RESUMO A couve-flor é uma brássica bastante produzida e consumida no Brasil, cujo cultivo é dependente do suprimento adequado de água e nutrientes. Portanto, objetivou-se com este estudo, avaliar o efeito da aplicação de lâminas de irrigação e doses de nitrogênio nos componentes de produção e na produtividade da água da cultura da couve-flor híbrida ‘Barcelona CMS’. Foram avaliadas as lâminas de 0, 75, 100, 125 e 150% da evapotranspiração da cultura combinadas com cinco doses de nitrogênio (0, 75, 150, 300 e 450 kg ha-1). O experimento foi conduzido em delineamento inteiramente casualizado com arranjo em parcelas subdivididas. Os efeitos da desses fatores foram avaliados pela metodologia de superfície de resposta. Observou-se que a produtividade da água pela cultura apresenta relação decrescente com a lâmina de água aplicada; portanto, a produtividade é maior quando a reposição de água é menor que o recomendado. A maior produtividade total da couve-flor estimada é de 24.547,80 kg ha-1, com diâmetro médio de 19,60 cm, altura média de 12,25 cm e massa fresca da inflorescência de 858,90 g por planta, obtida com irrigação equivalente a 132,09% da evapotranspiração da cultura e 450 kg ha-1 de nitrogênio. Para obtenção do maior diâmetro e altura de inflorescência é necessária lâminas de irrigação equivalentes a 128,70 e 108,20% da evapotranspiração da cultura, respectivamente, na dose de 450 kg ha-1 de nitrogênio. Portanto, a melhor resposta da produtividade da couve-flor híbrida ‘Barcelona CMS’ pode ser obtida com lâmina de irrigação superior à evapotranspiração da cultura, independentemente da dose de nitrogênio aplicada.

ABSTRACT Cauliflower is a brassica produced and consumed in Brazil, whose cultivation depends on the adequate supply of water and nutrients. The objective of this study was to evaluate the effect of irrigation depths and nitrogen doses on the production components and water yield of cauliflower hybrid Barcelona CMS. The treatments consisted of five irrigation water depths (0, 75, 100, 125 and 150% of the crop evapotranspiration) combined with five nitrogen doses (0, 75, 150, 300 and 450 kg ha-1). The experiment was conducted in a completely randomized design with a split-plot arrangement. The effects of these factors were evaluated using the response surface methodology. The water yield of the crop decreases with increasing irrigation water depth; therefore, the yield is higher when water replenishment is lower than the recommended. The highest estimated total inflorescence yield is 24,547.80 kg ha-1, with a inflorescence mean diameter of 19.60 cm, a inflorescence mean height of 12.25 cm, and an inflorescence fresh weight of 858.90 g plant-1, obtained with an irrigation water depth equivalent to 132.09% of the crop evapotranspiration (ETc) and a nitrogen dose of 450 kg ha-1. The highest inflorescence diameter and height are obtained with an irrigation depth equivalent to 128.70 and 108.20% of ETc, respectively, and a nitrogen dose of 450 kg ha-1. Therefore, the best productivity response of the Barcelona CMS cauliflower hybrid can be obtained using an irrigation depth greater than the crop evapotranspiration, regardless of the nitrogen doses.

ABSTRACT In the correct pasture management, nutritional factors such as nitrogen and potassium fertilization play an important role in the forage production and quality. The aim was to evaluate the effects of the application of water levels, nitrogen and potassium doses in the Xaraés grass in the south of the State of Tocantins. For this, Xaraés grass was cultivated in the experimental field of the Federal University of Tocantins, municipality of Gurupi, TO. We used a mixture of fertilizer, combinations of N and K2O following the 1 N: 0.8 K2O ratio. To evaluate the effect of irrigation water levels and combinations of N and K2O doses in Xaraés grass, the plant height, the crude protein content and neutral detergent fiber were determined. The greatest height observed in the grass was 61.6 cm, with the dose application of 700 kg ha-1 yr-1 of N: 0.8 K2O and a water level of 120% of the ETc. The highest protein content was 11.7%, with the highest dose application of fertilizer and absence of irrigation. The highest fiber content in neutral detergent was 64%, with the estimated amount of 385.5 kg ha-1 yr-1 of N: 0.8 K2O and a water level of 120% of ETc. The conclusion was that the plant height, fiber detergent and crude protein content were influenced by the change in water level of irrigation and fertilizer doses. The values of plant height and crude protein increased with the increase of water levels and manure dose, while the fiber content of neutral detergent decreased with the increase of irrigation and varied little with the increase of fertilizer dose.

Teve-se como objetivo neste trabalho avaliar os efeitos da aplicação de diferentes lâminas de água e doses de nitrogênio e potássio na qualidade do capim-Tanzânia, no sul do Estado do Tocantins. O experimento foi conduzido em faixas com aspersão convencional e aplicou-se, como tratamentos, uma mistura de adubo com combinações de doses de N e K2O sempre na relação de 1 N:0,8 K2O. Para o estudo, determinaram-se ao longo do experimento: a altura de plantas (PH) e os teores de proteína bruta (PB) e de fibra em detergente neutro (FDN). A maior altura de plantas obtida foi de 132,4 cm, com a dose de 691,71 kg ha-1 do adubo na proporção de 1 N para 0,8 de K2O, ou seja, 384,28 kg ha-1 de N e 307,43 kg ha-1 de K2O e lâmina de água de 80% da ETc. O maior teor de proteína bruta foi de 12,2%, com a aplicação da dose de 700 kg ha-1 ano-1 do adubo, na proporção de 1 N para 0,8 de K2O, ou seja, 388,89 kg ha-1 de N e 311,11 kg ha-1 de K2O e ausência de irrigação. O menor teor de fibra em detergente neutro foi de 60,7% com a aplicação da menor dose de adubo e da maior lâmina de água. Concluiu-se, neste trabalho, que houve aumento na altura das plantas, com o aumento da dose do adubo e da lâmina de irrigação. O teor de proteína bruta aumentou 5,4%, no período seco, com o incremento da dose de adubo e da lâmina de irrigação. No período seco, houve aumento do teor de FDN de 4,5% com o incremento da aplicação da dose de adubo e da lâmina de água.

The objective of this study was to evaluate the effects of the application of different water depths and nitrogen and potassium doses in the quality of Tanzania grass, in the southern of the state of Tocantins. The experiment was conducted on strips of traditional sprinklers, and used, as treatments, a mixture of fertilizer combinations of N and K2O always in the ratio of 1 N:0.8 K2O. This study determined throughout the experiment: plant height (PH), the crude protein (CP) and neutral detergent fiber (NDF). The highest plant height obtained was 132.4 cm, with a fertilizer dose of 691.71 kg ha-1 in the proportion of N:0.8 K2O, in other words, 384.28 kg ha-1 of N and 307.43 kg ha-1 of K2O, and water depth of 80% of the ETc. The highest crude protein content was 12.2%, with the fertilizer dose application of 700 kg ha-1 yr-1 in the proportion of 1 N to 0.8 of K2O, in other words, 388.89 kg ha-1 of N and 311.11 kg ha-1 of K2O and absence of irrigation. The lowest level of neutral detergent fiber was 60.7% with the application of the smallest dose of fertilizer and highest water depth. It was concluded in this study that there was an increase in plant height by increasing the fertilizer dose and water depth. The crude protein content increased 5.4% in the dry season, by increasing the fertilizer dose and water depth. In the dry season, there was an increase of NDF content by 4.5% by increasing the application of fertilizer and water depth.