不同修复措施下红壤水稳性团聚体中有机质分布特征

试验设置作物对照(CK)、作物+PAM(聚丙烯乙酰)(C1)、作物+稻草覆盖(C2)、作物+带状牧草(C3)、作物+PAM+带状牧草(C4)和作物+稻草覆盖+带状牧草(C5)6个处理,分别于种植花生前(A)、花生收获后(B)和小麦收获后(C)采集表层土样,研究不同修复措施下鄂东南侵蚀红壤团聚体的稳定性及水稳性团聚体中有机质的分布特征。结果表明,C时期各处理>0.25mm水稳性团聚体含量的平均值比A时期提高了24.78%,以C2处理的水稳性团聚体含量最高。不同时期土壤和各级水稳性团聚体中有机质含量表现为B>C>A。随着团聚体粒径(>4mm,4～2mm,2～1mm,1～0.5mm,0.5～0.25mm)减小,水稳性团聚体中有机质含量逐渐降低。土壤有机质含量与各粒径水稳性团聚体有机质含量呈线性正相关,小粒径(2～0.25mm)水稳性团聚体的有机质含量与土壤有机质含量呈极显著正相关(相关系数为0.779 2～0.828 6)。综合考虑土壤有机质含量和团聚体稳定性2个因素,稻草覆盖措施对侵蚀红壤的修复效果较好。

Distribution of Organic Matter in Water Stable Aggregates of Eroded Red Soil Under Different Restoration Measures

In the field experiment,several restoration measures like adding polyacrylamide(PAM)(C1),straw mulching(C2),planting zonal pasture(Paspalum notatum)(C3) and their combinations were adapted to restore the eroded red soil in southeast Hubei,and samples of surface soil were collected before planting peanut(A) and after harvesting peanut(B) and wheat(C) respectively,aiming at analyzing aggregate stability and the distribution of organic matter in water stable aggregates of the eroded red soil under different restoration measures.The results showed that the average content of >0.25 mm water stable aggregates(WSA) in the period C increased by 24.87% compared with that in the period A,and the maximum content appeared in treatment C2.The average content of organic matter in soil and water stable aggregates in different periods was B>C>A.With the decrease of aggregate size(>4 mm,4~2 mm,2~1 mm,1~0.5 mm,0.5~0.25 mm),the content of organic matter in water stable aggregates was reduced gradually.There was a linear positive correlation between the average content of organic matter in soil and water stable aggregates,and there was extremely significant correlation between the average content of organic matter in small aggregates(2~0.25 mm) and soil(with correlative coefficient of 0.779 2~0.828 6).From soil organic matter content and aggregate stability,it was considered that the measure of straw mulching had better repairing effect than other measures for the eroded red soil in southeast Hubei.