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Heilongjiang province was the main soybean producing areas of China, as the continuous expansion of cultivated area, let to soybean root diseases serious, thereby affected yield. Soybean root rot was a soil-borne diseases caused by variety of pathogenic fungi, has become the main reason of cuts or even. At present, despite the use of chemicals at domestic and abroad have significant effects, however, the composition of chemical which will not only pollute the environment, but also will be enriched by soybean and then harm to body’s health. In recent years, domestic and foreign scholars have started on the biological control on the root rot of soybean, but most of the research focused on single agents, and these studies were based on single agents on the soybean root rot. Since the occurrence of root rot of soybean and soybean rhizosphere soil formations have closely related, therefore, single agents in the practical application difficult to achieve the desired results.Therefore,in this study, regulation of soybean rhizosphere microbial formation and maintenance of soybean rhizosphere normal microbial environment as the starting point, carry out composite biological agents of prevention and control soybean root rot . This experiment from strains, antagonistic mechanism, soybean rhizosphere microbial flora changes and colonization of biocontrol agents do research, achieved the following results:1. By antagonistic strain the composition of bacteria, namely Trichoderma harzianum, Bacillus subtilis Cohn, Bacillus megaterium, Pseudomonas putida, Pseudomonas fluorescens, Serratia marcescens and Streptococcus faecalis. Soybean, rice, wheat and rape seed germination test results show that the composite biological agents on seed germination of certain growth-promoting effects.2. Trichoderma harzianum and 6 strains of bacteria Bacillus subtilis Cohn, Bacillus megaterium, Pseudomonas putida, Pseudomonas fluorescens, Serratia marcescens, Streptococcus faecalis have the capabilities of produced chitinase andβ-1, 3 - glucanase, proline content of soybean, POD activity ,PAL activity, PPO activity were promoted, the effect of Trichoderma harzianum was the most obvious.3. The composite biological agents can effectively regulate soybean rhizosphere soil bacteria, fungi and actinomycetes three bacteria. The results showed that application of the composite biological agents can reduce soybean rhizosphere Fusarium and Rhizoctoniaand and other harmful fungi, and increased the rhizosphere of soybean Rhizobium and nitrogen-fixing Azotobacter ratio significantly. The study results show that the composite biological agents can improve the soybean rhizosphere microbial environment, reducing harmful bacteria in the rhizosphere to increase the proportion of beneficial bacteria.4. By the detection of Trichoderma spores can showed that Trichoderma spores in the rhizosphere colonization of soybean capacity stronger than a single application of Trichoderma spores. Through plant height, the root length, dry weight, fresh weight, ATPnase activity, root activity and other physiological biochemical testing of first piece of leaf revealed that the composite biological agents on soybean seedling growth of certain promotion.
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