CORN DEVELOPMENT AND PRODUCTION IN FUNCTION OF SOURCES OF NITROGEN FERTILIZERS AND DOSES

ABSTRACT Nitrogen (N) is one of the nutrients that have the most significant effect on corn grain productivity increase. In order to evaluate the effect of sources of N topdressing and doses in the grown corn culture, in a conventional till system, it was installed an experiment in the city of Urutaí, Goiás, in the 2012/13 crop, in clayey textured Red Latosol. The experimental design was a randomized complete block design with four replications, with the treatments arranged in a factorial 3 x 5, consisting of three sources (coated urea, urea and ammonium sulfate) and five doses (0, 60, 120, 180 and 240 kg ha-1) of N, topdressing, applied in the surface and in a single dose, when the corn plants were in V4 stage. The hybrid used was the P3646H. We evaluated the following characters: stem diameter, plant height, height of ear insertion, leaf N, number of ears per plant, ear length, number of rows per ear, number of grains per row, 100 grains mass and grain productivity. All characters have a response to nitrogen fertilization and only the height of ear insertion showed no significant difference between sources. The source coated urea showed the best results, indicating that its use may be compensatory, especially in favorable conditions for the NH3 volatilization, as the application of high doses of N in the surface.

摘要：氮（N）是对玉米籽粒产量提升影响最为显著的营养元素之一。为评估传统耕作体系下，玉米追施氮肥的不同来源与施用量对其生长的影响，研究于2012/13作物季在戈亚斯州乌鲁塔伊市的黏质红色铁铝土（Red Latosol）地块布设田间试验。试验采用完全随机区组设计，设置4次重复，处理组按3×5因子设计排布，包含3种氮肥来源（包膜尿素、普通尿素与硫酸铵）以及5种追施施用量（0、60、120、180、240 kg·ha⁻¹），于玉米V4生育期一次性地表追施。供试玉米杂交品种为P3646H。本试验测定的性状包括：茎粗、株高、穗位高、叶片氮含量、单株穗数、穗长、穗行数、行粒数、百粒重与籽粒产量。所有测定性状均对氮肥施用产生响应，仅穗位高在不同氮肥来源间无显著差异。其中包膜尿素表现最优，表明其应用具有补偿效应，尤其在地表追施高剂量氮肥、易发生氨挥发的适宜条件下。