Compositional analysis of biomass and accumulation properties of mineral elements in Walnut

The aim of this study was to investigate the properties of accumulation and distribution of mineral elements in Walnut(Juglans regia L.) and to establish a reasonable fertilization protocol.Field experiments were conducted to analyze the character of biomass composition,mineral element content and its accumulation in different parts of Walnut trees which were about 5 years old.The total dry biomass of walnut was 32814 g·plant-1 in which new vegetative organs of the year accounted for 16.36%,fruits for 13.59% and old vegetative organs for 70.05%,respectively.The nitrogen(N) content was the highest in the kernel(36.4 g·kg-1),30.2 g·kg-1 in the leaf and the lowest in the shell(2.4 g·kg-1).The phosphorus(P) content was the highest in the petiole(7.2 g·kg-1),3.7 g ·kg-1 in the shuck and lowest in the shell(0.17 g·kg-1).The potassium(K) content was the highest in the shuck(75.3 g·kg-1),15.4 g·kg-1in the leaf,15.4 g ·kg-1 in the petiole and 11.0 g·kg-1 in the new branch.The calcium(Ca) content was the highest in the Petiole(44.9 g·kg-1),29.9 g·kg-1 in the leaf and the lowest in the kernel(0.62 g·kg-1).The magnesium(Mg) content was the highest in the petiole(6.4 g·kg-1),6.2 g·kg-1 in the leaf and 5.1 g·kg-1 in the shuck.Total N,P,K,Ca and Mg amount in Walnut tree were 366.67,48.92,247.37,440.19 and 62.32 g·plant-1,respectively.Nitrogen was mainly distributed in the kernel,leaf,limb and taproot.Phosphorus was mainly distributed in the taproot,kernel,limb,leaf and shuck.Potassium was mainly distributed in the shuck and leaf.Calcium was mainly distributed in the leaf,limb,3 years branch,2 years branch and trunk.Magnesium was mainly distributed in the leaf,taproot,shuck and Limb.To obtain 1 000 kg dry matter of fruits,Walnut trees must uptake N 77.05 kg,P 9.70 kg,K 62.24 kg,Ca 75.41 kg and Mg 13.35 kg.Walnut tree absorbed more N,K,Ca than P,Mg.The vegetative organs accumulated more N,Ca than P,K,Mg.The reproductive organs accumulated more N,K than P,Ca,Mg.