不同耕作措施及玉米生育期对黄壤坡耕地土壤团聚体稳定性的影响

为探讨耕作措施和玉米季对黄壤坡耕地土壤团聚体稳定性的影响,以横坡垄作坡面为研究对象,顺坡垄作坡面为对照,研究野外自然降雨条件下玉米季黄壤坡耕地土壤团聚体组成及其稳定性的变化特征,以期为山地黄壤区土壤抗蚀性研究提供理论依据。结果表明:①不同耕作措施对玉米种植土壤团聚体组成和稳定性影响显著,横坡垄作坡面较顺坡垄作含有更多大粒级团聚体;以(10,0.25]mm水稳性团聚体(WSA_>0.25)、平均质量直径(MWD)、几何平均直径(GMD)、结构体破坏率(PAD)、水稳性团聚体分形维数(D)、团聚体稳定性系数(ASI)为指标进行分析,得出横坡垄作坡面土壤团聚体稳定性较顺坡垄作坡面好。②随玉米生育期的推进,土壤大粒级团聚体含量及团聚体稳定性均呈现出显著升高的趋势,且在成熟期达极大值,表明玉米生育期也显著影响土壤团聚体组成及稳定性。③相关性分析得出,团聚体稳定性与根系密度、根表面积、根体积呈极显著正相关关系,根系的发育对增强研究区土壤团聚体稳定性具有重要的贡献。适宜的耕作措施和合理的种植模式均有助于研究区水土流失的有效防控。

Effects of Different Tillage Measures and Maize Growing Seasons on Soil Aggregates' Stability in Sloping Yellow Soil Cropland

The composition and stability of soil aggregates in sloping yellow soil cropland during the whole maize growing season under natural rainfall conditions were studied in an attempt to reveal the effects of tillage measures and maize growing season on soil aggregates' stability. Cross ridge slope was taken as research object, while longitudinal ridge slope as the control. The study is expected to provide theoretical basis for the study of anti-erodibility of mountain yellow soil in Sichuan Province. Results demonstrated that: 1) The composition and stability of soil aggregate were significantly affected by tillage measures. Compared with that on longitudinal ridge, more soil macro-aggregates were contained on cross ridge slope; the stability of cross ridge slope is better than that of longitudinal ridge slope according to analysis on such indicators as (10,0.25] mm water-stable aggregate (WSA_>0.25), mean weight diameter (MWD), geometric mean diameter (GMD), percentage of aggregate disruption (PAD), fractal dimension (D) of soil water-stable aggregate, and aggregate stability index (ASI). 2) With the advancement of maize growth, the content of soil macro-aggregate and soil aggregate stability both showed a significant increasing trend and reached a maximum value at maturing stage, implying significant influence of maize growing season on soil aggregate's composition and stability. 3) Correlation analysis unveiled that soil aggregate's stability was in extremely significant positive relationships with root density, root surface area and root volume, indicating that root development played an important role on improving soil aggregate's stability. The findings demonstrated that suitable tillage measures and proper planting patterns could effectively prevent and control regional soil erosion.