毛乌素沙地南缘保护性耕作措施对土壤物理性质的影响

The effects of conservation tillage on soil physical properties in the southern part of the MuUs desert

为了探讨不同保护性耕作措施在毛乌素沙地南缘的区域适应性，从2004开始，以靖边县北部风沙区农田为研究对象，选用了免耕、秸秆覆盖、覆膜和传统翻耕（CK）4种措施，采用完全随机试验设计进行了田间定位试验研究。比较分析了4种措施下土壤物理性质的变化规律。结果表明，秸秆覆盖和免耕地的地温在春播初期略比传统翻耕低0．1℃，但随后迅速回升，覆膜在玉米生长期都高于其他措施。耕作措施对播种前土壤容重没有显著影响，而对收获后土壤容重影响显著，与传统翻耕相比，免耕降低了表层土壤容重2．3％，但次层20～40cm容重增加了1．8％。3种保护性耕作措施均增加了土壤含水量，顺序依次为秸秆覆盖〉覆膜〉免耕〉翻耕，且在作物需水关键期免耕和秸秆覆盖下的土壤含水量相对稳定。免耕和秸秆覆盖措施下初始入渗率和稳定入渗率都高于翻耕，而覆膜低于翻耕。保护性耕作措施改善了土壤物理性质，适于在该风沙区推广。

Conservation tillage can reduce soil wind erosion and control soil degradation in sandy area. The objective of this field experiment was to compare the effects of four tillage measurements （no-till, stalkmulching, film-mulching and conventional tillage） on soil physical properties the sandy soil region of northern Jingbian County, Shaanxi Province. The experiment began in 2004. A completely randomized design was used. The results showed that at early spring planting, soil temperatures were 0. 1℃ lower in the stalk-mulching and no-till treatments compared to the conventional tillage treatment. Soil ＂temperatures were highest under film mulch. There was no significant difference in soil bulk density among the treatments before planting; however there was a significant difference among the treatments after harvest. Soil bulk density in the 0-20 cm layer was 2.3 96 lower in the no-tillage treatment compared to conventional tillage; however the bulk density in the 20 40 cm layer was 1.8 96 higher in the no-tillage treatment compared to conventional tillage. Soil water content decreased in the order stalk-mulching 〉 film-mulching 〉 no-till 〉 conventional tillage. Both initial and equilibrium infiltration rate infiltrate rate are higher in conservation tillage than conventional tillage. In summary, the resuits show that conservation tillage methods improved soil physical properties and therefore could be implemented in the southern part of Mu Us desert.