轮作豆科牧草对连作马铃薯田土壤微生物菌群及酶活性的影响

Effect of leguminous forage rotations on soil microbe consortiums and enzyme activity in continuously cropped potato fields

本试验研究了轮作不同种类豆科牧草对连作马铃薯田土壤微生物菌群、数量分布及酶活性的影响。结果表明,通过轮作箭筈豌豆、天蓝苜蓿和陇东苜蓿3种豆科牧草,对连作马铃薯田土壤可培养细菌和真菌数量分布,微生物活性,土壤脲酶活性,碱性磷酸酶活性及过氧化氢酶活性均有明显的促进作用,与种植牧草前相比,轮作牧草后土壤中真菌/细菌最高可降低50.72%,说明真菌数量下降,通过轮作不同连作年限马铃薯田土壤微生物菌群从真菌型向细菌型转化;与种植牧草前相比好气型固氮菌数量最高增加283.69%;脲酶活性最高增加6.4倍;碱性磷酸酶活性和过氧化氢酶活性均显著提高。但是对连作土壤的改良作用高低还与豆科牧草种类及土壤连作年限有关,不同连作年限的土壤对不同种类的豆科牧草表现出不同的敏感性。

The effects of different leguminous forage rotations on soil micr e consortiums, quantitative distri bution, and enzyme activity were studied in a continuously cropped potato field. The quantitative dis of soil culturable bacteria and fungi, microbial activity, soil urease activity, the activities of alkaline tributions phosphatase and catalase were significantly promoted in common vetch （Vicia sativa）, Medicago lupulina, and Longdong alfalfa （Medicago sativa） rotation systems compared with continuously cropped potato fields. Fungal/ bacterial ratios decreased by 50.72 % after legumes were included in the rotations, showing that rotations with common vetch and Medicago lupulina, converted the soil microbe consortium of continuously cropped potato field from fungal to bacterial types. After the inclusion of legumes, the number of aerobic types of nitrogen-fix- ing bacteria increased by 283. 69%, and urease activity increased by 6.4 times. There were also significant in- creases in the activities of alkaline phosphatase and catalase. However, the improving effect on the soil of con- tinuously cropping potato field depends largely on leguminous forage species. The duration of continuously cropped soils depended on the different continuous cropping durations which showed different sensitivities to different types of forage legumes.