Effects Of Three Kinds Of Apple Branch Materials And Nitrogen Application On Nitrogen Utilization And Loss Of Apple

This experiment was carried out at the Horticultural Experiment Station of Shandong Agricultural University from March 2021 to November 2021.M26 was used as the test material for pot experiments.By using the ¹⁵N isotope disappearance technology,the effect of three apple branch materials and nitrate nitrogen was studied.The effect of nitrogen absorption and loss,the effect of carbonized apple branches and three forms of nitrogen on apple growth and nitrogen transformation,the main research results are as follows:1.Effects of three apple branch materials（blank control（CK1）,apple branch powder（FF）,apple branch compost（DF）,carbonized fruit branch（BF））and nitrate nitrogen on nitrogen utilization and loss in apples:adding different apple branch materials to the soil all increased the growth of the plant;the root vigor,root length,total surface area,root volume and number of root tips were the best in the BF treatment;The activities of soil enzymes such as soil catalase,sucrase,cellulase,and protease can be improved by adding three kinds of apple branch materials.Among them,the activities of invertase,catalase and cellulase treated by BF are the highest,and those treated by FF are the highest.the highest protease activity.At the same time,the soil nitrite reductase and nitrate reductase activities of BF and DF treatments had the best effects,but the difference between them was not significant.The addition of three apple branch materials in the soil was beneficial to increase the nitrate nitrogen content in the soil.The nitrate nitrogen content in the early DF treatment remained the highest,and the nitrate nitrogen content in the late BF treatment reached the highest.Compared with the control,BF,DF and FF treatments can reduce soil bulk density and increase soil organic matter content and total nitrogen content.At the same time,the nitrate reductase activity（NR）,glutaminase activity（GS）,and glutaminase activity（GOGAT）of roots and leaves treated with BF,FF and DF were significantly increased compared with the control treatment,and the The activities of these three enzymes were higher than those of leaves,and the activities of these three nitrogen metabolism enzymes in the roots of plants showed the order of BF>DF>FF>CK1,and the leaves also had the same trend.From the perspective of the relevant indicators of ¹⁵N,adding apple branch material can improve the utilization rate of ¹⁵N and reduce the loss rate of ¹⁵N.The utilization rate of ¹⁵N in each treatment is BF>DF>FF>CK1,and the utilization rate of ¹⁵N in BF treated plants is BF>DF>FF>CK1.The highest rate was 10.13%.The loss rate and utilization rate of ¹⁵N showed the opposite trend,the CK treatment was the highest,and the BF treatment was the lowest.Based on the effects on plant growth,soil nitrogen content,soil enzyme activity and utilization rate of ¹⁵N,the effect of carbonized fruit branches is the best among the three apple branch utilization methods.2.Effects of carbonized apple branches and three forms of nitrogen（only carbonized fruit branches（CK2）urea（NS）,ammonium sulfate（LS）,calcium nitrate（XS））on apple growth and nitrogen transformation:Adding different forms of nitrogen to the soil can improve the growth of plants.XS treatment is the best for fresh weight,plant height,stem diameter and leaf area of plants,and NS treatment is the best for fresh weight of underground parts.The total root surface area and root volume were the highest in NS treatment,while the total root length,root tip number and root activity were highest in XS treatment.The content of nitrate nitrogen in the soil was always higher than the content of ammonium nitrogen.In the 30-60days after fertilization,the content of ammonium nitrogen and nitrate nitrogen in the soil gradually decreased,and the decrease trend of ammonium nitrogen in the LS treatment was the most.Obviously,the decreasing trend of nitrate nitrogen in NS treatment is the most obvious.There was no significant change in the contents of ammonium nitrogen and nitrate nitrogen in the soil from 60 to 90 days.The soil nitrification intensity showed a trend of decreasing first and then leveling off with the increase of fertilization days.The NS treatment had the strongest nitrification intensity,while the control treatment had the least effect on the soil nitrification intensity;Similarly,the application of different forms of nitrogen fertilizer increased the denitrification intensity of the soil,and the soil denitrification intensity of the XS treatment was the highest.The combined application of carbonized fruit branches and different forms of nitrogen can significantly increase the activities of nitrate reductase（NR）and glutaminase（GS）in plants,and the activities of these two enzymes in the roots of the plants are higher than those in the leaves.The NR activities of plant roots and leaves were XS>NS>LS>CK.the soil hydroxylamine reductase activity of NS treatment was the highest,and the soil nitrate reductase and nitrite reductase activities of XS treatment were the highest,which were higher than the control respectively.The soil nitrate reductase activity of NS treatment was higher than that of LS treatment,but there was no significant difference between the two on soil nitrite reductase activity.It can be seen that the combined application of carbonized fruit branches and different forms of nitrogen can promote the process of plant growth and nitrogen transformation,and the effect of combined application with nitrate nitrogen is the best.