Root and nitrate-N distribution and optimization of N input in winter wheat.

Scientific management of nitrogen (N) fertilizer has a significant effect on yield while also reducing the environmental risks. In this study, we conducted field experiments over three years at two different sites (Zhengzhou and Shangshui) in Henan Province, China, using different N application rates (0, 90,180, 270, and 360 kg ha) to determine the relationships between soil N supply and N demand in winter wheat (Triticum aestivum L.).