Effect of Different Afforestation Restoration Models on Soil Quality in Rocky Desertification Area in Sangzhi
To selected the best plant configuration restoration mode of rocky desertification,this study took the forest land of six different restoration modes of 10C(coniferous forest),7C3B(7 coniferous 3 broad-leaved),5C5B(5 coniferous 5 broad-leaved),3C7B(3 coniferous 7 broad-leaved),10B(broad-leaved forest)and CK(barren hills and wasteland)of rocky desertification in Sangzhi County as the research object,compared the soil physiochemical properties and differences of each restoration mode,and comprehensively evaluated the soil quality of each mode.The results showed that in the study area,the soil physiochemical properties of rocky desertification forest land in different restoration modes were significantly different.There were significant differences in capillary porosity,soil bulk density,available P and available K content and organic matter between the five afforestation restoration modes and the control mode.There were also significant differences in other physical and chemical indicators between some models and the control.Soil bulk density was negatively correlated with other physiochemical indicators,indicating that the greater the soil bulk density,the lower the various nutrient contents.Soil bulk density was negatively correlated with other physical and chemical indexes,while soil total N,total P,total K,alkaline hydrolysis N,organic matter and other three physical indexes were positively correlated.Principal component analysis showed that the weight coefficients of bulk density,water content,total porosity,capillary porosity,total N,total K,available K and organic matter content of rocky desertification forest land were larger than 0.8,indicating that these indexes were the main indexes to characterize the physiochemical properties of soil in rocky desertification forest land.The comprehensive evaluation of soil quality of each mode was comprehensively scored,and the order of scores was 5 coniferous 5 broad-leaved>3 coniferous 7 broad-leaved>coniferous forest>7 coniferous 3 broad-leaved>broad-leaved forest>CK(barren hills and wasteland).Overall,afforestation was beneficial to improve the soil quality in rocky desertification area,through nearly 30 years of phytoremediation,the nutrient level of rocky desertification soil has been significantly improved.Except that the contents of alkali-hydrolyzable N and total P are still kept a low level,other nutrient indicators have risen to the upper-middle and above levels.
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