【作者】 盛荣；

【导师】 谢达平； 肖和艾；

【作者基本信息】 湖南农业大学 ， 微生物学， 2010， 硕士

【摘要】 土壤微生物在土壤营养元素(N、P等)转化中起着重要作用。探讨红壤土壤磷素转化主要功能微生物种群及其磷素转化的作用机理,可为促进红壤土壤磷素微生物转化和提高土壤磷素作物有效性提供理论基础。本研究选择位于湖南桃源的红壤旱地和稻田施肥田间定位试验,研究了几种施肥方式对土壤可培养细菌和真菌、土壤微生物生物量磷以及土壤微生物植酸酶基因多样性的影响。结果表明,(1)在旱地土壤中,施NPK+稻草(NPK+Str)土壤可培养真菌数量和微生物生物量磷比不施肥(CK)分别增加68.4%-167.0%和230.7%-344.5%,比施NPK (NPK)处理分别增加38.5%-46.1%和161.1%-202.8%,而CK、NPK和NPK+Str处理土壤可培养细菌基本相同；(2)稻田土壤中,施NPK+稻草+绿肥(NPK+Str+GM)处理土壤可培养真菌和细菌数量及微生物生物量磷分别比CK增加53.7%-112.3%、140.3%-374.1%和33.9%-115.3%,比NPK处理分别增加45.1%-144.6%、366.5%-410.9%和21.4%-75.0%,土壤可培养细菌数量的增加幅度明显大于可培养真菌；(3)施NPK肥和NPK+Str处理的旱地土壤有效磷含量分别比CK提高93.1%-100.1%和81.9%-116.5%,稻田土壤有效磷含量分别比CK提高2-3倍和4-6倍,同时,土壤pH值却比CK显著降低；(4)通过对不同施肥处理土壤微生物植酸酶基因多样性的分析,结果表明单施化肥处理土壤微生物植酸酶基因多样性明显低于化肥配施绿肥和覆盖稻草处理。由此推断,(i)施加稻草后旱地土壤微生物生物量磷增加,且主要来源于土壤真菌；(ii)施稻草和紫云英对稻田土壤中微生物生物量磷含量的提高可能主要来源于土壤细菌；(iii)添加稻草和绿肥可提高土壤磷素有效性,但施肥红壤旱地和稻田土壤pH值降低；(vi)长期单施化肥会降低稻田土壤微生物植酸酶基因多样性,而施化肥的同时添加稻草可有效缓解这种情况。更多还原

【Abstract】 Soil microorganisms play an important role in the transformation of soil organic matter and soil nutrients (such as N, P, S, ect.). Researches on the mechanisms of soil phosphorus transformation and the functional microorganisms which involving in the soil phosphorus transformation can provide a theory reference for the effective usage and management of phosphorus in red soils. Responses of culturable microbial diversity and the amount of microbial biomass P (MB-P) in upland and paddy soils and the diversity of soil microbial phytase gene in paddy soils with various fertilization practices (inorganic and organic fertilizer) were investigated using a series of long-term field trials in Hunan, China. Results indicated that combined application of rice straw and chemical fertilizers (NPK+Str) significantly increased the amount of culturable fungi and MB-P in treatment of NPK+Str by 68.4%～167.0% and 230.7%～344.5% respectively compared to CK,38.5%～46.1% and 161.1%～202.8% respectively compared to NPK in upland soils, whereas there’s no significant dfference of culturable bacteria was observed among the treatment of CK、NPK and NPK+Str in upland soils, it suggested that fungi possibly played a key role in the phosphorus transformation in upland soils amended with rice straw. However, combined application of rice straw and chemical fertilizers with addition of astragalus (NPK+Str+GM) significantly increased the amount of culturable fungi, bacteria and MB-P significantly by 53.7%～112.3%,140.3%～374.1% and 33.9%～115.3% respectively compared to CK, 45.1%～144.6%.366.5%～410.9% and 21.4%～75.0% respectively compared to NPK in paddy soils, especially, the enhancement level of culturable bacteria was much higher than that of fungi, in compared with the treatment of CK and NPK. Consequently, this study demonstrated that bacteria and fungi likely play different roles of the information of microbial biomass P in upland and paddy soils, that is bacteria may contribute to the enhancement of MB-P which application of rice straw and organic green manure (astragalus) in paddy soils, however, fungi only play a major role in upland soil with the application of rice straw.Application of NPK fertilizer, rice straw and astragalus could increase the amount of Olsen-P by 2～3 times in upland and 4～6 times in paddy soils, meanwhile, the soil pH showed a significant decrease. The results suggested that the phosphorus transformation may be related to the decrease of soil pH. The long-term application of only NPK fertilizers had a potential to reduce the diversity of soil microbial phytase, however, application of NPK fertilizer amend with rice straw and astragalus could avoid the soil degradation to some extend.更多还原