LAUSR

In this study, the nylon net bag method was used to explore the characteristics of straw decomposition and nutrient release under different organic fertilizer replacement rates, which provided a scientific basis for rational straw returning in corn (Zea mays L.) planting. The results showed that the characteristics of straw decomposition and nutrient release in different treatments were fast in the early stage (0-20 d) and slow in the late stage (20-100 d). At the end of decomposition (100 d), the decomposition rate and nutrient release rate were 47.69%-56.07%, 47.55%-61.73%, 47.40%-62.67%, 48.04%-66.35% and 82.20%-100.00%, respectively, decomposition rate and nutrient release rate were 8%OF (organic fertilizer replaces 8% N fertilizer) > 16%OF (organic fertilizer replaces 16% N fertilizer) > 24%OF (organic fertilizer replaces 24% N fertilizer) > CF (only chemical fertilizer) > CK (no fertilizer control). Through the model (y = a·x) analysis of nutrient release rate, the time until complete release of C, N, P, and K was predicted to be 206-275 d, 167-271 d, 153-248 d, and 85-150 d, respectively, and it was verified that the nutrient release characteristics of fertilization treatment (CF, 8%OF, 16%OF, 24%OF) in this experiment were potassium (K) > phosphorus (P) > nitrogen (N) > carbon (C), and CK was K > P > N ≈ C. Based on the model and correlation analysis, the recommended organic fertilizer replacement rate is 12%, and according to the characteristics of straw decomposition and nutrient release, a strategy of rational straw returning and fertilization management was proposed.