【摘要】 研究了湖南省5个典型稻田长期定位监测点的土壤微生物磷(MB-P)对土壤有机碳和磷素变化的响应。结果表明,各监测点土壤MB-P含量对施肥的反应存在较大差异。大多数监测点的土壤MB-P对化肥的反应不敏感,而施有机肥(物)有利于土壤MB-P的增加。土壤MB-P对土壤有机碳和全磷的变化虽有响应,而其关系并不确定,但土壤MB-P与土壤微生物碳和Olsen法提取磷(Olsen-P)的关系却极为密切。土壤MB-P占土壤全磷的1.16%～3.19%,与Olsen-P占全磷的比例较为接近。在土壤Olsen-P含量低于8 mg穔g-1 的较低水平下,不论施肥与否,土壤MB-P含量均高于Olsen-P,较高的土壤MB-P有利于补充土壤Olsen-P。在不同形态的无机磷中,土壤MB-P与Al-P和Fe-P的相关性最好,Ca-P次之,但与闭蓄态磷(O-P)无显著相关性。微生物对土壤Al-P、Fe-P和Ca-P的利用可能是促进其向Olsen-P方向转化的关键途径。更多还原

【Abstract】 Responses of microbial biomass P (MB-P) to organic C and P in paddy soils with various fertilization practices (inorganic and organic fertilizers) were investigated using 5 long-term field trials in Hunan, China. Results indicated that the amount of soil MB-P and their responses to the applications of different fertilizers differed with soil types. Changes in soil MB-P was insensitive to inorganic fertilizers (NPK) applied in most of the trials. However, the amount of soil MB-P generally increased by application of organic manure and incorporation of rice straw. The relation between MB-P and total P or total organic carbon was indeterminate, although the content of MB-P, to some extent, could respond to the changes of total P or total organic carbon. Meanwhile, the MB-P was more closely related to NaHCO3 extractable P (Olsen-P) or MB-C than to total P or total organic carbon. MB-P amounted to 1.16%-3.19% of total P in the paddy soils, which was similar to the percentage of Olsen-P to total P. When the content of extractable P was less than 8 mg穔g-1, the content of MB-P was more than extractable P no matter where in fertilization or in non-fertilization plots, suggesting that a high content of microbial biomass P could regulate extractable P in paddy soil. The positive correlations between the amount of MB-P and various fractions of inorganic P except O-P indicated it was a possible key that the conversion of Fe-P, Al-P and Ca-P into extractable P was accomplished by soil microorganisms in paddy soils.更多还原