| Using 5-year old trees in southern Xinjiang, a field experiment was conducted to measure the effect of N∶P∶K ratio on physiological traits and fruit quality of Zizyphus jujube trees. Results showed the favorable effect on jujube tree growth and fruit quality of applying N (270 kg·hm-2), P2O5 (180 kg·hm-2) and K2O(67.5 kg·hm-2) at early stage, P2O5 (202.5 kg·hm-2) and K2O (180 kg·hm-2) at flowering stage and N (202.5 kg·hm-2), P2O5 (180 kg·hm-2), and K2O (67.5 kg·hm-2) at fruiting stage. Compared with conventional method, chlorophyll SPAD of each period for combined application treatment for the four periods, i.e., flower stage, young fruit stage, fruit expanding stage, and fruit havest stage was increased by 6%, 4%, 5%, and 6%. Net photosynthetic rate of each period at the time 09∶00, 11∶00,13∶00, 15∶00, 17∶00 and 19∶00 was increased by 11%, 14%, 11%, 82%, 15%, and 44%, stomatal conductance by 34%, 25%, 34%, 132%, 129%, and 96%, intercellular
CO2 by 13%, 22%, 14%, 22%, 24% and 15%, and transpiration rate by 50%, 45%, 28%, 45%, 33% and 52%. In addition, fruit vitamin C, reducing sugar, and protein content were 6.41 mg·100g-1, 19.33% and 2.53%, respectively, being significantly different from those of conventional fertilization. |