Produtividade da cultura do milho sob diferentes doses de nitrogênio em sistemas irrigados e não irrigados

Abstract

Corn plays a fundamental role in Brazilian agriculture both from the economic and agronomic point of view, composing the crop rotation system. Due to the increasing adoption of production Technologies by producers, such as the introduction of irrigation systems in their areas, it is necessary to study na devaluate these systems and fertilize in the crop, especially nitrogen fertilization, since Nitrogen (N) is the macronutrient most extracted and exported by corn crop. In this context, the objective of this work was to evaluate corn yield under diferente N doses in irrigated and non-irrigated systems. The experimente was carried out in na área belonging to UTFPR - Dois Vizinhos Campus, being evaluated 4 treatments composed of N doses (0,100, 200 and 300 kg ha-1), Simple factorial experimente with a completely randomized design, composed of two irrigation systems (irrigated and non-irrigated) and four doses of N, with inexperimental plots of 5m x 11.25m, totaling 56.25m2, the applications of N in cover were performed when the crop was in the phenological stage of V4. After the physiological maturation of the field crop, 15 ears per plot were collected, which were subsequently sent to the anual culture laboratory at the university itself, where it was counted in the number of grains per row (NGF), número de fileiras por espiga (NFE) and weight of one Thousand grains (PMG) in addition to determining the moisture contente of the grains (%) with correction for moisture of 13%, so that the yield of the crop could be estimated. The data were submitted to variance analysis (P<0.05) and when the effect of qualitative treatments (irrigated and non-irrigated) was evaluated by the Tukey test at 5% probability, for quantitative treatments (nitrogen doses) the data were submitted to regression analysis with the aid of the statistical program (SAS-academic version). In general, the crop presented excelente performance in the final productivity, even in the áreas of land, however, the data obtained throughout the Work suggest that the use of irrigation was positive and should be adopted in cases where it is possible and economically viable. Nitrogen doses showed a linear growth in productivity, out performing in irrigated crops, given the reduction of N losses by volatilization, as well as water supply at critical moments throughout crop development, which combined with high N doses provided high yields. The dose of 300 kg ha-1 of N presented the best response in the productivity in crement, presenting satisfactory averages above 14,000 kg ha-1, in irrigated plots and above 11,000 kg ha-1 in the land-ground plots.