山药田土壤微生物群落分布特征及间作豆科植物的改良效果

Distribution characteristics of soil microbial community in yam field and improvement effect of intercropping legumes

为解析山药田连作后的土壤微生态环境变化,探寻连作障碍产生的微生物学机理,采用田间小区试验和室内检测分析相结合的方法,以粮田土壤为对照,在分析山药田土壤微生物群落分布特征的基础上,探究间作苜蓿、三叶草和大豆3种豆科植物对土壤微生态环境的改良效果。结果表明:在0~100 cm土层中,山药田和粮田土壤细菌、真菌和放线菌三大微生物种群的数量基本表现为随土层加深而降低的趋势。与粮田相比,山药苗期0~100 cm土层土壤细菌和真菌数量均表现为山药田土壤高于粮田土壤,特别是真菌数量,高于粮田土壤1.86~4.48倍。而固氮菌和放线菌数量则表现为粮田土壤高于山药田土壤的趋势,特别是0~20 cm土层,分别比山药田土壤提高了1.51和0.75倍。山药收获期,0~20和20~40 cm土层山药田土壤细菌、固氮菌和放线菌数量均呈现出低于粮田土壤,而真菌数量高于粮田土壤的趋势,且0~100 cm土层土壤细菌与真菌数量的比值均降低。间作苜蓿、三叶草和大豆后可显著提高0~40 cm土层土壤中的固氮菌、解磷细菌及放线菌的数量。说明山药连作会明显影响土壤三大微生物群落的组成结构,而间作豆科植物对土壤微生物群落分布有一定的改良效果。

In this paper,a field experiment combined with laboratory analysis were used to study the characteristics of soil microbial community distribution in yam field compared with that in grain field,and the improvement effects of alfalfa,clover and soybean intercropping with yam on soil microecological environment.The results showed that the numbers of soil bacteria,fungi and actinomycetes in yam field and grain field both decreased with the deepening of soil layer in 0~100 cm.The numbers of soil bacteria and fungi in yam seedling stage were higher than those in grain field,especially the number of fungi,which was enhanced by 1.86~4.48 times.Nevertheless,the numbers of nitrogen-fixing bacteria and actinomycetes in grain field were higher than those in yam soil,with magnitudes being 1.51 and 0.75 times higher in 0~20 soil layer,respectively.At harvest,the numbers of bacteria,nitrogen-fixing bacteria and actinomycetes in 0~20 and 20~40 cm soil layers of yam field were lower than those in grain field,while the number of fungi was higher,and the ratio of bacteria to fungi in 0~100 cm soil layer was also decreased.Intercropping yam with alfalfa,clover and soybean could significantly increase the numbers of soil nitrogen-fixing bacteria,phosphate-solubilizing bacteria and actinomycetes in 0~40 cm soil layer.The results indicated that continuous cropping of yam could significantly affect the composition and structure of soil microbial communities,and intercropping legumes had been helpful for the remediation of soil microecological environment.