AVALIAÇÃO DE DOSES DE NITROGÊNIO NO DESEMPENHO AGRONÔMICO EM EXPERIMENTOS COM DIFERENTES CULTIVARES COMERCIAIS DE MILHO E CONDIÇÕES AMBIENTAIS EVALUATION OF NITROGEN DOSES ON AGRONOMIC PERFORMANCE IN EXPERIMENTS WITH DIFFERENT COMMERCIAL CORN CULTIVARS AND ENVIRONMENTAL CONDITIONS

Abstract

ABSTRACT

Evaluation of nitrogen doses on agronomic performance in experiments with different commercial corn cultivars and environmental conditions. 2023. Master's dissertation in Sustainability in Environmental Management - Federal University of São Carlos, Sorocaba, 2023.

Corn is one of the most important cereals produced in the country, serving the domestic and foreign consumer markets, and its productivity is directly proportional to fertilization and water availability. Based on the importance of nitrogen in corn productivity, the present work aimed to evaluate five doses of nitrogen (30; 60; 90, 120 and 150 kg N ha-1), and two commercial cultivars (one variety and one hybrid) in two environments: one with irrigation and other in the rainfed, close to around 400 meters, located at UFSCar campus Lagoa do Sino, Buri,SP. Four experiments were implemented, each with a randomized block experimental design with five replications and one cultivar. It was determined: mass of the ear with straw per plant, mass of grains per plant and length and diameter of the ear (without straw). The plots were composed of 4 rows of 5m, spaced 0.5m apart. Four experiments were conducted, each with a randomized block experimental design with five replications and one cultivar. It was determined: ear mass per plant with straw, grain mass per plant, and ear length and diameter (without straw). The plots were composed of 4 rows of 5m, spaced 0,5m apart. Sowing took place on November 21, 2022, in a direct planting system, using 300 kg ha^-1 of fertilizer 20:10:10. The application of N rates was manual, with Urea fertilizer in topdressing, 23 days after sowing, distributed alternately in two rows. Through the variations of the results and according to the linear regression, it was concluded that the different doses of nitrogen fertilization in topdressing provided an increase in productivity, however, with low adjustment to the linear model in most of the characteristics studied in the experiments evaluated.