不同利用方式和肥力红壤中水稳性团聚体分布及物理性质特征

DISTRIBUTION AND PHYSICAL PROPERTIES OF SOIL WATER-STABLE AGGREGATES IN RED SOILS DIFFERENT IN LAND USE AND SOIL FERTILITY

研究了不同土地利用方式和土壤肥力对红壤水稳性团聚体及土壤物理性质的影响。结果表明,同一肥力水平下不同土地利用方式的土壤中,>0.25 mm水稳性团聚体含量变化趋势相同,均以旱地土壤含量最低,林地土壤最高。不同肥力水平下,林地、果园、水田中>5 mm水稳性团聚体含量变化均为:高肥力>低肥力。说明随土壤肥力的逐渐增高,有机质胶结物质含量增加,有利于形成更多的水稳性大团聚体。土壤团聚体稳定性与>0.25 mm水稳性团聚体含量呈极显著正相关,这表明>0.25 mm水稳性团聚体含量是影响土壤团聚体稳定性的主要因素。不同土地利用方式下的土壤物理性质(土壤容重、土粒密度、土壤孔隙度)存在较大差异,变化规律也不一致。但土壤容重和土壤孔隙度与>0.25 mm水稳性团聚体含量有很好的相关性。

Distribution and soil physical properties of water-stable aggregates in red soils different in land use and soil fer- tility were studied. Results show that the content of soil water-stable aggregates 〉 0.25 mm is consistently affected by land use, and is the lowest in upland soil and the highest in woodland soil. When they are 〉 5 mm, their content is affected by soil fertility. The higher the fertility, the higher the content, which suggests that with increasing soil fertility, the content of soil organic matter increased, thus facilitating formation of more water-stable soil aggregates. Mean weight diameter （MWD） is positively related to content of water-stable aggregates 〉 0.25 mm, which is, therefore, the major factor affecting stability of soil aggregates. Soil physical properties （bulk density, particle density, porosity） differ sharply from pattern to pattern of land use and so do the rules of their variation. However, soil bulk density and soil porosity are favorable related to content of water-stable aggregates 〉 0.25 mm.