不同利用方式旱地红壤水稳性团聚体及其碳、氮、磷分布特征

DISTRIBUTION OF SOIL WATER-STABLE AGGREGATES AND SOIL ORGANIC C,N AND P IN UPLAND RED SOIL

针对江西红壤地区不同利用方式引起的土壤质量和肥力的相应变化,研究了不同肥力水平、不同利用方式下红壤旱地水稳性团聚体含量及其养分分布规律。研究表明,荒地土壤中>5 mm水稳性团聚体含量显著高于其他利用方式,花生地和果园土壤则以0.25～0.053 mm的水稳性团聚体为主。各肥力水平下,菜地土壤中除>5 mm水稳性团聚体外,各粒级团聚体中有机碳、全氮和全磷含量均显著高于花生地、果园和荒地土壤。说明菜地土壤长期大量施肥,导致土壤碳、氮、磷养分含量均相对丰富。不同利用方式旱地红壤中,有机碳、全氮主要分布在>5 mm、5～2 mm和2～1 mm的较大粒径水稳性团聚体中。说明随着团聚体粒径增大,其有机碳含量增加,土壤全氮的消长趋势和有机碳一致。土壤全磷较均匀地分布在水稳性团聚体中,如高肥力菜地和荒地土壤各粒级团聚体中全磷含量间均无显著性差异。各利用方式旱地红壤中2～1 mm和1～0.5 mm的水稳性团聚体含量与土壤有机碳、全氮和全磷含量间均达到了极显著正相关。

Distributions of water-stable aggregates and organic C, N and P were studied in upland red soils different in land use and fertility level. Results show that the content of aggregates 〉 5 mm in wasteland was significant higher than in fields of other land uses. And peanut land and orchard was dominated with the fraction of 0.25 - 0. 053 mm aggregates. Regardless of fertility levels, vegetable land was the highest in contents of soil organic C, N and P in all fractions of aggre-gates, except aggregates 〉 5 mm, which illustrates that long-term fertilization in vegetable land has resulted in enrichment of soil organic C, N and P. In these upland red soils, soil organic C, N and P accumulated in aggregates of fractions 〉 5 mm, 5 - 2 mm and 2 - 1 mm, which shows that soil nutrients in aggregate increased with the increase in particle size, especially soil organic C. Soil N followed a similar trend, but soil P was distributed quite evenly in water-stable aggregates. It was particularly so in high-fertility vegetable land and wasteland soil. The contents of 2 - 1 mm and 1 - 0.5 mm aggregates in upland red soils, regardless of land use, were extremely positively correlated with soil organic C, N and P.