| Silage maize(frumentum silage)is a good forage for herbivorous livestock.With the attention paid to silage maize industry,the planting area of silage maize is increasing year by year,which leads to the increase of fertilizer application and the change of soil microbial community,resulting in the shortage of soil nutrients.Microbial fertilizer can provide high-quality strains and improve the utilization rate of plant phosphorus in the soil.Among them,phosphorus dissolving strains can transform the ineffective phosphorus that can not be absorbed by crops into the effective phosphorus that can be absorbed and utilized,which plays a very important role in the soil.In this study,phosphate solubilizing strains were isolated from the rhizosphere soil of silage maize.After screening and identifying various insoluble phosphate sources,pot and field were used to evaluate the effect of strains on the growth of silage maize.In order to provide high-quality strains for the development of microbial fertilizer compatible with a variety of insoluble phosphorus sources,and lay a foundation for alleviating the environmental pollution caused by excessive use of chemical fertilizer.The main results are as follows:1.Isolation and screening of phosphate solubilizing strainsWith calcium phosphate as the sole source of phosphorus,37 strains of P-solubilizing strains were isolated from the rhizosphere soil of silage maize,and 20 strains of P-solubilizing strains were screened.Ten strains of dissolving calcium phosphate were screened by shaking flask,and then six strains of high efficient dissolving phosphorus bacteria were screened by screening experiments of various insoluble phosphorus sources.2.Identification of phosphate solubilizing strainsAccording to bacterial morphology,16 S r DNA sequence analysis and physiological and biochemical detection,the selected phosphate solubilizing bacteria were identified,and LH-2 were Bacillus aryabhattai.LH-5 were Bacillus megaterium.LH-8 were pantoea ananatis.LH-10 were pseudomonas helmanticensis.LH-12 were pseudomonas moraviensis.LH-13 were acinetobacter calcoaceticus.3.The growth promoting effect of phosphate dissolving strain on potted silage maizePot experiments were conducted to evaluate the effect of phosphate solubilizing strains on the growth of silage maize.The results showed that LH-5,LH-8,LH-10 and LH-13 could promote the germination of silage maize seeds in plate.Among them,LH-13 was the most significant(P < 0.05),while LH-2,LH-5,LH-8,LH-10 and LH-13 could promote the growth of potted maize.Among them,the inoculated strains LH-13 increased 46.83%,55.74% and 54.95% in plant height and aboveground dry and fresh weight respectively,and the range of underground dry and fresh weight also increased significantly(P < 0.05),2.26 g and 7.12 g respectively;in root length,strain LH-8 promoted the growth of root length,the longest root length was 29.90 cm.In terms of physiological indexes,the root activity value of LH-13 strain reached 8.69 mg/ g / h,and the chlorophyll content of LH-5 strain increased by 19.20%,which was the most significant(P < 0.05);the soluble protein from the largest to the smallest was LH-8,LH-5,LH-13,LH-10,LH-12 and LH-2.4.The effect of phosphate solubilizing bacteria on the growth of silage maizeFive phosphate solubilizing bacteria screened from pot experiments were used to further evaluate the growth promoting effect of silage maize in the field.The results showed that the effects of inoculating strains on plant height of silage maize were LH-8,LH-13,LH-10,LH-5 and LH-2 from the largest to the smallest,and the effects of inoculating strains LH-10 and LH-13 on stem diameter of silage maize were 13.40%and 13.70% respectively.Compared with the control group,the fresh and dry weight of silage maize increased by 22.67% and 24.53% respectively. |
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