h. zare abyaneh

A cultivation pattern in accordance with environmental conditions that reduces pollution of water and soil resources is one of the most important management strategies. This study aimed to simultaneously combine information related to soil, climate, crops and determine the potential of vulnerability and contamination of the aquifer, based on which susceptible cultivated areas (main cultivation -wheat and alfalfa) were evaluated. ArcGIS 10.3 software was used to investigate the effect of aquifer quality on cropping patterns. Climatic factors, soil parameters, and topographic characteristics were selected as effective parameters in selecting suitable cultivation sites. Nitrate content was collected in 46 wells in Shahrekord plain and averaged by kriging method, and a nitrate concentration map was obtained and combined with vulnerability map and aquifer quality area was investigated. Analytical Hierarchy Process was used to weight and finally, the layers were combined using the weighted linear combinationmethod. The results showed that areas without risk of contamination and with very low potential for contamination were 11 and 51%. Areas with low and medium to high risk of ontamination were 3 and 4%, respectively. About 25% of the aquifer area is in the high nitrate contamination range and its maximum nitrate concentration is 55 mg/l. Very high pollution (more than 75 mg/l) has not been estimated in Shahrekord plain aquifer. According to the results of this study, in terms of aquifer quality, the main part of the aquifer, about 41%, is in the safe range. 33% were classified in the low-risk group and 25% in the dangerous range. In Shahrekord plain, currently 4989 hectares are the area under irrigated wheat cultivation, which according to the results, can be increased to about 22,600 hectares. The current area under alfalfa is 3806 hectares, which according to the results, has the potential to increase the area under 28198 hectares.

In order to evaluate the effect of switching the furrow to drip irrigation methods on stem length, water used efficiency (WUE) and depth of root zone of Sultana grapevines, an experiment was conducted based on a randomized complete block design with four replicates in 2015-2016 growing season in Malayer, Iran. Treatments were: furrow irrigation (I1), combination of drip and furrow irrigation system (drip-furrow) (I2), bubbler irrigation (I3), drip 1: three dripper/plant (I4), surface-subsurface drip irrigation (I5), drip 2: five dripper/plant (I6) and drip 3: -eight dripper/plant (I7). The results showed that the drip irrigation caused significant decrease in the shoot length, leaf area and water consumption compared to the furrow irrigation. In the same order, the average of the mentioned parameters for furrow irrigation were 133 cm, 11.1 m2/vine and 5337m3/ha respectively, and for the drip irrigation, 121 cm, 6.5 m2/vine and 3625 m3/ha. These results indicated that there was positive correlations (R2) between the mentioned parameters. The treatments I6 and I7 had a yield of 31 and 29 ton/ha respectively, exceeding the furrow irrigation with yield 24 ton/ha. However, the other drip irrigation treatments showed less yield than furrow irrigation. The maximum WUE was evidenced by I6 treatment (10.3 kg/m3) and the minimum by furrow irrigation (4.9 kg/m3). The results showed that I6 with five dripper/plant, was the most efficient treatment, so it was considered an appropriate irrigation method to change from furrow to drip irrigation. At the end of the experiment, samples were taken from the vine roots revealing that the drip irrigation systems caused shallow roots.

Consuming energy and its costs in the irrigation network of Moghan plain analysis in WaterGems Softwar was estimated for three different methods using the grouping intakes method of lands and assumed that no changing of irrigation systems and compared with the existing strategy. The height range of 210-220 meter from sea as optimize height recommended wich 77 % of area was less than that. The result showed that the application of PS2 station could be provided pressure required for irrigation form 506 ha of lands. The annually energy costs were this existing strategy with 90 Rials rate 0.87, with 1000 Rials rate 9.65 million Rials per hectare. Althogh total costs irrigation work was 350.93 and 1261.12 billion Rials. While the annually energy costs in the grouping intakes method with 90 Rials rate 0.55 and with 1000 Rials rate was equal 6.14 million Rials per hectare and its total costs were 324.21 and 895.7 billion rials. Provide PS2 station was casued to decrease at consuming energy and number of pressur relif valves respectively about 37.2% and 44% compared to the existing strategy. Applying the grouping intakes method in the design of irrigation under pressure systems will reduce the costs of energy and irrigation supplies and become more economical of agricultural products.

The main objective of this study was to investigate the vulnerability of pressurized irrigation systems performed in the Sonqor region in terms of climate change during the period 2011-2030 based on different scenarios (A1B, A2 and B1) compared to the base period using the LARS-WG sub-scale model. In this study, the reference evapotranspiration and irrigation requirement under climate change scenarios for the present cropping pattern were calculated and then the performance of irrigation systems and defined indices (such as pressure and flow distribution adequacy) were evaluated for further investigation. Based on the results obtained, crop evapotranspiration in all three scenarios A1B, A2 and B1 will increase by 9.53, 9.6 and 9.54%, respectively. The average flow amount of the studied systems will change from 6.8 lit s-1 to 9.74 lit s-1 in the future period. Average values of water velocity, are considered to increase 19.6, 20.6 and 19.6 percent in three scenarios A1B, A2 and B1, respectively. In the studied systems, the average values of pressure drop per 100 meters were 1, 19.1, 21.1, and 19.1 meters in the base period and three scenarios (A1B, A2 and B2), respectively, so there is no need to change the sprinkler or pressure adjustment at the beginning of the line. The results of irrigation area stability index, pressure and flow adequacy index showed that the values of this index would be less than 100% in the future in all fields studied.

Data on soil hydraulic properties are required to model water movement in soils. Their direct measurements are difficult، time consuming، and expensive، because of high variability and complexity of soil systems. Pedotransfer functions are developed to estimate soil water retention curve (SWRC) using different techniques. In this study، pedotransfer functions were developed to estimate SWRC using the model of Groenevelt and Grant. Sixty nine soil samples were collected from Guilan Province. Soil particles and micro aggregate size distributions، SWRC، and basic soil properties were measured in the laboratory. Fractal and non-fractal models were fitted to the particles and micro aggregate size distributions and their parameters were calculated. Linear regression technique was used to predict the parameters of Groenevelt and Grant’s model. In order to estimate every parameter of the model of Groenevelt and Grant، four pedotransfer functions were developed using each technique and fractal parameters of particles and micro aggregates were used as predictors. Then، estimated parameters were used to simulate SWRC and were compared with the measured SWRC. Fractal parameters of the particle size distribution rendered better predictions of SWRC compared with the other predictors. In spite of the large number of the parameters، using Fredlund’s model did not result in more accurate predictions for SWRC in comparison with using fractal parameters. Probably، these results showed the priority of fractal theory in the particle size distribution and SWRC modeling.

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.

Assessing moisture in the soil under cultivation of crops to achieve high performance and reduced water are necessary. Knowledge of the moisture distribution in the root zone, time consuming and costly field tests that simulation models, a suitable alternative in answer to issues of movement and are water distribution. In this study assessment of soil moisture, to aid SWAP simulation model was and above model Empowerment compared with field results was assessed. SWAP model based on the information in a field irrigated onion, equipped with drip irrigation systems and soil hydraulic parameters obtained from model RETC, were performed. Moisture Information with harvest soil from emitter place and 10 cm of the layers 15-0, 30-15, 45-30 and 60-45 were obtained. Comparison of simulated moisture with observations moisture to a depth of 60 cm in the emitter place and 10 cm it, in the form of graphs and calculation criteria of Root Mean Squared Error (RMSE), Root Mean Squared error of normal (NRMSE) and mean absolute error (MAE) was performed. Values of RMS, RRMSE and MAE in the normal place dropper 0.001, 0.03 and 0.07 cm3cm-3 and in 10 cm were 0.08, 0.02 and 0.07 cm3cm-3, respectively. Low errors calculated from the model SWAP, shows good accuracy of the model simulated moisture distribution in the root zone. Operations irrigation through a drip irrigation system, with irrigation 48 hours was equivalent to performance kg/ha 14780 against 14134 kg/ha estimated by the model will follow. In total, the results indicate that the SWAP model is able to respond with a valid enough accuracy and precision in a relatively short time to provide. This model can be as effective and useful tool for evaluating and optimizing the distribution of moisture in the root-crop area, used.Keywords:

In this study، simulations of water table fluctuations and nitrate concentration of groundwater were investigated in paddy rice fields which were equipped with controlled drainage system. This research was done in Haraz Technology and Development center in Mazandaran province north of Iran. For simulating the qualitative and quantitative variations of groundwater surface in the drained area، DRAINMOD-N model was applied using calibrated and measured data. It was necessary to calibrate the mineralization، denitrification and dispersivity constants in acceptable range to achieve the best fitness between the measured and simulated data. Therefore، the above constants were obtained 0. 000035، 0. 4 and 5 respectively. The analysis was done in graphical and statistical modes between the measured and simulated data. The statistical comparison was done by the mean bias error (MBE)، model efficiency (EF) and correlation factor (r) indices. indices were achieved 3. 38، 0. 53، and 0. 80 for estimation of the ground water level and 0. 61، 0. 97، and 0. 99 for the estimation of nitrate concentration، respectively. The DRAINMOD-N model maybe used as a powerful model in simulation and management of water pollution in drained area for reducing the environmental risks which may be occurred in paddy rice fields.

Evapotranspiration as one of the important elements in agriculture has a considerable role in water resource management. Therefore, using a more exact estimation method is an essential step of agricultural development, especially in arid semi-arid area. In this research, in order to exact estimate of garlic evapotranspiration using lysimeteric data, an artificial neural network (ANN) model was developed. Maximum and minimum air temperatures, maximum and minimum relative humidity values, wind speed and sunshine hours were used as the input layer data. The crop evapotranspiration was measured using 4 lysimetres of 2×2×2m of the Bu-Ali Sina agriculture collage’s meteorology station during 2006-2008. Statistic indicators RMSE, MAE, STDMAE R2 were used for performance evaluation of the models. The results showed the more exact method concerned to the multilayer perceptron (MLP) model with the back propagation algorithm. The 6-6-1 layout with Levenberg-Marquat rule and sigmoid function had the best topology of the model. The evaluation criteria were 0.088, 0.07 and 0.061 mm/day as well as 0.88, respectively. The results also showed that the average daily garlic evapotranspiration were 8.3 and 6.5 mm based on the lysimeter ANN methods, respectively. Overall, evaluation of ANN results showed that the errors of ANN were negligible. The ANN showed high and low sensitivity to maximum air temperature and minimum relative humidity, respectively.

The estimation of reference evapotranspiration (ETo) is of great importance due to its applications in water resource management as well as irrigation scheduling. Difficulties associated with using lysimeters have encouraged researchers to use various ETo models, while the shortage of actual radiation data seems the main obstacle for users of radiation-based models. In this research the output of four radiation-based evapotranspiration models including: Penman-Montieth-FAO56 (PMF56), Penman-Montieth FAO-Irmak (PMFI), modified Jensen-Haise (JH1), and Jensen-Haise (JH2) are evaluated for a cold semi-arid climate. The daily ETo values were generated for 16 different scenarios and the results were compared against a two-year lysimeter data during the growing season (May to November). Deviations of model results were investigated using mean of R2, RMSE, MBE and t-test criteria. The results indicated that the JH2 model which uses radiation model of Daneshyar, can generate the most accurate ETo values (R2>0.85, P<O.05) in cold semi-arid climates. Although, the Angstrom radiation models are widely being used to generate radiation data in recent years, this research showed that other radiation models can provide more accurate radiation data for radiationbased ETo models. In places with lack or shortage of meteorological data, using an accurate radiation model might significantly reduce the errors generated by certain ETo models. The mentioned radiation models and ETo models should be examined for other climates.