Efeitos de níveis de nitrogênio e lâminas de irrigação no rendimento do milho verde (Zea mays L.).

Abstract

In order to study the effect of N levels and irrigation slides on the yield of the green maize (Zea mays, L.) cultivar BR 126 an experiment was carried out in a várzea belonging to the National Center for Research on Maize and Sorghum of EMBRAPA, Sete (0, 40, 80, 120, 160, and 200 kg / ha) were used in the study. The experimental design was a randomized block with subdivided plots having four replicates. ON was incorporated in the form of urea, being 1/3 in the planting along with the phosphorus and the potassium (30 kg / ha) and the remainder covered at 49 days after planting, while the irrigation system used was the infiltration with closed furrows, starting the treatments at 60 days after planting, and until then all treatments received irrigation slides equivalent to ETR less rainfall, through the sprinkler irrigation system. The following parameters were analyzed: plant and ear height, weight and number of commercial ears, percentage of impasto, quality, length and index of ears and average diameter of ear and grain. The obtained results allowed to conclude that: the heights of the plants and of the spikes were not affected by the irrigation slides, whereas for the production and its components the irrigation plates superior to 2S% of the ETR generally did not differ among themselves and showed increases in Most of the parameters in relation to the most critical lamina regarding N its application provided increases in all the parameters except for the length and quality of the spike, being these increases were on average 38; 64.5 and 103%, respectively, for plant height, number and weight of commercial ears. The highest production, 47,917 commercial ears / ha, was obtained with an application of 160 kg N / ha and an irrigation blade equivalent to 50% of ETR (from 60 days after planting to harvest). Multiple regression analyzes were performed for several parameters considering N levels and irrigation slides as independent variables. Isoquant maps were also made for some more important parameters. Considering the effects of irrigation slabs and N levels on the growth and production of green maize, an application of 120 kg N / ha and an irrigation blade equivalent to 50% of ETR may be recommended for the study conditions, however. , there is a need for a more detailed economic study of these factors.