Effects Of Modified Apple Waste Branches And Its Combination With Fertilizer On Apple Root-zone Soil And Plant Growth

As a fruit-producing country,China produces a large number of waste branches every year.These waste branches are rich in organic carbon and are important organic resources.In this study,potted apple saplings(rootstocks are Malus hupehensis Rehd.)were used as test materials.The effects of chemically modified apple waste sticks,modified apple waste branches and chemical fertilizers,and two kinds of fertilizers produced from modified apple waste branches on soil microorganisms,enzyme activities,and apple roots and plant growth were investigated.The results show that:1.The modified apple waste branches are made by crushing waste apple branches with polyol and acid.The modified materials are rich in organic carbon and acidic.According to the mass ratio,0,0.33%,0.67%,1.00%,1.33%,1.67% and 2.00% of modified apple waste branches are added to potting soil.The pH of potting soil decreases from 7.33 to 7.21,7.07,6.95,6.85,6.73 and 6.59,respectively,indicating that soil pH is the nearest to neutral after applying 1% modified apple waste branches.2.The modified apple waste branches with a mass ratio of 1% significantly improve soil water retention during moderate drought,increase the amount of soil microorganisms in the root zone,increase the ratio of bacteria and actinomycetes to fungi,increase activity of sucrase,urease,neutral phosphatase,and catalase in soil,increase root activity and total root length,surface area,volume,average diameter,number of root tips,and fractal dimension of roots,increase plant growth and leaf net photosynthetic rate and water use efficiency.The effect of combined application of modified apple waste branches and chemical fertilizers is more significant.It increases the total number of soil bacteria,actinomycetes and microbes by 249.03%,249.31% and 247.74%,respectively,increased soil sucrase,urease and neutral phosphatase activities by 33.55%,23.70% and 49.86%,respectively,increased root activity,total root length,surface area,volume and number of root tips by 115.56%,51.75%,46.71%,41.84% and 99.03%,respectively.3.The table and columnar fertilizers produced from modified apple waste branches have the effect of slowly releasing nutrients.The application of them in soil can significantly improve the ratio of bacteria,fungi,actinomycetes,total microorganisms,bacteria/fungi,and actinomycetes/fungi in the root zone soil,significantly increase the activity of sucrase,urease and neutral phosphatase in the root zone soil,increase root activity and total root length,surface area,volume,average diameter,root tip number,and root fractal dimension,improve the photosynthetic performance of leaves and promote the growth of shoots.These effects are better than single-application of equal amount of fertilizer.Moreover,the fertilizer table can still keep the monthly growth of the plant at a high level within 3-4 months after application.