Can Split Application of Slow-Release Fertilizer Improve Wheat Yield, Nitrogen Efficiency and Their Stability in Different Ecological Regions?

Abstract

Environmental conditions (precipitation, temperature and soil properties) differ greatly in different regions and have dual effects on the wheat growth and nutrient release of slow-release fertilizer (SRF). Conventional fertilization methods such as the multiple-split application of urea and the one-time application of SRF may have difficulty achieving a stable and high wheat yield and nitrogen (N) efficiency in various environments. Therefore, the exploration of a rational application strategy of SRF is needed for improving wheat yield and its stability in different regions. A two-year field experiment was conducted in different regions (eight test sites per year) with five patterns: 100% N (270 kg ha−1) SRF applied pre-sowing (M1); 60% N SRF applied pre-sowing and 40% N urea applied at jointing (M2); 60% N SRF applied pre-sowing and 40% N SRF applied at regreening (M3); M2 reducing the N rate by 15% (M4); M3 reducing the N rate by 15% (M5). The fourth-split application of urea was taken as the control (CK, 270 kg N ha−1). The results suggested that the average yield in M1 decreased by 3.65% of the CK, and the yield stability was poor. Both M2 and M3 significantly increased N efficiency, grain yield and benefit, but the stability of M3 was higher than that of M2 in different environments. Considering further improvements in wheat yield, N efficiency and profit, our results suggested that the twice-split application of SRF, which also improved the adaptability of wheat in different environments, could be recommended for wheat cultivation.