【摘要】 运用物理分组的方法对海南岛的次生林、水稻田、甘蔗地土壤(剖面分0～10cm,10～20cm,20～50cm,50～100cm四层)进行物理组分及其有机C含量进行研究。结果表明:土地利用方式由次生林变为农用地后,大团聚体占土壤的质量百分数显著降低,微团聚体和粉粒与粘粒大小的团聚体占土壤的质量百分数显著增加,几种团聚体中微团聚体的变幅最大;由次生林变为水田比变为甘蔗地对土壤不同团聚体所占的比例影响大;次生林改为水稻田和甘蔗地后,水稻田和甘蔗地土壤各物理组分的有机碳含量都显著降低,且水田土壤团聚体有机碳降低的幅度较大。土地利用变化主要使0～50cm土壤产生显著退化。更多还原

【Abstract】 Soil samples from the paddy,sugarcane land and natural secondary forest systems were separated in macroaggregate(>250μm),microaggregate(53～250μm)and silt and clay(<53μm)three aggregate size classes,and all fractions organic matter and quantity percent were analyzed.The results indicated that natural secondary forest soil with higher percentages of macroaggregate(>250 μm),compared to sugarcane land and paddy soils,and sugarcane land and paddy soils were characterized by higher proportions of microaggregate(53～250 μm)and silt&clay(<53 μm)fractions.The effect of rice cultivation is stronger than sugarcane cultivation on percentages of aggregates in soils.Rice cultivation and sugarcane cultivation are all result in significant loss of C in SOM fractions,the decrease of organic carbon in aggregate fractions of paddy soil is larger compared to that in aggregate fractions of corresponding depth layers soils of sugarcane land.更多还原