Enhancing Wheat Yield Through Microbial Organic Fertilizer Substitution for Partial Chemical Fertilization: Regulation of Nitrogen Conversion and Utilization

The efficacy of microbial organic fertilizer as a partial replacement for chemical fertilizer in augmenting crop yield and improving soil quality has been a topic of uncertainty. This study sought to clarify the influence of microbial organic fertilizer on soil nitrogen transformation across various growth stages and uncover the physiological mechanisms that contribute to the enhanced yield of wheat. The research focused on a winter wheat field in the North China Plain subjected to two consecutive years of microbial organic fertilizer application. We examined the soil’s physical and chemical properties and studied the biological characteristics of wheat. The application of microbial organic fertilizer significantly elevated soil nitrate nitrogen content during the overwintering and regreening stages, as well as soil ammonium nitrogen content during the filling and maturity stages. Additionally, it enhanced the activities of soil urease and sucrase during the flowering stage. This increase in soil-available nitrogen during critical growth stages provided a solid foundation for wheat growth. Furthermore, microbial organic fertilizer markedly boosted the phosphorus and potassium contents in grains and nitrogen in straw during the grain-filling stage, supporting essential nutrients for wheat grain development. Simultaneously, the fertilizer increased the activities of nitrate reductase and nitrite reductase enzymes, promoting efficient nitrogen utilization in winter wheat. Our findings suggested that the prolonged use of microbial organic fertilizer could augment winter wheat nutrient accumulation, enhance nitrogen-related enzyme activities, and regulate soil nutrient content. This, in turn, laid the groundwork for improving soil fertility and ultimately increasing wheat yield.