Ru Bai

In this study, we investigated the effect of partially substituting inorganic nitrogen with bio-organic fertiliser on the ‘Tianhong2’ Fuji apple planting in Xinjiang. Bio-organic fertiliser was applied, and nitrogen was reduced by 20% (T2), 40% (T3), and 60% (T4) during the blooming and fruit expansion periods with conventionally fertilised fields used as control (T1); soil nutrient, soil enzyme activity, leaf nutrients, fruit quality, and yield were measured. The total nitrogen (TN), total phosphorus (TP), total potassium (TK), total calcium (TCa), available phosphorus (AP), available potassium (AK), and soil organic matter (SOM) contents, as well as the soil catalase (S-CAT), soil uretrase (S-UE), soil saccharase (S-SC), and soil nitrate reductase (S-NR) activities, significantly increased in the experimental soils compared with those in T1. In addition, TP, TCa, and total magnesium (TMg) content in apples significantly increased. Compared to T1, the T2 and T3 treatments significantly improved the fruit yield and quality, increasing the sugar–acid ratio, soluble protein, soluble sugar, peel carotenoid, and anthocyanin content and reducing peel chlorophyll content. The brightness (L*), red–green axis (a*), yellow–blue axis (b*), colour intensity (C), and tone (h°) values changed. The yield per hectare and nitrogen fertiliser partial productivity values were significantly increased. Overall, the T2 treatment resulted in the best outcome for the Yili area. In conclusion, partially substituting inorganic nitrogen with bio-organic fertiliser can effectively increase soil and leaf nutrient content and improve fruit yield and quality.

The types and contents of organic acids in wine grapes determine wine quality. To explore the effects of different rootstocks on the acid metabolism of ‘Cabernet Sauvignon’ grapes, various perennial rootstock–scion combinations were used as experimental materials. High-performance liquid chromatography (HPLC) was used to determine citric acid, tartaric acid, and malic acid contents during fruit development. Succinic acid and oxalic acid contents and the activity of related enzymes were measured using spectrophotometry. The expression levels of related genes were measured using a real-time fluorescence quantitative method. The results showed that all four rootstock types significantly reduced oxalic acid and citric acid contents in the grapes, while increasing succinic acid content to varying degrees. Employing 110R, SO4, and Kangzhen3 rootstocks increased tartaric acid and malic acid contents. Enzyme activity analysis revealed that 110R, SO4, and Kangzhen3 rootstocks increased the NAD-MDH enzyme activity, which positively correlated with malic acid content. Simultaneously, these rootstocks reduced the NADP-ME enzyme activity level. NAD-MDH and PEPC gene expression levels were higher in ‘Cabernet Sauvignon’ grapes grafted with 110R, SO4, and Kangan3 rootstocks compared to control self-rooted seedlings. Grafting these three rootstocks enhanced malic acid accumulation in ‘Cabernet Sauvignon’ grapes.

In this study, we investigated unmanned aerial vehicle (UAV) pollination of ‘Kuerle Xiangli’, and screened the pollination operation parameters to determine the precise parameters needed for the implementation of a ‘Kuerle Xiangli’ UAV pollination operation. Different flight height gradients, nozzle atomization particle sizes, spraying volume, and flight routes were tested and their effects on the droplets deposited were compared. UAV operation parameters were screened and field operations were conducted, comparing the fruit set rate, cost, and efficiency of different pollination methods of ‘Kuerle Xiangli’. The results show that the mist droplet effect of 1 m above the top of the tree is higher compared with that of 2 m and 3 m. The mist droplet effect of 2 L/667 m² is better compared with that of 1.5 L/667 m² and 1 L/667 m². The mist droplet effect of 120 μm nozzle atomization particle size is better than that of 110 μm, 135 μm, and 150 μm. The mist droplet effect of flying above the canopy is better than that of flying between the rows of the canopy. The inflorescence and flower fruiting rates of ‘Kuerle Xiangli’ are 63.27% and 28.84%, respectively, and the inflorescence fruiting rate is not significantly different from hand and liquid sprayer pollination. The UAV pollination saves 12.69 USD/667 m² and 3.32 USD/667 m² compared with hand and liquid spray pollination, respectively. The efficiency of UAV pollination is greater than that of liquid and hand pollination. The best combination of parameters for pollination using a quadrotor UAV is 1 m from the top of the tree, 2 L/667 m² spray volume, 120 μm spray nozzle particle size, and the flight path above the canopy. The cost of UAV pollination is 11.83 USD/667 m² and the pollination efficiency 2.67 hm^2/unit·h.