保护性耕作和植物残体对土壤养分状况的影响

Effects of conservation tillage and crop residues on soil nutrient contents.

研究了不同耕作和秸秆还田方式对1年2熟(冬小麦-玉米)条件下壤质潮土养分含量的影响。结果表明,随着土壤耕翻程度的降低,土壤养分含量逐渐增加。免耕表土(0～10cm)有机质、全N和速效磷的含量显著(P<0.05)高于常规耕作(浅耕)方式,其速效钾含量也明显高于其他耕作方式,速效磷和速效钾的增加与免耕土壤有机质含量的提高以及由此导致的pH值下降显著相关,他们之间存在着显著(P<0.05)的线性关系;秸秆覆盖有利于表土养分的积累,但与其他秸秆还田方式积累养分量的差异未达到显著水平。

The experimental results showed that the nutrient contents of loamy soil under two crops a year (winter wheat + maize) was increasing with the decrease of tillage practices to the soil. The contents of organic matter,total N and available P of surface soil (0- 10cm) under zero tillage were significantly higher (P<0. 05) than those under conventional tillage (shallow tillage) ,and available K was the highest among all the treatments. The increasing of available P and K for the zero tillage is significantly related to the increasing of organic matter and decrease of pH value resulting from the organic matter increasing. There was a linear relationship existing among those factors. Straw mulch is favorable to the nutrient accumulation at surface soil, but itsingnificant different effects have nat found compared with other crop residue retention measures.