Study On Soil Bacillus In Chengdu Suburb

27 soil samples located by GPS (Global Position System) were collected at 0-20cm depth by the approaches of grid and stratum sampling in Chengdu Suburb. Bacillus spp. were isolated and identified by traditional methods. The regional spatial variability of Bacillus spp. was performed firstly by the software ArcGIS8.1 which combined geographic information system (GIS) with geostatistics method. The correlations between the diversity-indexes of Bacillus spp. were studied. Potential which could antagonize to pathogen, solubilize phosphate and potassic-compound was also analyzed.The results showed that the quantity of Bacillus spp. was about 4.30×10~3~8.53×10~5 cfu.g~-1 dry soil in Chengdu Suburb and it was higher in the North than that in the other area. In about 1/6 area of Chengdu Suburb, the geometric mean probability of Bacillus spp. more than 1.693×10~5 cfu.g~-1dry soil could reach about 0.5640~0.9410. Based on the characteristics of morphology and physiology-biochemistry, 16 species (311 strains) and 5 unknown (22 strains) species were identified among 333 isolates. The known species included B. circulans, B. megaterium, B. cereus, B. mycoides, B. licheniformis, B. pumilus, B. spaericus, B. subtilis, B. alcalophilus, B. globisporus, B. coagulans, B. pantothenticus, B. pseudomycoides, B. thuringiensis, B. insolitus, B. marinus. Among these species, B. circulans, B. megaterium, B. licheniformis and B. cereus were predominant species in Chengdu Suburb. The species diversity of Bacillus in Chengdu Suburb was rich, whereas 5~10 species could be identified in each sample. Diversity index, average index and ecosystem advantage index were 1.3681 ±0.4531, 0.6976±0.1871, 0.3187±0.1410 in this area.The quantity trend of B. circulans, B. megaterium, B. licheniformis and B. cereus were diversity in Chengdu Suburb. B. circulans was the highest in the North. B. megaterium was the highest in the Northwest and the least in the Southeast. B. licheniformis was highest in the midst of Chengdu Suburb and the least around it. B. cereus was highest in the East. The quantity of B. circulans, B. megaterium, B. licheniformis and B. cereus had spatial variability characteristics. The region of the highest quantity of B. circulans was from Jingniu to Shuangliu. The region of the least quantity of B. circulans was in Longquanyi. The region of the highest quantity of B. megaterium was in Shuangliu. The region of the least quantity of B. megaterium was in Longquanyi. The region of the highest quantity of B. licheniformis existed from Jinniu to Longquanyi. The region of the least quantity of B. licheniformis was in Shuangliu. The region of the highest quantity of B. cereus was in upstate of Longquanyi. The region of the least amount of B. cereus was in Sansheng and Wenjiang. In 1/3 area of Chengdu Suburb, the geometric mean probability of B. circulans more than 3.00×10~3 cfu.g~-1 dry soil could reach about 0.8284~1.0000. In 1/2 area, the geometric mean probability of B. megaterium more than 2.72×10~3 cfu.g~-1 dry soil could reach about 0.8468~1.000. In 1/3 area, the geometric mean probability of B. licheniformis more than 3.70xl02cfug"'dry soil could preponderate over 0.6631. In 1/3 area, the geometric mean probability of B. cereus more than 9.35x102cfu-g''dry soil could reach about 0.7213~0.8845.333 isolates were obtained in this study, 85 antigonist Bacillus strains shows inhibition to one of Rhizoctonia solani, Colltotrichum coccodes and Curvularial lunata, among which 25 strains controlled effectively against these three pathogens. The control effect from better to worse was Rhizoctonia solani, Colltotrichum coccodes and Curvularial lunata. Antagonistic strains mainly belonged to B. licheniformis and B. subtilis. Trend of antagonistic Bacillus was richest in midst of Chengdu Suburb and the least around it. The region of the highest value of antagonistic Bacillus existed part of Xinjin or Xindu. The region of the least value of antagonistic Bacillus was existed from Pixian to Jinniu and part of Longquanyi. In 1/6 area in Chengdu Suburb, the geometric mean probability of antagonistic Bacillus more than 2.00x104cfu-g"'dry soil could reach about 0.8~1.0. The Bacillus strains in Chengdu Suburb grew well in abiophosphate medium and organic-phosphate medium, but grew slowly in kalium-compound medium. 50 strains which mainly belong to B. licheniformis and B. megaterium were abiophosphate-solubilizing Bacillus. The highest quantity of abiophosphate-solubilizing Bacillus reached 9.35xlO4 cfu-g'1 dry soil in one samples. Trend of abiophosphate-solubilizing Bacillus was richest in the North and least in the South. The quantity of abiophosphorus-solubilizing Bacillus had distinct spatial variability characteristics. The region of the highest value of abiophosphate-solubilizing Bacillus was in Xindu which could reached 2.60xl04~9.35xi04cfu-g"'dry soil .The region of the least value of abiophosphorus-solubilizing Bacillus existed from Shuang-liu to Long-quanyi that could reach under 1.60x104cfu-g''dry soil. The results suggested that the Bacillus strains in Chengdu Suburb which could antagonize to pathogen, solubilize abiophosphate would be potentially materials further utilized in future.