نشریه علوم آب و خاک (علوم و فنون کشاورزی و منابع طبیعی)
سال هفدهم شماره 1 (پیاپی 63، بهار 1392)

In order to investigate the effects of municipal solid waste enriched with mineral fertilizers on some soil physical properties and lead (Pb) and chromium (Cr) concentration in plant organs of spinach، a field experiment was carried out in a factorial arrangement based on the randomized complete block design with three replications in 2008. The main plot included four levels of fertilizer، control without fertilizer، 20 tons of multiple solid waste + 50% chemical fertilizers and 40 tons of multiple solid waste + 50% chemical fertilizers per hectare and sub-plot consisted of a period of application in 3 levels of time (one، two and three years). The results showed that application of enriched municipal compost increased field capacity، soil porosity and moisture holding capacity، but particle and bulk density of soil decreased compared to the control. Also، the physical parameters in the two levels of emriched waste compost were higher than chemical fertilizer treatment. On the other hand، using for three-years the urban waste compost enriched fertilizer at all levels increased significantly (p 0. 05) lead and chromium concentrations in spinach. The Pb and Cr accumulated in roots and shoots of spinach in urban using 40 tons of waste compost per hectare with 50 percent of chemical fertilizer for a period of three years and showed a significant increase. The amounts of fertilizer in all three levels were higher than the root element shoot.

Application of the modern irrigation systems such as T-Tape irrigation system is one of the ways to achieve aptimal irrigation The present study deals with the effect of surface and subsurface drip irrigation systems on the cotton yield For this purpose، a field experiment was conducted in the Agricultural and Natural Resource Research Institute of Orzoueyeh، located in the Kerman province. The experiments were conducted in a split plot design based on the Randomized Complete Block Design (RCBD) with three replications. The treatments were comprised of three levels of the crop water requirements (i. e. irrigation based on 100، 80 and 60 percent of crop water requirement) in main plot and with the two irrigation systems، surface one and subsurface one. The results showed that the yield resulting from treatments with 60 and 80 percent crop water requirement was respectively 981 and 413 kg/ha lower than that of treatment with 100 percent crop water requirement. In addition، the obtained yield due to subsurface system was 248 kg/ha greater than that of the surface pattern. The interaction of treatments on the yield of the crop also indicates that the treatment with subsurface system and 100 percent crop water requirement produces the maximum yield. Despite equal water consumption in each sub plots، the WUE in subsurface system was 14 percent higher than that of surface system. From the economical point of view، benefit to cost ratio in the subsurface system is 8 percent less than surface system. Considering the results obtained in this study in the light of water saving as the main objective in deficit irrigation and water use efficiency (WUE) for cotton cultivation in Orzoueyeh، the 80% of crop water requirement is preferred

Composting and vermicomposting are two efficient methods to recycle organic wastes. In order to investigate the structural changes in organic matter during the composting and vermicomposting processes، cattle manure and filter-cake of sugar cane were incubated with and without earthworm''s presence in a controlled temperature and moisture condition for 16 weeks. Compound samples were taken at 0، 8، and 16 weeks. Carbon، nitrogen and C: N ratio were measured by a CN analyzer apparatus. Solid samples were used for structural analysis using FTIR and solid state CP MAS 13C NMR devices. C: N ratio was decreased with improving decomposition process. The C: N ratio was slightly elevated after 16 weeks of vermicomposting. Structural analysis with both spectroscopic methods showed a decrease of O-alkyl C and increase of aromatic and carboxylic functional groups. The analysis of samples with 13C NMR showed that after 16 weeks، the percentage composition of O-alkyl filter-cake decreased from 41 percent in the first sample to about 33. 1 percent. The amount of these compounds in manure samples decreased from 56. 7 percent to 43. 6 percent. Aromatic compounds in samples of raw filter-cake and manure increased from 12. 5 and 13. 5 percent to 16. 4 and 18. 7 percent، respectively. Percentage of carboxyl compounds increased، respectively، from 8. 5 and 5. 6 percent to 9. 7 and 7. 2% in the filter-cake and manure sample. Vermicomposts had higher content of aromatic groups compared to composts (In manure samples 18. 7 instead of 17. 1 percent). After 16 weeks of incubation the aromatic and carboxylic compounds slightly decreased in the vermicomposting process. Analysis of composts and vermicomposts with FTIR and 13C NMR resulted in similar signals with the different frequency intensities. There was a suitable correlation (r=0. 897**) among the spectroscopic methods in characterization of composts and vermicomposts

Mycorrhizal fungus colonization of roots may modify plant metal acquisition. In order to study the role of external hyphae of mycorrhizal fungi in metals transferring، the root and hyphal growth zone were separated by 30 µm nylon meshes. Plants were inoculated with G. mosseae and G. intraradices and grown in the root compartment. Six combinations of metals (400 mg of Zn، 25 mg of Cd، 400 mg of Zn + 25 mg of Cd، 50 mg P، 50 mg of P+ 400 mg of Zn + 25 mg of Cd، and no metal kg-1 soil sample) were added to the hyphal compartments. This experiment was carried out as a completely randomized design (CRD) with factorial arrangement in three replications. The results showed that dry shoot weight and phosphorus concentration in mycorrhizal treatments increased significantly compared with non mycorrhizal treatments. of the two fungal species، G. mosseae had more effect on phosphorus concentration in white clover plant. AM fungi increased the Zn concentration in shoot and root of white clover. AM fungi also significantly increased cadmium concentration in root of mycorrhizal treatments compared to non mycorrhizal plants. of the two fungal species، G. intraradices accumulated more cadmium in clover roots. ALL in all the results demonstrated that AM fungi increased phosphorus and Zn transferring to the shoots while cadmium transferring was decreased by stabilizing in the roots.

Soil characteristics are the most powerful factors in desertification phenomenon. The purpose of this study was investigating soil characteristics as indices for evaluating desertification intensity. The most important indicators of the soil that affect desertification were selected in the present study. Soil samples were taken from Segzi desert vicinity located in the east of Isfahan city with surface area of 112،167 ha. Soil indices such as Soil texture، soil gypsum percentage، the content of HCO3-1، electrical conductivity (EC)، pH، the percentage of the organic matter، the content of the soil sodium، chloral and sodium absorption ratio (SAR) were selected. All of these indices were calculated on the thirty four soil samples. After ensuring of the normality of the samples by Klomogrov-Smirnov test، the mentioned indices were imported into GIS for delineating soil characteristics maps. To delineate distribution maps of each soil indice، inverse distance weighting and ordinary and discrete Kriging methods were applied، and appropriate method was selected. Each layer was scored based on MEDALUS model، and the final characteristic maps were then generated using soil geometric mean indices. Results showed that the affected areas of the average، severe and very severe classes of desertification were calculated about 66000، 45650 and 517 ha، respectively. The results also revealed that the indices of the organic matter، soil gypsum percentage، electrical conductivity and SAR were the most influential indicators، which affected desertification in the study area.

Stage – discharge relationship is mainly developed from measured data in any hydrometry station. Measured data usually obtain in low to medium flow discharge، because in most cases it is very difficult to measure the flow discharge during flood. Therefore، the stage–discharge is extrapolated beyond the measured data to compute the flood which may estimate low or higher value. This is because during the high flow، the bed form is developed which causes the flow resistance to change. In order to establish a better stage – discharge relation، it is important to apply methods which consider the bed form resistance. In this study an attempt has been made to determine the best method for developing such relationship. To reach the goal، the required data such as river cross section، discharge and related stage and bed material gradation from Ghorbaghestan hydrometry station were measured for two years. Then a computer program was developed. Using this program and applying the measured data، the stage – discharge relationships were computed by five different methods. From the statistical comparison of the results of these methods with measured data، it was found that Shen، Brownlie، Engelund and White’s method overestimate the flow discharge. The best method was found to be the Einstein – Barbarossa’s method that provided the minimum absolute mean errors 0. 31 and 1. 468 m3/s and minimum root mean square error 0. 112 and 0. 466 m3/s for the two study years، respectively

Nitrate leaching from agricultural lands can pollute groundwater، and the degree of pollution caused significantly depends on agricultural practices implemented on farms. Field studies required to evaluate the effects of various agricultural management strategies on nitrate leaching are expensive and time consuming. As a result، it is suggested to use crop models to simulate the effects of management practices on nitrate leaching. Plant growth models such as DSSAT software package can simulate daily plant growth and development، and also are capable of simulating daily nitrate leaching and nitrogen uptake by plants. However، it is required to evaluate the performance of any model before using it for any specific region. In this study، the performance of nitrogen balance model of DSSAT software package was evaluated to simulate nitrate leaching from the root zone of silage maize at different levels of applied water and nitrogen fertilizer. The experiment consisted of three levels of nitrogen fertilizers، including zero، 150 and 200 kg N ha-1 and four levels of applied water 0. 7SMD (soil moisture depletion)، 0. 85SMD، 1. 0SMD and 1. 13SMD. Nitrate-nitrogen leaching from 36 plots at the 60 cm depth during the growing period was measured by soil moisture suction equipment (ceramic suction cups، CSC). After calibrating the model by using field data، its performance was evaluated to simulate nitrate leaching. Maximum amount of N leaching 8. 4 kg N ha-1 was obtained from over irrigation treatment with the application of 150 kg nitrogen per hectare. The model simulated nitrate leaching for this treatment as 7. 8 kg N ha-1. The model consistently underestimated the nitrate leaching; however، it followed the behavior of nitrate leaching during the growing season. In deficit irrigation treatments، the nitrate leaching was very low and close to zero and the model simulated the same result accordingly. The results showed that the model، in addition to phenological stages and performance indicators، can simulate nitrate leaching from the root zone and could be used to evaluate the effects of various irrigation and fertilizer management strategies on nitrate leaching.

This research was carried out to determine spatial distribution of heavy metals concentration in soil particle size classes using Landsat ETM+ reflectance in Southern Isfahan city in the vicinity of Bama mine. To fulfill this goal، 100 compound soil surface samples were collected randomly from the area. The samples were air dried and soil particle size classes 250-500، 125-250، 75-125، 50-75 and <50 μm were determined using appropriate sieves after dispersion of the bulk samples of soil using ultrasonic apparatus. Total Zn، Pb and Cd concentrations were measured using Atomic Absorption Spectrophotometer after wet digestion of samples in acid nitric. The results indicated significant negative correlation coefficients between heavy metals concentrations of soil particle size classes and soil spectral reflectance in the visible، near infrared and panchromatic bands of Landsat ETM+ satellite. Stepwise multiple regression models were used for estimating heavy metals concentration in soil particle classes through satellite data. Furthermore، spatial distributions of heavy metals were mapped using stepwise multiple regression equations. Results also showed heavy metals concentrations in all soil particle size classes were maximum close to the mines and decreased by increasing the distance from these sources.

Riparian vegetation is a component of river system that performs certain basic functions including primary vegetative production، protecting stream banks from erosion، trapping sediments، promoting water quality، wildlife habitat and fisheris، forage for livestock، etc. In this research، spatio-temporal change of vegetation riparian area of Aghbolagh-river as an upstream of Karoon-river for 65-km was investigated using 1956، 1969، 1998 aerial photos and 2006 satellite images. Results showed a significant change in riparian area between different periods (kappa=26. 55%). This change is the result of construction of dam in the upstream in 1993، alteration of riparian area to arabal land، exploitation of groundwater for agricultural usage، etc

The real estimation of the volume of sediments carried by rivers in water projects is very important. In fact، achieving the most important ways to calculate sediment discharge has been considered as the objective of the most research projects. Among these methods، the machine learning methods such as decision trees model (that are based on the principles of learning) can be presented. Decision tree method is a hierarchical multi step method which is a recursive data collection technique to binary and smaller sub-divisions until the final analysis cannot be divided. Decision trees consider a priori known set of data and derive a decision tree from it. Then، tree can be used as the set of laws to predict unknown features. In this research، the efficiency of this technique for predicting the suspended sediments in Ilam dam basin has been investigated. To evaluate the accuracy of the methods (written by MATLAB software)، statistical criteria such as R، BIAS، RMSE، r2 and MAE were computed. The results showed that based on all the statistical criteria، decision tree in comparison with the sediment rating curve had most consistency with the observed data. Meanwhile، the most important factors for creating tree in the model (that had high correlation with sediment data) are the corresponding discharge and daily rainfall.

In order to evaluate the effect of arbuscular mycorrhizal (AM) fungi and Pseudomonas fluorescens bacteria on phosphorus fertilizer use efficiency، mycorrhizal dependence and grain yield and dry matter yield of maize under water deficit conditions، a field experiment was conducted as split-split plot arrangement based on randomized complete block design with three replications. The treatments in this experiment were included as follows: irrigation (normal irrigation and water deficit stress based on evaporation from class A pan evaporation); combined different seed inoculations with AM and Pseudomonas fluorescens and treatment of chemical phosphate fertilizer (non- consumption of phosphate fertilizer، consumption of 50 percent of triple superphosphate fertilizer needed، and consumption of rock phosphate، based on the quantity of consumed phosphorus of triple superphosphate source). The results showed that effects of irrigation، seed inoculation with AM and Pseudomonas fluorescens biological phosphate fertilizer and chemical phosphate fertilizer were significant on yield and yield components، dry matter yield، relative agronomic efficiency and root colonization. Mild stress significantly reduced grain yield، relative agronomic efficiency and fertilizer agronomic efficiency compared to optimum irrigation. Results showed that grain and dry matter yield are highly correlated with root colonization under mild stress condition. Maximum mycorrhizal dependence was obtained in mild stress condition. Maximum relative agronomic efficiency، fertilizer agronomic efficiency، yield and yield components was related to seed inoculation with AM and Pseudomonas fluorescens. The use of triple superphosphate fertilizer were increased grain yield in comparison with rock phosphate along with inoculation of phosphate solubilizing microorganisms. However، maximum root colonization and mycorrhizal dependence was achieved in non- consumption treatment of phosphate fertilizer.

Organic carbon is the most important component of terrestrial ecosystems and any change in its abundance can have a major impact on the processes that take place in ecosystem. The aim of this study was to estimate carbon sequestration in three different elevations (200 to 1200 m from sea level) and according to vegetation type in the Khairoodkenar forest. The highest carbon sequestration was observed in the surface layer of a soil with Fig-Carpinus betulus vegetative cover and it was estimated to be 167. 4 ton/ha. But when carbon sequestration was measured in soil solum، it was found that soils with Fagus orientalis-Carpinus betulus vegetation cover had the highest amount of organic carbon (514. 4 ton/ ha). The results showed that clay fraction had the highest carbon content but the highest enrichment factor (1. 59) was measured for sand fraction in soils with Fagus orientalis- Carpinus betulus vegetative cover. The highest organic carbon content (7. 89%) and aggregate stability (MWD= 7. 79mm) and lowest bulk density (1. 21 g/cm3) were measured in soils with Figs- Carpinus betulus vegetative cover.

Rubber dam body is a lying cylinder that lies in the width of channels، rivers and weir crests and is filled with water or air or a combination of both. Shape of this structure is one of the obvious features that does not change in the path of rivers or dam spillways. Rubber dams may be with or without deflectors. Deflector is a triangular or rectangular fin that is installed down the stream of the dam. The purpose of installing a deflector is separating the water from the rubber dam body and avoiding the reattachment between the water and dam body. In this study، four Physical models of rubber dams and deflectors were made at height and ratio of h/p=0. 05 in 2 triangular and rectangular shapes and 25 cm length. Experiments were carried out in three different angles (30-45-60). After all the analyses and experiments were done according to the water napes profile and their lengths، it was observed that the 45 degree is more suitable than 30 and 60 degrees. In addition، experimental data and presented equation in this study were compared with the past equations، the results of which were close، showing the validity of the experiments and equations

Free and uncontrolled pasture grazing by animals may decrease soil aggregate stability through reductions in plant cover and subsequent soil organic C، and trampling. This could expose the soil surface layer to degradation and erosion. The objective of this study was to determine the influence of pasture management (free grazing، controlled grazing and long-term non-grazing regimes) on aggregate-size distribution and aggregation parameters by wet and dry sieving methods in two native pastures، protected areas in Chaharmahal va Bakhtiari province. The studied pastures were 1) SabzKouh pastures protected from grazing for 20 years، and 2) Boroujen pastures protected from grazing for 25 years. Soil samples were collected from 0-15 cm depth during the grazing season in summer 2008. Samples (finer than 2 mm) were analyzed for aggregate-size distribution and aggregation parameters by wet and dry sieving methods. Results showed that pasture management had a significant influence on aggregate-size distribution and aggregation parameters in the two areas. The two methods indicated that macro-aggregates in non-grazing and controlled grazing regimes were higher than those in free grazing regime، whereas in free grazing management micro-aggregates showed an opposite trend، and were greater compared with the other grazing regimes. Similarly، soil aggregate stability indices (i. e. mean weight diameter، aggregate geometric and ratio mean diameter) were all improved by non-grazing regimes، suggesting that animal grazing and trampling break down large soil aggregates due largely to compaction and reduced plant coverage. However، the extent to which grazing affects soil aggregation depends in large part on grazing intensity and duration، and the area involved.

Hydraulic conductivity is an important parameter in the design of geotechnical structures such as earth dam، floor construction، retaining walls and environmental structures. In unsaturated soils، hydraulic conductivity is a function of moisture content and soil water suction i. e. soil moisture characteristic curve. In this study، the values of unsaturated hydraulic conductivity in two soil types (Ramjerdi and Molasadra core dam series) at 5 different compactions using Gardner method were measured. Then، the unsaturated hydraulic conductivity was estimated by different models using the soil moisture characteristic curve and was compared with measured values. The results showed that Fredlund and Xing models predict the soil moisture characteristic curves more accurately compared with van Genuchten model. For Ramjerdi soil series and up to nearly 0. 25 volumetric water content، (VGM) and (FM) models indicated a good estimation for unsaturated soil conductivity. Also، for Molasadra core dam none of the models resulted in acceptable estimations for unsaturated hydraulic conductivity.

Nitrogen (N) loss from irrigated cropland، particularly sandy soils، significantly contributes to nitrate contamination in surface and groundwater and increases N applications to crops. This is because negatively charged nitrate normally does not have much affinity to soil particles. To retard the movement of nitrate، materials should have high affinity for anions، which most naturally occurring minerals do not have. The cation-exchange properties of natural zeolites can be exploited to modify their surface chemistries so that other classes of compounds، particularly anions and non-polar organics are retained. In this study، the ability to remove nitrate from aqueous solutions with different Cl- concentrations using Iranian zeolite (Semnan) modified by hexadecyltrimethylammonium bromide in millimeter and nanometer particle sizes was determined and the equilibrium isotherms were characterized. The nitrate release as affected by time and ionic strength was also evaluated. It was demonstrated that SMZ is capable of adsorbing more than 60 mmol kg-1 and 80 mmol kg-1 nitrate in millimeter and nanometer sizes، respectively، and adsorbed nitrate can be easily released under different ionic strengths. The millimeter and nanometer-sized SMZ showed 26. 7% to 82. 3% and 37. 8% to 85. 5% nitrate removal efficiency، respectively. The average of nitrate released by millimeter-sized SMZ was 6. 92 mmol kg-1 in deionized water while it was 14. 68، 22. 71، and 34. 91 mmol kg-1 in releasing solutions with ionic strengths of 0. 03، 0. 1، and 0. 3 M، respectively

Quantity-Intensity (Q/I) curves and their derived parameters provide general information about soil Potassium (K) availability. This investigation was conducted to obtain K different varieties and their correlations with K، Q/I parameters in 13 soils sample from Bahar area as the major potato producing area in Iran. Soil Samples were equilibrated with solution containing different potassium activity ratios (ARK)، and changes in potassium concentrations in the equilibrium solution (ΔK) were ploted against activity ratio of K، and Q/I parameters were determined. The results showed that، potassium activity ratio at equilibrium (AR0) ranged from 0. 007 to 0. 995 with an average of 0. 16 (mmol L-1) 0. 5، The readily exchangeable potassium (ΔK0) ranged from 0. 04 to 2. 199 with an average of 0. 49 cmol kg-1، The potassium potential buffering capacity (PBCK) ranged from 13. 21 to 75. 37 with an average of 42. 02 (mmol kg-1) / (mmol L-1) 0. 5. Highly significant linear correlations were found between PBCK and CEC (r = 0. 6*)، AR0 and KSO (r = 0. 99**)، AR0 and Kex (r = 0. 85**). Among the studied soils، one soil (Chopolgh Lo soil) absorbed potassim on edge position of clay minerals and the others absorbed potassium on planar surface.

Physicochemical characteristics of soil، land cover/use and human activities have effects on heavy metals distribution. In this study، we applied Classification and Regression Tree model (CART) to predict the spatial distribution of zinc in surface soil of Hamadan province under Geographic Information System environment. Two approaches were used to build the model. In the first approach، 10% of total data were randomly selected as test data and residual data were used for building model. In the second approach، all data were used to build and evaluate the CART model. Determination coefficient (R2) and Mean Square Error (MSE) were applied to estimate the accuracy of model. Final model included 51 nodes and 26 terminal nodes (leaf). Calcium carbonate، slope، sand، silt and land use/cover were determined by the CART model to predict spatial distribution of Zn as the most important independent variables. The regions of western Hamadan province had the highest concentration of Zn whereas the lowest concentration of Zn occurred in the regions of northern Hamadan province. The results indicate good accuracy of CART model using R2 and MSE indices.