SLOW-RELEASE UREA APPLIED TO SURFACE AND REGULAR UREA INCORPORATED TO SOIL ON MAIZE YIELD UREIA DE LIBERAÇÃO LENTA APLICADA SUPERFICIALMENTE E UREIA COMUM INCORPORADA AO SOLO NO RENDIMENTO DO MILHO

&lt;p style="margin-bottom: 0cm; font-style: normal; font-weight: normal; line-height: 120%; text-decoration: none;" lang="pt-BR" align="JUSTIFY"&gt;&lt;span style="color: #000000;"&gt;&lt;span style="font-family: Times New Roman,serif;"&gt;&lt;span style="font-size: small;"&gt;Urea applied to the soil surface results in high losses of nitrogen (N) by volatilization of NH&lt;sub&gt;3&lt;/sub&gt;. The use of polymers covering urea granules is an alternative management to reduce such losses. The experiment was carried out in Entisols (Quartzipsament), with 6% of clay, in the 2007/2008 harvest, in Jata&amp;iacute;, Goi&amp;aacute;s State, Brazil, in order to assess the efficiency of the following management systems: urea incorporated to the soil and polymer coated urea applied to the surface, concerning the agronomic and economic aspects of maize cultivation. It was implemented an experimental design in randomized blocks, with eight replications, totaling 24 plots. The covering nitrogen fertilization was performed in a single application, at the V&lt;sub&gt;5&lt;/sub&gt; stage. The urea incorporated to the soil resulted in higher values related to ear length and diameter, number of grains per ear, mass of one hundred grains, and relation between earned revenue and invested capital. The highest grain yield and profitability were obtained with the application of urea incorporated to the soil. For each Real (R$ 1.00) invested in the cultivation, the urea incorporated to the soil produced R$ 1.37 as profit. &lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/p&gt; &lt;p style="margin-bottom: 0cm; font-style: normal; font-weight: normal; line-height: 120%; text-decoration: none;" lang="en-US" align="JUSTIFY"&gt;&lt;span style="color: #000000;"&gt;&lt;span style="font-family: Times New Roman,serif;"&gt;&lt;span style="font-size: small;"&gt;KEY-WORDS:&lt;strong&gt; &lt;/strong&gt;&lt;em&gt;Zea mays &lt;/em&gt;L.; slow-release fertilizer; nitrogen; polymers; no-tillage system.&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;<br>&lt;p style="margin-bottom: 0cm; font-style: normal; font-weight: normal; line-height: 120%; text-decoration: none;" lang="pt-BR" align="JUSTIFY"&gt;&lt;span style="color: #000000;"&gt;&lt;span style="font-family: Times New Roman,serif;"&gt;&lt;span style="font-size: small;"&gt;A ureia aplicada sobre a superf&amp;iacute;cie do solo apresenta elevadas perdas de nitrog&amp;ecirc;nio (N), por volatiliza&amp;ccedil;&amp;atilde;o de NH&lt;sub&gt;3&lt;/sub&gt;. O uso de pol&amp;iacute;meros recobrindo gr&amp;acirc;nulos de ureia &amp;eacute; uma alternativa de manejo para reduzir tais perdas. O trabalho, desenvolvido em Neossolo Quartzar&amp;ecirc;nico, com 6% de argila, na safra 2007/2008, no munic&amp;iacute;pio de Jata&amp;iacute; (GO), teve por objetivo avaliar a efici&amp;ecirc;ncia dos seguintes manejos: ureia incorporada ao solo e ureia revestida com pol&amp;iacute;meros, aplicada em superf&amp;iacute;cie, nos aspectos agron&amp;ocirc;micos e econ&amp;ocirc;micos da cultura do milho. Adotou-se o delineamento experimental em blocos casualizados, com oito repeti&amp;ccedil;&amp;otilde;es, totalizando 24 parcelas. A aduba&amp;ccedil;&amp;atilde;o nitrogenada de cobertura foi realizada em uma &amp;uacute;nica aplica&amp;ccedil;&amp;atilde;o, no est&amp;aacute;dio V&lt;sub&gt;5&lt;/sub&gt;. A ureia incorporada ao solo proporcionou maiores valores de comprimento da espiga, di&amp;acirc;metro da espiga, n&amp;uacute;mero de gr&amp;atilde;os por espiga, massa de cem gr&amp;atilde;os, produtividade de gr&amp;atilde;os e da rela&amp;ccedil;&amp;atilde;o entre a receita obtida e o valor investido. O maior rendimento de gr&amp;atilde;os e a maior lucratividade foram obtidos com a aplica&amp;ccedil;&amp;atilde;o da ureia incorporada ao solo. Para cada real (R$ 1,00) investido na cultura, a ureia incorporada ao solo promoveu retorno de R$ 1,37.&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/p&gt; &lt;p style="margin-bottom: 0cm; font-style: normal; font-weight: normal; line-height: 120%; text-decoration: none;" lang="pt-BR" align="JUSTIFY"&gt;&lt;span style="color: #000000;"&gt;&lt;span style="font-family: Times New Roman,serif;"&gt;&lt;span style="font-size: small;"&gt;PALAVRAS-CHAVE: &lt;em&gt;Zea mays&lt;/em&gt; L.; fertilizante de libera&amp;ccedil;&amp;atilde;o lenta; nitrog&amp;ecirc;nio; pol&amp;iacute;meros; sistema plantio direto.&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;