Application of HYDRUS-2D in simulation of nitrate leaching and nitrogen uptake in corn cultivation under different drip fertigation scenarios

Managing nitrogen fertilizers application in the field is an effective tool to mitigate groundwater pollution. The objective of this research was to investigate the effect of various fertigation scenarios on the nitrate leaching and nitrogen absorption by corn in surface tape micro-irrigation system and sandy clay loam soil. For this purpose, HYDRUS-2D model was used to simulate water and nitrogen movement in soil and the requirement data for the model calibration and validation were collected by the field experiments. Then, the nitrogen uptake and nitrate leaching in the different fertigation frequencies were simulated in the calibrated model. The mentioned scenarios in a sandy loam soil were also exerted to compare with the results of the previous stage. The results showed that the nitrate uptake by the plant, leaching and its accumulation at the end of the growth season in the root zone were similar in weekly and biweekly frequencies in the studied soils. Reducing the number of fertigation frequencies to three splits, nitrate uptake by the plant in sandy clay loam soil increased to 73 percent and total losses of leaching and accumulation in the root zone, decreased to 27 percent. However, in three-stage splits in sandy loam soil, the nitrate uptake by the plant decreased to 48 percent and total nitrate losses increased to 52 percent.