保护性耕作下西南黄壤坡地的土壤结构效应

Soil Structure Effect of Conservation Tillage in Yellow Soil Slope Cropland in Southwest China

设置两种保护性耕作措施,通过6年连续试验,研究了保护性耕作措施对黄壤土结构性状的影响,为西南黄壤地区保护性耕作技术应用与发展提供理论依据。结果表明:(1)垄播沟覆轮耕与免耕秸秆覆盖两种保护性耕作措施均可降低黄壤容重,增加土壤孔隙,且此作用是由表及里的渐进过程,垄播沟覆措施的土壤容重优化作用要优于免耕覆盖,而免耕覆盖对较深层次土壤孔隙状况优化效果更显著。(2)保护性耕作可提高0~20 cm土壤>0.25 mm干筛团聚体含量,水稳性团聚体含量处理之间差异不显著,但0~20 cm层含量略大于20~40 cm层。(3)保护性耕作可提高土壤团聚体稳定性,降低团聚体破坏率,免耕覆盖措施对提高土壤团聚体稳定性具有更加显著的效果。该试验证明了保护性耕作对黄壤土容重、孔隙、团聚体等结构性状有一定的改善作用,这种改善作用是一个非常漫长的由表及里的渐进过程,为西南黄壤地区保护性耕作技术应用与发展奠定了坚实的基础。

Effect of conservation tillage on yellow soil structure was explored through setting two kinds of conservation tillage by continuous testing of 6 years, in order to provide a theoretical basis for the conservation tillage technology application and development in yellow soil area in south China. The results showed that （1） soil bulk density decreased and soil porosity increased under the two kinds of conservation tillage, which were rotational tillage of sowed on ridge with mulch （LS） and no-tillage with mulch （NTS）, and the effect advanced gradually from surface to inside, the soil bulk density optimize effect of LS was better than that of NTS, but soil porosity optimize effect of NTS was better than that of LS in deeper soil; （2） conservation tillage could increase soil 〉0.25 mm aggregate content in 0-20 cm soil layer, water stable aggregate content had no obvious difference, but the content in 0-20 cm soil layer was slightly larger than that in 20-40 cm soil layer; （3） conservation tillage could increase soil aggregate stability and reduce aggregate destruction, NTS had more significant effect on improving the stability of soil aggregates. The results proved that conservation tillage had improving effect on soil bulk density, porosity, aggregates and other structural traits of yellow soil, and the change was a long process from surface to inside. The study laid a solid foundation for conservation tillage in yellow soil region.