مجله پژوهش آب ایران
پیاپی 12 (بهار و تابستان 1392)

To study the crop coefficients of summer maize a lysimeter experiment was conducted under conditions that shallow and saline groundwater contributes to supply required water. Twenty-four lysimeters each with 1.2 m depth and 0.8 m diameter were installed. Thereafter, maize was planted in each lysimeter. The depth of groundwater table in the lysimeters was set to 0.6 m by using Marriotte Bottles. In this experiment, Three groundwater salinity levels (2.5, 5 and 7.5 dS/m) with two irrigation levels (at 70% and 100% rates of evaporation from pan class A before irrigation period) were used. Soil water was replenished on a weekly basis. Factorial experiment was established in a randomized complete block design with three replications. In an individual treatment, maize was planted with full irrigation on one hand and no ground water (NGW) considered as the control treatment on the other hand and they both were replicated three times. In this study, the equation of actual crop coefficient Kca, and its components including Kci (the coefficient related to irrigation) and Kcg (the coefficient related to groundwater), was obtained based on the water balance equation. Then regression analyses were used to develop the Kci, Kcg and Kca crop coefficient curves for each salinity and irrigation treatments.

This research was carried out through laboratory tests by two physical models of permeameter. Considering the necessity of entranced water quality assessment in our laboratory tests, besides utilizing a sample of normal water by EC=0.78 dS/m and SAR=1.23 (mEq/lit)0.5, two samples of saline drainage water from Khorram-shahr area with EC=124, 22.2 dS/m and SAR=79.28, 26.27 (mEq/lit)0.5 and a sample of saline-sodic soil (EC= 169.3 dS/m and SAR=45.18 (mEq/lit)0.5) were also applied in permeability tests. A PP450 synthetic envelope which was suitable for the selected soil was applied. Permeability tests were implemented in 1, 2.5, 5, 7.5 and 10 hydraulic gradients in three replications and indicators as hydraulic conductivity and gradient ratio (GR) were measured and statistically investigated as factorial experiments in a form of randomized complete design. The results showed that gradient ratio was less than 1.0 in all tests; however, applying the highest water salinity resulted in its critical amount (1.0). Hence, the results demonstrate that the more salinity of water the lower the hydraulic conductivity. The average hydraulic conductivity was calculated 3.55 by applying normal waterand1.25 times of average hydraulic conductivity was measured via applying saline water with EC= 124 dS/m and EC= 22.2 dS/m. In sum, remarkable reduction of hydraulic conductivity of soil-envelope system and considerable increase of gradient ratio were obtained with applying higher saline water.

Soil salinity is one of the important issues in agriculture that hampers soil fertility and crop production in arid and semi arid regions. Hence, the study of soil salinity is of great importance and using appropriate methods for predicting and modeling soil salinity is essential in order to control and prevent its development. In this study, temporal and spatial changes of soil salinity modeling were carried out using combined Geostatistics and SaltMod computer model. To predict the soil salinity in five and ten year's period of time, SaltMod was applied and Salinity values were determined at 98 points in downstream lands of Hajilarchay dam located at northwest Iran. Simulation results showed that in the root zone within a period of five and ten years the salinity values with amount of less than 6/3 ds/m increase and with higher values decrease. Since the SaltMod model does not have the capability of spatial analysis and mapping, therefore, the GS+ software, which includes different geostatistics methods was used to evaluate and study spatial variations of soil salinity in desired times.,. Salinity values in non-sampling sites were estimated and relevant maps were drawn. The geo- statistical methods used in this research included Kriging, Cokriging and Inverse Weighted Distance.

Shahrekord aquifer is the primary resource of water for various uses across Shahrekord plain. The main objectives of this study were to investigate the fluctuations in spatial variability and zonal mapping of conductance (EC), total dissolved solids (TDS), total suspended solids (TSS) and turbidity of Shahrekord groundwater during a year. Ninety-seven wells were sampled during four occasions (June, July, September, and November) in 2010. The mean of EC (both approximately 530 µS/cm) in June and July reduced to 370 µS/cm (P<0.05). The mean of TDS in June (400 mg/L) was higher (P<0.05) than the means in other samplings (300 mg/l). TSS decreased along with approaching the fall (P<0.05). A Gaussian variogram model described the spatial variations of EC and TDS in all sampling times while for TSS a spherical and sometimes an exponential model suited the best. According to the maps, TDS and TSS are highest in the southern half of the aquifer in all sampling occasions. On average, TDS is always suitable for drip irrigation while TSS indicates a moderate dripper clogging in most cases.

In Iran, many waste disposal sites are the source of environmental pollution problem. This problem has occurred due to increasing amount of solid waste, especially in major cities.The technology of using plants (phytoremediation), is a new green technology that can be used very easily with low cost to prevent, uptake and refine water and soil contamination. Vetiver has been successfully used for erosion and sediment control as well as soil and water conser-vation due to its unique morphological, physiological and ecological characteristics. In this research the potential of using vetiver to refine landfill soil of Shiraz city was studied. Results indicated that vetiver can growth in landfill leachate up to 20% concentration without any problem, while the growth decreases at 50% concentration till the plants die and was mini-mum at 80% concentration. Absorption of heavy metals such as Ni, Zn, and Mn was lower than the toxic level for Vetiver. The uptake of Cu in 80% leachate concentration was 14.25 mg which was in the threshold toxic level for vetiver. Result indicated that the Vetiver grass can be used to prevent, uptake and refine water and soil contamination in a young landfill where the leachate strength is high at the site.

Finding a procedure for removing pollutants from wastewater agriculture can play an important role in the reuse of wastewater in agricultural operations and also cost reduction. Therefore, in this study, low cost sorbents with high performance such as lemon activated carbon with Nano pores (0.1-2 nm) and natural clinoptiolite zeolite were used to remove cadmium and nitrate, respectively. The results showed that increasing the sorbent mass will increase the removal up to 97.7 for activated carbon and 76.5 for zeolite. In the other hand by increasing the sorbent dose, at first the amount of adsorbed pollutant is increased and then decreased and this maximum point is named maximum potential. This point is depending on sorbent and sorbets. Furthermore the results indicated that by increasing the concentrations of dissolved pollutant the removal percent decreases to 24.2 and 11 for cadmium and nitrate respectively. Since different parameters of isotherms are functions of initial pollutant concentrations and sorbent dose, so some new relations are developed that are independent to these factors. Furthermore for simple design of treatment systems, new relations were developed for estimation of removal percent as a function of initial pollutant concentration to sorbent dose ratio.

Due to high cost of energy, desalination of saline waters by low-cost methods is important. Therefore, widespread investigations have taken place to achieve appropriate and low-cost solution. The objective of this work was to determine the rate of sorption of Ca2+, Mg2+, Cl- and HCO3- by bentonite (as inorganic sorbent) and almond shell (as organic sorbent) in raw, acid washed and base washed conditions. The results showed, maximum sorption of Ca2+ (7.8%), Cl- (9.8%) and HCO3- (66.9%) occurred by basic, raw and acidic almond shell respectively. Raw bentonite removed maximum content of Mg2+ (29%). Likewise, combination of acidic almond shell and basic bentonite as compared with single sorbent, increased the percent of sorption of Ca2+ and Mg2+. However, the increase in combination of cationic resin and mentioned modified sorbents was far more.

The important species of eucalyptus are Eucalyptus microtheca and Eucalyptus sargentii. The species use for forestry and plantation for create green space with a relatively long history. The aim of this experiment determining water requirements, Kc and water use efficiency of this species whit drainage and weighting lysimeters and three old trees in Yazd Shahid Sadughi Desert Research Station. The experiment carried out whit three treatments, 100% (control), 70% (moderate stress) and 40% (severe stress) field capacity in a completely randomized design with three replications. The results showed that E.microtheca and E.sargentii have evapotranspiration annual less than potential evapotranspiration and the species called of drought resistance. The Kc of E.microtheca under field capacity, 0/45 with the annual water requirement of 833.4 mm and E.sargentii, 0.67 with an annual water requirement of 1227.9 mm. Water use efficiency, was also influenced by the amount of water available, so that they have access to water at moderate stress reduction, increased water use efficiency. Although E.microtheca of resistance to drought and has low water requirements, nevertheless, both species could be drought resistant species and are suitable for forestation, creation of green areas and fixation of sand dunes in arid and semi arid zones.

An optimization technique is used to determine pumping rates to prevent and management of seawater intrusion into coastal aquifers in this study. The concept of optimization of the pumping rates is programming for groundwater extraction such that freshwater pumped from the wells be maximized, without undesirable increase in salt concentration of the pumped water and drawdown in the wells not occurred from allowable limit. To this aim, simulation model and genetic algorithm tool were integrated in an optimization model. The simulation model is based on the solution of the governing differential equations of the density-dependent flow and solute transport. The optimization model was verified based on various combinations of salinity and drawdown constraints applied in a coastal aquifer including four pumping wells. The results show drawdown as a constraint exerts a more effectively limitation rather than salinity. These solutions establish the feasibility of simulating various management scenarios under complex processes in coastal aquifers for the optimal and sustainable use of groundwater.

In order to cope with water scarcity and reduction of water quality in arid and semi-arid environment; using saline water, deficient irrigation method and halophytes cultivation in marginal area and increasing water productivity are the most important management practice. To determine the crop coefficient, yield response factor and water productivity of Kochia on marginal land which are irrigated with saline water, plants was grown with six levels (1.5, 7, 14, 21, 28, and 35 dS/m) of saline water and four levels of applied water (50, 75, 100, and 125 percent of water requirement) at north of Golestan province in 2009. Results showed that salinity decreased water productivity and crop coefficient. Up to 21 dS/m salinity there was not significant effect on yield response factor, but it increased at 28 and 35 dS/m under deficit irrigation. Therefore, deficit irrigation can be used successfully up to 21 dS/m salinity. In addition to that, crop coefficient reduction should be considered for irrigation management. Kochia is drought tolerant plant and deficit irrigation and saline water can be used for producing kochia.

To study the effect of salinity stress on seed yield, uptake and transmission of elements in three local populations of castor (Ricinus communis L.), a factorial experiment was performed with three replications in a completely randomized design including five levels of salinity (1.2, 2, 2.6, 3.8 and 4.8 dS/m in soil saturation paste) as the first factor and castor populations (Shiraz, Kerman and Urumieh) as the second factor. The results showed a significant effect of salinity stress on seed weight and concentration of K, Ca and Mg in the shoots and the roots of castor. The results also showed that different populations have a significant difference considering all their studied factors except Na in roots. Salinity reduced the concentrations of potassium, calcium and magnesium in shoots and roots while the concentration of Na increased. The highest and the lowest of seed yield were observed for Shiraz and Urumieh populations, respectively. The results suggest that Shiraz population is suitable for saline condition.

In this paper the amount of yield was simulated under applying the drain water of irrigation and drainage networks of Operation Company of Karkheh and Shavoor as irrigation water by using SALTMED model. Before using SALTMED model were performed sensitivity analysis and calibration. Among climatology parameters, maximum temperature was the most sensitive with sensitive coefficient equal to 1.18 and wind speed was the less sensitive parameter with sensitive coefficient equal to 0.33. Also, two factors as plant parameters in sensitive analysis stage were evaluated. The results showed that the depth of root and the height of plant had sensitive coefficient equal to 1.11 and 0.33 respectively. Generally, the amount of irrigation water was the most sensitive parameter among all parameters. After sensitive analysis of model calibration of model was performed. In this stage was selected single and dual crop coefficients and the result of this stage were used in simulation stage. According to the measurement data during one year, the average of maximum and minimum of electrical conductivity of drain water in eight drainages were 22.97 and 6.10 (dS/m). Comparison between these results and crop tolerant indicated that could not be used drain water for irrigation directly. Therefore various scenarios of using a combination of drain water with river water were defined. Eight drains were evaluated and just 5000-hectare drainage Shavoor and Zam -Zam were usable for all crops.

To investigate the effect of sowing date and salinity on spike sterility, yield and yield components of two wheat cultivars, a field experiment was conducted at Sadouq Salinity Research Farm, National Salinity Research Center during 2008-2010. The experiment was arranged as split-split plot based on RCBD with three replications. Sowing dates (planting at 23 Oct., 6 Nov., 21 Nov. and 6 Dec.), salinity treatments (ECiw= 2 & 10 dS/m) and cultivars (Bam & Marvdasht) were main, sub and sub sub plots, respectively. Results showed that Bam cultivar produced more grain yield than Marvdasht in all planting dates. Mean grain yield of Bam and Marvdasht in non-saline condition were 624.57 and 560.89 g.m-2 and in saline condition were 539.35 and 487.34 g.m-2, respectively. Grain yield for Bam and Marvdasht cultivars of planting dates at 23 Oct., 6 Nov., 21 Nov. were significantly more than 6 Dec. Delay in sowing date until 6 Dec. reduced wheat grain yield by 30 percent. Mean wheat grain yield were 562.84, 607.15, 614.78 and 423.49 g.m-2 for sowing date at 23 Oct., 6 Nov., 21 Nov. and 6 Dec., respectively. Water use efficiencies were 0.75, 0.85, 0.90 and 0.62 Kg.m-3 for sowing date at 23 Oct., 6 Nov., 21 Nov. and 6 Dec., respectively. In addition the best planting date for wheat in central region of Yazd province is early November, regardless to soil salinity rate.

To study the effect of salinity on yield and yield compopnents of hulless barley genotypes, a field experiment was conducted in Sadough Salinity Research Center during 2011-2012. Seven hulless barley genotypes and a common barley genotype, (Onfarm no. 4) as the control were planted in saline (ECiw= 10 dS/m) and normal (ECiw= 2 dS/m) conditions arranged as RCBD with three replicates. Results showed that salinity up to 10 dS/m had not any significant effect on seed germination. The highest seed germination were for genotypes number 3 (85.6%), 4 (86.67%) and 5 (86.13%), regardless to salinity. Common barley genotype had the lowest seed germination by 72.27%. Genotypes number 5 and 3 had the highest thousand kernel weight and kerner number per spike by 43.2 g and 40.93 in saline and 44.4 g and 44.56 in non-saline conditions, respectively. Genotypes number 2 and 4 produced the highest grain yield in non-saline conditions by 437.5 and 458.43 g.m2, respectively. The highest grain yield in saline conditions was observed for genotypes number 2 and 7 by 372.17 and 366.50 g.m2, respectively. The lowest SSI in hulless barley genotypes was observed for genotypes number 2 and 7. Genotypes number 2, 3 and 7 had the highest yield stability in order to STI. Based on the experiment, genotypes number 2 and 7 had the best performance in saline and non saline conditions.

Analysis and interpreting spatial variability of soil properties and distribution maps is an effective strategy in order to have a better management of soil and water resources. In this study spatial variability of infiltration rate, saturated hydraulic conductivity (Ks), electrical conductivity (EC), sodium adsorption ratio (SAR) and sodium ion was discussed in the marginal of Qezel Ouzan River in Tarom area,Zanjan Province. The results indicated that all the hydraulic and chemical properties of the soils had medium to low coefficients of variation in study area. The results of the evaluations of the Kriging, Co-Kriging and Inverse Distance Weighting (IDW) methods with root mean square error (RMSE) values, and mean absolute error (MAE) showed that the Kriging had the best performance for estimating hydraulic properties and Co-Kriging for chemical properties of soils.

Irrigation water quality is one of the parameters that affect application efficiency in furrow irrigation. Application efficiency has an important role in management and irrigation scheduling. In this investigation irrigation water qualities were applied at three different levels as control with EC=0.6 dS/m and SAR=0.9, EC=2 dS/m with SAR=10 and EC=6 with SAR=30 throughout the maize growing season. Using volume balance model, Kostiakov-Lewis coefficients were determined. Also temporal infiltration throughout the season determined for maize. These findings were used for calculating application efficiency. Results showed that the basic infiltration rate decreased during the season. At the end of season, the soil basic infiltration rate in control, EC=2 and EC=6 dS/m treatments decreased about 34, 45 and 61 % respectively as compared to beginning. Also application efficiency at the end of the season in the control, EC=2 and EC=6 dS/m decreased about 27, 49 and 62% as compared to the beginning of the season respectively. Thus, it is necessary to have proper irrigation scheduling for increasing application efficiency in furrow irrigation under saline and sodic water application.

To reclamation of salt-affected soils, in addition to using chemical amendments, phytoremediation also can be effective. This experiment was conducted in the columns filled with a saline-sodic soil to evaluate the effectiveness of cultivating Rubia tinctorum to improving soil characteristics. There were 7 treatments with 2 replications including 3 plants (Sesbania acuelata, Rubia tinctorum and Cynodon dactylon), 3 chemical treatments (Gypsum in 2 levels and sulfuric acid) and a control. Chemical treatments 1 month after applying to the soil, plants 5.5 months after cultivation and the control were leached with 41 liters of water. After leaching, some of soil properties including saturated hydraulic conductivity (Ks), mean weight diameter (MWD), electrical conductivity of saturation extract, sodium adsorption ratio (SAR) and the amount of drainage water soluble sodium were measured. The results showed that Rubia tinctorum was most effective plant in improving soil physical properties, so that the highest Ks (20.5×10-5cm s-1) and MWD (0.92) is related to that and lowest values is related to the control (2.4×10-5cm s-1 and 0.2). The most sodium leaching from soil columns was related to Rubia tinctorum (55.37 g) which was 3 times greater than control. All of the treatments also significantly decreased SAR compared to the control.

In addition to surface water resources, groundwater resources supply the urban, industrial and agricultural demands. So its quality should also be considered in addition to its quantity. To assess the quality of groundwater, some parameters should be considered where salinity is the most important. The purpose of this study was to identify and characterize areas in Guilan plain with certain salinity levels of groundwater for agricultural purposes. Thus, the water samples were collected from 130 wells across the Guilan province, in September 2008 and concentrations of Ca2+, Mg2+, HCO3-, SO42-, CO3-, Cl- and electrical conductivity (EC) were measured. Then geostatistical analysis of data with GS+ software was performed. Finally, the critical areas of Guilan plain in terms of groundwater salinity were identified for agricultural purposes, and proper strategies for groundwater were proposed. The electrical conductivity of central and eastern areas is between 1-1.5 dS/m, being critical for rice cultivation. Also in this area, average potential salinity and average effective salinity range from 3 to 15 mmol/lit which is a warning for the future of groundwater resources.

In Iran, vast amounts of saline lands, shortage of fresh water and secondary land salinization are major limiting factors for conventional crop production. Use of salt tolerant crops such as madders (Rubia tinctorum L.) for utilization of saline soil and water resources has been the subject of many studies. In order to study the effect of salt stress on yielding of madder roots, a factorial experiment was conducted in the form of complete randomized block design with three replicates at Sadooq Salinity Research Farm, Yazd, Iran. Treatments were two planting methods (seeding, root-cutting) and different salinity levels of irrigation water (2.5, 7, 14, 17 dS/m). Results showed that at low salinity levels madders gives higher yield when planted by root-cutting method. However, at high salinity levels there is no difference between the two methods. Results of the experiment also showed that salt tolerance threshold value of madders is about 4 dS/m and the slope of yield reduction is 3.2 percent, classifying it as a moderately salt tolerant crop.

One of the important indicators of the quality status of groundwater is electrical conductivity. Increase in electrical conductivity reduces water and soil quality and as a result agriculture product. Vulnerability is arrival inclination or probability of pollutant to a certain place of aquifer after producing in earth surface. Vulnerability assessment as a suitable method is very important in managerial decisions. In this study among the popular models, DRASTIC model was used due to its power in combining effective hydrologic and hydro-geological parameters on transfer or lack of transfer of pollution.. Salinity is assumed as one of the important and effective factors on water quality which is weighted and rated as pollution index. It is also used as one of the required layers for drawing modified drastic index map. Fuzzy logic system as a more realistic ranking comparison of overlap-index methods (Bolin logic) offers a suitable method to solve problems related to the high levels of boundary classified returns. Hence, fuzzy logic was used to refine and modify ranking quantity parameters of DRASTIC model and EC factor. Results of the simulation of DRASTIC model with using artificial neural network showed high correlation of artificial neural network' output and modified DRASTIC model index.

The shortage of irrigation water with suitable quality for use in domestic, irrigation and industrial sectors is one of the most important problems in arid and semi-arid regions that include one-third area of the world. There is a progressive request for low quality water in regions, due to fresh water shortage. Therefore, many efforts have been taken place to decrease water salinity and increase the quality of abnormal waters such as saline and brackish waters. In this research, the impact of wheat straw and sawdust in sand filters on the physical and chemical properties of water was investigated and compared. For this purpose, saline water passed through a column of pure sand, a column of mixed wheat straw and sand and a column of mixed sawdust and sand, all having the same weight. The turbidity, hardness, chloride anions, magnesium and calcium cations concentration were measured with time. The results showed that the highest sorption of chloride anions (30 percent), magnesium (22 percent) and the maximum reduction of turbidity (74 percent) and hardness (19.27 percent) were achieved by passing water through straw wheat, but the sawdust had the most impact on electrical conductivity reduction (6.34 percent) and removal of calcium cations (23.7 percent) from saline water.

Salinity and drought are the major problems in arid and semi arid areas. To evaluate the effect of water table control on the root zone salt balance and plant growth, lysimeter experiments were conducted. The statistical design was a split–plot-plot arrangement of randomized complete block design with three replicates that included 3 levels of ground water salinity (main plot; S1= <4, S2= 8 and S3=12 dS/m), 2 water table depths (sub plot: D1=60 and D2=90 cm) and two levels of soil surface cover (sub plot plot: M1= no mulch and M2= date palm leaves mulch). In these experiments, sufficient leaching was not provided. The results showed that shallow water table increased accumulated ETc 4.43-9.23 % in treatments without mulch and 9.28-12.23 in mulched treatment. Also mulching and water table control helps to increase salt leaching and decrease soil EC. The survival rate of plants was 100% in all the treatments. Also mulch improved the growth of date palm. The ANOVA analyses indicated that mulch had a significant effect on water balance and salt change rate of the root zone, new leaf and leaflet numbers at level of 1%. However, the levels of salinity did not have a significant difference.

Surface water quality is influenced by land use changes over time. Taleghan River is one of the branches of Sefidrood, which its water quality is important due to the use of its water in various urban and agricultural lands. Mutually, mentioned land uses have an important influence in water quality of the river over the time. In present study the land use changes during the period 1970 to 2002 in the Taleghan watershed was investigated. Results showed the reduction of irrigated and non-irrigated agricultural lands, by 60.86% and 73.23%, respectively. Rangelands were increased 20.62% in the studied basin. Then, in the study period the process of changing water quality factors were investigated. The results showed that the overall trend of changes were decreasing in TDS, EC, SAR and also amount of anions and cations within the study period.. Assessment of water discharge of the river during the study period with an annual average rate trend, presented no significant change. This issue indicates that there was no effect of water discharge on improving the quality of water trend.. Therefore it could be said that improving water quality in Taleghan River during the study period is attributed to land use changes in the basin.

In this article, to draw a zoning map of Borujen-Fradonbeh aquifer vulnerability using the DRASTIC method was used which is one of the most applied overlaping methods. Zoning map of aquifer vulnerability integrated into raster maps of seven DRASTIC parameters (ground water depth, recharge, aquifers environment, soil environment, topography, hydraulic conductivity and unsaturated zone environment) In GIS environment showed that DRASTIC indexes range varies between 98 and 172. It also discovers that 53, 15, 7 and 25 percent of the average surface area are substantial, low, medium, high and very high vulnerable respectively. Rating and weight DRASTIC parameters were computed using the relationships between each parameter and the nitrate concentration in the groundwater. The correlation coefficient between measured nitrate concentrations and corresponding vulnerability ratings increased from 0.47 to 0.80 by optimizing the layer weights. The final map showed that about 32, 38, 12 and 18 percent of the average basin surface area has are low, medium, high and very high respectively.

Coagulation, Flocculation and Sedimentation are essential processes in water treatment plants. The purpose of this study was to consider the efficiency of natural polyelectrolyte chitosan as a coagulant in water turbidity removal. Chitosan is a cationic biopolymer with high molecular weight that is produced from the crust of crustaceans like shrimp and crab. This investigationwas performed on water samples containing synthetic water turbidity by applying caoline in high, middle, and low turbidities in the laboratory scale. Optimum dosage of Chitosan in turbidity removal of 1000, 500, 100, 50 and 10 NTU were 10, 6.5, 2, 1.5 and 1 mg/L respectively. Efficiency of turbidity removal were 99.77, 99.25, 94.84, 90.96 and 57.50 and optimum pH values were 8, 8, 7.5, 7.5 and 8 respectively. Chitosan has insignificant effect on water pH and its efficiency in high turbiditie's removal is more than its efficiency in lower turbiditie's levels.

Seasonal maps of groundwater pollution may be deployed in respective aquifer management. The aims of this research were to study the seasonal fluctuations in concentration, spatial variability, and zonal maps of nitrate and phosphate in Shahrekord Aquifer. For this purpose, 100 agricultural wells were sampled in the spring, summer and fall of 2010 and analyzed for nitrate and phosphate. Kriging was used for zonal mapping of both pollutants. Mean concentrations of both pollutants varied over seasons. Suitability of spherical variogram model in the spring and Gaussian variogram model in the summer and fall shows that spatial patterns of nitrate and phosphate change along with season of the year. Highly nitrate-polluted areas maximized in the spring and then decreased towards the fall. In the fall, about two-third of the aquifer, particularly northern zone, contained between 0 to 20 mg/L of nitrate. Phosphate-polluted area of the aquifer was at maximum level in the fall, decreased during the spring and minimized in the summer. Therefore, we conclude that concentration, spatial distribution pattern and zonal maps of both nitrate and phosphate in Shahrekord aquifer changes with season.

One of the potential advantages of drip irrigation is allowing the use of fertilizer and poison with irrigation water. In this study, the effect of fertilizers on clogging dripper and drip irrigation system performance has been investigated. This study in a randomized block design framework was done that its factors were three treatment of fertilizer (ammonium phosphate) includes treatment F0 (control), and two F1 and F2 treatments with concentrations of 5 g/l and 8 g/l, respectively, and three dropper treatment (the in line long path and two outline long path). Dropper with codes A, B and C were named. In order to investigating dropper clogging, reduce discharge rate, efficiency of uniform distribution, Kristiansen uniformity coefficient and coefficient of discharge variation was calculated. After test period the percentage of reduce discharge for droppers was obtained 19.9, 20.78, and 11 percent for treatment F0 (control) respectively, and 26.48, 26.49 and 16.65 percent for treatment F1, and 33.67, 33.06 and 18.59 percent for treatment F2, respectively. The results were shown increasing concentration of irrigation fertilizer caused increasing dropper clogging and have a significant effect on discharge variation.

A pot experiment was carried out as a factorial in completely randomized design with superabsorbent polymer (A200) at 0 (control), 10, 20, 30, 40 and 50 g/kg soil as the first factor and different levels of salinity including 0 (ordinary water), 3, 6, 9, 12 and 15 dS/m as the second factor and a total of 108 pots containing 2 kg soil. The pots contain 2 kg of a farm soil. Analysis of variance showed that the effect of super absorbent, salinity and these interactions on soil moisture and drainage water EC was at P<0.01. According to the results, super absorbent polymers application, when irrigation water is saline, is not recommended and mixture application of this polymer with organic fertilizers is suggested.