Effects of shading and micro‐spray of canopy on photosynthetic characteristics, quality and yield of drip‐irrigated grapes
2022
Zheng, Ming | Bai, Yungang | Zhang, Jianghui | Liu, Hongbo | Cai, Junshe | Bai, Shijian | Ding, Bangxin | Ding, Ping
Grapes are prone to midday depression of photosynthesis (MDP) under the action of high temperature and strong light, which can reduce the accumulation of organic matter, resulting in a decline in yield and quality. In this study, the grapes in Shanshan County, Xinjiang, China, were taken as an example to implement shading and micro‐spray measures. Shading degrees of 0, 15 and 30% were combined with micro‐spray flow rates of 20, 30 and 40 L h⁻¹. Nine treatments and one control treatment (the control treatment is without shading and mist spraying) were designed through a combination of the shading and micro‐spray conditions. The photosynthetic prediction model of the multivariate nonlinear model was constructed and had high simulation accuracy. The decline of air temperature at the top of the canopy increased as the degree of shading and the amount of micro‐spray increased; MDP could be eliminated under the combined conditions of shading and micro‐spray. The mean daily net CO₂ assimilation rate (An) increased by more than 0.53 μmol m⁻² s⁻¹. The combination of shading and micro‐spray conditions significantly increased fruit size and promoted greenness. The WP1 (15% and 40 L h⁻¹) treatment had the highest mean daily An and the largest fruit volume. The vitamin C (VC) content of WP1 treatment was the highest, 4.13 mg kg⁻¹, which was 1.2 times that of the control (CK) treatment. The yield of the WP1 treatment was the highest, which was 19.7% higher than that of the CK treatment. Thus, the WP1 treatment was the optimal treatment for promoting the An of grape leaves and improving the fruit quality of grapes. This research could provide a reference for improving the photosynthesis, fruit quality and yield of grapes and alleviating the photosynthetic MDP of crops.
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