Nitrogen and zinc effects on cotton yield and quality: Insights from a 6‐year field study

The physiological utility of nitrogen (N) and zinc (Zn) in cotton ( Gossypium hirsutum L.) is interlinked, but the level of their contribution to nutritional balance and production remains unexplored. Therefore, this study explored the interactive effects of N and Zn on cotton lint yield, seed yield, and fiber quality under field conditions. The experiment was conducted from 2016 to 2021 within a randomized complete block design replicated five times, testing a full factorial treatment structure with four N rates (34, 67, 101, and 134 kg N ha −1 ) and four Zn rates (0, 6, 11, and 17 kg Zn ha −1 ). Overall, cotton lint and seed yield were significantly influenced by the three‐way interaction between N, Zn, and year. Applying just N never resulted in high yield, except in 2017. Each year, applications of 101 kg N ha −1 and 6 kg Zn ha −1 were found to be the optimum rates, and in 2021 this combination resulted in the highest lint (1804 kg ha −1 ) and seed cotton (4484 kg ha −1 ) yields, while the lowest lint yield was recorded in 2016 when 34 kg N ha −1 was applied alone. Increasing N rates from 34 to 101 kg N ha −1 reduced micronaire by 6%, while the opposite was observed with Zn. Overall, the synergistic effects of both N and Zn were noted. Lint, seed, and fiber quality responses to N and Zn varied slightly each year, underscoring the annual environmental variations and the need for adaptive nutrient management plans.