天津半干旱地区不同种植年限菜田土壤微生物变化特征的研究

对天津周边半干旱地区不同种植年限的菜田土壤微生物状况调查研究表明 ,该地区土壤微生物以细菌为主 ,夏季微生物总量大大高于冬季 ;随着种菜年限的增加 ,耕层和亚耕层微生物总量都有增加趋势 ,其中细菌和放线菌增加明显 ,真菌有下降趋势 ;真菌类群分析表明 ,少数纤维素分解菌 ,如青霉 (Penicillium)、木霉 (Trichoderma)等为优势菌 ,而糖和木质素分解菌仅占少数。用尖孢镰刀霉 (Fusariumuoxysporum)、大肠杆菌 (Escherichia coli)接种不同种菜年限土壤 ,检测土壤拮抗菌状况发现 ,拮抗菌仅在种植年限长的老菜田的放线菌中发现。表明北方半干旱地区菜田土壤细菌为优势菌 ,主要存在于土壤微孔隙中 ;而适于生活在土壤疏松大孔隙中的真菌数量极少。应注意土壤结构的改良 ,为丰富土壤微生物提供良好的生态环境

Macroflora in vegetable soils in semi-arid region at Tianj in City

Microfloras in continuous planting vegetable soils in semi-arid region at Tianjin were studied． In this area， bacteria were main member in microorganisms and which increased in summer season．Microorganisms of continuous planting fields were more vigorous than those of new fields．The numbers of bacteria increased with increasing years of planting．The actino．Mycetes had same tendency to the bacteria but the numbers were low．The numbers of fungi were low and variation of the numbers with planting years changed according to the area of fields．In the fungal flora，a few cellulose decomposers such as Penicillium and Trichoderma were dominant，and sugar or lignin decomposers were few．Antagonists were recognized in the part of actinomycetes mainly in continuous planting fields．From these results showed that the majority of microfloras in this semi-arid region were bacteria which inhabited in micro-pore spaces．But fungi，which lived in macropore that did not develop in this region even in mature fields，were little．There is a need to pay more attention to the physical amelioration in soil structure in this area so as to provide a favorable ecology environment for developing of microorganisms．