Effects Of Years Of Planting On Soil Fertility And Biological Characters In Apple Orchard And Research On Soil Remediation Technology Of Aged Orchard

Shaanxi Province is one of the major apple production areas in China and even has a place in the world's apple industry system.Weibei Dryland apple production has a significant place in Shaanxi apple industry system.However,in recent years,due to numerous problems such as consecutive monoculture problem and poor management,the continuous degradation of soil quality in apple orchards in Weibei dryland has even affected the orchard's yield.The study was conducted at Baishui Apple Experimenta l Station,Northwest A&F University,Baishui County,Weinan City,Shaanxi Province.To determine the differences in physical and chemical properties,enzyme activities,and microorganisms of different ages of orchards,and explore the effect of organic fertilizers and microbial agents on orchards.The test is mainly divided into two parts.First,apple orchard soils of different ages for the study,sample surveys were conducted on orchard soils for 5,10,20 and 30 years.The second is the 20-year orchard as the research object.Single treatment with chemical fertilizer,single application of organic fertilizer and organic fertilizer combined with microbial agents applied three treatments.Determination of soil physicochemical properties,enzyme activity and microbiological status of surface soil in the crown projection area,and the microbial status of soil agglomerates in different orchard apple orchards,analysis of the law of change and their relationship.The main findings are as follows:1?The long-term cultivation of apples puts a lot of organic fertilizers,organic fertilizers can improve the soil's buffer capacity.Therefore,the soil pH of the originally alkaline orchard fell during 25 years.With the increase of the age of orchards,the biomass of fruit trees keeps increasing and the absorption of soil available nutrients increases.As a result,the available nitrogen content in soil decreases by more than 30%.With the growth of fruit trees,the absorption of nutrients increases first and then weakens.Orchard soil organic matter and total nitrogen content reached a trough between 10 a and 20 a,respectively,35% and 40% lower than 5a.2 ? Long-term cultivation of apples,orchard soil ?-1,4-N-acetylglucosaminidase,?-1,4-xylosidase,?-1,4-glucosidase,cellobiohydrolase and alkaline phosphatase the activity of the five enzymes of increased significantly with the growth of orchard age.Long-term planting apple orchards have invested a large amount of organic fertilizer,can provide a good soil micro-ecological environment.Soil ?-1,4-N-acetylglucosaminidase,?-1,4-xylosidase,?-1,4-glucosidase,cellobiohydrolase and alkaline phosphatase activity,both With the increase of orchard age significantly increased,30 a more than 5a acetylglucosaminidase activity increased 145.34%,the other four enzyme activity increased by 15%-30%.3? The amount of soil fungi and bacteria in the orchard differ greatly,and the number of fungi is much lower than the number of bacteria.There was no significant difference in the number of bacterial species in each grade of soil aggregate in different tree age orchards.The ten genera with relatively high relative abunda nce of soil fungi in different tree ages orchard were mostly bacteria belonging to the Zygomycota and basidiomycota.The number of fungal populations in each tree age orchard and each grade of soil agglomerates is not much different.And the fungal relative abundance ranks in the top 35 genera,of which more than 70% are from Ascomycota,most of the bacterial speciesof the Ascomycete was saprophytic life.4? Organic fertilizer can improve the soil and it works better under the influence of microorganisms.After two years of treatment,the pH of single applied organic fertilizer decreased by 0.16,and the p H of organic fertilizer combined with microbial inoculants applied decreased by 0.21.The application of organic fertilizer in orchards increased soil organic matter content by 10.52%,effective phosphorus content by 306.35%,and available potassium content by 50.31% compared with single fertilizer application.5 ? The application of organic fertilizer can provide a good soil micro-ecological environment,and promote microbial activity and plant root growth.Single application of organic fertilizer or organic fertilizer combined with microbial agents,The activity of ?-1,4-N-acetylglucosaminidase,?-1,4-xylosidase,?-1,4-glucosidase,cellobiohydrolase and alkaline phosphatase was significantly higher than that of the single fertilizer treatment,which increased by 30% to 110%.6?In the different fertilization treatments,there was no significant difference in soil bacteria in the three treatments,there were differences in Agaricaceae,Cystofilobasidiaceae and Melanophyllum in soil fungi.The relative abundances of Agaricaceae and Myra corals treated with organic fertilizers and microbial agents were significantly higher than other treatments.The relative abundance of Aspergillus flavus treated with organic fertilizer alone was significantly higher than the other two treatments.