Effects of Water-Fertilizer-Heat Coupling on Yield and Resource Utilization Efficiency of Cotton under Drip Irrigation

Abstract

Seed cotton yield is a critical factor influencing the international competitiveness of cotton.  To enhance water and fertilizer use efficiency and promote sustainable cotton production, a two-year field experiment was conducted during 2024–2025 to explore the effects of plastic film mulch layers, irrigation levels, and fertilizer levels on seed cotton yield, economic benefits, irrigation water use efficiency (IWUE), and nutrient partial factor productivity in the Alar region of southern Xinjiang, China. An L₉(3⁴) orthogonal design comprised of nine treatments was employed. Three water levels (W1: 3080 m³·ha^-1, W2: 3850 m³·ha^-1, W3: 4620 m³·ha^-1), three fertilizer levels (F1: 330-135-147 kg·ha^-1 (N-P₂O₅-K₂O), F2: 412.5-168.75-183.75 kg·ha^-1 (N-P₂O₅-K₂O), F3: 495-202.5-220.5 kg·ha^-1 (N-P₂O₅-K₂O)) and three heat levels (H1: one layer of plastic film, H2: two layers of plastic film, H3: three layers of plastic film)were set. The results showed that water levels, fertilizer levels and heat levels all significantly influenced seed cotton yield, IWUE, and nutrient partial factor productivity. Technique for order preference by similarity to an ideal solution (TOPSIS) was adopted for the comprehensive evaluation of seed cotton yield, IWUE, nutrient partial factor productivity, and economic rate of return. The highest seed cotton yield, IWUE, nutrient partial factor productivity, and economic rate of return were achieved in treatment W2F1H2 (T2). These results provide a practical and valuable reference for sustainable cotton production in the Alar region of southern Xinjiang and other regions with analogous agro-ecological conditions in improving both seed cotton yield and water and fertilizer use efficiency.