Development Of Phosphorus-Solubilizing Biofertilizer And Its Effect Of Promoting Corn Growth

Phosphate-solubilizing microorganism in soil plays an role in phosphorus cycling and converting insoluble phosphate into soluble forms.Therefore,the application of phosphate-solubilizing microorganism fertilizer is an effective measure to improve the utilizating efficient of phosphorus.The two efficient phosphate-solubilizing fungi were isolated from the rhizosphere soil,the two strains were preliminary identified,and the biological characteristics,solid-state fermentation of the two phosphate-solubilizing fungi were researched.Finally,pot experiment was conducted to evaluate the effect of phosphate-solubilizing microorganism fertilizer to growth of maize and absorption of phosphorus.The research is as follows:1.Strain NJDL-03 and NJDL-12 were cultured in PVK medium with Ca3(PO4)2 as the sole source of phosphorus,the water soluble phosphorus concentration were 1209 mg/L and 1332 mg/L respectively.Strain NJDL-03 and strain NJDL-12 which have efficient phosphate-solubilizing,were isolated from the rhizosphere calcareous soil of a soybean plant in Fengyang,Anhui Province and the rhizosphere soil of a corn plant in Kylin,Jiangsu Province.Strain NJDL-03 and strain NJDL-12 were identified as Penicillium oxalicum and Aspergillus niger by cultural traits and morphological characteristics observed and by ITS sequences analysis,respectively.2.The biological characteristics of strain NJDL-03 and NJDL-12 were studied.The result is as follows:(1)It was found that strain NJDL-03 and NJDL-12 could tolerate a wide pH range by the shake flask experiments,it grew well in the medium at initial pH =7.0 for strain NJDL-03 and at initial pH = 8.0 for strain NJDL-12;(2)the filter paper activity of strain NJDL-03 and NJDL-12 were 0.118U/mL and 0.109 U/mL respectively.(3)Strain NJDL-03 and NJDL-12 could produce organic acids detected with HPLC.The test was curried out at neutral pH conditions,the organic acids secretion of strain NJDL-03 was 902 mg/L(oxalic acid),1546 mg/L(formic acid)and 530 mg/L(citric acid),and the organic acids secretion of strain NJDL-12 was 2353 mg/L(oxalic acid),7656 mg/L(formic acid)and 322 mg/L(citric acid).3.This paper has optimized the solid material proportion of solid-state fermentation and the culture time of the two strains,and determined the solid-state fermentation culture medium formula for comparison:wheat bran:vermicompost:rice husk:soybean meal= 8:2:8:1:1.On the fiveth day of the shallow tray fermentation at 28 ?,the spore number of strain NJDL-03 and NJDL-12 had reached 3.21 x 108 cells/g and 5.60 x 108 cells/g respectively.4.The experiment results showed that application of biofertilizer NJDL-03 and NJDL-12 significantly increased maize dry weight by 58.47%,32.15%and 61.51%,58.47%respectively in the pot experiments compared to the control.The total phosphorus content of corn plants and the soil enzyme activities(invertase,urease,neutral phosphatase)were significantly increased compared to the control.In conclusion,the pot experiment showed that biofertilier NJDL-03 and NJDL-12 have a good application prospect.