Effects Of Organic Matter Application On Continuous Cropping Obstacle Of Peach(Prunus Persica)

Peach is an important economic fruit tree in our country,with a wide range of cultivation,large planting area and frequently updated of varieties.The phenomenon of young trees are not growing well and not living often occurs when plant on the old peach orchard because of peach continuous cropping obstacle.At present,there are no effective measures to prevent the continuous cropping obstacles in peach,which seriously restricts the sustainable development of the peach industry.A large number of studies showed that the application of organic matter can alleviate the harm caused by the continuous cropping obstacles and promote plant growth.Therefore,in this experiment,soybean,rapeseed meal,and soybean meal as organic matter is separately added into fallow soil and continuous cropping soil to plant peach seedlings after fermentation.The alleviating effects of three kinds of organic matter on peach continuous cropping obstacles can be found by observing the biomass such as plant height,stem diameter,dry and fresh weight,leaf number and leaf area,root morphology,and leaf photosynthetic capacity of peach seedlings,determining the changes in soil physicochemical properties and soil microbial community structure.The main results are as follows:1.After 105 days of planting,all the three kinds of organic matter can significantly improve the biomass and photosynthetic capacity of peach seedlings.Compared with peach seedlings grown in continuous cropping soil,the individual application of soybean,rapeseed meal and soybean meal can significantly increase plant height and stem diameter,and the increase effects on plant height is 92.84%,68.92%and 63.08%,respectively.The number of leaves and the area of leaves also increased,and the effect of increasing the area of leaves is 68.33%,56.94%and 65.29%,respectively.The application of three kinds of organic matter significantly increased the fresh weight and dry weight of aboveground and underground parts,with the increasing effect being meal>soybean>soybean meal.In addition,the three kinds of organic matter promoted root growth and improved root configuration.All of organic matter increased total root length,average root diameter,root surface area,root volume,number of branches,and root tips.Among organic matter,soybean had the best effect.The increasing effects of soybean,rapeseed meal and soybean meal on F_v/F_m of peach seedling leaves is as follows:soybean>rapeseed meal>soybean meal.The increasing effects on soil-plant analysis development(SPAD)of peach seedling leaves are as follows:71.98,80.01%and 84.15%,respectively.The improvement effect of total chlorophyll is soybean meal>rapeseed meal>soybean.2.Physicochemical properties of the three kinds of organic matter were significantly different before planting.Soybean had the highest organic matter content,available sodium content,and carbon nitrogen ratio.The content of available phosphorus and available calcium in rapeseed meal was the highest.The available potassium content of soybean meal was the highest.After 105 days of planting,the physical and chemical properties of the soil changed to different degrees.Soybean,rapeseed meal and soybean meal might increase the contents of organic matter,nitrogen,phosphorus and potassium in the soil,and also increase the p H value to maintain high fertility of the soil.3.After 105 days of planting,the Chao index and Shannon index of soil microorganisms decreased with the addition of rapeseed and soybean,indicating to a certain extent that the species diversity and richness of bacteria and fungi in soil was decreased.At the same time,rapeseed meal and soybean changed the soil microbial community structure and build beneficial flora.The addition of soybean,rapeseed meal and soybean meal increased the abundance of soil beneficial bacterial phylum such as Rhodanobacter,Bacillus and Burkholderia,and beneficial fungi such as Candida,Mortierella,and Geotrichum,and decreased the abundance of plant pathogenic fungi functionally predicted.It also improved the functions of 20 soil bacteria in four categories of cell transformation,genetic information processing,environmental information processing and metabolism related to plant growth.In summary,soybean,rapeseed meal and soybean meal increased the contents of organic matter,nitrogen,phosphorus and potassium and other elements in soil,which enhance soil fertility,promote the growth of peach seedling roots and shoots,and also promote photosynthetic capacity to some extent.Meanwhile,rapeseed meal and soybean increased the abundance of soil beneficial bacteria and fungi,reduced the abundance of plant pathogenic fungi functionally predicted to improve peach seedlings growth.In general,soybean had the best effect on promoting the growth of peach seedlings and alleviating continuous cropping obstacles.