Desempenho agronômico do milho cultivado sob diferentes manejos de adubação nitrogenada

Abstract

Corn (Zea mays L.) is the most produced cereal in the world and of great importance for human and animal food. It is nutritionally demanding and responsive, mainly to nitrogen, which is an element of complex recommendation due to its dynamics of losses and transformations. The main source of nitrogen used in Brazil is urea, but it is susceptible to losses that reduce its efficiency. Nitrogen fertilizers of increased efficiency have been a good alternative to reduce losses and reduce climatic dependencies for applications. However, they have high prices when compared to urea. Thus, the present study aimed to analyze which sources and managements of nitrogen fertilization provide the best productive performance and economic return for corn. The experiment was carried out in the agricultural year 2021/2022, in the municipality of Três Palmeiras - RS, in a randomized block design with 7 treatments, as follows: T1 - nitrogen fertilizer of increased efficiency, gradual release, encapsulated, incorporated before sowing; T2 - nitrogen fertilizer of increased efficiency with urease inhibitor (NBPT) in topdress (V4+V8); T3 - urea incorporated before sowing; T4 - urea in coverage (V4+V8); T5 - urea incorporated before sowing and in top dressing (V8); T6 - Nitrogen fertilizer of increased efficiency with urease inhibitor (NBPT) in topdress (V8); T7 - without nitrogen fertilization (control) and 4 repetitions. The following agronomic traits were evaluated: number of grain rows, number of grains per row, number of grains per ear, chlorophyll A and B indices, leaf and grain nitrogen content, thousand seed weight, productivity and insertion height. of spikes. The economic feasibility of applying the different sources was also evaluated and, for this, the collection of data on productivity and costs from the different sources was carried out. The data were submitted to analysis of variance and the means were compared by Duncan's test, at 5% probability, with the aid of the R statistical program. V4 and V8, being also the most economically viable treatment.