保护性耕作对土壤理化性质和作物产量的影响

应用定位田间试验的方法，研究了不同耕作方式和秸秆还田方式对作物产量和土壤理化性质的影响。研究结果表明，传统翻耕的土壤容重大于进行保护性耕作的土壤容重；随着免耕年限的增加，土壤团聚体不断增大，进行5年保护性耕作的土壤团聚体比进行2年、3年保护性耕作的土壤团聚体有明显增加：进行免耕秸秆覆盖处理的土壤养分除碱解氮外．有机质、全氮、全钾、全磷及速效磷、速效钾均高于免耕无秸秆覆盖和传统翻耕的土壤：在施肥量相同的情况下。进行保护性耕作处理的小麦和水稻产量均比传统翻耕高，其中以半量秸秆还田免耕增产幅度最高，分别达小麦14．45％，水稻6．47％。

Effect of Conservation Tillage on Soil Physicochemical Properties and Crop Yields

Applying the method of field fixed position experiments, this article studied the effect of different tillage methods and modes of getting straw and stalk back to the field on the crop yields and soil physicochemical properties. The results indicated that bulk density of soil under traditional plowing was higher than soil under conservation tillage. As the no-tillage number of years increasing, soil aggregate degree was increasing continuously. Moreover, soil which had carried on conservation tillage for 5 years, the soil aggregates amount had improved obviously than the soil that only carried on conservation tillage for 2 or 3 years. For no-tillage and straw mulch tillage soil, except available N (aN), the content of soil physicochemical properties including total N (tN), total K (tK), total P (tP) and available K (aK), available P (aP) were all higher than the soil which carried on no-tillage and no straw mulch tillage, also higher than the traditional plowing soil. Under the condition of same amount of applied fertilizer, wheat and rice yields in the fields of ongoing conservation tillage were both higher than that in traditional plowing fields. Furthermore, increase production range of half straw returning to field was the highest, the wheat was 14.45% and the rice was 6.47%.