Enhancing peanut production under short-term continuous cropping with straw biochar: Modulating soil biochemical properties, microbial communities, and their functions

Short-term continuous cropping poses major challenges to peanut production, characterized by soil degradation, microbial dysbiosis, and substantial yield decline. This study evaluated straw biochar as a sustainable soil management strategy to alleviate these obstacles in short-term continuous cropping systems. A three-year field experiment (2021–2023) was conducted to compare traditional planting (TP) with straw biochar amendment (BC). Key indicators, including photosynthetic parameters, soil organic carbon (SOC) fractions (POC, DOC), pH, total nitrogen (TN), water content (SWC), enzyme activities (invertase, N-acetyl-β- D -glucosaminidase, β-glucosidase), microbial community composition, carbon utilization capacity, and peanut yield were assessed to unravel the regulatory mechanisms. Results showed that straw biochar significantly enhanced peanut leaf SPAD values, actual photochemical efficiency (ΦPSII), and net photosynthetic rate (P N ) by 26.56%, 11.17%, and 35.92%, respectively, compared to TP. Furthermore, BC treatment significantly increased SWC, SOC, POC, DOC, and TN, and effectively increased soil pH over the three years. These biochemical improvements were coupled with consistently higher activities of key enzymes. Crucially, biochar restructured the soil microbiome by enriching beneficial bacterial genera (e.g., Chthoniobacter , Pseudomonas ) and, more importantly, significantly suppressing the relative abundance of potential fungal pathogens, particularly Fusarium and Aspergillus . Predicted functional profiling showed an enhancement in chemoheterotrophy, and Biolog EcoPlates analysis revealed a time-dependent, cumulative enhancement of soil microbial carbon utilization, which largely recovered to pre-cultivation levels after three years. Collectively, these results demonstrate that straw biochar alleviates short-term continuous cropping stress by modulating soil biochemical properties—specifically through pH elevation, nutrient enrichment, and increased enzyme activity. This improvement fosters the restoration of microbial equilibrium and functional diversity, which in turn enhances peanut photosynthesis and yield. Consequently, straw biochar emerges as a promising sustainable solution for overcoming continuous cropping challenges. • Straw biochar improved yield of short-term continuously cropped peanut. • Biochar enhanced soil biochemical properties including SOC, pH and enzymes. • Biochar enriched beneficial Pseudomonas and suppressed pathogenic Fusarium . • Biochar mitigates obstacles of short-term continuous peanut cropping.