Study on biomass and nutrient accumulation of Zizyphus jujube tree under dwarfing and high density culture

Abstract: Zizyphus jujube trees at age of five under dwarfing and high density cultivation are selected to study the dynamic changes of nutrient accumulation. The outdoor sampling and general analysis method indoor were adopted to carry out the research. The results show that the net increase of Zizyphus jujube tree biomass and the accumulated amount of dry fruit weight are 2090.1 g and 1177.2 g respectively in annual period, which account for 56.3% of the annual net increase of biomass. The fastest accumulation period of Zizyphus jujube biomass is at the fruit expanding stage and the accumulate rate is 21.80 g/d. The N, P and K contents of the root system in 10-20 cm soil layer are higher than those of other soil layers. The N, P and K contents of the taproots are 13.81 g/kg, 6.41 g/kg and 11.61g/kg in 10-20 cm soil layer, and those of the lateral roots are 10.20 g/kg, 4.91 g/kg and 12.90 g/kg. The accumulation amounts of whole Zizyphus jujube trees at various periods are in order: fruit harvest stage fruit expanding stage young fruit stage flower stage early bud stage. The sequence of the nutrient accumulation in the whole plants is K N P. To attain 1000 kg economic yield, Zizyphus jujube trees should uptake 21.03 kg N, 8.60 kg P and 31.92 kg K.