Effects of Land Use Changes on Soil Aggregates and Associated Organic Carbon in Urban Suburbs
Soil samples at a depth of 0-20 cm were collected from traditional croplands,facility-vegetable lands,landscape greening forests and grasslands in the suburbs of Xinxiang City of Henan Province,and soil water-stable aggregates were separated by wet-sieving method and their associated organic carbon were determined to compare the characteristics of aggregate stability and changes of organic carbon.The results showed that the aggregate mass proportion and stability were greatly impacted by land use types.Compared with traditional cropland,facility-vegetable plantation for 6 years significantly reduced macro-aggregate mass composition(WR0.25),values of mean weight diameter(MWD)and geometric mean diameter(GMD)by 42.40％,54.84％and 129.41％,respectively.While the values of WR0.25 in the same years constructed forest and grassland were significantly increased by 33.65％and 23.63％,respectively.Fu thermore,the values of MWD and GMD of forest and grassland were increased by 0.64％and 26.92％,83.87％and 77.42％,respectively.Compared to traditional cropland,the concentrations of organic carbon associated within aggregates with various sizes were all increased in facility-vegetable plantation,forest and grassland,while their contribution rates of associated organic carbon depended on particle size.The highest organic carbon concentration was obtained in 0.25-2 mm aggregates from the facility-vegetable soil,being 35.02 g/kg,but the contribution rates of associated organic carbon within aggregate fractions＞0.25 mm were both significantly reduced.Grassland greatly decreased the contribution rate of aggregates＜0.053 mm but significantly increased the contribution rate of aggregates＞0.25 mm.In conclusion,cropland converted to landscape greening forest and grassland could promote the water-stable macro-aggregate formation,stability and associated organic carbon accumulation during the early stages,Which indicates a great potential for soil organic carbon sequestration.
UrbanizationLand use changeAggregatesAggregate stabilityAssociated organic carbon
万方数据
维普
