QUALIDADE FISIOLÓGICA DE SEMENTES DE Brachiaria E AVALIAÇÃO DA PRODUTIVIDADE DE MASSA SECA, EM DIFERENTES SISTEMAS DE INTEGRAÇÃO LAVOURA-PECUÁRIA SOB IRRIGAÇÃO PHYSIOLOGICAL QUALITY OF Brachiaria SEEDS AND DRY MASS YIELD ESTIMATE UNDER DIFFERENT IRRIGATED CROP-LIVESTOCK INTEGRATION SYSTEMS

• Main Authors: Carlos Alessandro Chioderoli, Marcelo Andreotti, Marco Eustáquio de Sá, Roberta Leopoldo Ferreira, Cristiano Magalhães Pariz, Ana Paula Ribeiro
• Format: Article
• Language: English
• Published: Universidade Federal de Goiás 2010-08-01
• Series: Pesquisa Agropecuária Tropical
• Subjects: Deterioração controlada; envelhecimento acelerado; germinação; tetrazólio; vigor
• Online Access: http://www.revistas.ufg.br/index.php/pat/article/view/6590

&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&gt;&lt;span style="font-size: small;"&gt;A velocidade e a amplitude da expans&amp;atilde;o de pastagens tropicais, no Brasil, est&amp;atilde;o associadas &amp;agrave; disponibilidade de sementes de qualidade. Assim, objetivou-se avaliar, neste estudo, a qualidade fisiol&amp;oacute;gica de sementes de duas esp&amp;eacute;cies de braqui&amp;aacute;ria, submetendo-as a testes de germina&amp;ccedil;&amp;atilde;o e viabilidade, e, ainda, estimar, para ambas as esp&amp;eacute;cies, a produtividade de massa verde e seca,&lt;em&gt; &lt;/em&gt;em diferentes sistemas de integra&amp;ccedil;&amp;atilde;o lavoura-pecu&amp;aacute;ria (ILP), sob irriga&amp;ccedil;&amp;atilde;o. Na avalia&amp;ccedil;&amp;atilde;o a campo, o arranjo experimental foi o de blocos completos casualizados, em parcelas subdivididas, alocando quatro cons&amp;oacute;rcios nas parcelas (&lt;em&gt;Brachiaria brizantha&lt;/em&gt; cv. Marandu e &lt;em&gt;Brachiaria ruziziensis&lt;/em&gt; estabelecidas, simultaneamente, ao milho e por ocasi&amp;atilde;o da aduba&amp;ccedil;&amp;atilde;o nitrogenada de cobertura) e quatro &amp;eacute;pocas de corte da forragem, no inverno/primavera, nas subparcelas, com quatro repeti&amp;ccedil;&amp;otilde;es. Em laborat&amp;oacute;rio, o delineamento foi inteiramente casualizado, com quatro repeti&amp;ccedil;&amp;otilde;es por tratamento/teste. Os testes de germina&amp;ccedil;&amp;atilde;o e viabilidade indicaram que as sementes de &lt;em&gt;B. brizantha&lt;/em&gt; apresentaram qualidade fisiol&amp;oacute;gica superior &amp;agrave;s de &lt;em&gt;B. ruziziensis&lt;/em&gt;, enquanto o teste de tetraz&amp;oacute;lio e as caracter&amp;iacute;sticas das pl&amp;acirc;ntulas germinadas foram semelhantes. A &lt;em&gt;B. ruziziensis&lt;/em&gt;, consorciada simultaneamente ao milho, foi o cons&amp;oacute;rcio que se mostrou menos vi&amp;aacute;vel, em fun&amp;ccedil;&amp;atilde;o da menor produtividade de massa verde, massa seca e deposi&amp;ccedil;&amp;atilde;o de res&amp;iacute;duos vegetais na superf&amp;iacute;cie do solo. No geral, a forma&amp;ccedil;&amp;atilde;o de pastagem para a entressafra, por interm&amp;eacute;dio do cons&amp;oacute;rcio com o milho, se mostrou excelente alternativa na integra&amp;ccedil;&amp;atilde;o lavoura-pecu&amp;aacute;ria, sob irriga&amp;ccedil;&amp;atilde;o, em sistema plantio direto.&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&gt;&lt;span style="font-size: small;"&gt;PALAVRAS-CHAVE: Deteriora&amp;ccedil;&amp;atilde;o controlada; envelhecimento acelerado; germina&amp;ccedil;&amp;atilde;o; tetraz&amp;oacute;lio; vigor.&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&gt;&lt;span style="font-size: small;"&gt;The speed and magnitude of tropical pastures expansion in Brazil are related to the availability of quality seeds. This research aimed to evaluate the physiological quality of seeds of two &lt;em&gt;Brachiaria&lt;/em&gt; species submitted to germination and viability tests and also estimate, for both species, the fresh and dry mass yield, under different irrigated crop-livestock integration systems. For field analysis, the experimental design was a randomized complete block, in subplots, with four intercrops in the plot (&lt;em&gt;Brachiaria brizantha&lt;/em&gt; cv. Marandu and &lt;em&gt;Brachiaria ruziziensis&lt;/em&gt; simultaneously established with corn and nitrogen fertilization coverage), and four forage cutting times, in the winter/spring season, in subplots, with four replications. In the laboratory, the experimental design was completely randomized, with four replications per treatment/test. The germination and viability tests indicated that &lt;em&gt;B. brizantha &lt;/em&gt;seeds showed higher physiological quality, when compared with &lt;em&gt;B. ruziziensis&lt;/em&gt;, while the tetrazolium test and germinated seedlings characteristics were similar. The &lt;em&gt;B. ruziziensis&lt;/em&gt;, simultaneously intercropped with corn, was the less viable intercrop, due to the lower fresh and dry mass yield and litter deposition on the soil surface. In general, the pasture formation for the second season cultivation, intercropped with corn, was an excellent alternative for crop-livestock integration under a no-tillage system.&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&gt;&lt;span style="font-size: small;"&gt;KEY-WORDS: Controlled deterioration; accelerated aging; germination; tetrazolium; vigor.&lt;/span&gt;&lt;/span&gt;&lt;/span&gt;&lt;/p&gt;