Composition Characteristic of Soil Aggregates and Their Stability in Red Soils As Affected by the Soil Parent Materials and Land Use Types

A total of 12 combination soils were randomly collected from the sites nearby the Ecological Experimental Station,in Liujiazhan near Yingtan,Jiangxi Province,China(28° 04′-28° 37′ N,116° 41′-117° 09′ E).They included three soil parent materials(i.e.originated from the Ganite,Tertiary Red Sandstone and Quaternary Red Clay) and four land use types(i.e.forest,bush,upland and paddy).The mechanical-stable and water-stable aggregates in different sizes were collected through the dry-wet sieving method,then the composition characteristics of soil aggregates and their stability in the 12 red soils were discussed.The results showed that the proportions of different size mechanical-stable aggregates in the tested red soils,except for Bush soil originated from Granite,ordered as 2 mm 2-0.25 mm 0.25-0.053 mm 0.0.53 mm.Proportions of 2 mm water-stable aggregates were significantly decreased after wet sieving,but 2-0.25 mm,0.25-0.053 mm and 0.053 mm water-stable aggregates increased significantly.There was significant positive relationship between the mean weight diameter of mechanical-stable aggregates(MWDd) and the percentage of aggregate destruction(PAD) in tested soils,and they could be used to characterize the stability of soil structure.The △MWD and PAD had significant negative relationship,i.e.the increasing of △MWD accompanied with the decreasing of soil stability.The interaction effects of soil parent material and land use types on soil aggregate composition and their stability were obvious.Therefore,the soil parent materials and land use types should be considered together during the development and utilization of red soil resource.