土地利用方式对土壤大团聚体的影响

Impact of Land Use Types on Distribution of Macro-Aggregates

[目的]探讨不同土地利用方式对土壤大团聚体的影响。[方法]通过江西省某农业园区农地(水稻田和旱地)、林地和荒地土壤团聚体的测定,分析了不同土地利用类型土壤团粒结构的差异,并讨论了其主要影响因素。[结果]不同土地利用方式下大于2.00 mm土壤团聚体的比例约占一半,其他各粒径团聚体的比例占10%左右,而且,随土壤粒径的减小团聚体数量呈先减少后增加的趋势。各土地利用类型土壤中大于2.00 mm的团聚体所占的比例依次为林地>农地>荒地,而不同农业用地土壤中大于2.00 mm团聚体所占的比例为芝麻>水稻>花生。此外,高含水量水稻土中大于2.00 mm团聚体数量约为低含水量水稻土的4倍,但对于0.50～0.25 mm粒径的团聚体,前者数量不足后者的1/5。[结论]随着土壤粒径的减小,团聚体数量呈先减少后增加的趋势,且不同土地利用方式下土壤团聚体以大于2.00 mm团聚体为主。土地利用过程中的植被覆盖状况、人类干预强度、土壤含水量等因素都能在不同程度上影响土壤大团聚体的稳定性。

[Objective] To discuss the impact of land uses on distribution of soil macro-aggregates.[Method]The composition of soil macroaggregates for different land uses was analyzed,the major effected factors in a certain agricultural park,Fengchang City,Jiangxi Province was discussed.[Result] The distribution patterns of soil aggregates for different land uses decrease and then increase with the size of soil aggregates becoming small.The soil is mainly composed by aggregates of more than 2.00 mm（approximately half） and the others each take a percentage of about 10.For the soil aggregate with a size above 2.00 mm,its percentage follows as forest land,crop land and unused land,and sesame,paddy and peanut for the crop lands in decending order.Additionly,the soil water also has an effect on distribution of soil aggregates.Amount of 2.00 mm aggregate in higher water content paddy soil is about 4 times that of lower water content paddy soil,but the former is less than one fifth of the latter for the aggregate of 0.50-0.25 mm.[Conclusion]There is a trend of decrease and then increase for the soil aggregates when the size of them becomes small and the major aggregate for the different land uses is 2.00 mm soil aggregate.The factors including plant covering,human activities and soil water content could,to a certain extent,infulence the stability of soil macro-aggregate in the process of land use.