Effects of sulfur application rate on the absorption and translocation of nitrogen and sulfur and grain yield of winter wheat in Guanzhong area of Shaanxi

The objective of this field experiment was to clarify the effect of sulfur application on the absorption and translocation of nitrogen and sulfur and grain yield of winter wheat. The experiment included five sulfur application rates(S 0, 37.5, 75, 112.5, and 150 kg/ha). The experiment was conducted in the Guanzhong area, Shaanxi Province, China, from October 2011 to June 2012. The results showed that sulfur concentrations in winter wheat plants gradually increased as the sulfur application rate increased. In contrast, nitrogen concentrations increased, reached a maximum, and then decreased as the sulfur application rate increased. The application of sulfur fertilizer increased nitrogen and sulfur translocation from vegetative organs to grain after anthesis. The nitrogen translocation rates(71.40%-75.27%) were much higher than those of sulfur(8.52%-27.73%). The application of sulfur fertilizer also increased the contribution of both nitrogen and sulfur translocation to grain. The leaf nitrogen/sulfur ratios were highest at booting and then declined after anthesis. Throughout the growing season, we observed that the nitrogen/sulfur ratio decreased as the sulfur application rate increased. Correlation analysis showed that the nitrogen/sulfur ratio at the booting stage was closely related with grain yield. The study also indicated that grain yield increased as the sulfur application rate increased. Grain yield was 30.14% higher in the sulfur 150 kg/ha treatment than in the unfertilized treatment. In conclusion, the application of sulfur fertilizer at rates between 37.5 and sulfur 150 kg/ha increased the uptake and translocation of nitrogen and sulfur. The sulfur fertilizer input also increased the number of spikes per unit area and grains per spike, therefore increasing winter wheat yield significantly.