Effects of Water-Nitrogen Interactions on Cotton (Gossypium hirsutum L.): Growth, Yield and Water-Nitrogen Use Efficiency

Ahmed Elshafay and Özgür Tatar

Background and Objective: Cotton production in water-limited environments is constrained by the availability of irrigation and the efficiency of nitrogen fertilization. Optimizing the interaction between water and nitrogen inputs is essential to sustain yield while improving resource use efficiency. This study aimed to evaluate the combined effects of irrigation regimes and nitrogen application rates on the growth, yield, water use efficiency, and nitrogen use efficiency of cotton (Gossypium hirsutum L.). Materials and Methods: A field trial was conducted using a split-plot randomized complete block design, with two irrigation levels-well-watered (100% of crop ETc) and limited irrigation (75% of crop ETc)-and two nitrogen rates (100 and 200 kg N/ha). Agronomic and physiological traits, including plant height, root depth, total biomass, yield components, water use efficiency (WUE), and nitrogen use efficiency (NUE), were measured. A 10% significance level was used due to low replication (n = 3) to detect treatment differences, with significant ANOVA traits compared via mean separation accounting for replication variability. Results: Well-watered conditions significantly enhanced vegetative growth. The combination of limited irrigation with higher nitrogen (200 kg/ha) produced the highest seed cotton and lint yields, while also achieving maximum WUE (1.46 g/kg). In contrast, the highest NUE (59.2 g/g) occurred under full irrigation with the lower nitrogen rate (100 kg/ha). Increasing nitrogen consistently decreased NUE across both irrigation levels, highlighting the trade-off between yield and nitrogen efficiency. Conclusion: Optimizing water-nitrogen interactions is crucial for sustainable cotton production. Limited irrigation combined with higher nitrogen application can maintain yield performance and enhance WUE in water-scarce regions, while lower nitrogen rates favor nitrogen use efficiency. These findings provide practical guidance for resource-efficient cotton management and support strategies for sustainable agricultural production under water-limited conditions.

View Fulltext Back