Studies On Solubilizing Effects On Phosphate Rock Powder And Insoluble Phosphorus In Soil Of P-solubilizing Microorganisms And Their Mechanism

Severing and filtration of P-solubilizing microorganisms were studied in this article. More than two hundred P-solubilizing microbes were filtered again and compared with P-solubilizing microbes safe-deposited in our microbiological laboratory. P-solubilizing microbes with preferable P-solubilizing effects were found, consisting of bacteria, yeasts, and fungi. P-solubilizing microbes sources survey was conducted at the same time. Through colony and thalli configuration observation and physiological, biochemical experiment, P-solubilizing microbes strain P17, P10, Y3, F4 were identified as Bacillus megaterium, Brevibacterium, Rhodotorula and Penicillium, respectively.P-solubilizing effects and methods of different microbes were different Research results showed that such difficultly soluble phosphates as Ca3(PO4)2, FePO4, A1PO4 were dissolved by yeasts and fungi easily. Phosphate rock powder was solubilized better by bacillus. Different kinds of microbes could dissolve different chemical configuration of phosphates or other substances containing phosphorus. Microbes chosen in this study were representative of all P-solubilizing microbes, belonged to bacteria including bacillus, yeasts, and mildew respectively. Results showed that mildew could dissolve best not all the difficultly soluble phosphates. Bacillus and yeasts also played much important role in P-solubilizing. Some conferences reported that P-solubilizing ability of fungi was always higher than bacteria (Ghani A, 1994). This thesis is unilateral, to some extent. Results showed that different kinds of microbes have different P-solubilizing ability on phosphates. Carbon, nitrogen sources needed by fungi were more than bacteria, and generation time is longer; but biological gross and metabolistic products of fungi are more than bacteria, which do good to solubilization of phosphorus. P-solubilizing ability of phosphate rock powder is stronger and their generation time shorter. All results above showed biological phosphorus fertilizer need consist of mixture of bacteria and fungi. So bacteria and fungi can bring out the best in each other in P-solubilizing. More contribution would be done to agriculture.P-solubilizing effects study results showed that strain P17 could facilitate solution of phosphate rock powder from different sources. So strain P17 could solubilize and transform difficultly soluble phosphorus. Results suggested that microbiological methods to improve P-solubilizing effects of phosphate rock powder are probable. Phosphate rock powder from haikou in Yunnan province, Kaiyang inGuizhou province, yichang in Hubei province are sediment phosphate rock, while phosphate rock from huangmailing, huangjinkahuang are metamorphose phosphate rock. Available P content is different because of geology formation conditions. After inoculation by strain P17, available P content of hangmailing and huangjinkahuang phosphate rock powder were increased largely. Through shaking bottle experiment and SEM observation, biological efflorescence evidences of solubilization from huangmailing and huangjinkahang phosphate rock were brought. Accumulative available P were increased from 291.46 mg L-1, 316.6 mg L-1 to 869.71mg L-1 and 837.04 mg L-1 after 70d inoculation. Poorly soluble phosphate were solubilized by P17 gradually. 81.02% of whole P content of huangmailing phosphate rock powder was released as available P. Accumulating available P of inoculation treatment was 5.93 times of control. While strain P17 could solubilize 78.97% whole P of huangjinkahuang phosphate rock powder. Accumulating available P content after inoculation in filtrate was 5.4 times of ck. Sterilized bacteria inoculation could bring such metabolism product as nonvolatile organic acids into fermentation liquid, which could have effects on phosphate rock powder. Inorganic P is basis in difficultly soluble phosphate rock powder. Huangmailing and huangjinkahuang phosphate rock powder are metamorphose phosphate rock, which are adapted to growth and metabolism production of strain P17. Difficultly soluble P o...