Integrating Foliar Nutrition Strategies for Sustainable Cotton Production in Arid Regions

Balanced cotton nutrition is fundamental to sustaining crop productivity, enhancing nutrient-use efficiency, and maintaining environmental stability. A field experiment was conducted over two consecutive growing seasons (2024–2025) at the experimental station of Tashkent State Agrarian University, Uzbekistan, to evaluate the effects of foliar nutrition in combination with basal fertilization rates on cotton yield and nutrient-use efficiency parameters. The experiment was established using a split-plot design with three replications. Three basal fertilization rates (N150P105K75, N200P140K100, and N250P175K125) were considered the main-plot factor, while the sub-plot treatments consisted of foliar urea applications at the true-leaf, bud-formation, and flowering stages of cotton, using three regimes (3:5:7, 5:7:9 and 7:9:11 kg ha−1). The results demonstrated that cotton yield increased with increasing basal fertilization rates up to the moderate fertilization rate; however, a decline in yield was observed under the highest fertilizer application rate (N250P175K125). This response suggests that excessive nutrient inputs may have adversely affected crop growth and productivity, potentially due to nutrient imbalance, increased osmotic stress, or reduced nutrient use efficiency. The highest cotton yield was observed at the moderate (N200P140K100) inorganic fertilization norm in tandem with the 7:9:11 kg ha−1 foliar nutrition regime, averaging 21.5% higher than the same fertilization regime without foliar feedings. Under the moderate fertilization regime, foliar application further increased cotton yield to 3.87 Mg ha−1, 4.15 Mg ha−1, and 4.45 Mg ha−1, depending on foliar treatment intensity, corresponding to 17.6%, 26.1%, and 35.3% increases, respectively. However, increasing the basal fertilization rate to N250P175K125 did not yield further improvement in maximum cotton output. Cotton seed and fiber quality indicators also increased significantly in response to the applied agronomic interventions, demonstrating the beneficial effect of balanced nutrition on quality traits. These findings suggest that foliar nutrition can effectively improve cotton productivity and nutrient-use efficiency, thereby reducing reliance on excessive basal fertilization and supporting more sustainable crop production in fragile dryland ecosystems.