Abstract: To explore the influence of different rotation systems on soil improvement in dry farming region of middle Gansu of loess plateau,the effects of 4 treatment rotation systems,that is,Zea mays combined with Medicago sativa,Solanum tuberosum,Glycine max and Triticum aestivum, on soil total nitrogen,available nitrogen,total phosphorus,available phosphorus,total potassium,available potassium,total organic carbon and soil aggregates were measured and analyzed. In the rotation modes,the total nitrogen and available nitrogen content increased by 7.08%~20.35% and 9.89%~37.52%,respectively. Phosphorus and potassium content increased,and organic carbon content increased by 13.14%~27.52%. The soil aggregate in each rotation patterns was dominated by macroaggregates (≥ 0.25 mm soil aggregates),and the mean weight diameter and mean geometry diameter of soil aggregates in corn-soybean rotations were at a higher level than other treatments. Four different rotation systems were calculated by the entropy weight and TOPSIS model,and showed that corn-alfalfa rotation had the best effect on soil fertility. The rational rotation could improve soil nutrient status,and increase yield and income.

Key words: The arid region of central Gansu, Rotation system, Soil improvement, TOPSIS, Entropy weight

摘要： 为探索陇中黄土高原旱作区不同轮作系统对土壤改良的影响，本研究对玉米（Zea mays）与苜蓿（Medicago sativa）、马铃薯（Solanum tuberosum）、大豆（Glycine max）、小麦（Triticum aestivum）4种轮作模式的土壤全氮、碱解氮、全磷、速效磷、全钾、速效钾、有机碳、团聚体进行测定分析。结果表明：轮作较连作相比土壤养分有一定程度的提高。轮作下土壤全氮和碱解氮含量分别提高7.08%~20.35%和9.89%~37.52%，土壤磷素和钾素含量提高，土壤有机碳含量提高13.14%~27.52%，土壤团聚体均以大团聚体（≥ 0.25 mm的土壤团聚体）为主，玉米-大豆轮作土壤团聚体平均重量直径和几何平均直径的值较高。利用熵权法及TOPSIS模型对各处理的土壤肥力进行综合评价，结果显示玉米-苜蓿轮作对土壤肥力的改良效果最好，合理轮作可实现土壤养分内生状态良质化。

关键词: 陇中旱作区, 轮作系统, 土壤改良, TOPSIS, 熵权