An increase in plant density of cotton (Gossypium hirsutum L., cv. FM 966 LL) results in increased interplant competition for resources, and consequently the flowering period is shortened and the rate of dry matter accumulation changed. The purpose of this study was to determine the N, P and K uptake rates by cotton plants, identifying the time of greatest absorption and the total uptake and export in narrow spacing (48 cm - 20.58 plants m-2), intermediate (75 cm - 13.30 plants m-2 ) and conventional spacing (96 cm - 10.39 plants m-2). Three competitive plants were sampled per plot 46, 69, 99, 139, 148, and 166 days after plant emergence, when dry matter accumulation, and N, P and K contents were determined. Dry matter accumulation was faster in the beginning in the narrower spacing of 48 cm, but in the end equal to the other densities; N accumulation was highest in the narrower spacing, between 69 and 99 DAE. High plant density results in an earlier absorption peak of nutrients, suggesting an anticipated sidedressing with N and K in cotton grown in this system. For medium or highly fertile soils, the nutrient rates to be applied would not have to be changed at a higher plant density, because the amounts of N, P and K exported per kg in cotton fiber or cotton seed were not significantly different.
Gossypium hirsutum; plant population; nutrient accumulation; cotton nutrition
