Effects of legume-wheat rotation patterns on wheat yield, quality, and soil microbial community in the North China Plain

Incorporating legumes into crop rotation systems is an environmentally sound agricultural practice that improves soil quality and crop productivity. However, the mechanisms underlying these benefits, particularly the relationship between soil properties and microbial communities, remain unclear. This study evaluated the impact of three different rotation patterns, namely wheat-maize (WM), wheat-peanut (WP), and wheat-soybean (WS), on wheat yield, grain quality, soil physicochemical properties, soil enzyme activities, and microbial community. Our results demonstrated that legume-based rotations significantly improved wheat performance. In contrast to WM, WP consistently achieved the highest wheat yield, with a 3 year average increase of 10.7%. Furthermore, significant improvements in key quality parameters were observed in WP. Specifically, crude protein and wet gluten contents increased by 9.2% and 27.4%, respectively. These improvements were attributed to the enhancement of soil health. Legume rotations, particularly WP, led to significant improvements in soil total nitrogen (TN), available phosphorus (AP), and soil water content (SWC). This was accompanied by a strategic shift in soil enzymatic functions, with significantly higher activities of N-cycle (LAP, NAG) and P-cycle (ALP) enzymes. High-throughput sequencing revealed that legume rotations enriched specific bacterial phyla, such as Acidobacteria and Chloroflexi, and fostered a more complex and stable fungal co-occurrence network. Mantel test analysis revealed that wheat yield and quality were significantly correlated with several key soil parameters, including soil pH, TN, and the activities of NAG and ALP. PLS-PM analysis revealed that soil properties enhanced soil enzyme activity by shaping microbial communities, ultimately improving crop performance, demonstrating that microbial communities and soil enzyme activity play crucial roles. Collectively, these findings reveal that introducing legumes, especially peanut, boosts wheat yield and quality by enhancing soil nutrient availability and shaping a beneficial microbial community, serving as a sustainable strategy for wheat production.