Effects of water and nitrogen coupling on cotton nitrogen absorption and utilization under alternate root partition drip

In this study, nitrogen application (N90, N180, N270) and irrigation (W140, W200, W260) was completely modular designed for studying the coupling effects of water and nitrogen on cotton nitrogen absorption and utilization under alternate root partition drip. Amount of dry matter and nitrogen content of cotton with increased irrigation were markedly improved, medium nitrogen and high water coupling (N180, W260) was the best treatment for high dry matter amount and nitrogen content. From the perspective of improving yield, nitrogen uptake and utilization analysis, the results of medium nitrogen and high water (N180W260), high nitrogen and medium water (N270W200), high nitrogen and high water (N270W260) treatments were compared, which showed that nitrogen derived from fertilizer (Ndff), nitrogen recovery, apparent N-fertilizer recovery efficiency(ANRE), agronomic efficiency of applied N-fertilizer ( AENF) in N180W260 treatment is higher than that in the other treatments. There is no significant difference in physiological N-fertilizer use efficiency (PNUE) in all the treatments. Medium nitrogen and high water (N180W260) was the best coupling of water and nitrogen, which provided a reference for water and fertilizer management in cotton.