Effects of nitrogen and sulfur interaction on their accumulation, translocation and use efficiency in winter wheat

A field experiment was conducted in Guanzhong Plain of China to identify the effects of the interactions of nitrogen and sulfur on the absorption, translocation and use efficiency of nitrogen and sulfur by winter wheat ('Xiaoyan 22'). A two-factor (nitrogen and sulfur) central composite rotatable design was used in the experiment with five levels of nitrogen (75 kg·hm^-2, 108 kg·hm^-2, 187.5 kg·hm^-2, 267 kg·hm^-2 and 300 kg·hm^-2) and five levels of sulfur (75 kg·hm^-2, 97.5 kg·hm^-2, 150 kg·hm^-2, 202.5 kg·hm^-2 and 225 kg·hm^-2). The results showed that dry matter, N and S contents reached peak values during jointing to anthesis stage, accounting for 43.33%-48.42% dry matter, 28.71%-44.77% N and 40.11%-50.43% S contents of the entire winter wheat growth season. Translocation rates of nitrogen (63.61%-70.64%) were much higher than those of sulfur (10.63%-30.98%). The application of nitrogen and sulfur fertilizers increased nitrogen and sulfur contents and translocation from vegetative organs to grains after anthesis. The application of nitrogen and sulfur fertilizers also increased the contribution of both nitrogen and sulfur translocation to grain yield. Under N level of 108 kg·hm^-2 and S level of 97.5 kg·hm^-2, nitrogen and sulfur contents increased significantly with increasing sulfur or nitrogen application levels. At N level of 187.5 kg·hm^-2 and S level of 150 kg·hm^-2, nitrogen and sulfur contents increased initially before stabilizing with increasing sulfur or nitrogen input. Sulfur content was positively correlated with nitrogen appliction. The combined fertilizaton of nitrogen (170.64-204.52 kg·hm^-2) and sulfur (97.35-139.32 kg·hm^-2) had higher fertilizer use efficiency and apparent recovery. In conclusion, N & S uptake, translocation and use efficiency were increasable through optimizing the application rates of nitrogen and sulfur.