The Effect Factors On Colonization In The Rhizosphere And Growth-promoting Of Streptomyces Vinaceusdrappus 506 And Rhizosphere Effect

Continous cropping obstacle was the bottleneck to restrict sustainable development of protected vegetable. The main factors causing continous cropping obstacle were soil secondary salinization, soil microbe environment, antotoxicity of plant and so on. Nowadays chemical control was the main means. But more and more evidences showed that chemical control had many negative problems, such as polluting environment, bringing about drug-fast problems and so on. Biological control centred function microorganism showed promising perspect and was presently research focus at home and abroad. Low and unstable control effect was the main cause of restricting practical biological control technology and prodution at present, it was maybe related to the researchers'excessively paying attention to function and property of microorganism, neglecting environmental effect on colonization and fuction of strains. Therefore, for continous cropping obstacle caused by mutil-factors, it is in need of obtaining multi-fuctional dominant strains and comprehensive control from the angle of ecology by systematic method.Streptomyces vinaceusdrappus 506 was a multi-fuctional dominant strain isolated from tomato rhizosphere. Many experiments showed if the live bacteria agent was applied to vegetable rhizosphere, it could effectively control root diseases of many vegetables such as fusarium wilt, root rot, root-knot nematode and so on. It could also significantly promote root development and degrade autotoxicity of the root. The strain had wide application prospect in effectively controling continous croppiny obstacle. In the study, S506 was used as test material , population quantity of the strain in rhizosphere and growth-promoting were used as test index. Soil texture, temperature and moisture, nutritional factors, soil amendments on colonization of the strain and growth-promoting were studied. Meanwhile, ecological effect and applied effect of field were studied in suitable condiction.The effects of soil natural factors on colonization of S506 and growth-promoting were studied. The results showed the optimum factors that S506 colonized in tomato rhizosphere were loam soil, temperature 30℃and water content 20～50%. The optimum factors that promoted root and overground growth were in good agreement with those of colonization, except for temperature 25℃. In other soil texture and for other factors, though population quantity of S506 in rhizosphere obviously decreased, population quantity always keep more than 106cfu/g dry soil and the effect of growth was also significantly superior to control groups.The effects of soil regulatory factors on colonization of S506 and growth-promoting were studied. The results showed, when objective strain inoculation amount is in range of 105～107cfu/g dry soil, population quantity of S506 in rhizosphere increased and growth-promoting effect enhanced accordingly with the increasing of objective strain inoculation amount. Loam soil was used as test material. Soil physical and chemical properties of loam soil were organic matter 31.2g/kg, total nitrogen 0.61mg/kg, available nitrogen 56.6mg/kg, available phosphorus 38.7mg/kg, available potassium 104.5mg/kg, PH value 7.8. The optimum application amount of available nitrogen, available phosphorus, available potassium were 0.15g/kg dry soil, 0.5g/kg dry siol, 0.3g/kg dry soil, respectively. Decomposed manure addition such as chicken manure, pig manure, cattle manure could significantly promote colonization of objective strain in rhizosphere and the development of the root. The best synergier was cattle manure, secondly decomposed pig manure and chicken manure. Combination chicken manure and pig or cattle manure was between two single manure in synergism.Ecological effects of the root of S506 were studied in suitable condition. The results showed, S506 had obvious root-promoting and strong seedling effects on many vegetables such as tomato, cumcuber and so on. The root dry weight was improved by above 30%. The root hairs number was improved by above 2 times. S506 could regulate microbial communities structure of the rhizosphere, It was showed the number of filamentous fungi, especialy pathogen obviously decreased. It reached a highly significant level (p<0.01). S506 could degrade and shield poisonous matters of the root such as benzoic acid ,coumarin and so on. S506 could relieve root damage caused by toxin.Combination S506 agent and organic fertilizer made S506 fertilizer. S506 fertilizer were applied tomato and cumcuber production in greenhouse, S506 fertilizer could promote growth-plant, control root diseases. Apperance, taste, flavor, storage of the fruit were improved. Vitamin C content increased, nitrate content decreased. Per mu yield increase rate of tomato and cumcuber were 26.3% and 24.2% respectively.