陇中旱作区不同轮作方式对土壤碳、氮含量及酶活性的影响特征

为探索陇中旱作区不同玉米轮作模式对土壤碳、氮含量及土壤酶活性的影响，本试验对玉米（Zea mays）与苜蓿（Medicago sativa）、马铃薯（Solanum tuberosum）、大豆（Glycine max）、小麦（Triticum aestivum）4种轮作模式的土壤碳、氮含量和酶活性进行测定分析。结果表明：轮作模式下土壤有机碳含量提高13.14%~27.52%，微生物碳含量提高1.78%~18.11%，全氮含量提高18.47%~58.69%，微生物氮含量提高18.31%~40.43%，蔗糖酶活性提高5.20%~17.11%，脲酶提活性高4.25%~26.42%，过氧化氢酶活性提高7.69%~13.46%；土壤碳、氮含量与酶活性呈显著正相关关系（P<0.05）；聚类分析表明，玉米与苜蓿、大豆轮作土壤养分状况聚类距离最近，距离值为0.96，相似程度高，综合表现好。从土壤碳、氮含量和酶活性角度考虑，玉米与豆科作物轮作改良土壤肥力效果最好。本研究可为陇中旱作区建立良好的作物轮作制度提供理论依据。

Effects of Different Rotation Patterns on Soil Carbon and Nitrogen Contents and Enzyme Activities in the Arid Region of Central Gansu

In order to explore the effects of different corn rotation patterns on soil carbon and nitrogen content and soil enzyme activity in the arid region of central Gansu province. Soil carbon and nitrogen content and soil enzyme activity of 4 treatment rotation patterns,that is,Zea mays combined with Medicago sativa,Solanum tuberosum,Glycine max and Triticum aestivum,were measured and analyzed. Under rotation mode,the soil organic carbon content increased by 13.14%~27.52%,the microbial carbon content increased by 1.78%~18.11%,the total nitrogen content increased by 18.47%~58.69%,the microbial nitrogen content increased by 18.31%~40.43%,the invertase increased by 5.2%~17.11%,urease increased by 4.25%~26.42%,and the catalase increased by 7.69%~13.46%. There was a significant positive correlation between soil carbon and nitrogen content and soil enzyme activity (P<0.05). Cluster analysis demonstrates that clustering distance of soil nutrient status in the rotation of corn combined with alfalfa and soybean were the closest with the distance value of 0.96,the highest similarity and good overall performance. Considering the soil carbon and nitrogen content and soil enzyme activity,corn-legume crop rotations have the best effect on improving soil fertility. The study provides a theoretical basis for establishing a good crop rotation system in the arid region of central Gansu.