Evaluation of Suitable Amount of Water and Fertilizer for Mature Grapes in Drip Irrigation in Extreme Arid Regions

Low water and fertilizer use efficiency have become important factors restricting the sustainable development of agriculture in extreme arid areas, typically like Xinjiang in China. In order to optimize the water and fertilizer management system of grape drip irrigation in the region, field experiments were carried out to study the effects of different water and fertilizer treatments on the physiological growth, yield, and quality of grapes. Meanwhile, principal component analysis, grey correlation analysis, and regression analysis were used to quantify the relative optimal amount of water and fertilizer. The results showed that the effects of water and fertilizer interaction on the photosynthetic index and fluorescence index of grape leaves, in different growth periods, ng reached extremely significant levels (p < 0.01). The physiological indicators showed regular changes with the increase and decrease of water and fertilizer use and the appropriate amount of water and fertilizer could maintain the index at a superior level. Meanwhile, there are differences in the index of different growth stages and regular changes with the growth period. The effects of water and fertilizer interaction on the yield, water use efficiency, and quality of drip irrigation reached a very significant level (p < 0.01). The yield reached the maximum in W3F2 treatment and the yield increased by 29.76% compared with the minimum yield of W1F1. The quality index reached a superior level in W3F2 treatment. The results of principal component analysis and grey correlation analysis showed that the optimal water and fertilizer dosage was W3F2 (irrigation 750 mm, fertilization 750 kg ha−1), of which N (300 kg ha−1)-P2O5 (150 kg ha−1)-K2O (300 kg ha−1), and multiple regression analysis was employed to determine the optimal range of water and fertilizer use is the following: Irrigation volume 725–825 mm and fertilization amount 684–889 kg ha−1, of which N (273.6–355.6 kg ha−1) - P2O5 (136.8–177.8 kg ha−1) - K2O (273.6–355.6 kg ha−1). The research results can provide a scientific basis for the water and fertilizer management and drip irrigation technology of drip irrigation in seedless white grape fields in extremely arid areas and it is of great significance for the efficient use of regional water and fertilizer resources and the realization of sustainable socio-economic development in the region.