| Abstract: | Due to the significant overlap in the phenological stages of jujube trees, there is intense competition for nutrients among various organsin jujube trees. To provide scientific basis for precision management of nitrogen fertilization in jujube trees, 5 nitrogen application rates (0.08, 0.12, 0.16, 0.20 and 0.24 kg/plant) were set up in 8-year-old densely planted Ziziphus jujuba Mill. cv. ''Hupingzao'' plants to determine the effects of different nitrogen levels on the growth and fruit quality of ''Hupingzao''. The results showed that all nitrogen application treatments were conducive to the increase of the basal diameter and leaf area of ''Hupingzao'' trees and had little effect on the chlorophyll content in leaves at the late growth stage. The single fruit weight, fruit cross diameter, contents of soluble solids and total sugar, and sugar acid ratio were the highest under the nitrogen application rate of 0.16 kg/plant (nitrogen application rate were set at 40%, 30% and 30% of toal nitrogen fertilizer applied in the early germination, flowering and fruit expansion stages, respectively), which were 61.29%, 17.64%, 6.23%, 28.04%, and 55.51% higher than those of the control,no nitrogen application, respectively, the vertical diameter of the fruitwas increased by 9.42% compared with that of the control, no nitrogen application, and the total acid content was reduced by 17.47% compared with that of the control, no nitrogen application. In conclusion, under the conditions of this experiment, nitrogen application rate of 0.16 kg/plant was the optimal nitrogen application rate for the growth and fruit quality improvement of ''Hupingzao'' in Wuwei and other areas with similar conditions. |
