Improving the quality of cotton fiber is an important way to increase the competitiveness of cotton in the international market. However, how to improve fiber quality as much as possible without significantly reducing seed cotton yield is still a challenge to the cotton industry. A two-year field experiment was conducted in 2018 and 2019 to investigate the effects of irrigation amount and nitrogen rate on seed cotton yield and fiber quality traits of drip-fertigated cotton in northwest China. A comprehensive evaluation model was also developed to determine the optimal supply range of water and nitrogen to simultaneously improve seed cotton yield and fiber quality. There were four irrigation amounts (W_0.6-60 % ET_c, W_0.8-80 % ET_c, W_1.0-100 % ET_c and W_1.2-120 % ET_c, ET_c was the crop evapotranspiration) and four nitrogen rates (N₂₅₀-250 kg N ha⁻¹, N₃₀₀-300 kg N ha⁻¹, N₃₅₀-350 kg N ha⁻¹ and N₄₀₀-400 kg N ha⁻¹). Increasing irrigation amount and nitrogen rate had positive effects on seed cotton yield. However, there was no significant difference in seed cotton yield between W_1.0 and W_1.2 and between N₃₅₀ and N₄₀₀. The optimal seed cotton yield was obtained under W_1.0N₃₅₀ in both 2018 (6655.58 kg ha⁻¹) and 2019 (6309.3 kg ha⁻¹). Water use efficiency (WUE) increased with the increase of nitrogen rate, and decreased with the increasing irrigation amount. Nitrogen partial factor productivity (PFPN) increased with the increase of irrigation amount, and decreased with the increasing nitrogen rate. There was a positive correlation between irrigation amount and fiber length, fiber strength, fiber quality index (FQI) and textile parameter, but a negative correlation with micronaire and short-fiber index. Fiber length, fiber strength, FQI and textile parameter first increased and then decreased with the increasing nitrogen rate. Irrigation amount and nitrogen rate had no significant effect on maturity index. There were strong correlations between the results of various evaluation methods, but the ranking differed among the methods. Based on the comprehensive evaluation model, the optimal combination of irrigation amount and nitrogen rate was W_1.0N₃₅₀. Through the combination of multiple regression and spatial analysis, the optimal supply range of irrigation amount of 334∼450 mm and nitrogen rate of 320∼400 kg ha⁻¹was able to obtain over 90 % of the optimal seed cotton yield and 80 % of the optimal fiber quality.

提高棉纤维质量是提高棉花国际市场竞争力的重要途径。然而，如何在不显着降低籽棉产量的情况下，尽可能提高纤维品质，仍然是棉花产业面临的挑战。2018年和2019年进行了为期两年的田间试验，研究了灌水量和施氮量对西北地区滴灌棉籽棉产量和纤维品质性状的影响。还开发了综合评价模型，以确定水和氮的最佳供应范围，以同时提高籽棉产量和纤维质量。有四种灌溉量（W _0.6 -60 % ET _c，W _0.8 -80 % ET _c，W_1.0 -100 % ET _c和 W _1.2 -120 % ET _c , ET _c是作物蒸散量）和四种氮肥率（N ₂₅₀ -250 kg N ha ^-1 , N ₃₀₀ -300 kg N ha ^-1 , N ₃₅₀ - 350 kg N ha ^-1和 N ₄₀₀ -400 kg N ha ^-1 )。增加灌水量和施氮量对籽棉产量有积极影响。然而，W _1.0和W _1.2之间以及N ₃₅₀和N ₄₀₀之间的籽棉产量没有显着差异. 在 W _1.0 N _{350 条件下}，2018 年（6655.58 kg ha ^-1）和 2019 年（6309.3 kg ha ^-1）。水分利用效率（WUE）随着施氮量的增加而增加，随着灌溉量的增加而降低。氮分因子生产力（PFPN）随着灌水量的增加而增加，随着施氮量的增加而降低。灌水量与纤维长度、纤维强度、纤维质量指数（FQI）和纺织参数呈正相关，与马克隆值和短纤维指数呈负相关。纤维长度、纤维强度、FQI和纺织参数随着氮肥用量的增加先增加后减小。灌水量和施氮量对成熟指数无显着影响。各种评价方法的结果之间存在很强的相关性，但方法之间的排名不同。基于综合评价模型，_1.0牛顿₃₅₀。通过多元回归和空间分析相结合，灌溉量334～450 mm、施氮量320～400 kg ha ^-1的最佳供给范围能够获得90%以上的籽棉最佳产量和80%的最佳籽棉产量。最佳的纤维质量。