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 À1 . 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 CO 2 assimilation rate (An) increased by more than 0.53 μmol m À2 s À1 . The combination of shading and micro-spray conditions significantly increased fruit size and promoted greenness. The WP1 (15% and 40 L h À1 ) 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 À1 , 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. K E Y W O R D S air temperature, fruit volume, model, quality, yield, Résumé * Effets de l'ombrage et de la micropulvérisation du couvert végétal sur les caractéristiques photosynthétiques, la qualité et le rendement des raisins irrigués au goutte à goutte.

Irrigation with saline water is a possible solution to alleviate freshwater shortages. The long-term use of saline water for irrigation requires consideration of the influence of salt on the environmental conditions of the soil. The objective of this field study was to determine the effects of three continuous years of saline water irrigation on physiochemical properties and microbial communities in drip-irrigated cotton fields. The three total dissolved solid (TDS) levels of irrigation water treatments were (i) 1 g L−1 (fresh water, FWI), (ii) 3 g L−1 (brackish water, BWI), and (iii) 7 g L−1 (salt water, SWI). After three years, the electrical conductivity (EC), sodium adsorption ratio (SAR), and contents of K+, Na+, Mg2+, Cl−, and SO42− in the SWI treatment were significantly higher than those in the FWI and BWI treatments, but there were no significant differences in EC and K+ between the FWI and BWI treatments. BWI treatment significantly increased microbial biomass carbon (MBC), microbial biomass nitrogen (MBN), urease, and sucrase contents. The diversity and abundance of bacteria and fungi were not affected by saline water irrigation, but the microbial community structure was altered. Saline water irrigation resulted in an elevation in the bacterial abundance of the phylum Chloroflexi and a decline in Proteobacteria and Actinobacteria. For fungi, the abundance of the phylum Ascomycota in the BWI treatment was greater than that in the FWI and SWI treatments. Linear discriminant analysis effect size (NMDS) results indicated clear variation in the microbiota profiles between the FWI, BWI, and SWI treatments for bacteria. Regarding the fungal microbiota profiles, the BWI and SWI treatments had similar microbiota profiles but were different from the FWI treatment. The number of bacterial biomarkers gradually increased with increasing total dissolved solids of irrigation water, while the number of fungal biomarkers gradually decreased. Additionally, cotton yield was significantly and positively correlated with the observed species of fungi, while it was significantly and negatively correlated with EC. Redundancy analysis (RDA) showed that bacterial community structure was regulated by SAR and fungal community structure was regulated by soil salinity and bulk density (BD). Future research will need to look into how the structure of the microbial community and the associated functional microorganisms are gradually changing with increased irrigation frequency under saline irrigation, as well as explore and screen for advantageous functional microorganisms.