| According to the present status that soil potentially phosphorus was rich, whereas available phosphorus was deficiency, black soil from Corn Belt of Songliao Plain was chosen as study object. Some field trials combined with indoor analysis, screening strains and development of the product, biological control and the cultivation technology were carried out to investigate the mechanism of soil microbiota in black soil, the spatial-temporal change law of soil nutrient and enzyme activities and the correlation, screening and identification of the PSB and their mechanisms on phosphorus solubilization, elevate the ability in phosphorus uptake, and development of phosphorus solubilization microbial fertilizer, and the effects of field experiments, etc. This project wishes to find the mechanisms of soil phosphorus bioactivation and provide theory evidence to scientific utilization of soil phosphorus and rational application phosphorus fertilizer. The research results are as follows:1. Variation of soil microflora and enzyme activity in black soilThe activity of bacterium. Fungi, and actinomycete mainly concentrate in the0-30cm scope with different conservation tillage modes, the quantity of soil microorganisms under30cm are very few, During the different growth period of Maize. The bacterium populations in narrow-row and wide spacing practice methods were more than that of cultivation tillage methods at corn pre-planting, jointing and post-harvest stages, the changes of Fungi populations in cultivation tillage methods were more than that of narrow-row and wide spacing practice methods at jointing stage to tasseling stage, however at seedling stage to jointing stage the actinomycete populations in narrow-row and wide spacing practice methods were more than that cultivation tillage methods, At jointing stage to tasseling actinomycete populations in stage cultivation tillage methods were more than that of narrow-row and wide spacing practice methods, soil urease activity was the most highest in Maize at filling stage,and the activity of soil neutral phosphatase were the lowest, the activities of acid phosphatase and alkaline phosphatase at pre-planting stage in narrow-row and wide spacing practice methods were higher than that of cultivation tillage methods.2. The spatial-temporal variation of soil nutrientsThe higher NH4+-N was measured at each soil layer at different growth stages of maize, and that of cultivation tillage methods were higher than that of narrow-row and wide spacing practice methods at pre-planting stage.while higher available phosphorus was measured at table of the poly. For potassium content, a minor change was found at each layer. As well as, total nitrogen, phosphorous was decreased with the soil depth and minor changes were investigated in total potassium. During the growth period, organic matter content was maintained at2～3%and the pH value was positively correlated with the soil depth which demonstrates that both applications may contribute to soil acidification. 3. Correlation Analysis of black soil nutrients and enzyme activityThe correlations among soil enzyme activities, soil nutrient and variations of microflora was investigated at black soil are of central Jilin during different developmental stages of maize. Soil urease activity was significantly correlated with soil total N and total P contents (p≦0.01) at post-harvest stage and pH (p≦0.01) after filling stage. As well as. soil urease was significantly correlated with alkali-hydrolyzable N (p≦0.05) at pre-planting, jointing and post-harvest stages. However, soil urease showed no significant correlations with available P, K contents and no correlations with the amount of soil microflora, respectively. Soil phosphatase (acid, alkaline and neutral) activities were significantly correlated with soil total N (p≦0.05) and total P (p≦0.01) during the main development stages of maize. As well as, soil phosphatase (acid, alkaline and neutral) activities showed relatively significant correlations with available P, K contents and pH (negative) except filling stage. It means that, activities of soil phosphatase were mostly infected by the distribution of soil nutrient and pH values. Soil phosphatase activities were significantly correlated with soil microflora (p≦0.01) at pre-planting stages and no continuous regularity correlations were investigated at the end of maize growth. Soil enzyme activities showed relative significant correlation with soil organic matters. While no significant correlation was investigated with soil total K content.4. Screening and identification of phosphorus solubilizing microorganisms and Determination of phosphorus solubilization capacity and fermentation conditions of phosphorus solubilizing microorganismsThe80strains of PSB were screened from phosphorus deficiency black soil samples in maize cultivation belt of northeast china.Then.24strains of microbial were isolated by their abilities in phosphorus solubilization, gelatinase, and protease and cellulose production ability. These strains were identified as Bacillus subtilis strain Q1, Bacillus thuringiensis serovar kurstaki strain AR-10. Pseudomonas fluorescens Pf0-1, Bacillus cereus, Burkholderia sp. CEB01056, Oxalobacteraceae bacterium NR186、Enterobacter ludwigii strain K9and Bacillus megateriun.In the following study, Bacillus megaterium was selected by their strong ability in phosphorus solubilizing for this work. The soluble-P concentration continuously increased during the incubation periods and the total amount of soluble P released in culture filtrate was detected at420mg.L-1after4days of inoculation. The optimal culture condition for the phosphatase production by Bacillus megaterium was72hours of cultivation at28℃in a medium composed of0.1%inoculation concentration.1%glucose.0.5g.L-ammonium sulfate at initial pH7.0.5. Phosphorus solubilization mechanism of phosphorus solubilizing microorganismsThe particle size of calcium phosphorus surface was found to destroyed and the size were changed to between77fnm～124.2nm. while no changes in the surface and size were found in the control with the size132.7nm～181.7nm. The bacterium was found to release gluconic acid by the HPLC and FT-IR analysis and the solubilization of hydroxyapatite in the liquid medium by a significant drop in pH to4.1from an initial pH 6. The development of phosphorus solubilizing fertilizer and the effect of phosphorus solubilizing biofertilizer on improving effectivenessof black soil phosphorus and utilization efficiencyIn this study, insoluble phosphorus could be indented and screened and solubilizing bacillus megaterium and burkholderia were functional strains. The4biological fertilities from different dosage forms were experienced in the field. The vegetative growth, photosynthesis, biomass production and grain yield were improved by utility of biological fertilities. The results showed that biomass productions of maize were increased from5.67%to10.02%and grain yield were escalated from5.21%to13.18%. Under different condition of utility of phosphorus fertility, productions of biomass and grain yield increased2.47%and1.79%respectively by using biological fertility. The biomass and grain yield of soybean increased5.45%and9.24%individually by utility of biological fertility.The condition of phosphorus in the soil were improved by the utility of dissolving phosphorus obviously at main growth stage of different crops such as maize and soybean. The effective phosphorus in the soil was increased from0.89mg/kg to3.53mg/kg at jointing of maize by utility of biological fertility. However, after harvesting of maize, effective phosphorus was increased from9.03mg/kg to11.91mg/kg to11.91mg/kg. The available phosphorus in the soil was increased13.48mg/kg dissolving phosphorus fertility than single fertility. The results showed that dissolving biological fertility could enhance utility ratio of fertility and improve the condition of phosphorus in soil. In total, the dissolving biological fertility could improve the phosphorus efficiency in field experience. The results showed that utility ratio of phosphorus was increased from21.75%to37.98%.Application amount of chemical phosphorus fertilizer was reduced by1/3～1/2by microbial phosphorus fertilizer amendment and activation rate of insoluble phosphorus in different ecological zone of Jilin province and yield of maize were increased obviously. The scope of yield was increased from8.2%to11.7%in semi moist zone in the middle of Jilin province. The scope of yield was increased from4.1%to8.3%in semiarid zone in the west zone of Jilin province. The scope of yield was increased from5.6to13.0%in most and cold zone in the east zone of Jilin province. These results showed that dissolving biological fertility could reduce the utility of phosphorus and have better ecological function to save energy source, protect environment and increase profits. |
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