Is non-legume green manure rotation or straw biochar more effective in promoting peanut production?

Abstract

In contemporary agronomy, the adoption of green manure rotation and straw biochar amendment has emerged as an important strategy, explicitly targeting the enhancement of soil health and crop productivity. This study aimed to investigate the impacts of incorporating non-legume green manure rotation and straw biochar application on soil physicochemical properties, microbial community structure, and peanut production, along with a comprehensive assessment of their effectiveness. Over the three-year experimental period, the treatments included: a control treatment that followed traditional planting practices (PT); ryegrass was planted and then returned to the field before peanut cultivation (GM); and straw biochar was applied prior to peanut planting (BC). The results demonstrated that both GM and BC treatments led to a significant (P < 0.05) reduction in soil bulk density. They also increased water-stable aggregates measuring >5 mm and 2–5 mm, while decreasing aggregates measuring 0.25–2 mm, 0.053–0.025 mm, and < 0.053 mm when compared to PT. Additionally, GM and BC improved soil mean weight diameter and geometric mean diameter. They also enhanced the soil's organic carbon and nitrogen content, attributing these changes to shifts in microbial taxa crucial for carbon and nitrogen fluxes, as revealed by soil metagenomic sequencing analysis. Specifically, GM increased the relative abundance of genera such as Solirubrobacter, Arthrobacter, and Bradyrhizobium, while BC favored Methylibium, Burkholderia, and Acinetobacter, etc. Despite both GM and BC significantly increasing yield and net income, a comprehensive assessment using the entropy weight-TOPSIS indicates that non-legume green manure rotation is more effective in promoting peanut production based on soil quality attributes, inputs, and outputs.