中文摘要：

比较研究了不同耕种时间下新疆奇台县沙漠-绿洲交错带用地的土壤养分含量及相关指数变化。结果表明：不同耕种时间用地的土壤养分呈正态或对数正态分布，速效养分为中等变异性，其余均为弱变异性；土壤pH值和全盐含量均随着耕作时间的延长而下降，由高到低表现为盐碱地〉荒地〉灌木林地〉3年耕种地〉5年耕种地〉10年耕种地；土壤养分指数（SNI）和养分等级均以未耕地为最高，耕种地为最低，且耕种地的SNI值随耕种年限的增加呈现先减后增的趋势；各土壤养分含量（全钾磷除外）均随着耕种时间的延长而下降，降幅表现为速效养分〉有机质〉全量养分，而速效养分的降幅由小到大为速效磷（-4．49mg／kg·a）〈碱解氮（-14．88mg／kg·a）〈速效钾（-38．18mg／kg·a）；未耕地的年均土壤养分退化指数（SNDI，-10．56％）明显慢于耕种地（-21．16％），而耕种地的SNDI均值在最初3年为-4．32％，随后2年（5年）是-6．49％，而后5年（10年）仅为-0．79％，即早期退化速度快，之后（〉5年）退化速度减缓。速效氮磷钾退化指数远大于全氮磷钾。

英文摘要：

The Qitai County, Xinjiang Uygur Autonomous Region was taken as study area, methods of soil nutrient index and soil nutrient degeneration index were selected to be used to study the soil nutrient content index characteristics, evolvement and degradation degree of lands in Gurbantunggut Desert-Qitai Oasis ecotone. The results showed that, the soil nutrients of lands under different cultivation years showed a normal distribution or logarithmic normal distribution, available nutrients （rapidly available potassium, alkaline hydrolysis nitrogen, rapid available phosphorus ） were all medium variability, and the rest were low variability. Soil pH value and total salt content decreased with the cultivation year extending, with the order of land-use types＇ contents or values ： alkali soil 〉 wasteland〉 shrubland〉 3-year farmland〉 5-year farmland〉 10-yearfarmland. The values of soil nutrient index （ SNI ） and nutrient rank were the highest in uncultivated land, while they were the lowest in cultivated land, and the SNI in cultivated land decreased with the cultivation year extending. Soil nutrient contents all decreased with the cultivation year extending except the total potassium and phosphorous, and the order of degree of reduction form high to low was as follows ： available nutrients 〉 organic matter 〉 total nutrients. The degree of reduction in available nutrients was obvious, and the order of degree of reduction form low to high was as follows ： rapid available phosphorus （ -4.49% mg/kg ~ a 〈 alkaline hydrolysis nitrogen （-14.88% mg/kg ~ a ） 〈 rapidly available potassium （-38.18% mg/kg ~ a ）. The annual mean soil nutrient degradation index （ SNDI ）of uncultivated land was -10.56%, and which in cultivated land was -21.16%, so the SNDI in uncultivated land was significantly slower than that of cultivated land. The SNDI in cultivated land was -4.32% in the first three years, and it was -6.49% in the following two years （ 5 year ）, and it finally was -0.79% in the follow