免耕与覆盖施肥对水稻土结构的影响

Impacts of No-tillage and Manure Mulching on Paddy Soil Structure

对连续免耕3—7年试验地水稻土结构系数和收缩性能进行测定。结果表明,免耕能改善水稻土结构和土壤排水通气状况。而耕作对水稻土结构的作用机制除机械破坏外,有机物料翻埋入土,淹水后产生大量还原物质对土壤结构的破坏影响较大。在免耕条件下有机物料面施,淹水种稻过程中不会引起土壤内部强烈的还原作用,有利于土壤结构的保持。

For the determination of soil structure coefficient, soil samples were collected from three no-tillage field experiments which were conducted at different sites in South Jiangsu. In those experiments, no-tillage had been continued for 3-7 years with conventional tillage as the control. The resulst showed that no-tillage cultivation could improve soil structure, water percolation and aeration of paddy soil. In another experiment of soil incubation, inorganic and organic manures were either incorporated with potted soils or applied as mulch on the soil surface, to simulate conventional tillage and no-tillage respectively. It showed that the soil aggregation of the paddy soil was deteriorated not only by the effects of tillage practices but also by strong reduction process and total reduced substances in soil in which organic manure was incorporated under waterlogging condition. However, the effect of intensive reduction could be avoided by mulching organic manure on soil surface in the no-tillage cropping system, and as a result, the structure of paddy soil could be well protected.