Productivity and agronomic efficiency of cotton plants in response to nitrogen and sulfur supply

Abstract

The Brazilian Savanna (Cerrado) ecosystem concentrates most of the area under cotton cultivation in the country, and is characterized, predominantly, by  low fertility soils. Nitrogen (N) is the most extracted nutrient from the soil by most crops, while sulfur (S) fertilization has been little explored in studies with cotton plants. This study aimed to evaluate the effects of N and S fertilization on the N content of leaf, weight of 30 bolls, productivity, and agronomic
efficiency of cotton plants grown in an Oxisol from the Brazilian Cerrado region. Two independent field experiments were carried out simultaneously in a completely randomized block design with four replications. The first experiment was composed of five levels of N (17, 100, 150, 200 and 250 kg ha^-1) and the second with five levels of S (24, 50, 75, 100 and 125 kg ha^-1). The leaf N content of the cotton plants increased linearly with the supply of up to 250 kg ha^-1 of
N in the soil. The weight of 30 bolls and the seed-cotton productivity were considerably increased with the increase of the N and S levels in the soil. The maximum agronomic efficiency of the N and S fertilization was obtained with the application of 150 and 100 kg ha^-1 of N and S, respectively. Therefore, this study clearly showed the positive effects of the adequate fertilization of N and S on the productivity of cotton in soils from the Brazilian Cerrado region.