Water and Nitrogen Inputs Optimization Based on Different Soil Water Storage at Planting

Abstract:

In order to explore the nitrogen rate and water management, the multivariate regression analysis was applied to explore how levels of available soil water storage at planting (WB), supplemental water during the growing period (R) and nitrogen rate (N) affected yields of winter wheat (Triticum aestivum L.) and water use efficiency (WUE) in a mobile rain-proof shed between 2013 and 2015. The results showed that effects of all factors on yields of winter wheat followed the sequence of WB, N and R. Likewise, effects of all factors on WUE followed the sequence of WB, R and N. The coupling of all factors on yield and WUE had significant negative and positive effects, respectively; in adequate WB, nitrogen rate could fully exploit the role of WB on yield increasing, and improve WUE. Acceptable yield and WUE were defined as greater than or equal to 0.95 of the maximum predicted response within the range of the treatments. Overlap of acceptable zones of grain yields and WUE were respectively 90~100mm and 104.5~224.5kg/hm2 (WB=450mm),94.3~100mm and 105.8~186.4kg/hm2 (WB=350mm). At WB=650mm, overlap of acceptable zone of the maximum grain yield and the high WUE was 71~100mm and 141.2~264.8kg/hm2.