Effects Of Three Bacillus Species On Nitrogen Reduction And Improvement Of Orchards Soil Properties And Fruit Quality In Sweet Cherry

Due to the short reproductive period of sweet cherry,a large amount of nutrients are needed to be replenished quickly during the growth process,so the daily production and management of orchard is mainly supplemented by a large amount of fertilizers,but the excessive application of fertilizers,especially chemical fertilizers,will cause some adverse effects on the orchard soil and fruit quality,and the fertilizers are not well utilized,resulting in waste and even pollution of the environment.In this study,we applied three kinds of Bacillus(Bacillus jelly-like,Bacillus megaterium and Bacillus siderophore)in three periods:basal fertilizer,budding fertilizer and fruiting fertilizer based on formula fertilization,The effect of the three Bacillus mycobacteria on nitrogen reduction and improvement of orchard soil properties and fruit quality of sweet cherries was studied by using conventional fertilizer formulations as controls to provide theoretical basis and practical solutions for weight loss and efficiency in sweet cherry production.The specific results of the study are as follows:(1)The comprehensive performance of all three Bacillus cereus treatment groups could achieve better results with 10% nitrogen fertilizer reduction treatment,and the overall performance of each treatment was best in all aspects with Bacillus cereus + 10% nitrogen reduction treatment,indicating that Bacillus cereus could effectively replace 10% of nitrogen fertilizer application.(2)Soil with pH 6.0-7.5 was the most suitable for sweet cherry growth,and the Bacillus cereus fungicide treatment reduced soil pH,with the best effect of Bacillus cereus + 10%nitrogen reduction treatment in all treatments,down to 6.97.After fruit picking,soil organic matter content was best in Bacillus megaterium + 10% nitrogen reduction treatment,and Bacillus cereus + 10% nitrogen reduction treatment had the best performance on soil effective phosphorus and The organic matter content was close to the soil background value,and the alkaline nitrogen and effective phosphorus content increased by 52.83% and 17.37%,respectively,compared with the soil background value,and the fast-acting potassium content was significantly higher than that of the control in all periods and was always at a higher level.The soil exchange calcium and magnesium content was better with the treatment of Bacillus cereus + 10% nitrogen reduction,which increased by 15.23% and 45.67%,respectively,compared with the background value.(3)Bacillus saprophyticus + 10% nitrogen reduction treatment was most effective in increasing the activities of urease,sucrase and acid phosphatase in the soil from 0-60 cm;after fruit harvesting,the soil urease and sucrase contents increased by 28.76% and 12.29%,respectively,compared with the background value,and the acid phosphatase content was close to the soil background value.(4)The treatment of Bacillus megaterium + 10% nitrogen reduction could better increase the fruit weight per fruit,and the treatment of Bacillus jelly-like bacteria + 10%nitrogen reduction was second,and the effects of each treatment on fruit shape index were not significant.In terms of fruit intrinsic quality,Bacillus megaterium + 10% nitrogen reduction treatment was more effective in increasing soluble solids and soluble sugars content in fruits,and their contents increased by 17.3% and 23.79%,respectively,compared with the control during ripening;Bacillus megaterium + 10% nitrogen reduction treatment had better effects on total phenol,total flavonoid and flavanol contents in fruits,and total phenol and flavanol contents decreased by 25.15% and 18.232%,respectively,compared with the control.The total phenol and flavanol contents were reduced by 25.15% and 18.232,respectively,and the total flavonoid content was increased by 17.57% compared with the control,while the effect of Bacillus megaterium + 10% nitrogen reduction treatment was the second.In conclusion,Bacillus can effectively replace part of the nitrogen fertilizer content,with the best performance of 10% nitrogen reduction in all treatment groups;Bacillus can also significantly improve soil properties,effectively improve soil enzyme activity and fruit quality;the overall performance of Bacillus jelly-like bacteria + 10% nitrogen reduction treatment is the best.