辽西低山丘陵区不同密度荆条下表层土壤抗蚀性特征

Soil Anti-erosion Characteristics of Surface Soil Under Vitex negundo L. with Different Densities in Low Mountainous Upland Region of Western Liaoning Province

为探究不同水土保持树种对土壤侵蚀的调控机理,以广泛分布在辽西低山丘陵区土石质山坡的荆条为研究对象,通过现场调查荆条植被覆盖度,选取3种不同株密度荆条样地,采用室内土壤理化分析测定土壤机械组成、土壤团聚体分布特征和土壤有机质含量等土壤性质指标,并应用主成分分析方法分析不同密度荆条下的表层土壤抗蚀性。结果表明:荆条对土壤物理性粘粒形成的促进作用高于草本植物,但株密度对其影响不大;随着荆条株密度增加物理性砂粒含量增加,荒草地显著大于荆条样地,说明荆条的土壤质地更为黏重;土壤大粒径团聚体的稳定性随着荆条株密度的增加变得更好;不同荆条株密度的土壤物理性粘粒含量大于荒草地,呈显著差异,但不同样地间(<0.001mm、0.001~0.01mm)土粒没有显著性差异,随着荆条株密度增加,物理性砂粒含量增加,荒草地显著大于荆条样地;大团聚体分散总量为YD小>YD中>CG>YD大,且随着荆条株密度增加,土壤的改良进程更快,而荒草地对土壤的改良强度小于荆条;>0.25mm水稳性团粒含量、>0.5mm水稳性团粒含量、>0.25mm团聚体破坏率和>0.5mm团聚体破坏率是影响土壤抗蚀性的主要因素。土壤抗蚀性强弱为YD大>CG>YD中>YD小,且存在一个荆条株密度阈值,使荆条土壤抗蚀性与荒草地相等。

In order to explore the regulation mechanism of soil erosion with different soil and water conservation tree species, the surface soil erosion resistance under the different density of Vitex negundo L. was analyzed by the sampling from the field investigation and the soil physical and chemical properties analysis indoors. The results showed that the promoting effect of thorns on soil physical clay formation was higher than that of herbaceous plants, but the plant density had little effect on soil physical clay formation. With the increase of plant density, the content of physical sand grain increased significantly, which indicated that the texture of soil was more viscous, and the stability of large-grain aggregate became better with the increase of plant density of thorns, and the soil texture was more viscous in the barren land than in the sample plot of thorns, and the stability of soil aggregates became better with the increase of plant density. The soil physical clay content of the Vitex negundo L. with same plant density was significantly higher than that of the grassland, but there was no significant difference between the <0.001mm, 0.001-0.01mm soil grains. With the increase of the plant density, the physical sand content of the Vitex negundo L. was significantly higher than that of grassland. The total dispersed amount of macroaggregates was YDs>YDm>CG>YDl. With the increase of plant density of Vitex negundo L., the improvement process of soil was faster, while the improvement intensity of grassland on soil was less than that of Vitex negundo L.>0.25mm water stable aggregation content,>0.5mm water stable aggregation content,>0.25mm aggregation damaged rate and > 0.5mm aggregation damaged rate were the main factors affecting the soil erosion resistance. The soil erosion resistance was YDl>CG>YDm>YDs, and there was a threshold of the Vitex negundo L.var planted density, which made the soil erosion resistance equal to that of the grassland.