Application of Potassium along with Nitrogen under Varied Moisture Regimes Improves Performance and Nitrogen-Use Efficiency of High- and Low-Potassium Efficiency Cotton Cultivars

Low nitrogen-use efficiency (NUE) is a serious issue for cotton production and environmental sustainability in arid climates. A pot study was conducted to evaluate the effect of K nutrition on NUE performance low- high-K-efficiency cultivars under two moisture regimes. Treatments included soil levels—i.e., normal irrigation, 100% available water content (AWC); reduced 50% AWC—three levels nitrogen (N)—i.e., 0, 375, 750 mg N pot?1—and levels, i.e., 0 208 pot?1. Results reveal that pot?1 application with significantly enhanced N-use efficiency, growth, yield attributes both compared sole fertilization. Similarly, combined NK @ 375 + caused up 83% increase AWC50% AWC100%, as control (0 K). Compared control, imposed low-moisture stress decrease 13.9% stomatal conductance (gs), 2.5% transpiration rate (E), 6.5% net photosynthetic (PN), respectively. The physiological use (PN/E) decreased by 13.2% AWC50%. Applied N:208 K, 27.39 27.56% improvement PN/E HKE LKE AWC50%, cultivar, CIM-554, maintained highest gs PN than FH-901, low-K-efficiency cultivar. suggests varietal selection adequate fertilization have prospects improve save considerable quantities fertilizer irrigation environments.