Optimization of a Water-Saving and Fertilizer-Saving Model for Enhancing Xinjiang Korla Fragrant Pear Yield, Quality, and Net Profits under Water and Fertilizer Coupling

To develop an optimal irrigation and fertilization system for Korla fragrant pear in the Xinjiang region, the effects of water and fertilizer coupling on the quality, yield, irrigation water use efficiency (IWUE), fertilizer partial productivity (PFP), and net profits of Korla fragrant pear under the condition of limited water drip irrigation were studied through field experiments by combining multiple regression analysis and spatial analysis. A comprehensive quality evaluation model of fragrant pear was constructed using the principal component analysis, and 12 quality indices were evaluated comprehensively. The experiment adopted a two-factor crossover design with three irrigation levels (W1: 5250 m(3) ha(-1), W2: 6750 m(3) ha(-1), W3: 8250 m(3) ha(-1)), accounting for 60%, 80% and 100% of the ETe (where ETe denotes evapotranspiration under sufficient water supply for crops); four fertilizer application levels (F1: 675 kg ha(-1), F2: 750 kg ha(-1), F3: 825 kg ha(-1), F4: 900 kg ha(-1)), designated F80%, F90%, F100%, and F110%, respectively; and 12 treatments. The results showed that the overall quality of fragrant pear was improved based on the integrated quality of pear. Four principal components were extracted through the fragrant pear comprehensive quality evaluation model, and their cumulative contribution was 89.977%; the best comprehensive quality was obtained in the W3F2 treatment and the worst comprehensive quality in the W1F1 treatment. The spatial analysis showed that when the irrigation range is 7484-8250 m(3) ha(-1) and the N-P2O5-K2O fertilization range is (181-223-300)-(200-246-332) kg ha(-1), the comprehensive quality, yield, IWUE, PFP, and net profits of fragrant pear can reach > 85% of the maximum value. These results provide a scientific basis for water and fertilizer management of fragrant pear orchard with drip irrigation in Korla, Xinjiang.