紫色土区植物篱篱前淤积带与篱下土坎土壤抗蚀性研究

为探究紫色土坡地植物篱篱前淤积带与篱下土坎土壤抗蚀性的差异及变化规律,选取遂宁市水土保持试验站10°新银合欢植物篱小区(T1)、10°和15°香根草植物篱小区(T2和T3)进行研究。研究小区布设有上、中、下坡篱带,分别采集篱前淤积带和篱下土坎(下坡无)的表土样,测定有机质含量、水稳性团聚体和微团聚体组成,运用主成分分析法对土壤抗蚀性进行分析。结果表明:同一篱带,土壤有机质含量、团聚度和团聚状况均是篱前淤积带高于篱下土坎,土壤水稳性团聚体含量和抗蚀性综合指数则反之,篱下土坎的抗蚀性综合指数是篱前淤积带的1.48～3.17倍;同一小区,篱前淤积带土壤有机质含量、团聚度和团聚状况均表现为下坡中坡上坡,篱下土坎为中坡上坡,而土壤水稳定性和抗蚀性综合指数在坡位间则无显著性差异;同坡度下,香根草植物篱小区土壤有机质含量、团聚度、团聚状况和水稳定性均高于新银合欢植物篱小区;坡度越大,香根草植物篱小区土壤有机质含量、团聚状况和水稳定性表现越差;主成分分析发现,水稳性团聚类指标能较好地反映紫色土坡地土壤抗蚀性能的强弱,研究小区土壤抗蚀能力表现为T2T1T3。

Study on Soil Anti-erodibility Between Sedimentation Zone in Front of Hedgerows and Ridge Behind Hedgerows in Purple Soil Area

This paper studied the differences and variation of soil anti-erodibility between sedimentation zone in front of hedgerows and ridge behind hedgerows on purple soil slopping land. We collected soil samples form three runoff plots (10° Leucaena leucocephala hedgerows plot (T1), 10° and 15° Vetiveria zizanioides hedgerows plots (T2 and T3)). These plots were selected from Soil and Water Conservation Experimental Station in Suining as the research object. The plots were provided with up, middle, and down hedge belts, and surface soil samples from the zone in front of hedgerows and ridge behind hedgerows were collected to determine the organic matter content, water-stable aggregates and micro-aggregate composition. Combined with the principal component analysis, we obtained the following results: The soil organic matter content, degree of aggregation and state of agglomeration of sedimentation zone in front of hedgerows were better than those of ridge behind hedgerows in the same hedge, and water stable aggregate content and the comprehensive index of soil anti-erodibility were opposite. The comprehensive index of soil anti-erodibility of ridge behind hedgerows was 1.48~3.17 times higher than that of sedimentation zone in front of hedgerows. The organic matter content, degree of aggregation and state of agglomeration of sedimentation zone in front of hedgerows showed the largest in the down slope, followed by the middle slope, and the smallest in the up slope, while that of ridge behind hedgerows showed the largest in the up slope and followed by the middle slope, and the water-stable aggregate content and the comprehensive index of soil anti-erodibility had no significant difference between the slope positions. In the same slope position, the soil organic matter content, degree of aggregation, state of agglomeration and water stable aggregate of Vetiveria zizanioides hedgerows plot were better than that of Leucaena leucocephala hedgerows plot. The higher the slope, the worse the soil organic matter content, status of agglomeration and water stable aggregate in Vetiveria zizanioides hedgerows. It was discovered by principal component analysis that the index of water stable aggregate could better reflect the strength of soil anti-erodibility in purple soil slopping land, and the best soil anti-erodibility was given by T2, followed by T1 and T3 in sequence.