The effect and relative contributions of C and P inputs on soil microbial biomass P (MBP) accumulation were studied in three long-term soil fertility experiments with various soil and climate characteristics at Qiyang, Yangling, and Wulumuqi. The maximum of soil MBP in all three sites was 47.8 mg P kg^-1. The MBP accumulated per unit in soil (mg P kg^-1 soil) was correlated with a 4.91 mg kg^-1 increase in Olsen P. For each unit increase in P surplus (kg P ha^-1), manure C (kg C ha^-1), and stubble C (kg C ha^-1), MBP accumulation increased by 330, 3.7, and 13 units (μg P kg^-1 soil), respectively. The soil MBP was positively correlated with crop yield and P uptake, making the soil MBP a useful soil P fertility index. The critical levels of the soil MBP pool were 140 kg ha^-1, 57–62 kg ha^-1, and 33–35 kg ha^-1 in acidic red soil, loessial soil, and grey desert soil, respectively. This is the first report to establish a quantitative index of soil fertility based on the soil MBP pool. Our findings demonstrate that C input is a good driver of soil MBP accumulation. Integration of the soil MBP as an index of soil P fertility into agricultural P management is useful to help manage mineral P fertilizers as part of sustainable agricultural practices.

在祁阳，杨凌和乌鲁木齐不同土壤和气候特征的三个长期土壤肥力试验中，研究了碳和磷输入对土壤微生物生物量磷（MBP）积累的影响和相对贡献。三个地点的土壤MBP最大值为47.8 mg P kg ^-1。每单位土壤中的MBP累积量（mg P kg ^-1土壤）与Olsen P增加4.91 mg kg ^-1相关。对于每单位增加的P过剩量（kg P ha ^-1），粪肥C（kg C ha ^-1）和留茬C（kg C ha ^-1），MBP积累量增加了330、3.7和13个单位（μgP kg ^-1土壤）。土壤MBP与作物产量和磷素吸收呈正相关，使土壤MBP成为有用的土壤磷肥力指数。土壤MBP池的临界水平140千克公顷^-1，57-62公斤公顷^-1，和33-35公斤公顷^-1在酸性红壤，垆土，和灰漠土，分别。这是第一份基于土壤MBP库建立土壤肥力定量指标的报告。我们的发现表明，碳输入是土壤MBP积累的良好驱动力。将土壤MBP作为土壤磷肥力的指标整合到农业磷肥管理中，对于帮助管理矿物磷肥作为可持续农业实践的一部分非常有用。