selected in each region and the changes of cross section area for gullies in four points along its length were measured as indicator of gully development during two years. 17 physical and mechanical of surface and subsurface soil properties in each point were measured and the most important properties that affect on gully development were selected based on principle component analysis (PCA) method. Finally, the stepwise regression model was fitted to the soil properties selecting from PCA for gully's development in each region.
Results: The relationship between Slope classes and gully density showed that in MollaAhmad region gully density was increased with increasing the slope. In OrtaDaghregion, similar trend was observed up to 20-30% slope, while in Sarcham region these was no relationship between slope classes and gully density. According to the topographic threshold it seems that runoff is the main agent for gully forming in MollaAhmad,but in Sarchamthe piping and tunnel erosion might have caused gully formation and in Ortadagh both surface and subsurface flows were recognized as effective agents for gully formation. Increasing values of the cross section for the selected gullies during 2 years was 0.9, 0.6, and 0.8 m2 for Ortadagh, MollaAhmad, and Sarcham regions respectively, which were 41, 44 and 61 percent more than their initial cross sections. Among mechanical soil properties, liquid limit (LL), plastic limit (PL) and shear strength (SS) had the negative and significant correlations with increasing the cross sections of gullies in 3 regions. Among the particle size fractions, Water dispersible clay had the most effect on increasing the gully’s cross sections and except for surface depth of Molla Ahmad, its correlation with gully’s cross section was significant. Principle component analysis (PCA) demonstarated that in MollaAhmad and Ortadagh mainly mechanical properties of soil and aggregate stability had the more effect on increasing the gully cross section, but in Sarcham soil particle size classes and aggregate stability indices had more effect on gully’s cross section.
Conclusion: According to topography threshold, it can be concluded that surface runoff is the main agent for gully forming in MollaAhmad and gully density increases by increasing the slope classes. In this region the effect of surface runoff on surface soil erosion was sever. In Sarcham there was no relationship between slope and gully density and it was found that the subsurface flow is predominant factor for gully forming. In OrtaDagh both surface and subsurface flows were the main factors for gully forming, so due to increasing the surface flow up to slope 20-30% class, maximum gully density was noted in this slope class and the effect of subsurface soil properties in developing gully cross section was higher than surface soil properties. In general, the relationship between gully density with slope classes, topographic threshold and soil physical and mechanical properties which were effective on gully development indicated the close consistency between the type of hydrologic flow in gully forming and the most important soil properties on increasing the gully’s cross section.
H. Karimi; A. Lakzian; Gh. haghnia; H. Emami; M. Soufi
Abstract
Introduction: Soil erosion by water is one of the most widespread forms of land degradation and it has caused many undesirable consequences in last decades. On steep slopes, rill erosion is the most important type of erosion, which produces sediment and rill flow. It can be also considered as a vehicle ...
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Introduction: Soil erosion by water is one of the most widespread forms of land degradation and it has caused many undesirable consequences in last decades. On steep slopes, rill erosion is the most important type of erosion, which produces sediment and rill flow. It can be also considered as a vehicle for transporting soil particles detached from upland areas. Recent studies indicate that soil detachment rates are significantly influenced by land use. It is also known that there is a major difference between detachment rates of disturbed and natural soils (Zhang et al., 2003). Plowing rills especially in steep slopes increases sediment production. Sun et al. (2013) reported that the contribution of rill erosion in hill slope lands in china was more than 70%, which was approximately 50% of total soil erosion. In addition, measured soil loss is statistically related to hydraulic indicators such as slope, water depth, flow velocity, flow shear stress and stream power (Knapen et al., 2007). This study aims to evaluate the effects of hydraulic variables (shear stress and stream power) on spatial-temporal soil detachment rate. The focus is on the plowing rills in hillslope areas under wheat dry farming cultivation.
Materials and Methods: The study area is located in hilly slopes with the slope of 22.56% under dry farming wheat cultivation at 60 km of west of Shiraz, Iran. Top-down conventional plowing was carried out in order to create 10 meters furrows. Slope and cross sections of rills were measured throughout the experiment at 1 m intervals by rill-meter. Water was added to the top of the rills for 10 minutes and inflow rates were 10, 15 and 20 L min-1. Hydraulic parameters such as shear stress and stream power were calculated measuring rill morphology and water depth. Flow velocity and hydraulic radius along the different rill experiments were also calculated. Sediment concentrations were measured in three equal regular time and distance intervals (measurement points (MPs)), they were considered to calculate sediment detachment rate in different times and sections of each rill experiment for spatial and temporal soil detachment rate evaluation. One-way analysis of variance (ANOVA) was employed to test the significance of differences of sediment detachment rate among different treatments.
Results and Discussion: The results showed that the maximum values of shear stress and stream power were 14.07 Pa and 10.29 Wm-2 and the minimum values were 7.41 and 2.77 respectively. This research also indicated that changes in longitudinal profile of these hydraulic parameters along the rills affected the soil detachment rate values. Obtained average, minimum and maximum of the soil detachment rate were determined as 0.09, 0.02 and 0.22 kgm-2s-1, respectively. Due to Detachment-Transport Coupling mechanism, there was a significant difference between the initial and following MPs (P
amir ranjbar; H. Emami; Ali reza Karimi; R. Khorassani
Abstract
Introduction: Saffron is one of the most important economic plants in the Khorasan province. Awareness of soil quality in agricultural lands is essential for the best management of lands and for obtaining maximum economic benefit. In general, plant growth is a function of environmental factors especially ...
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Introduction: Saffron is one of the most important economic plants in the Khorasan province. Awareness of soil quality in agricultural lands is essential for the best management of lands and for obtaining maximum economic benefit. In general, plant growth is a function of environmental factors especially chemical and physical properties of soil (20). It has been demonstrated that there was a positive and high correlation between soil organic matter and saffron yield. Increasing the yield of saffron due to organic matter is probably due to soil nutrient, especially phosphorous and nitrogen and also improvement of soil physical quality (6, 28, 29). The yield of saffron in soils with high nitrogen as a result of vegetative growth is high (8). Shahandeh (6) found that most of the variation of saffron yield depends on soil properties. Due to the economic importance of saffron and the role of soil properties on saffron yield, this research was conducted to find the relationship between saffron yield and some soil physical and chemical properties, and to determine the contribution of soil properties that have the greatest impact on saffron yield in the Ghayenat area.
Materials and Methods: This research was performed in 30 saffron fields (30 soil samples) of the Ghayenat area (longitude 59° 10΄ 10.37˝ - 59° 11΄ 38.41˝ and latitude 33° 43΄ 35.08˝ - 33΄ 44΄ 02.78˝), which is located in the Khrasan province of Iran. In this research, 21 soil properties were regarded as the total data set (TDS). Then the principal component analysis (PCA) was used to determine the most important soil properties affecting saffron yield as a minimum data set (MDS) and the stepwise regression to estimate saffron yield. To estimate the yield of saffron in stepwise regression method, saffron yield was considered as a dependent variable and soil physical and chemical properties were considered to be independent variables.
Results and Discussion: According to the PCA method, among the 21 studied properties, 7 out of them including calcium, iron, zinc contents, sand, calcium carbonate equivalent percent, mean weight diameter of aggregates (MWD) and manganese (Mn) had the higher Eigenvalues. Therefore, the above properties were introduced as the most important soil properties in saffron fields. Calcium carbonate had the negative effect on the availability of micro-nutrients (26). Christensen et al. (15) found that by increasing the calcium carbonate in soil due to high pH and formation of insoluble components, the uptake of micro-nutrients is especially limited.
The results of stepwise regression method (equation 1) showed that soil acidity (pH), zinc content, bulk density, MWD, iron content, salinity (EC), organic carbon and available potassium in soil were the most important properties that affect the yield of saffron, so that the determination coefficient (R2) of the regression model was high (Table 2) and it can explain 74% of the variation of saffron yield.
Y = 6924.51 – 1187.31 pH – 89.65 EC + 71.6 Fe – 826.02 Zn + 471.55 OC, + 5490.96 K + 1353.56 BD + 752.82 MWD (1)
where Y: saffron yield (kgha-1), pH: soil acidity, EC: electoral conductivity (dSm-1), Fe: iron concentration (mgkg-1), Zn: zinc concentration (mgkg-1), OC: organic carbon (%), K: soil potassium (%), BD: soil bulk density (Mgm-3), and MWD: mean weight diameter of aggregates (MM).
Based on the absolute values of standard ß in the regression model (Table 3), pH value and then after Zn concentration had the most effect on saffron yield. In general, responses of different plants to soil pH is varied, and saffron grows satisfactory in pH = 7.8 (5). Soil pH influences the uptake of soil nutrients by plants (15), so that this parameter had the most effect on saffron yield and by increasing the soil pH, the yield of saffron decreases. According to the regression model, Zn concentration was the second parameter in saffron yield. Zn has the important role in structure of plant enzymes (30). After these 2 parameters, Bd, MWD, Fe concentration, EC, Organic carbon and K concentration in soil had more effect on saffron yield (Table 3).
Conclusion: According to both PCA and regression methods, the concentration of iron and zinc and MWD were determined as the important and effective soil properties on saffron yield in the Ghayenat area. In addition, soil pH in stepwise regression method and calcium carbonate in PCA method were determined as the effective properties on saffron yield. Therefore, it is suggested that the parameters of Zn, Fe, and MWD along with soil pH and calcium carbonate which were regarded individually in two methods, were considered as the most soil properties in saffron yield.
M. J. Pajand; H. Emami; Alireza Astaraei
Abstract
Introduction: Topography is an important and effective property affecting the soil quality. Some researchers demonstrated that degree and aspect of land slope may influence the particle size distribution and gravel. Slope degree affects the surface and subsurface run-off, drainage, soil temperature, ...
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Introduction: Topography is an important and effective property affecting the soil quality. Some researchers demonstrated that degree and aspect of land slope may influence the particle size distribution and gravel. Slope degree affects the surface and subsurface run-off, drainage, soil temperature, stability of soil aggregates and soil erosion. This research was carried out to determine the spatial variation of soil properties in different slope degrees of northern and southern slopes in Khorasan Razavei province, Iran.
Material and Methods: This study was performed in Sanganeh research station (longitude 60o 15ʹ60ʺ and latitude 36o 41ʹ 36ʺ), of north-eastern, Khorasan Razavi province of Iran. In order to study the effects of topography on some soil physical and chemical properties, a topo-sequence with the same slope length, parent materials and cover crops was selected. 30 soil samples (0-30 cm depth) were collected from different slopes of less than 5, 5-15, 15-30, 30-50 and more than 50 percent of both southern and northern aspects. In this study, the soil particle size distribution (texture) was measured by hydrometer method, organic carbon and calcium carbonate were determined by wet oxidation and titration with HCl 6 M, respectively and soil structural stability index, aggregates mean weight diameter and particles fractal dimension were calculated by related equations. Finally, the studied soil properties of 5 slopes (less than 5, 5-15, 15-30, 30-50, and more than 50%) and 2 aspects (north and south) with 3 replicates were compared by nested experimental design and Tuky test in JMP statistical software.
Results and Discussion: The maximum and minimum clay contents as well as fractal dimension and organic carbon contents were found in less than 5% and more than 50% of south slopes, respectively. Clay content and fractal dimension in north aspect were also significantly (P
H. Emami; A.R. Astaraei; A. Fotovat
Abstract
Soil quality is important for evaluating the soil fertility and physical condition. Soil physical and chemical indicators should be regarded for determining the soil quality. This research was conducted to study the effect of organic matter on quantitative value of soil quality. Three level (15, 30, ...
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Soil quality is important for evaluating the soil fertility and physical condition. Soil physical and chemical indicators should be regarded for determining the soil quality. This research was conducted to study the effect of organic matter on quantitative value of soil quality. Three level (15, 30, and 60 ton/ha) of different organic compounds including municipal waste compost, sewage sludge, cattle manure, and wheat straw to gether with control treatment in three replications were applied into loamy soil. The treated soils were kept for 6 months at 70% of field capacity moisture in greenhouse condition. Then soil quality determined based on non-linear score function by using of 14 physical and chemical indicators. The results showed that the score of control treatment was 52.7, which it belong to class 4, i.e. low quality. Addition of different organic matter into studied soil led to improve soil quality score and soil quality class was increased one to 2 degrees. Among the studied treatments, the highest score of soil quality was obtained in 60 ton/ha sewage sludge and 30 and 60 ton/ha compost. Also, addition the other organic treatments cause to increase the quantitative soil quality score in relation to control, and soil quality class increased one degree. Among the studied indicators, iron (Fe), Manganese (Mn), zinc (Zn) micro-nutrients, aeration porosity (AC), and mean weight diameter of aggregates (MWD) were the important limiting indictors in degrading the soil quality in control treatment, and applying the compost and sewage sludge increased their scores.
M. Ghaemi; A. Astaraei; M. Nassiri Mahalati; S.H. Sanaeinejad; H. Emami
Abstract
Successful implementation of soil and crop management program requires quantitative knowledge of site characteristics and interactions that affect crop yield. Soil properties are one of the most important site variables affecting within- field yield variability. The objective of this research was to ...
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Successful implementation of soil and crop management program requires quantitative knowledge of site characteristics and interactions that affect crop yield. Soil properties are one of the most important site variables affecting within- field yield variability. The objective of this research was to identify intercorrelations among soil properties (chemical, physical and biological) using principal component analysis (PCA) and their relationships with maize yield variability in field. Site variables (18) and maize yield were measured in selected parts of Astan Quds agricultural fields in Mashhad city. The principal component analysis was used to reduce the site variables numbers and remove multicollinearity among variables. The first four PCs with eigenvalues>1 accounted for > 67% of variability in measured soil properties. Soil properties were grouped in four PCs as: (PC1) Soil highly descriptive fertility potential, (PC2) Soil moderately descriptive fertility potential, (PC3) Soil permeability potential, (PC4) Soil aggregation potential. The results showed that the factor of soil highly descriptive fertility potential explained 43% of variance and accounted for 77% of the yield variability in the field. Principal component analysis allows explaining a major part of crop yield variability by removing the multicollinearity.
Ali reza Karimi
Abstract
Loess deposits of Kopeh Dagh area usually occur patchy, with low thickness and should be identified and differentiated from other deposits for environmental planning and landscape evolution studies. The objective of this study was to identify distribution and determine the characteristics of loess deposits ...
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Loess deposits of Kopeh Dagh area usually occur patchy, with low thickness and should be identified and differentiated from other deposits for environmental planning and landscape evolution studies. The objective of this study was to identify distribution and determine the characteristics of loess deposits and investigate their formation in the Sarakhs area. Thirty surface samples were collected from the study area and analyzed for particle size distribution. Coarse silt and very fine sand are the dominant fraction of the sediments and overally exceed 70%. Dominance of coarse silt and very fine sand, lack of coarse fragments and abrupt boundary of these sediments with underlying materials are evidences of eolian origin. With decreasing very fine sand and increasing coarse silt, sand dunes in the east and center of the area gradually change to loess deposits from Sarakhs city towards Dousti dam (along Hariroud River) and Kopeh Dag heights in the south and west. The maximum thickness of loess sediment occurred around the Dousti dam. Dominance of coarse silt and very fine sand in the sediments and gradual boundary between sand dunes and loess deposits shows the local source of the particles. Kopeh Dagh heights in southern and western parts of the area, like a barrier have trapped eolian sediments and caused their formation.
M.S. Hosseini; Gh. Haghnia; A. Lakzian; H. Emami
Abstract
Soil enzyme activities can be used as indicators of soil quality for assessing the sustainability of agricultural ecosystems. The objective of this study was to determine the effects of barley residue input rate, burning, urea fertilizer and tillage management on activities of alkaline phosphatase and ...
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Soil enzyme activities can be used as indicators of soil quality for assessing the sustainability of agricultural ecosystems. The objective of this study was to determine the effects of barley residue input rate, burning, urea fertilizer and tillage management on activities of alkaline phosphatase and urease under field conditions, after a period of 90 days. The experiment was carried out based on a completely randomized design with a factorial arrangement in two replications. The treatments included two levels of barley residue input rate (3 and 6 t ha-1), burning (without and with stubble burning), urea fertilizer (0 and 125 kg ha-1) and tillage systems (no-till, conventional tillage). Results showed that 6 t ha-1 crop residue treatment increased enzyme activities in comparison with 3 t ha-1treatment at 0-5 cm. Whereas stubble burning and tillage treatments significantly decreased urease and alkaline phosphatase activities. The urea fertilizer had no effect on alkaline phosphatase activity, whereas urease activity positively affected by urea application. Urease activity was affected more than alkaline phosphatase activity by management practices in soil. The results of this experiment showed that no-tillage system along with crop residue retention of 6 t.ha-1 and without stubble burning systems would be the most effective management to protect and promote soil alkalin phosphatase and urease activity.
H. Shohab Arkhazloo; H. Emami; Gh. Haghnia; A.R. Karimi
Abstract
Abstract
Soil quality evaluation is an essential issue in soil management for agriculture and natural resource protection. Soil quality indices are useful tools for determination and comparison of soils quality. Using of principle component analysis in this study we selected 6 important properties as ...
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Abstract
Soil quality evaluation is an essential issue in soil management for agriculture and natural resource protection. Soil quality indices are useful tools for determination and comparison of soils quality. Using of principle component analysis in this study we selected 6 important properties as a soil quality minimum data set (MDS) among 18 soil properties (TDS). Then, soil quality of agriculture and pasture lands in DehSorkh region in south of Mashhad city was evaluated by Integrated quality index (IQI) and Nemero quality index (NQI) in two collections of soil properties include MDS and TDS. The results showed that soils of the region had low quality in respect to studied indices and was significant correlation between IQITDS - IQIMDS and between NQITDS - NQIMDS. Generally those results show that determined MDS can be a suitable representative of TDS. In addition, comparison of soil quality indices between agriculture and pasture soils showed that efficiency of TDS collection in determining land use effect on soil quality indices was better than that of MDS.
Keywords: Integrated quality index, Nemero quality index, Principle component analysis
H. Shohab Arkhazloo; H. Emami; Gh. Haghnia; A.R. Karimi
Abstract
Abstract
Soil quality is an essential concept for maximum agriculture production without environmental destruction. Studying soil physical quality indicators, that express soil structural stability and soil air-water balance in root zone, is one of the most important aspects of soil quality. So determination ...
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Abstract
Soil quality is an essential concept for maximum agriculture production without environmental destruction. Studying soil physical quality indicators, that express soil structural stability and soil air-water balance in root zone, is one of the most important aspects of soil quality. So determination of optimal range for pore volume distribution is important and this research carried out to determine i) the optimal range for pore volume distribution according to soil physical quality indicators ii) the effect of soil properties on the slope of retention curve at its inflection point or Sgi index and iii) the effect of type of land use on soil physical quality indicators. The classification of studied soils was Haplocalcid, soil texture varied from sand to clay loam and organic carbon (OC) also changed between 0.2 to 2.2 percentages. In this study, Sgi index and pore volume distribution were determined by fitting the experimental soil retention curve data of 40 soil samples to van Genuchten equation in agricultural and rangeland land uses in south of Mashhad plain. Also some other soil physical quality indicators such as, percentage of organic carbon, bilk density, sodium absorption ratio (SAR), mean weight diameter of wet aggregates (MWD), relative field capacity (RFC), plant available water capacity (PAWC), air capacity (AC), and structural stability index (SI) were measured. Then the optimal range of pore volume distribution was determined by using of 8 soil physical quality indicators. Also the correlation between Sgi index and soil physical properties was determined. The positive and significant correlation between Sgi index and percentage of %OC, mean MWD, RFC, and PAWC was shown. But there was a negative and significant correlation between Sgi index and SAR in both land uses. In addition, mean comparison of indicators in two land uses showed that, among the 8 indicators, Sgi index, MWD, PAWC has been decreased significantly in agriculture land use samples.
Keywords: Pore volume distribution, Sgi Index, Soil physical quality
Z. Naghizadeh Asl; E. Dordipour; A.L. Gholizadeh; F. Kiani; H. Emami
Abstract
Abstract
In order to assess the availability of phosphorous (P), different methods have been proposed in the last decades. The results of these methods in soils with various pH, calcium carbonate, organic matter, Al and Fe oxides and hydroxides and other properties especially in Iranian soils can not ...
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Abstract
In order to assess the availability of phosphorous (P), different methods have been proposed in the last decades. The results of these methods in soils with various pH, calcium carbonate, organic matter, Al and Fe oxides and hydroxides and other properties especially in Iranian soils can not be used. In addition, knowledge about transformation of P forms is necessary for perception of P behavior. The objective of this research was to study the relationship between P extracted by some extract ants and soil properties and, different forms of inorganic P. Therefore 20 soil samples were collected from 0-30 cm depth of Glosetan province soils. Soil P was extracted and measured by sodium bicarbonate at pH = 8.5 (NaHCO3), DTPA- Ammonium bicarbonate (NH4HCO3-DTPA), DTPA- Sodium bicarbonate (NaHCO3-DTPA), and 0.01 M CaCl2. Also, different forms of inorganic P in the studied soils were measured by Jiang and Gu sequential fractionation method. The results showed that the amount of P extracted by different extract ants was in the order NaHCO3 > NaHCO3-DTPA > NH4HCO3-DTPA > CaCl2. There was a significant correlation between P extracted by different extract ants and determination coefficient between P extracted by NaHCO3 and NaHCO3-DTPA, NaHCO3 and NH4HCO3-DTPA, and NaHCO3-DTPA and NH4HCO3-DTPA were 0.91**, 0.85**, and 0.82** respectively. P extracted by NaHCO3, NH4HCO3-DTPA, and NaHCO3-DTPA with pH, EC, clay and Calcium carbonate percentage had a negative and significant correlation, but with Organic matter it was significant and positive. Also among the P forms only di, octa and Al oxides P had a significant correlation with P extracted by studied extract ants. In general the distribution of inorganic P forms in these soils was as below: Ca10-P > Al-P > Ca8-P > Fe-P > Ca2-P > Fe- Occluded-P. According to significant correlation between P extracted by studied extract ants with some P forms it seems that, some P forms can be transferred to available form of plants.
Keywords: P Extract ants, Sequential fractionation, Inorganic P forms
H. Emami; A. Lakzian; M. Mohagerpour
Abstract
Abstract
Different definitions have been proposed for soil quality. Various soil properties have been suggetsted as soil quality indices by researchers. This research was conducted to study the relationship between slope of retention curve at its inflection point (S index) and other soil physical quality ...
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Abstract
Different definitions have been proposed for soil quality. Various soil properties have been suggetsted as soil quality indices by researchers. This research was conducted to study the relationship between slope of retention curve at its inflection point (S index) and other soil physical quality indices, because the reserches between S index and soil physical properties are little. Thirty five soil samples were collected and some physical and chemical properties measured . The moisture contents were measured at 0, 1.5, 2.5, 5.5, 10, 20, 30, 50, 100, 200, 300, 500, 1000 kpa pressure heads. The parameters of Van Genuchten equation (1980) were determined by using of RETC software. The slope of retention curve at the inflection point were determined and it was considered as soil physical quality index (S). Then the relationship between S index and soil physical properties was determined by SPSS software. According to the S index and penetration resistance (PR), It seems that the physical quality of studied soil samples was suitable for accesssing. Also there was a significant correlation between S index with mean weight diameter (MWD), clay percentage, sodium absorption ratio (SAR), organic matter percentage, electrical conductivity (EC), least limiting water range (LLWR), available water content (AWC), and penetration resistance (p
