Doses e formas de aplicação de nitrogênio no desenvolvimento e produção da cultura do trigo

Objetivou-se avaliar o efeito de doses e formas de aplicação de nitrogênio sobre o desempenho e produção de duas cultivares de trigo. O experimento, conduzido em Viçosa-MG, de maio a setembro de 2005, foi instalado segundo um esquema fatorial 2x2x5 no delineamento de blocos casualizados, com quatro repetições. Os tratamentos avaliados consistiram da combinação das cultivares de trigo, BRS 210 e Pioneiro, duas formas de aplicação de adubo nitrogenado (dose total aplicada por ocasião da semeadura ou 20 kg ha-1 na semeadura e o restante em cobertura no início da fase de perfilhamento) e cinco doses de nitrogênio (40, 60, 80, 100 e 120 kg ha-1) tendo como fonte o sulfato de amônio. A cultivar Pioneiro apresentou maior potencial produtivo que a cultivar BRS 210, mas foi menos resistente ao acamamento. O parcelamento da adubação nitrogenada proporcionou maior acamamento e não trouxe benefícios à produtividade dos grãos. As doses de N promoveram resposta quadrática da produtividade dos grãos, com ponto de máxima estimado na dose de 96,8 kg ha-1 e, aumento linear do acamamento de plantas da cultivar Pioneiro.The objective of this work was to evaluate the effect of doses and methods of nitrogen application on the development and yield of two wheat cultivars. The experiment was conducted in Viçosa-MG, from May to September 2005, and it was arranged in a 2x2x5 factorial, randomized block design with four repetitions. The treatments consisted of the combination of the two wheat cultivars, BRS 210 and Pioneiro, two nitrogen application methods (total dose applied at seed sowing or 20 kg ha-1 at sowing and the remaining as topdressing in the beginning of tillage) and five N doses (40, 60, 80, 100 and 120 kg ha-1) with ammonium sulfate as N source. Cultivar Pioneiro showed higher yield potential than cultivar BRS 210, but it was less resistance to lodging. Splitting nitrogen fertilization increased lodging and brought no benefit to grain yield. Grain yield response to N doses was quadratic, reaching maximum at 96.8 kg ha-1, and linear increase in lodging of cultivar Pioneiro plants

Production of cuttings and nutrient export by Coffea canéfora in different periods in the Southwestern Amazon

ABSTRACT Cutting is the main vegetative propagation method used for the production of Coffea canephora plantlets. In this method, parent plants are conducted in a specific field, called clonal garden, which must be managed to produce clonal cuttings. The objective of this study was to evaluate the production of cuttings and the export of nutrients by Coffea canephora in different periods in the Southwestern Amazon. The experiment was carried out in a 6 × 3 split-plot scheme (repeated measures in time), consisting of the combination of six clonal Coffea canephora genotypes (plot) and three cutting collection periods (subplots). The genotypes were: C-057, C-088, C-089, C-125, C-130 and C-160; and the evaluation sampling times were January/2017, May/2017 and September/2017. The applied design was a completely randomized design with four repetitions. The dry season, from May to September, promotes lower orthotropic stem dry mass accumulation by Coffea canephora, but allows obtaining a larger number of viable cuttings for the production of clonal plantlets. Nutrient accumulation by orthotropic stems for cutting production follows the following order: N &gt; K &gt; Ca &gt; Mg &gt; S &gt; P &gt; Mn &gt; Fe &gt; Zn &gt; Cu. Nutrient export by the cuttings follows a descending order: K &gt; N &gt; Ca &gt; Mg &gt; P &gt; S &gt; Mn &gt; Fe &gt; Zn &gt; Cu.</jats:p

Rates of urea with or without urease inhibitor for topdressing wheat

The urease inhibitor NBPT(N-(n-butyl) thiophosphoric triamide) is a management alternative to increase urea efficiency in topdressing because it reduces NH3 volatilization. The objective of this study was to evaluate N recovery and yield performance of wheat ( Triticum aestivum L.) ‘BRS 254’ fertilized with different urea or urea + NBPT rates in topdressing. The experiment was conducted from May to September 2007 in Viçosa, Minas Gerais, Brazil. Treatments followed a 5 × 2 + 1 factorial design consisting of five N fertilizer rates (30, 60, 90, 120, and 150 kg ha-1) as urea or urea + NBPT (Agrotain® ) applied as topdressing and a control without N. The experiment was a randomized complete block design with four replicates. Adding NBPT to urea resulted in better N utilization by wheat plants. The 100 kg N ha-1 topdressing rate provided the best apparent N recovery by wheat plants, whereas 90 kg ha-1 provided the best N use efficiency

Rates of urea with or without urease inhibitor for topdressing wheat

The urease inhibitor NBPT(N-(n-butyl) thiophosphoric triamide) is a management alternative to increase urea efficiency in topdressing because it reduces NH3 volatilization. The objective of this study was to evaluate N recovery and yield performance of wheat ( Triticum aestivum L.) ‘BRS 254’ fertilized with different urea or urea + NBPT rates in topdressing. The experiment was conducted from May to September 2007 in Viçosa, Minas Gerais, Brazil. Treatments followed a 5 × 2 + 1 factorial design consisting of five N fertilizer rates (30, 60, 90, 120, and 150 kg ha-1) as urea or urea + NBPT (Agrotain® ) applied as topdressing and a control without N. The experiment was a randomized complete block design with four replicates. Adding NBPT to urea resulted in better N utilization by wheat plants. The 100 kg N ha-1 topdressing rate provided the best apparent N recovery by wheat plants, whereas 90 kg ha-1 provided the best N use efficiency

YIELD AND NITROGEN RECOVERY OF WHEAT PLANTS SUBJECTED TO UREA APPLICATION WITH OR WITHOUT A UREASE INHIBITOR IN THE ABSENCE OF IRRIGATION

The use of urease inhibitors and irrigation are management options to increasing the efficiency of top-dressed urea by reducing NH3&nbsp;volatilization. The purpose of this study was to evaluate the productive performance and N recovery of &lsquo;BRS 254&rsquo; wheat plants without irrigation after applying urea or urea+NBPT [N-(n-butyl)thiophosphoric triamide] as the top dressing. The experiment was carried out in Vi&ccedil;osa, MG, Brazil, between May and September of 2008 using a complete randomized block design with a 2&times;6+1 factorial arrangement of the following treatments: 1) urea or urea+NBPT, 2) six periods without irrigation (0, 48, 96, 144, 192 or 240 h after applying the top-dressing fertilizer), and 3) a control without N; there were four replications. The data were subjected to an analysis of variance (P&le;0.05). The mean values of the treatments with urea or urea+NBPT were compared by Tukey&rsquo;s test (P&le;0.05), and the effects of the periods without irrigation were analyzed by a regression (P&le;0.05). The results of the study show that NBPT did not lead to agronomic advantages for the wheat crop under the study conditions, and the absence of irrigation after urea application as the top dressing led to less N utilization by the wheat plants.El uso de inhibidores de ureasa o de riego son opciones de manejo para aumentar la eficiencia de la urea aplicada en cobertera, a trav&eacute;s de la reducci&oacute;n de la volatilizaci&oacute;n de NH3. La investigaci&oacute;n tuvo como objetivo la evaluaci&oacute;n del desempe&ntilde;o productivo y la recuperaci&oacute;n de N por plantas de trigo &lsquo;BRS 254&rsquo; sin riego, despu&eacute;s de la aplicaci&oacute;n de urea o urea+ NBPT [N-(n-butyl)thiophosphoric triamide] en cobertera. El experimento se llev&oacute; a cabo en la ciudad de Vi&ccedil;osa, MG, en Brasil desde mayo hasta septiembre de 2008. Los tratamientos siguieron un arreglo factorial 2&times;6+1, en el cual la urea o urea + NBPT se combinaron en seis periodos sin riego: 0, 48,96, 144, 192 y 240 horas despu&eacute;s de la aplicaci&oacute;n del fertilizante en cobertera, adem&aacute;s de una muestra de control sin la aplicaci&oacute;n de N. Para el dise&ntilde;o experimental, se utilizaron los bloques completos al azar con cuatro repeticiones. Se concluy&oacute; que el NBPT no proporciona ventajas agr&iacute;colas a la cosecha de trigo, bajo las condiciones estudiadas. La ausencia de riego despu&eacute;s de la aplicaci&oacute;n de urea en cobertera provee un aprovechamiento menor de N por las plantas de trigo

Yield and nitrogen recovery of wheat plants subjected to urea application with or without a urease inhibitor in the absence of irrigation

The use of urease inhibitors and irrigation are management options to increasing the efficiency of top-dressed urea by reducing NH3 volatilization. The purpose of this study was to evaluate the productive performance and N recovery of 'BRS 254' wheat plants without irrigation after applying urea or urea+NBPT [N-(n-butyl)thiophosphoric triamide] as the top dressing. The experiment was carried out in Viçosa, MG, Brazil, between May and September of 2008 using a complete randomized block design with a 2×6+1 factorial arrangement of the following treatments: 1) urea or urea+NBPT, 2) six periods without irrigation (0, 48, 96, 144, 192 or 240 h after applying the top-dressing fertilizer), and 3) a control without N; there were four replications. The data were subjected to an analysis of variance (P≤0.05). The mean values of the treatments with urea or urea+NBPT were compared by Tukey's test (P≤0.05), and the effects of the periods without irrigation were analyzed by a regression (P≤0.05). The results of the study show that NBPT did not lead to agronomic advantages for the wheat crop under the study conditions, and the absence of irrigation after urea application as the top dressing led to less N utilization by the wheat plants.El uso de inhibidores de ureasa o de riego son opciones de manejo para aumentar la eficiencia de la urea aplicada en cobertera, a través de la reducción de la volatilización de NH3. La investigación tuvo como objetivo la evaluación del desempeño productivo y la recuperación de N por plantas de trigo 'BRS 254' sin riego, después de la aplicación de urea o urea+ NBPT [N-(n-butyl)thiophosphoric triamide] en cobertera. El experimento se llevó a cabo en la ciudad de Viçosa, MG, en Brasil desde mayo hasta septiembre de 2008. Los tratamientos siguieron un arreglo factorial 2×6+1, en el cual la urea o urea + NBPT se combinaron en seis periodos sin riego: 0, 48,96, 144, 192 y 240 horas después de la aplicación del fertilizante en cobertera, además de una muestra de control sin la aplicación de N. Para el diseño experimental, se utilizaron los bloques completos al azar con cuatro repeticiones. Se concluyó que el NBPT no proporciona ventajas agrícolas a la cosecha de trigo, bajo las condiciones estudiadas. La ausencia de riego después de la aplicación de urea en cobertera provee un aprovechamiento menor de N por las plantas de trigo

Production of cuttings and nutrient export by Coffea canéfora in different periods in the Southwestern Amazon

ABSTRACT Cutting is the main vegetative propagation method used for the production of Coffea canephora plantlets. In this method, parent plants are conducted in a specific field, called clonal garden, which must be managed to produce clonal cuttings. The objective of this study was to evaluate the production of cuttings and the export of nutrients by Coffea canephora in different periods in the Southwestern Amazon. The experiment was carried out in a 6 × 3 split-plot scheme (repeated measures in time), consisting of the combination of six clonal Coffea canephora genotypes (plot) and three cutting collection periods (subplots). The genotypes were: C-057, C-088, C-089, C-125, C-130 and C-160; and the evaluation sampling times were January/2017, May/2017 and September/2017. The applied design was a completely randomized design with four repetitions. The dry season, from May to September, promotes lower orthotropic stem dry mass accumulation by Coffea canephora, but allows obtaining a larger number of viable cuttings for the production of clonal plantlets. Nutrient accumulation by orthotropic stems for cutting production follows the following order: N > K > Ca > Mg > S > P > Mn > Fe > Zn > Cu. Nutrient export by the cuttings follows a descending order: K > N > Ca > Mg > P > S > Mn > Fe > Zn > Cu.</div