Study On Application Of Citrus Pruning Waste In Citrus Container Seedling

Citrus is the most consumed fruit in the world,with a wide cultivation area and a large demand for nursery.Peat is often used as substrate for citrus nursery.Peat is a non-renewable resource in the short term.Continued use of peat leads to the quantity decreasing.This increases the cost of citrus nursery.In this study,composting experiments were carried out using citrus pruning wastes.The purpose was to study the feasibility of using this composting product instead of peat as the substrate for citrus nursery,and to promote the resource utilization of citrus leaf wastes in citrus nursery.The main findings are as follows:1.After 35 days,the compost product of citrus pruning wastes reached maturity.The nutrient elements of compost product were increased significantly,and their physicochemical properties satisfied the conditions as a plant cultivation substrate.It can be used in plant cultivation.2.Using river sand,vegetable garden soil,gravel and citrus pruning wastes composting products as matrix materials,five treatment were prepared in different volume ratios.And the peat matrix(peat: river sand: chaff = 1:1:1)was used as control(CK).The physicochemical properties of different treatments and control were studied.The results showed that the nutrient content of each treatment was rich and the pH was in the range of 6.39~7.53,which can be used for the planting of citrus container seedlings.The available nutrient content of T3(river sand: compost product = 1:4)was the highest,and the index of unit weight,air-water ratio were the closest to the peat matrix,but the pH value was high.3.The substrates which were made up of the compost product and river sand in different volumes,were used for the cultivation of trifoliate orange rootstocks.The results showed that the growth of stems and shoots of T1(river sand: compost product = 1:1)and T3 were significantly higher than that of the control.The dry weight and fresh weight of whole plants,roots and stems of each treatment were significantly higher than CK.In terms of nitrogen content of leaf,T2(river sand: compost product = 1:2)was the highest,followed by CK and T3,and T1 was the lowest.In terms of the phosphorus content of leaf,T2 was significantly lower than CK,and T1 and T3 had no significant differences with CK.In terms of the potassium content of leaf,each treatment was significantly lower than CK.The contents of Ca and Zn in leaf were significantly higher than CK,while the contents of Mg,Fe,Mn and Cu were significantly lower than CK.4.The substrates which were made up of the compost product and river sand in different volumes,were used for the cultivation of citrange rootstocks.The results showed that the growth indexes of T2 and T3 were significantly higher than CK.The dry weight and fresh weight of whole plants and different organs of each treatment were significantly higher than CK.In terms of the nitrogen content of leaf,T1 was significantly lower than CK,but T2 and T3 had no significant differences with CK.The contents of phosphorus and potassium of leaf in each treatment were significantly lower than CK,but all of them were at an appropriate level.Among the microelements,the Ca content of each treatment was significantly higher than CK,and the contents of Mg and Cu were significantly lower than CK,and there was no significant difference in the content of Fe between each treatment and CK.In terms of the contents of Mn and Zn,there was no significant difference between T2 and CK,but T1 and T3 were significantly lower than CK.5.The substrates which were made up of the compost product,river sand,vegetable garden soil and gravel in different volumes,were used for the cultivation of grafted seedlings.The results showed that the stem diameter,trunk and shoot growth of T2 were significantly higher than CK.In terms of dry weight and fresh weight of whole seedlings,roots,stems and leaves of seedlings,T2 was the largest and significantly higher than CK,but T4(vegetable soil: compost product = 3:2)was the least and significantly lower than CK.In terms of nitrogen content,all treatments were significantly higher than CK,except T5(gravel: compost product = 1:2).In terms of phosphorus content of leaf,all treatments except T5 were significantly lower than CK,but all were at the appropriate level.In terms of potassium content,the T4 was the highest and significantly higher than CK,and T3 and T5 were significantly lower than CK,and there was no significant difference between other treatments and CK.In terms of microelements content,there were no significant difference in Fe and Cu content between each treatment and CK.The Ca contents of T3,T4 and T5 were significantly higher than CK,and the other treatments were significantly lower than CK,but all were at the appropriate level.The Mg contents of T1 and T3 were significantly higher than CK.The Mn content of T1 was the highest,but it was not significantly different from CK.The Zn content of T3 was the highest and significantly higher than CK,and there was no significant difference between T4 and CK,and the other treatments were significantly lower than CK.In summary,composting of citrus pruning wastes can obtain the products with high maturity,strong stability and harmlessness,and it is feasible to replace peat in citrus nursery.The results of this study can provide reference for the substrate utilization of citrus pruning wastes.