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以大棚甜瓜连作土壤为研究对象,选择种植1、3、5、7、9年甜瓜大棚,采集根区土壤,采用平板计数法对土壤中细菌、真菌和放线菌数量进行统计,测定种植1年和连续种植3、5、7、9年甜瓜大棚土壤中细菌、真菌和放线菌数量及土壤酶活性的变化。结果表明:随着种植年限的增加,土壤中微生物总量、细菌和放线菌的数量呈现先升高后降低的趋势;真菌数量则呈上升趋势,且连作9年时真菌数量极显著增加。脲酶(Urease,UREA)、多酚氧化酶(Polyphenol oxidase,PPO)和过氧化氢酶(Catalase,CAT)的活性也呈现先升高后降低的变化趋势,UREA活性在连作3年时最高,PPO和CAT活性在连作5年时活性最高;而蔗糖酶(Saccharase,SAC)活性随着连作年限的增加呈降低的趋势,连作7年时活性极显著下降。表明甜瓜连作9年,根际土壤微生物结构失调,微生物由“细菌型”向“真菌型”过渡,土壤酶活性下降,连作障碍明显。
With melon continuous cropping greenhouses as the research object, we chose to grow 1, 3, 5, 7, 9 years melon greenhouses, collected root zone soil, counted the number of bacteria, fungi and actinomycetes in the soil by plate count method, Changes of the number of bacteria, fungi and actinomycetes and the activities of soil enzymes in the soils of melon greenhouse cultivated for three, five, seven and nine years. The results showed that the total amount of microorganisms, bacteria and actinomycetes increased firstly and then decreased with the increase of planting years. The number of fungi increased while the number of fungi increased significantly after 9 years of continuous cropping. The activity of Urease (UREA), Polyphenol oxidase (PPO) and Catalase (CAT) showed the trend of first increasing and then decreasing. The activity of UREA was the highest at 3 years of continuous operation, And CAT activity had the highest activity at 5 years of continuous cropping. However, the activity of Saccharase (SAC) decreased with the increase of continuous cropping duration, and the activity of Saccharase decreased significantly at 7 years of continuous cropping. The results showed that the melon was continuous for 9 years, the rhizosphere soil microbial structure was disorganized, the microorganism transitioned from “bacteria type ” to “fungal type ”, soil enzyme activity decreased and the continuous cropping obstacle was obvious.