Effects of actinomycetes fermentation liquid fertilizer on growth, physiology, yield and quality of Ziziphus jujuba‘Junzao’

【Objective】Xinjiang has become the most important high-quality jujube production area in China due to its unique climatic conditions, of which the jujube is particularly outstanding due to its excellent quality in the desert fringe areas such as Hotan. However, there are some problems in that area such as low organic matter content, poor water retention and imbalance of fertilizer micro-ecology in the soil directly caused by jujube trees, resulting in decline of fruit quality and yield. Actinomycetes fermentation liquid fertilizer can produce a variety of small molecules of organic matter and other metabolites, and even antibiotics and hormones, etc. through the decomposition of organic matter. This study aimed to investigate the effects of different concentrations of actinomycetes fermented liquid fertilizer on the growth and fruiting of Ziziphus jujuba‘Junzao’.【Methods】The experiment was carried out in Beijing Agricultural Park, Lopu County, Hotan Region, Xinjiang. The actinomycetes fermented liquid fertilizer at three concentrations (the original solution diluted 50 times, 100 times, 200 times) were sprayed on 4-year-old Junzao trees in the leaf spreading stage, the young fruiting stage, and the white ripening stage, respectively, water was used as the control (CK). The sampling was carried out 3-5 d after each spraying to determine the basal diameter of the first branch, basal diameter of the second branch, leaf thickness, leaf area, Pn, Gs, Tr, Ci, SPAD, LRWC, SOD, PAL, PPO, weight of non-merchantable fruit, weight of superior fruit, yield of a single plant, weight of a single fruit of superior fruit, rate of superior fruit, total sugar, titratable acid, and sugar-acid ratio of jujube. The data were analyzed using Excel 2019, and SPSS 27 was used to perform ANOVA, Pearson correlation analysis and principal component analysis (PCA). Origin 2025 was used for mapping.【Results】The basal diameter of the first branch of the new jujube significantly increased by 7.42% and 5.94%, respectively, in May and July under treatment with YF100, compared with that of the control; the basal diameter of the second branch was significantly increased by 8.21% and 7.16%, respectively, in May and August under treatment with YF100, compared with that of the control, and it significantly increased by 7.14% compared with that of the control under the treatment of YF50 in July, while the differences between the other treatments and the control were not significant. The thickness of the leaf blade significantly increased by 7.05%, 13.27% and 9.19% under YF100 treatment in May, July and August, respectively, compared with that of the control, and leaf area significantly increased in July and August under YF50 and YF100 treatments compared with that of the control. The net photosynthetic rate (Pn) of the leaves increased significantly by 5.38% and 6.50% under the treatments of YF50 and YF200, compared with that of the CK, respectively. The transpiration rate (Tr) significantly increased by 5.51% , 4.09% and 6.92% under the three treatments respectively, whereas the interstitial CO2 concentration (Ci) was significantly lower under the treatments of YF50 and YF100.There was no significant difference in stomatal conductance (Gs) under the three treatments. The leaf greenness (SPAD) increased under YF50 and YF100 treatments compared with the control in June and July. The leaf relative water content (LRWC) also significantly increased by 12.71% under the YF100 treatment compared with the control; at the same time, SOD and PPO significantly increased under the YF50 and YF100 treatments compared with that of the control and PAL increased under all treatments compared with that of the control, with a significant increase under YF200 treatment. The weight of superior fruit, yield per hectare and superior fruit rate increased under each treatment compared with those of the control, and the weight of non- commercial fruit was reduced, especially the differences were significant under the YF50 and YF100 treatments. Moreover, the total sugar increased under the three treatments compared with that of the control, and the sugar-acid ratio and titratable acid also increased compared with those of the control, but the differences were not significant among treatments, the difference was only significant under the YF50 treatment compared with the control.【Conclusion】The actinomyces fermentation liquid fertilizer can promote the growth and physiological function of jujube tree, and improve the yield and quality of jujube fruit. 100 times dilution of the original solution seems to be mostly beneficial. 3-5 times of stand-alone spraying or combined spraying with pest control or flower and fruit management would be suggested in jujube plantations in the sandy area of Southern part of Xinjiang.