机械化保护性耕作条件下土壤质量的数值化评价

通过9年的长期田间定位试验研究了陕西关中平原中部冬小麦 夏玉米轮作条件下深松耕（ST）、旋耕（RT）、秸秆还（SR）、免耕（NTS）等保护性耕作措施及传统耕作（TT）对土壤理化性状和作物产量的影响，并采用主成分分析方法进行土壤质量的综合评价.结果表明：与传统耕作相比，保护性耕作模式提高了土壤肥力质量，改善了土壤物理环境条件；显著提高了土壤脲酶和碱性磷酸酶的活性；除秸秆覆盖免耕处理的玉米和小麦产量低于传统耕作外，其他保护性耕作措施均不同程度地提高了作物产量，其中小麦增产13%～28%，玉米增产3%～12%.与传统耕作相比，保护性耕作土壤质量指数提高了19.8%～44.0%.综合考虑经济效应和生态效益，隔年深松、秸秆粉碎联合旋耕作业以及秸秆覆盖联合深松作业不仅能增加作物产量还可改善土壤质量，可在研究区进行推广应用.

Numerical evaluation of soil quality under different conservation tillage patterns

A 9-year field experiment was conducted on the Guanzhong Plain of Shaanxi Province to study the effects of subsoiling, rotary tillage, straw return, no-till seeding, and traditional tillage on the soil physical and chemical properties and the grain yield in a winter wheat-summer maize rotation system, and a comprehensive evaluation was made on the soil quality under these tillage patterns by the method of principal components analysis (PCA).Comparing with traditional tillage, all the conservation tillage patterns improved soil fertility quality and soil physical properties. Under conservative tillage, the activities of soil urease and alkaline phosphatase increased significantly, soil quality index increased by 19.8%-44.0%, and the grain yield of winter wheat and summer maize (expect that under no till seeding with straw covering) increased by 13%-28% and 3%-12%, respectively. Subsoiling every other year, straw- chopping combined with rotary tillage, and straw-mulching combined with subsoiling not only increased crop yield, but also improved soil quality. Based on the economic and ecological benefits, the practices of subsoiling and straw return should be promoted.