Estudio del fraccionamiento de la fertilización nitrogenada en maíz

This experiment seeks to generate information on fertilization strategies with nitrogen (N) in irrigated maize. The experiment was carried out in the experimental station “De. L. A. Cassinoni” in Paysandú, Uruguay, in the spring-summer 2019-2020. The effect of four levels of fractionation of the N dose was evaluated, under irrigation and rainfed conditions. This experiment consisted of six treatments: T1: 150 kg N ha^-1 fractionated 41 kg N ha^-1 in two leaves (V2) and 109 kg N ha^-1 in six leaves (V6) under irrigation, T2: 150 kg N ha^-1 fractionated 21 kg N ha^-1 in V2 and four applications of 33 kg N ha^-1 between V6 and tasseling (VT) under irrigation, T3: 150 kg N ha^-1 divided into 21 kg N ha^-1 in V2 and seven applications of 19 kg N ha-1 between V6 and tasseling (VT) under irrigation, T4: 150 kg N ha^-1 fractionated 41 kg N ha^-1 in two leaves (V2) and 109 kg N ha^-1 in six leaves (V6) under rainfed conditions, T5: 150 kg N ha^-1 fractionated 21 kg N ha^-1 in V2 and four applications 33 kg N ha^-1 between V6 and tasseling (VT) under rainfed conditions, T6: 150 kg N ha^-1 divided into 21 kg N ha^-1 in V2 and seven applications 19 kg N ha^-1 between V6 and tasseling (VT) under rainfed conditions. The factorial arrangement used was divided plots, with three blocks where the largest plot was the water availability and the least was the fractionation of N. When performing the statistical analysis, an interaction was found between the fractionation of the N dose and the water availability for the yield. Where under irrigation conditions significant differences in yield were found for the different levels of fractionation, having obtained a higher yield where T4 was applied. Fractionation had an effect on PG, which explains the differences in performance in favor of the T4. Regarding the NG, no significant differences were detected between the different levels of fractionation. The PG by surface was the component that had more correlation with the yield (R²: 0,83), the effect of NG being the least important (R²: 0,56). The results indicate that under irrigation conditions or abundant PP, the fractionation of the N dose allows satisfying the needs of N during grain filling, which allows an increase in the PG, which means an increase in grain yield.