宁夏中部不同年限退耕压砂地土壤质量评价OA北大核心CSTPCD

Information on the change over time in soil properties when retiring cultivated land in Ningxia's gravel-sand mulched field areas is highly relevant for advancing ecological conservation and constructing high-quality development pilot zones in the Yellow River Basin.Focusing on the gravel-sand mulched fields in the Xiangshan area of Zhongwei City,Ningxia,a spatial sequence method was employed instead of a time series approach.Gravel-sand mulched fields with consistent terrain and soil type are selected for study of the variations in soil physicochemical properties and enzyme activities 2,5,10,15,20,30 and 100 years after retirement from cultivation.The soil quality for these fields with differing retirement dates was evaluated using a combination of subordinate function and factor analysis methods.Results indicate:1)Soil potassium content decreased overall after five years of retirement.Soil nitrate-nitrogen content peaked at two years of retirement,with no significant differences between other periods.Soil total phosphorus,available phosphorus,and available potassium content fluctuated with years of retirement,peaking at 15,2,and 15 years of retiring,respectively.2)Soil porosity initially decreased and then increased with increased years of retirement.Field capacity and soil moisture content were highest at two years after retirement,sharply decreased at five years,and significantly increased with years of retirement,thereafter.Soil water content tended to be stable after 20 years of returning farmland.3)Soil urease and invertase activities initially decreased and then increased with increasing years of retirement,both peaking at 30 years of retirement.4)The multi-trait scores for soil quality under different retirement periods were ranked:2 years>30 years>100 years>15 years>20 years>10 years>5 years.Soil quality evaluation scores peaked at 2 years of retirement.We interpreted this to indicate that after an initial recovery evident at 2 years,a decline is seen at 5 years,and then soil quality improves with time in retirement.