Assessing the influence of water fertilizer, and climate factors on seed cotton yield under mulched drip irrigation in Xinjiang Agricultural Regions

Cotton is an important raw material, and its production has a profound impact on global economic and social development. Developing a further understanding of the optimal growing environment for cotton would help establish a reasonable management system and improve seed cotton yield. In the present study, we established a water-fertilizer coupling mathematical model based on the comprehensive analysis of existing field experimental data; this model was used to determine the optimal water and fertilizer requirements when the seed cotton yield reached a maximum in different regions. In addition, the grey relational degree between the climate factors and seed cotton yield during the cotton-growing period were analyzed using grey relational analysis, including average air pressure (AAP), sunshine duration (SD), average relative humidity (ARH), average maximum temperature (MAXT), average temperature (AT), average minimum temperature (MINT), and rainfall (RF). The results showed that the optimal irrigation levels were determined as 675.61 mm for southern Xinjiang and 345.59 mm for northern Xinjiang. In addition, the ideal fertilizer application rates (N-P-K) were found to be 150.26-115.66-76.28 kg/ha for southern Xinjiang and 290.32-162.57-72.22 kg/ha for northern Xinjiang. These optimal practices resulted in yield potentials of 7140.30 kg/ha for northern Xinjiang and 8693.69 kg/ha for southern Xinjiang. Simultaneously, AAP, MAXT, SD, AT, and ARH exhibited a strong influence on seed cotton yield in Xinjiang. Conversely, RF and MINT had minimal impact on seed cotton yield. This research determined the optimal water and fertilizer requirements and highlighted the significance of climate factors in Xinjiang agricultural regions. These findings offer a scientific foundation and practical guidance to enhance seed cotton yield, water and fertilizer efficiency, optimize management practices, and address climate fluctuations during the cotton-growing season.