施肥对红壤旱地和稻田土壤可培养微生物和微生物生物量磷的影响

Effects of Application of Fertilization on Culturable Microorganisms and Microbial Biomass Phosphorus in Upland and Paddy Soils of Red Earth Region

选择位于湖南桃源的红壤旱地和稻田长期施肥田间定位试验,研究了不施肥(CK)、施NPK(NPK)、施NPK+稻草(NPK+Str)或施NPK+稻草+绿肥(NPK+Str+GM)对旱地和稻田土壤可培养细菌和真菌及土壤微生物生物量磷的影响。结果表明,在旱地土壤中,NPK+Str处理土壤可培养真菌数量和微生物生物量磷比CK和NPK处理显著增加,而CK、NPK和NPK+Str处理土壤可培养细菌基本相同。在稻田土壤中,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比CK和NPK处理均显著增加,但土壤可培养细菌数量的增加幅度明显大于可培养真菌。由此推断,施稻草后旱地土壤微生物生物量磷的增加可能主要来源于真菌,而施稻草和紫云英对稻田土壤中微生物生物量磷的增加可能主要来源于细菌。

An upland and paddy soil samples of red earth region were collected from various treatments of a long-term fertilization experiment in Hunan, China.And the culturable bacteria, fungi and amount of microbial biomass phosphorus （MB-P） were analyzed.The results indicated that combined application of straw and chemical fertilizers （NPK-Str） significantly increased the amount of culturable fungi and MB-P compared with the treatment of no fertilization （CK） and chemical fertilizers （NPK） in upland soils.Whereas there＇s no significant difference of culturable bacteria 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 of upland soils amended with rice straw.However, combined application of straw and chemical fertilizers with addition of astragalus （NPK-Str-GM） significantly increased the amount of culturable fungi, bacteria and MB-P in paddy soils, especially, the enhancement level of culturable bacteria was much higher than that of fungi, in comparison with the treatment of CK and NPK.Consequently, this study demonstrates that bacterial and fungi likely play different roles on microbial biomass P in upland and paddy soils.That is bacteria may contribute on the MB-P which application of rice straw and organic green manure （astragalus） in paddy soils, however, fungi only play a majorrole in upland soil with the application of rice straw.