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Increased Dryland Winter Wheat Yields by Nitrogen Fertilizer Topdressing and its Relationship to Soil Moisture, Available N, P and K in Northwestern China
- Zhao, Hu-Bing, Wang, Zhao-Hui, Xue, Cheng, Huang, Dong-Lin, Malhi, Sukhdev S.
- Communications in soil science and plant analysis 2016 v.47 no.5 pp. 543-553
- Triticum aestivum, ammonium nitrogen, arid lands, autumn, drought, farmers, fertilizer industry, field experimentation, grain yield, growing season, nitrate nitrogen, nitrogen, nitrogen fertilizers, phosphorus, potassium, soil depth, soil profiles, soil water, soil water content, sowing date, spring, winter wheat, China
- Winter wheat (Triticum aestivum L.) production in northwestern China as a monoculture is hampered by unfertile soil and drought. With the fast-developing Chinese chemical fertilizer industry, many farmers now use more nitrogen (N) fertilizer as topdressing for winter wheat in early spring, in addition to a basal dose of N fertilizer applied in the previous autumn at seeding time. The objective of this study was to evaluate the increase in grain yield of dryland winter wheat by early spring N fertilizer topdressing, and its relationship to soil moisture, available N, phosphorus (P) and potassium (K). Field experiments with no N fertilizer topdressing (F b) and N fertilizer topdressing (F b₊ₜ) treatments were carried out over two growing seasons at 54 site-years to assess the relationship between increase in winter wheat grain yield by early spring N fertilizer topdressing and soil moisture, available N, P and K in Changwu county, Shaanxi province, China. Compared to F b treatment, the F b₊ₜ treatment produced grain yields lower at 10 site-years, and increased by <10% at 21 site-years and by >10% at 23 site-years. The results indicated that topdressing N fertilizer could increase wheat grain yield when soil nitrate-N accumulation in the 0–20, 20–40 and 40–60 cm depths was less than 121.7, 36.4 and 24.1 kg N ha ⁻¹, and soil moisture content in the 40–60, 60–80 and 80–100 cm depths was more than 15.7%, 16.7% and 16.9%, respectively. The findings also suggested that it is not necessary to analyze soil for ammonium-N, available P and K before topdressing N fertilizer. It is necessary to analyze 0–60 cm soil profile for nitrate-N and 40–100 cm depth for soil moisture before topdressing N fertilizer for winter wheat in dryland areas of northwestern China.