Soil drainage water and nutrient leaching in winter wheat field lysimeters under different management practices.

The objective of this study was to investigate the effects of different irrigation strategies, planting methods and various nitrogen application rates on water and solutes transport under the root zone. Furthermore, Hydrus-1D model was used to simulate the drainage water and soil nutrient (N, K) leaching by the drainage water in the experimental treatments. Results indicated that variable alternate furrow irrigation (VAFI) decreased drainage water by a mean value of 30% compared with that obtained in full irrigation (OFI); whereas, precipitation played a significant role in increasing drainage water. About 60% and 80% of drainage water occurred due to rainfall in the full irrigation strategy in the first and second year, respectively, and most of the drainage water in VAFI strategy occurred due to precipitation as 90% for both years. Additionally, precipitation during the low growth stages of winter wheat (fall and winter) had noticeable influence on solute transport. On average, 75%, and 65% of leached nitrate, and potassium, respectively, occurred due to rainfall in OFI method; however, about 85% of leached nitrate, and potassium in VAFI strategy occurred due to rainfall events. Application of 150 kg N ha−1 decreased about 40% nitrate leaching below the root zone in comparison with that obtained in 300 kg N ha−1 without significant difference in crop yield. Hydrus-1D model reasonably simulated solute transport especially nitrate and potassium. Therefore, Hydrus-1D could be a successful tool for predicting N, and K transport and making proper management decisions to improving environmental problems. [ABSTRACT FROM AUTHOR]