Land use change from rice paddies to upland fields aggravates soil microbial metabolic limitation and reduces soil quality index and ecosystem multifunctionality

Abstract With rapid urbanization and economic development, the area of paddy fields has seriously declined in rice‐producing region. However, the impacts of land use change (LUC) on soil enzymatic stoichiometry, microbial metabolic limitations and ecosystem multifunctionality (EMF) have not been well‐documented. Hence, four adjacent paired soil samples were collected in rice‐producing areas. Soil microbial carbon (C), phosphorus (P) and nitrogen metabolic limitations were assessed via vector model. The impacts of LUC on soil structure, microbial activity, quality and multifunctionality were evaluated via soil structure stability index (SSI), soil biological activity (SBA), soil quality index (SQI) and EMF, respectively. Result showed that LUC from rice paddies to upland fields markedly decreased soil structure stability by 19.6%. Soil microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), microbial biomass phosphorus (MBP) and nutrient‐acquiring enzymes activities in the paddy soils were significantly higher than that in upland soil. Compared with paddy soil, microbial relative C and P limitations in upland soil were significantly aggravated by 10.9% and 4.2%, respectively. Additionally, variation partitioning and redundancy analyses revealed that soil pH, available P and P‐acquiring enzymes were the crucial edaphic factors affecting microbial metabolic limitations. Comprehensive assessment showed that LUC from rice paddies to upland fields significantly reduced SBA, SQI and EMF by 5.2%, 17.4% and 17.2%, accordingly. Overall, LUC from rice paddies to upland fields significantly destroyed soil structure, aggravated microbial relative C and P limitations and reduced soil quality. Therefore, artificial managements should be strengthened to counteract the adverse effects of LUC on soil quality and EMF. This study deepened our understanding of sustainable development and efficient management of field under LUC condition.