Effects Of Photosynthetic Bacteria J1 On Soil Nitrogen Supply And Related Factors In Rice Seedlings

The application of biological fertilizers in combination with inorganic fertilizers and organic fertilizers can increase the utilization of chemical fertilizers,reduce the amount of chemical fertilizers and environmental pollution.Photosynthetic Bacteria（abbreviated as PSB）has the effects of nitrogen fixation and growth promotion.In this paper,the strain J1（Rhodopseudomonaspalustris J1）preserved in the laboratory is used in rice seedlings with single application and organic and inorganic fertilizers,and its nitrogen supply level and related factors are studied.The impact provides a theoretical basis for improving PSB’s contribution to agricultural production.The results of the study are as follows:（1）PSB single application results show that PSB can significantly increase soil NH₄⁺-N and alkali-hydrolyzable nitrogen,increase the amount of nitrogen-fixing bacteria,bacteria,and actinomycetes in the soil,reduce the number of fungi,and make the soil more healthy to bacteria type conversion.The optimal application rate of PSB was 30%bacteria solution,5.1×10⁶ particles per gram of soil,which can maintain its certain effect within 30 days.（2）The results of PSB combined with total inorganic fertilizer and total organic fertilizer respectively showed that the content of NH₄⁺-N in the soil after the total amount of organic fertilizer added bacteria and total inorganic fertilizer added bacteria was significantly higher than that at 15 days and 30 days.After treatment with bacteria,the content of NO₃^--N and alkali-hydrolyzed nitrogen in the total organic fertilizer plus bacteria treatment was significantly higher than that of the total inorganic fertilizer plus bacteria treatment at 15 days and 30 days.（3）The results of PSB combined with organic-inorganic fertilizers shows that the application of PSB combined with organic-inorganic fertilizers could promote the increase of soil NH₄⁺-N,NO₃^--N and alkali-hydrolyzable nitrogen,and increased soil organic matter content.,but had little effect on pH.At 15 d-30 d,it was significantly higher than that of PSB,total organic fertilizer or PSB and total ration fertilizer treatment.PSB had the best effect with 70%bacteriostatic solution,1.19×10⁷ CFU·g^-1per gram of soil and 50%inorganic fertilizer and 50%organic fertilizer.（4）The presence of organic fertilizer was beneficial to the growth and reproduction of beneficial microorganisms in the soil,and promotes the increase of PSB,nitrogen-fixing bacteria,bacteria and actinomycetes,while inhibiting the growth of fungi.This effect increased with the increase of PSB application amount.The amount of PSB,azotobacter,bacteria,and actinomycetes that were treated with all organic fertilizers plus bacteria was higher than that without organic fertilizers.The fungal situation was the opposite.（5）Correlation analysis shows that when PSB was applied to the soil alone,PSB was positively correlated with NH₄⁺-N,and positively correlated with pH,nitrogen-fixing bacteria and NO₃^--N and alkaline hydrolysis.There was a significant negative correlation between nitrogen content and significant positive correlation between alkali-hydrolyzable nitrogen and NO₃^--N.When PSB and organic-inorganic fertilizer were applied in soil,there was a very significant positive correlation between PSB and nitrogen-fixing bacteria and bacteria.The number of actinomycetes was significantly positively correlated,and the number of Azotobacter,actinomycetes,and bacteria was significantly positively correlated with the NO₃^--N and alkaline dissolved nitrogen contents.The number of actinomycetes and NH₄⁺-N and alkaline hydrolysis and the nitrogen content was significantly positively correlated,the number of fungus was significantly negatively correlated with the NO₃^--N content,and significantly negatively correlated with the alkaline dissolved nitrogen content.（6）Pot experiment of rice seedlings shows that PSB combined with organic-inorganic fertilizer had a long-term effect on plant height and plant root length,especially when tested for 30 days,the effect was significantly better than other treatments.The combination of PSB and organic-inorganic fertilizers increases the antioxidant capacity of plants,promoted the synthesis of chlorophyll,increased the accumulation of dry matter,and could effectively increase the amount of microbial carbon and nitrogen in the soil and enhance soil microbial activity.The application of PSB combined with organic-inorganic fertilizers can effectively increase the nitrogen content of the plant.In terms of soil microbial population abundance,PSB reduced the richness of soil fungi and changes the soil microbial community structure.In summary,PSB can increase the level of soil nitrogen supply,and the combination of organic and inorganic fertilizers can significantly improve soil nitrogen capacity.After 30 days,it can replace inorganic nitrogen fertilizer by more than 50%,with 70%bacteria solution and 50%inorganic compound.Nitrogen and50%organic fertilizer worked best.