Soil pH and Nutrient Stoichiometry as Key Drivers of Phosphorus Availability in Crop Rotation Systems

作者：Yang Yuan, Yiyong Zhu, Yichen Zhao, Meng Wang, Zhaoming Qu, Dongqing Lv, Yanli Liu, Yan Song, Tingting Wang, Chengliang Li, Haojie Feng · 发表于：Agronomy · 年份：2025 · DOI：10.3390/agronomy15051023 · 被引用次数：7 · 研究领域：Soil Carbon and Nitrogen Dynamics、Plant Micronutrient Interactions and Effects、Plant nutrient uptake and metabolism

Crop rotation systems profoundly influence soil phosphorus (P) dynamics through physicochemical and microbial interactions. The mechanisms regulating P availability under various rotational practices remain poorly understood. This five-year field experiment investigated the effects of four rotation systems (WM: wheat–maize; WP: wheat–peanut; WS: wheat–soybean; MV: maize–hairy vetch) on soil P fractions, phosphatase activities, P-cycling gene abundance, and their interactions with soil properties. The WM rotation substantially reduced soil pH (6.29) while increasing labile P fractions (Ca2-P) and moderately labile P (Al-P, Fe-P, and Ca8-P), which was attributed to enhanced acid phosphatase activity. The WP rotation elevated soil pH (8.13) but reduced P availability due to calcium–P immobilization. The MV rotation stimulated microbial P cycling, exhibiting the highest phoD (2.01 × 106 copies g−1) and phnK (33,140 copies g−1) gene abundance, which was linked to green manure-induced microbial activation. Redundancy analysis identified soil pH, total nitrogen, and stoichiometric ratios (C/N and N/P) as key shared drivers of P fractions and enzymatic activity. Partial least squares path modeling (PLS–PM) indicated that crop rotation directly regulated P availability through pH modulation (r = −0.559 ***) and the C/N ratio (r = 0.343 ***) while indirectly regulating P fractions through phosphatase activity. Lower C/N ratios (<10) across all rotation regimes amplified the carbon l...