[Effects of Straw Returning and Fertilizer Application on Soil Nutrients and Winter Wheat Yield].

In order to explore the effects of straw returning combined with fertilizer on soil nutrients and winter wheat yield in the Guanzhong area, an experimental split plot design was utilized. The main plot consisted of no straw returning (S) and straw returning (S). The sub-regions consisted of no fertilizer (WF), nitrogen fertilizer (NF), and nitrogen and phosphate fertilizer (NPF). Ecological stoichiometry was used to study the relationship between soil carbon, nitrogen, phosphorus content, and yield under straw returning combined with nitrogen and phosphorus fertilizer conditions. The results showed that straw and fertilization interactions had significant effects on soil organic carbon, total nitrogen, and total phosphorus contents in the surface layer (0-20 cm) (<0.05). Compared with that in the SWF treatment, the SNPF treatment significantly increased soil organic carbon and total nitrogen contents in the surface layer (0-20 cm) (<0.05). The interaction between straw and year had significant effects on soil total nitrogen content in the surface layer (0-20 cm) (<0.05). With the increase in straw returning time, the total nitrogen content of soil 0-20 cm under the SWF treatment was significantly higher than that under the SWF treatment (<0.05). Straw and fertilization and their interaction had no significant effects on organic carbon and total nitrogen contents in the 20-40 cm soil layer (>0.05). Straw and straw interaction with fertilization significantly affected total P content in 20-40 cm soil (<0.05). Compared with that in the SWF treatment, the SNPF treatment significantly increased the total phosphorus content in the 20-40 cm soil layer (<0.05). Straw returning combined with chemical fertilizer also had a significant effect on soil stoichiometry. Compared with that in the SWF treatment, the SNPF treatment decreased soil C:N in the surface layer (0-20 cm) and increased soil C:P and N:P in the surface layer (0-20 cm). Compared with that in the SWF treatment, the SNF treatment reduced soil C:N in the surface layer (0-20 cm). Straw returning combined with chemical fertilizer also had a significant effect on winter wheat yield. In 2020 and 2021, the SNPF treatment increased production by 24.23% and 28.9%, respectively, compared with that of the SWF treatment. Correlation analysis showed that yield was significantly positively correlated with C:N (<0.05) and C:P (<0.01). At the same time, total nitrogen and N:P were positively correlated with treatment years (<0.001). In conclusion, straw returning and that combined with nitrogen and phosphate fertilizer (SNPF) can improve soil nutrient characteristics, change soil stoichiometric characteristics, and increase yield in the Guanzhong area. Therefore, the results of this study indicate that straw returning combined with nitrogen and phosphate fertilizer (SNPF) is an effective way to optimize regional farmland nutrient management and improve grain production capacity.