陇中黄土高原不同类型土壤团聚体稳定性及抗蚀性研究

Study on Stability and Anti-erodibility of Different Types of Soil Aggregates in the Loess Plateau of Central Gansu Province

以陇中黄土高原地区黄绵土(LS)、灰钙土(CS)、红黏土(RC)和灌淤土(SS)四种典型土壤为研究对象,探讨不同土壤类型农田土壤团聚体稳定性和抗侵蚀能力。本研究采用干筛-湿筛法得到不同粒级团聚体比例,来计算水稳性团聚体平均质量直径(MWD)、几何平均直径(GMD)、颗粒分形维数(D)、团聚体破坏率(PAD)、>0.25 mm占比[M_((w>0.25))]和土壤可蚀性因子K值。结果表明,水稳性团聚体平均质量直径红黏土和灌淤土显著性大于黄绵土和灰钙土,几何平均直径红黏土>灌淤土>黄绵土>灰钙土,分别为0.41、0.30、0.23和0.21 mm,各土壤类型间差异性显著;颗粒分形维数灰钙土最大,红黏土最小,分别为2.97和2.90;湿筛对土壤团聚体的破坏率红黏土和灌淤土显著小于黄绵土,黄绵土最大;>0.25 mm水稳性团聚体占比最大的是红黏土,为45.87%,灌淤土次之,黄绵土最小,为23.53%。相关性分析结果表明,土壤团聚体稳定性各指标间的相关性良好,其中MWD与GMD、M_((w>0.25))呈极显著正相关(p<0.01),与D、K呈极显著负相关(p<0.01),与PAD呈显著负相关(p<0.05);GMD与其他土壤团聚体各项指标均表现出极显著相关性(p<0.01);土壤有机质与土壤稳定性各指标之间也呈现出极显著相关性(p<0.01)。结论表明,土壤抗蚀性红黏土灌淤土较好,黄绵土居中,灰钙土最差。研究结果可为陇中黄土高原地区不同土壤类型农田土壤抗侵蚀能力提供参考,对黄土高原土壤水土保持功能的提升及水土保持效应的持续稳定发挥具有重要意义。

Taking loessial soil(LS),calcareous soil(CS),red clay(RC)and silted soil(SS)as the research objects,the stability and anti-erosion ability of farmland soil aggregates with different soil types were discussed.In this study,the dry-wet sieve method was used to obtain the proportions of aggregates with different particle sizes,and then the average mass diameter(MWD),geometric average diameter(GMD),fractal dimension(D),aggregate destruction rate(PAD),the ratio of>0.25 mm[M_((W>0.25))]and soil erodibility factor K were calculated.The results show that the average mass diameter of water-stable aggregates in red clay and silted soil is significantly larger than that in loessial soil and calcareous soil.The average geometric diameters of red clay>silted soil>loessial soil>calcareous soil are 0.41 mm,0.30 mm,0.23 mm and 0.21 mm,respectively,with significant differences among different soil types.The fractal dimension of calcareous soil is the largest and that of red clay is the smallest,which are 2.97 and 2.90 respectively.The damage rate of wet sieve to soil aggregates is significantly lower in red clay and irrigated soil than that in loessial soil,and the largest in loessial soil.The largest proportion of water-stable aggregates larger than>0.25 mm is red clay,accounting for 45.87%,followed by irrigated silt,and the smallest is loessial soil,accounting for 23.53%.The results of correlation analysis showed that the indexes of soil aggregate stability had a god correlation,among which MWD was positively correlated with GMD and M_((v>0.25))(P<0.01),negatively correlated with D and K(P<0.01)and negatively correlated with PAD(P<0.05).GMD was significantly correlated with other soil aggregates(P<0.01).There is also a significant correlation between soil organic matter and soil stability indicators(P<0.01).The conclusion shows that,soil erosion resistance of red clay is better,loessial soil is in the middle,and calcareous soil is the worst.The research results can provide reference for the anti-erosion ability of farmland soil of different soil types in the Loess Plateau of central Gansu,and have important significance for the improvement of soil and water conservation function and the sustained and stable play of soil and water conservation effect in the Loess Plateau.