morteza khoshsimaie chenar

Using simulation models is a key strategy in agricultural water management and an effective way to predict the impact of irrigation management and water quality on crop yield. This study aimed to evaluate the performance of the SWAP and AquaCrop models in simulating the growth and biomass production of three maize varieties under the conditions of using saline water for irrigation with a drip irrigation system at the research farm of Tehran University of Agriculture and Natural Resources Campus. In order to calibrate and validate the models, field data obtained from a factorial experiment with two factors of maize variety (SC704, 400, and 260) and irrigation water salinity (0.7, 3, and 5 dS/m) were used. In the validation stage of the AquaCrop model, the R2, RMSE, and NRMSE statistics for the canopy cover (CC) showed a high level of agreement between the measured and simulated data, with values of 0.953, 5.69, and 8% respectively. For the SWAP model, the calculated statistics for the leaf area index (LAI) were 0.477, 1.610, and 54.2%, respectively. Despite the poor performance of the SWAP model in estimating LAI, both the SWAP and AquaCrop models effectively simulated the biomass of maize cultivars under different treatments. In the calibration and validation stage, RMSE and NRMSE of both models were less than 0.5 ton/ha, with 3% (calibration) and 1 ton/ha, 7% (validation), respectively. In general, both models can be used in various studies for different maize cultivars under irrigation water and soil salinity conditions.

Due to the lack of highquality water resources, in many cases there is no other choice but to use lowquality or unconventional water. The filtration method is an efficient method for removing pollutants. For compare the amount of water purification in vertical and horizontal filters, two models of vertical and horizontal filters were made in Department of Irrigation and Development Engineering, University of Tehran.Three absorbent layers including sand, zeolite and rice husk were used. The purification rate was measured for three solutions contaminated with nitrate, salinity and TSS of each solution at two different concentrations. For each concentration of contamination, two purified samples were taken at two times of 5 and 10 minutes to determine the purification process over time. t-test was used in SPSS software to compare the filtration rate of vertical and horizontal filter and to observe the significance of the difference in filtration rates. The results showed that the amount of nitrate purification with concentrations of 36.72 and 59.08 mg/liter and at times of 5 and 10 minutes, respectively, in the vertical filter was 6.99, 9.25 and 7.72, 7.13% and in the horizontal filter was 3.18, 8.21 and 8.36, 5.70%. For EC, the filtration rate in two electrical conductivities is 31.6 and 11.02 dS/m and in two times for vertical filter 5.39, 2.54 and 5.26, 2.18% and horizontal filter 12. 4, 1.90 and 2.99, 1.54% were measured. The filtration rate of TSS for two solutions containing TSS with concentrations of 0.75 and 1.5 g/l and at two times were checked and the filtration rate of the vertical filter was 48.93, 43.87 and 73.20, 80.25% and the horizontal filter purification rate was 29.66, 38.40 and 61.31, 67.05%. Finally, the obtained results showed; There is no significant difference in nitrate, EC and TSS purification between vertical and horizontal filters.

In order to evaluate the SWAP model a study was conducted in 2017 in the farm of the Department of Irrigation and Reclamation Engineering, University of Tehran, located in Karaj as a factorial experiment in a randomized complete block design. The treatments consisted of three maize hybrids SC-704, SC-400 and SC-260 (V1, V2 and V3, respectively) and three levels of irrigation water salinity 0.7, 3 and 5 dS m-1 (S1, S2 and S3, respectively). In each maize cultivar, for the model calibration, the crop yield data measured in the field from the salinity level of irrigation water 3 dS m-1 and for its validation, the salinity levels of 0.7 and 5 dS m-1 were used. Also, to evaluate the model in estimating soil moisture and salinity, field data of V1S2 (calibration) and V1S3 (validation) were used. Based on the obtained results, SWAP model has a good performance in estimating soil moisture so that in the validation stage in three soil layers (0-20, 20-40 and 40-60 cm) with RMSE (Root Mean Square Error) of 0.03, 0.03 and 0.04 cm cm-3 respectively and has a good accuracy in predicting soil salinity of 0-20 cm surface layer (RMSE = 0.67 mg cm-3) but with increasing soil depth, the accuracy of the model decreases so that RMSE of 1.16 and 1.19 mg cm-3 were obtained in two layers of 20-40 and 40-60 cm, respectively. The SWAP model detected the inherent differences between different cultivars of maize and the best simulation results were obtained for SC 704.

Biochar as a soil amendment improves soil physical and chemical properties, increase nutrient availability, reduce nutrient leaching and ultimately increase crop production. Drought stress is one of the most important factors that limit plants growth. Arid lands have a little organic matter, and because of high pH, nutrients deficiency was observed in these soils. In order to study the effect of biochar on growth and concentration of nutrient in basil under water stress, one factorial experiment in Randomized Complete Block Design (RCBD) was carried out in Karaj, Iran. Experimental treatments included three levels of deficit-irrigation 100, 75 and 50% of water requirement of basil (a1, a2 and a3) and three levels of application of biochar 10, 5 and 0% by volume of each pot (b1, b2 and b3). The results of analysis of variance and comparison of the mean of measured traits (fresh and dry weight of leaves, stems and roots) showed that these traits were significantly different under the influence of different levels of irrigation and biochar application; So that the highest value of each of these traits was observed in treatment a1b1 and the lowest value was observed in treatment a3b3. The highest percentage of nitrogen (2.83 %) and phosphorus (0.16 %) was observed in the medium water stress treatment and the application of 10% by volume of biochar (a2b1) and the highest percentage of potassium (1.21 %) was observed in the a3b1 treatment. Also, the highest water productivity was obtained based on fresh (3.53 kg / m3) and dry (0.44 kg / m3) basil leaves in a3b1 treatment. Therefore, it can be concluded that the use of biochar in conditions of water stress has an effective role in improving nutrient uptake, which ultimately leads to increased vegetative growth and water productivity of basil.