Research On The Development And Preliminary Application Of Inorganic Phosphorus Solubilizing Bacteria For Plant Growth In The Drawdown Area Of ??the Three Gorges Reservoir

As the last ecological barrier for fertilizers,pesticides and surrounding sediments to enter the waters of the Three Gorges Reservoir sink zone,it can maintain the ecological balance of water and land systems,and also has a strong ecological service function.Human activities cause a series of ecological and environmental problems,such as soil compaction,natural vegetation stripping,reduced vegetation coverage.Since the impoundment of the Three Gorges Reservoir,ecological restoration in the drawdown area is also a hot issue of national policy concern,and the application of microbial inoculants is one of the important technologies to realize the plant-microbial combined repair in the sinking area.In this paper,three high-efficient phosphorus-resolving strains were selected from the suitable plant rhizosphere soil in the drawdown area of the Three Gorges Reservoir made Phospholytic microorganism,a Box-Behnken response surface method was used to optimize the formulation of microbial agent carrier with different peat,charcoal and diatomite as factors/levels and the number of viable bacteria as response values.Through pot experiments,investigated the effects of phosphate-resolving microbial inoculants on the growth of suitable plants of Aconiti Lateralis in the drawdown area and its application to soil conditions in the drawdown area of the Three Gorges Reservoir.The main results are as follows:1.Screening of high-efficiency phosphate-resolving bacteria in the drawdown area of Three Gorges ReservoirAdopt traditional microbial separation and culture method,three high-efficiency phosphate-solubilizing bacteria strain were screened of H1,H2,H3 in the rhizosphere soil of Melilotus officinalis(L.)Pallas,Cynodon dactylon(L.)Pers,Aeschynomene indica(L.)which are resistant to water logging in the hydro-fluctuation belt of Three Gorges Reservoir.Its phosphorus-removing ability is 125.00 mg/L,103.67 mg/L,and 104.53 mg/L respectively.By 16SrDNA sequencing and Blast search of homologous sequences,the three strains of Phosphate-degrading bacteria were identified as Acinetobacter.2.Optimization of Phospholytic Microbial Agent FormulaPeat,charcoal and diatomite,three commonly used carriers,was simultaneously selected to optimize to formulation,which could achieve“strong combination”to a certain extent.The optimal formulation is peat:charcoal:diatomite=3:4:3 of H1,H2,T Microbial agent.Under this condition,the number of viable bacteria of the above agent achieved2.55×10~8/g,2.23×10~8/g,2.56×10~8/g.The optimal formulation is peat:diatomite=1:1 of H3Microbial agent,the number of viable bacteria of the above agent achieved 2.3×10~8/g.3.Effects of different treatments on the growth-promoting effect and soil physical and chemical properties of Aconiti LateralisCompared with CK(No Bactericide),application of microbial inoculants(H1,H2,H3,T:H1,H2,H3 mixed inoculation)can significantly increase the plant height and fresh weight of Aconite.At the 10th day after application,the growth rate of Aconiti Lateralis was fastest;T treatment showed significant difference with CK in the measurement period.Compared with CK,The fresh weight of H1,H2,H3 and T treatments increased by 4.3%,20.82%,12.03%,37.94%respectively,the soil pH of H1,H2,H3 and T treatments decreased by 5.5%,7.8%,7.6%,8.5%respectively;the available phosphorus content at H1,H2,H3 and T decreased by 59.46%,60%,62.7%,5 2.43%;the content of available potassium in H1,H2,H3 and T treatments increased by 4.12%,4.67%,18.81%,14.94%and the content of hydrolyzed nitrogen increased by 7.55%,11.32%,20.75%,26.42%respectively.Organic matter content increased by 8.89%,2.96%,20%,28.89%respectively.The content of total phosphorus,total nitrogen in soils increased with CK application except total potassium content and H2 treatment total phosphorus.Correlation analysis showed that organic matter was significantly positively related to available potassium,and pH was significantly positively related to available phosphorus.The results of soil nutrient determination showed that the application of phosphorus-resolving microbial inoculants could effectively promote the growth of aconite and improve soil nutrients,and T treatment had the best effect.In addition,the application of phosphate-resolving microorganisms will not promote soil phosphorus into water bodies.