Fontes e parcelamento do nitrogênio em cobertura, na cultura do milho sob plantio direto

Abstract

The effect of the split-application of different sidedressed nitrogen sources on maize crop under zero tillage, in a sandy soil, was evaluated. A randomized block design was used in a factorial scheme of 3x3+1, with four replications. Treatments consisted of three nitrogen sources (urea, urea extruded with starch (Amiréia® 180S) and ammonium sulfonitrate with nitrification inhibitor of 3.4-dimethylpyrazole phosphate (Entec® 26)), three nitrogen split-application (120, 60+60 e 40+40+40 kg ha-1, applied as sidedressing, when the plants showed 4, 8, and 12 expanded leaves, respectively), and one control (without sidedressed N). Entec® applied in a unique dose when plants had 4 expanded leaves resulted in greater N concentration on the maize leaves. Sidedressing nitrogen application resulted in higher plant and ear heights, number of grains per ear and grain yield. Sidedressing nitrogen split-application did not influence the yield components and grain yield of the maize crop grown under zero tillage in sandy soil, regardless of the nitrogen source.