南方双季稻田秸秆厢沟腐熟还田免耕土壤生态效应研究

对为期2年的双季稻田秸秆厢沟腐熟还田免耕试验的土壤理化性质，微生物数量及3种土壤酶(脲酶，过氧化氢酶，转化酶)活性变化进行比较研究。结果表明，秸秆厢沟腐熟还田免耕试验2年后，土壤密度减小，孔隙度增加，土壤有机质、全氮、水解氮、速效钾含量增加。与常规翻耕相比，厢沟免耕0～5cm土层养分富集不明显，细菌、真菌数量增多，土壤酶活性增强；15～25cm土层土壤密度显降低，土壤有机质、全氮和水解氮分别比对照增加55．23％、44．73％和43．48％。因此，秸秆厢沟腐熟还田免耕能够提高土壤肥力，为作物生长提供良好的土壤环境。

Soil ecological effect of no-tillage and stubble return with ditch-degeneration on double-cropping rice field in the south of China

The characteristics of the physical and chemical properties,the micro biomass amount and the activity of three enzymes(urease,catalase,invertase)in paddy soil under a two-year no-tillage and stubble return with ditch-degeneration were studied and contrasted with those of soil under cultivated treatment.The results showed that the soil density was reduced,the hole capacities was augmented,and the content of the organic matter,the total and the hydrolyzable N,available K were increased after two-year no-tillage and straw return with ditch-degeneration.Compared to conventional tillage treatment,under no-tillage with ditch the nutrient enrichment was unapparent,the quantities of bacteria and fungi were improved and the activity of enzyme was enhanced in 05 cm soil layer,and the soil density was apparently decreased,the content of the organic matter,the total N and the hydrolyzable N were increased by 55.23%,44.73%,43.48%,respectively in 1525 cm soil layer.Conclusion:no-tillage and stubble return with ditch-degeneration was beneficial for improving soil fertility,and produced a suitable soil environment for crop growth.