稻草还田少免耕对稻田土微生物及酶活性的影响

为探明少免耕和稻草覆盖对土壤生物特征的影响，合理利用稻草覆盖及耕作制度来保障土壤的可持续利用，研究了33％（约2500ks／hm^2）、67％（约5000kg／hm^2）、100％（约7500kg/hm^2）稻草覆盖少免耕对稻田土微生物区系及活性的影响。定位试验2年后，少免耕与稻草覆盖提高了稻田土好气性细菌数量、真菌数量和微生物活度，但厌气性细菌和放线菌的数量则略减少。33％和67％稻草还田时，翻耕土壤的好气性细菌和厌气性细菌数量均高于免耕和少耕土壤。33％稻草还田时，免耕和少耕土壤的放线菌和真菌数量均高于翻耕土壤。同时，少免耕提高了土壤木聚糖酶、纤维素酶、蛋白酶、脲酶、过氧化氢酶的活性，也提高了土壤微生物活度、氨化作用强度和硝化作用强度。少量稻草还田少耕要优于少量稻草还田翻耕和免耕。

Effects of No or Minimum Tillage with Rice-straw on Microbial Counts and Enzyme Activity in Paddy Soil

In order to reveal the effect of agricultural technology on biological characteristics in soil and provide scientific basis for reasonable culturing system,the effect of no or minimum tillage on the microbial flora and its activity in paddy soil covered with 33% （about 2500 kg/ hm^2 ） ,67% （ about 5000 kg/hm^2 ） ,100% （ about 7500 kg/hm^2 ） straw were conducted. After two-year-test,the number of aerobic bacteria, fungi and microbial activity increased. However, the number of anaerobic bacteria and actinomycetes slight drop. With 33 % ,67 % straw returing to soil ,the number of aerobic bacteria and anaerobic bacteria in tilling soil was more than that in no-tillage and minimum tillage. With 33% straw returing to soil, the number of fungi and actinomycetes in no-tillage and minimum tillage soil was more than that in tillage treatment. Meanwhile, xylanase activity, cellulose activity, protease activity, urease activity, catalase activity microbial activity, ammonification and nitrification increased in no-tillage and minimum tillage soil Minimum tillage with minimum straw was a better technology to improve soil quality and did good to crops than tillage or no tillage.