Abstract: In order to understand the impacts of long-term double-rice cropping rotation on soil fertility quality,we selected adjacent paddy soils with more than 30 a double-cropping rice-rape(DRR) rotation,and double-cropping rice-fallow(DRF) rotation,DRF as a control in southern Hunan Province.We analyzed differences of soil pH,organic matter,nutrient content,and fertility quality among soil layers,or in rhizosphere and bulk soils between the two systems.Results showed that,compared with DRF,the content of soil organic matter,available Ca and Mg significantly decreased by 9%-11%,10%-33%,and 14%-42% in DRR,respectively,while the content of total P,available P,Cu and Zn increased by 14%-56%,21%-46%,20%-36%,and 7%-36%,respectively.Principal component-cluster analysis showed that the quality grade of soil fertility in DRR (Ⅰ-Ⅲ) was remarkably higher than that in DRF (Ⅲ-Ⅵ),indicating long-term DRR rotation would be good for enhancing paddy soil nutrient availability as well as improving soil fertility quality.However,it would be necessary to add organic fertilizer and lime appropriately to offsetting the reduction of soil organic matter and Ca and Mg availability in the long-term DRR rotation system.