JWSS - Journal of Water and Soil Science

To design cost-effective and efficient drip irrigation systems, it is necessary to know the vertical and horizontal advance of the wetting front under the point source; also, the proper management of drip irrigation systems requires an awareness of the soil water distribution. Many factors influence wetting pattern dimensions, including discharge, land slope, irrigation time and soil texture. The purpose of this study was to investigate the applicability of the support vector machine in simulating the wetting pattern under trickle irrigation. After preparing a physical model made of Plexiglas with specific dimensions and filled with silty clay loam soils, experiments were conducted in the irrigation laboratory of Razi University, Iran, with emitters of 2, 4, 6 and 8 l/hour discharge during the irrigation intervals of 2 hours and 24 hours redistribution and 0,5,15 and 20% slope with three replications. In this study, the statistical indicators R², RMSE, MBE and MEF were used. R² values for the wet depth, width and area were 0.96, 0.96 and 0.92, respectively. Regarding the MBE value, the SVM model estimated the wet width and depth parameters to be 3% less than the actual value, and simulated the wet area 2.04% less than the real value. Also, according to the MEF and RMSE values, the SVM model simulated the wet area parameter with more error.  Overall, the results showed that the SVM model had a high ability to estimate the wetting pattern parameters.

In this research, the impact of the Alagol wetland on the water treatment of Atrak River was studied. From June, 2016, to May, 2017, on the fifteenth day of the month, four samples of water were collected from the middle and the outlet of the wetland. Also, the wetland was fed only in the months of September, November and February. The parameters of acidity, electrical conductivity, phosphate, nitrate, dissolved oxygen, biochemical oxygen demand, chemical oxygen and ammonia were measured. The water pH at the entrance and exit was significantly different. EC was higher at the entrance, and its value was decreased in the middle and output. DO in the outlet of the wetland was higher than that in the middle and inlet, indicating the improved water quality and high dissolved oxygen in the wetland output. NO₃, NH₄, PO₄, BOD and COD were higher at the entrance to the wetland; also, it was decreased in the outlet and middle, and the difference was significant. Further, according to the results of September, November and February, which were fed to the wetland, water quality in the middle and outlet of the wetland was improved toward the entrance of the wetland. According to the results, Alagol wetlands could reduce the phosphorus, ammonia, BOD, COD and DO, and their concentrations were lower than the limit. However, given that the salinity at the entrance of wetland was too high, its amount in the output was higher than the standard limit and the wetland could not significantly reduce salinity. The results of this study showed that that of water pollution in the inlet, except that the dissolved oxygen parameters and the temperature were high and decreased in the middle outlet. Due to the quality of the wetland outlet, Alagol wetland water could be used for fish farming centers.