Dynamics of soil quality after cropland was converted to natural regeneration and alfalfa in the emiarid Loess Plateau
作者单位：MOE Key Laboratory of Arid AgroecologySchool of Life ScienceLanzhou University Soil and Fertilizer Research InstituteAnhui Academy of Agricultural Sciences
会议名称：《土肥水资源高效利用与农业面源污染防控技术研讨会》
会议日期：2011年
学科分类：090503[农学-草业科学] 0909[农学-草学] 0905[农学-畜牧学] 09[农学]
关 键 词：alfalfa soil total carbon soil organic carbon light fraction organic matter light fraction organic carbon total nitrogen soil phosphorus
摘 要：Cropland has suffered from extensive tillage and degraded severely in the semiarid Loess Plateau of *** improve the agro-ecosystem and develop sustainable agriculture,this experiment was *** 2003,cropland was enclosed with two treatments:one was natural regeneration(NR),and the other was alfalfa which is a perennial legume specie planted into the cropland at a density of 22.5 kg *** four-year treatment,the soil total carbon (STC) and light fraction organic carbon(LFOC) increased significantly in both NR and ***,there were no significant differences between NR and AF on the soil organic carbon(SOC).In the fragile semiarid areas,alfalfa growth helped improve soil total nitrogen(TN),but exploited amount of soil available phosphorus(AP).Compared to NR,the ratios of soil organic carbon to available phosphorus(C/P) in AF was significantly higher in 2007,which indicated the low AP content would result in degradation of alfalfa *** AP was the limited factor for plant growth and soil ***,the results suggested that changes in land use from cropland to NR and AF both helped improve soil C pools,but P fertilizer was required for plant growth.