The present study evaluated the accumulation and export of nutrients in cactus pear (Opuntia ficus-indica) cv. Gigante, fertilized with combinations of nitrogen (10, 70, 100, 130, and 190 kg ha −1 year −1 N) and phosphorus (10, 70, 100, 130, and 190 kg ha −1 year −1 P 2 O 5) under annual and biennial harvests, in Quixadá and Tejuçuoca, using a split-plot randomized block design with four replications. In Quixadá, under annual and biennial harvests, the following orders of accumulation of macronutrients (in kg ha −1 year −1) were found, respectively:

SUMMARY This study was carried out aiming to evaluate the biomass components of elephant grass cv. Roxo at seven growth ages, during rainy, transition and dry seasons. A completely randomized design was adopted with a split plot arrangement over time. The treatments consisted of seven growth ages (9, 18, 27, 36, 45, 54 and 63) and three seasons (rainy, transition and dry). The variables green forage biomass, dead forage biomass, green stem biomass and green leaf blade biomass showed positive linear responses to age and had their magnitude influenced by the evaluated seasons. The live/dead material ratio showed a decreasing linear response as a function of age. The leaf blade/stem ratio showed a negative linear adjustment in the rainy season, reaching a critical value of 1.0 at 59 days, and it showed a quadratic adjustment in the transition season, with the maximum point at 27.53 days; however, this ratio was not influenced by age in the dry season, revealing an average value of 2.22 ± 0.27. The canopy height and leaf area index showed a positive linear response to age in the three seasons. Tiller population density showed quadratic behaviour for age, with maximum estimated values of 134 and 110 til. m-2 at 31.24 and 37.40 days in the rainy and dry seasons, respectively. Rainfall seasonality influences the magnitude of the daily increase of the distinct biomass components of Pennisetum purpureum cv. Roxo.

The objective of this work was to evaluate the effects of combined phosphorus and nitrogen fertilization and of harvesting frequency on the chemical composition of 'Gigante' cactus pear (Opuntia ficus-indica) cladodes. The experiment was carried out in two municipalities, Quixadá and Tejuçuoca, in the state of Ceará, Brazil. Fertilization with nitrogen (urea) and phosphorus (single superphosphate) was done with nine doses, respectively: 10 and 70, 70 and 10, 70 and 70, 70 and 130, 100 and 100, 130 and 70, 130 and 130, 130 and 190, and 190 and 130 kg ha-1 per year, besides 100 kg ha-1 N and P2O5 per year as the control. The harvesting frequencies evaluated were annual and biannual. A randomized complete block design was adopted, in split plot, with four replicates. The effect of fertilization on the contents of total dry matter, crude protein, neutral detergent fiber, organic matter, and total carbohydrates in the cladodes varies with harvesting frequency and site. Regarding harvesting frequency, there were higher contents of organic matter, total carbohydrates, and neutral detergent fiber, but lower contents of crude protein for the biannual harvesting in both municipalities. Annual harvesting improves the nutritional quality of primary and secondary cladodes in the municipality of Quixadá and of secondary and tertiary cladodes in Tejuçuoca.

SUMMARY The objective of this study was to evaluate the macronutrient accumulations in leaf, stem, and shoot of elephant grass cv. Roxo. The treatments consisted of seven growth ages (9, 18, 27, 36, 45, 54, and 63 days) and three growing seasons (rainy, transition, and dry). A completely randomized design and a split-plot time arrangement were used, where the ages were the plots and the seasons the subplots, with three replications. Interaction between the factors age and season of cultivation for the contents and the daily accumulation rates of N, P, K, Ca, Mg, and S in leaf, stem, and shoot fractions were calculated. The margins of daily accumulation of nutrients N, P, K, Mg, and S presented positive linear behavior in all seasons studied; however, with variation in the magnitude of the response between them. The daily accumulation rate of Ca in the canopy was adjusted to a linear model for the rainy and dry seasons and to a quadratic model for the transition season, reaching a maximum of 4.60 kg ha-1 at 59.76 days of growth. The accumulation of nutrients in elephant grass cv. Roxo showed the following decreasing order: K > N > P > Mg > Ca > S in the rainy and transition seasons, while in the dry season the following decreasing order was observed: K > P > N > Ca > Mg > S.

Objetivou-se avaliar o fluxo de biomassa do capim-canarana erecta lisa (Echinochloa pyramidalis LAM.) pastejado por novilhas leiteiras num delineamento em blocos casualizados com cinco repetições (piquetes) e arranjo fatorial 2 x 2 (frequência e intensidade). As frequências de desfolhação (FD) corresponderam à intercepção de 85 e 95% da radiação fotossinteticamente ativa e as intensidades de desfolhação (ID) corresponderam aos índices de área foliar residual 1,0 e 2,0. Foram avaliadas as seguintes variáveis: a taxas de alongamento foliar (TAlF) e das hastes (TAlH), a razão entre a taxa de alongamento da folha 1 e da folha 2 (TAlF1/TAlF2), taxa de senescência total (TST), o número de folhas vivas (NFV), o número de folhas totais (NFT); o tempo de vida da folha (TVF); a taxa de aparecimento da folha (TApF) e a taxa de acúmulo da cultura (TAC). A TAlF1/TAlF2, TAlF, TAlH e TST não foram influenciada pelas FD e ID, mas aumentaram com os ciclos. A TApF foi maior na FD de 85% em relação a FD de 95%. O capim-canarana pastejado por novilhas deve ser manejado com frequência de desfolhação de 95% de interceptação da radiação fotossinteticamente ativa associada a um índice de área foliar residual de 2,0.

Se objetivó evaluar el estado nutricional y la dinamica de acumulación de micronutrientes en la parte aérea del pasto elefante cv. Morado en diferentes épocas bajo secano. Se analizarón siete edades de crecimiento (9, 18, 27, 36, 45, 54 y 63 días) y tres épocas de cultivo (lluviosa, transición y sequía), en un delineamiento completamente casualizado en el arreglo de parcelas subdivididas en el tiempo, las edades fueron asignadas en las parcelas y las épocas de cultivo en las subparcelas, con tres repeticiones. Se constató la interacción entre las edades de crecimiento y la época de cultivo para los contenidos y las acumulaciones de hierro (Fe), zinc (Zn), cobre (Cu) y manganeso (Mn). En la hoja, los niveles de Fe (épocas lluviosa y transición), Zn, Cu y Mn (época lluviosa) redujeron en respuesta al avance en la edad de crecimiento. En la época de sequía, el contenido de Fe fue incrementado linealmente, mientras que los niveles de Cu y Mn presentarón respuestas cuadráticas con el aumento de las edades de crecimiento. Los acúmulos de Fe, Zn, Cu y Mn presentarón una respuesta lineal creciente con el avance en las edades en todas las épocas de cultivo. A los 63 días de crecimiento, se estimaron acúmulos de Fe de 915.51, 463.93 y 360.00 g ha 1, Zn de 439.19, 111.48 y 86.37 g ha 1, Cu de 56.07, 31.43 y 35.30 g ha 1 y Mn de 333.16, 155.78 y 225.40 g ha 1 (épocas lluviosas, transición y sequía, respectivamente). La acumulación de micronutrientes en el pasto elefante cv. Morado manejado sobre secano presenta el siguiente orden Fe > Mn > Zn > Cu para las épocas lluviosas y de transición, y Fe > Mn > Zn > Cu para época de sequía.

The objective was to estimate the growth indexes of elephant grass cv. Roxo managed under rainfed conditions in different growing seasons. Seven growth ages (9, 18, 27, 36, 45, 54, and 63 days) were evaluated in three growing seasons (rainy, transition and dry). A completely randomised design was adopted, with split-plot arrangement with time repeated measures, with the ages being the plots and the seasons the subplots. Interaction of age x season was observed. The specific leaf area mean was 0.0286 ± 0.0039 during the rainy season. In the transition season, it adjusted to a third-degree polynomial model; in the dry season it declined linearly (0.0003 m2 g-1). The leaf weight ratio adjusted to the third-degree polynomial model in the rainy and dry seasons, and in the transition season it was maximised at 28 DAC (0.694 g g-1). The leaf area ratio continuously declined in the rainy season. In the transition and dry seasons, it adjusted to the third-degree polynomial model. The net assimilation rate presented averages of 3.73 ± 2.50 and 3.63 ± 1.48 g m-2 day-1 in the rainy and transition seasons, respectively. In the dry season, it was minimised at 48.4 days. The relative growth rate mean was 0.0075 ± 0.0037 during the rainy season. In the transition and dry seasons, it adjusted to the third-degree polynomial model. The growth index rates of elephant grass cv. Roxo are modified by growing seasons, and the pattern and magnitude of the response varies throughout the growth cycle.

RESUMOAvaliou-se as respostas morfofisiológicas em capim-aruana pastejado sob lotação rotativa por ovinos da raça Morada Nova submetidos a quatro níveis de suplementação concentrada, com período de ocupação de quatro dias e descanso quando da interceptação de 90% da radiação fotossinteticamente ativa (IRFA), em delineamento de parcelas subdivididas, sendo as parcelas os níveis de suplementação (0,0; 0,6; 1,2 e 1,8% do PC) e as subparcelas, os ciclos de pastejo. As variáveis das trocas gasosas das folhas recém-expandidas: transpiração, condutância estomática, taxa de fotossíntese foliar, mostraram efeito somente de ciclo de pastejo. Não houve nenhum efeito significativo sobre as variáveis das trocas gasosas das folhas emergentes. Os níveis de suplementação não influenciaram as características fisiológicas do capim-aruana, independentemente da folha avaliada, recém-expandida e emergente, contudo, as folhas recém-expandidas apresentaram uma aclimatação aos fatores abióticos da região, o que demonstra a plasticidade fisiológica dessa espécie para regiões de clima tropical. Palavras-Chave: índice de área foliar, interceptação da radiação fotossinteticamente ativa, trocas gasosas, Megathyrsus maximus cv.aruana. RESUMENSe evaluaron las respuestas morfofisiológicas en pasto Aruana pastoreo en repoblación rotacional por ovejas Morada Nova sometidas a cuatro niveles de suplementación concentrada, con un período de ocupación de cuatro días y reposo cuando se interceptó el 90% de la radiación fotosintéticamente activa (IRFA). En un diseño de parcela dividida, siendo las parcelas los niveles de suplementación (0.0; 0.6; 1.2 y 1.8% del PV) y las subparcelas, los ciclos de pastoreo. Las variables de intercambio de