中文摘要：

【目的】了解土壤无机磷含量对土壤微生物量磷及碳磷比的影响。【方法】向土壤中加入^32P标记的KH2PO4（3．7KBq·g^-1），同时分别加入KH2PO4 0、10、20、40、80和240mgP·kg^-1，再加入葡萄糖（5000mgC·kg^-1）和尿素（200mgN·kg^-1），25℃下培养30d后，分别在2、6、12、18和30d采样测定土壤微生物量碳和微生物量磷。【结果】加入的无机磷对土壤微生物量碳无显著的影响，但迅速被微生物吸收并富集在微生物量中。在培养的第2天，微生物量磷有一半以上来自加入的无机磷。并且，在一定范围内（01sen—P约50mg·kg^-1），土壤微生物量磷随土壤01sen—P提高而增加，土壤01sen—P每提高1个单位，土壤微生物量磷增加0．65个单位。微生物量碳磷比则相反，随土壤01sen-P增加而降低。【结论】在碳源供给充足的条件下，微生物能够吸收富集土壤无机磷，在一定的土壤有效磷含量范围内，土壤微生物量磷及微生物量磷浓度随土壤有效磷含量增加而提高。

英文摘要：

[Objective] The purpose was to investigate the influence of inorganic P on soil microbial biomass P and C/P. Soil microbial biomass P （SMBp） is an important resource of plant P nutrition. It changes widely and is influenced by soil conditions. [Method] Following the addition of 0, 10, 20, 40, 80, 240 mgP·kg^-1 （KH2PO4） labeled with KH2^32 PO4 （3.7 KBq·g^-1） together with glucose （5 000 mgC·kg^-1） and urea （200 mgN·kg^-1）, the soils were incubated at 25℃ for 30 d. Soil microbial biomass C and P were determined at 2, 6, 12, 18, 30 d. [Result] The added phosphates had no significant impact on soil microbial biomass C （SMBc）. However, the added P was soon absorbed and accumulated by soil microbial biomass. On the second day, more than half of the soil microbial biomass P was determined by the addition of inorganic E When soil Olsen-P was lower than 50 mg·kg^-1, soil microbial biomass P increased by about 0.65 mg·kg^-1 with increased 1 mg·kg^-1 Olsen-P. On the contrary, the ratio of soil microbial biomass C to P decreased with increasing soil Olsen-P. [ Conclusion] At the condition of sufficient C, soil microorganisms absorbed and enriched soil inorganic P. Within a certain range of soil Olsen-P, both soil microbial biomass P and soil microbial biomass P concentration increased with increasing soil Olsen-P.