Resumen: Este estudio tuvo como objetivo evaluar la ingesta, digestibilidad aparente, balance hídrico, balance de nitrógeno y rendimiento productivo en corderos alimentados con ensilaje de nopal asociado con forrajes tropicales. En el experimento se utilizaron 40 corderos machos cruzados intactos, con un peso corporal inicial de 18.85 ± 1.2 kg. El diseño experimental fue completamente al azar, con 5 tratamientos y 8 repeticiones. Los tratamientos consistieron en dietas con diferentes proporciones de pasto buffel y salvado de trigo como fuentes de fibra detergente neutro (FDN), en ensilaje de alimento total (EAT) a base de nopal: EAT1 - 279 g/kg de pasto buffel; EAT2 - 240 g/kg de pasto buffel y 17 g/kg de salvado de trigo; EAT3 - 198 g/kg de pasto buffel y 34 g/kg de salvado de trigo; EAT4 - 108 g/kg de pasto buffel y 74 g/kg de salvado de trigo; EAT5 - 118 g/kg de salvado de trigo. La ingesta más baja de FDN se encontró en corderos que consumieron EAT5 (402 g/día). La digestibilidad aparente de los carbohidratos no fibrosos fue mayor para EAT5, mientras que la digestibilidad aparente de FDN de EAT5 y EAT4 fue mayor que la de EAT1. Las dietas promovieron una ganancia diaria de peso promedio de 180.8 g/día. En condiciones experimentales, el uso de nopal forrajero y concentrado en forma de raciones mixtas totales de ensilaje conduce a una mayor ingesta de proteína cruda, carbohidratos no fibrosos, extracto etéreo y mayor digestibilidad de carbohidratos no fibrosos y fibra detergente neutro, sin embargo, todas las dietas fueron viables en la alimentación de ovinos confinados, proporcionando ganancias de hasta 198 g/d según la formulación de la dieta.

Abstract This study aimed was to evaluate the intake, apparent digestibility, water balance, nitrogen balance, and productive performance in lamb fed cactus pear silage associated with tropical forages. Forty male intact crossbred lambs, with an initial body weight of 18.85 ± 1.2 kg, were used in the experiment. The experimental design was completely randomized, with 5 treatments and 8 replications. The treatments consisted of diets with different proportions of buffelgrass and wheat bran as sources of neutral detergent fiber (NDF), in total feed silage (TFS) based on cactus pear: TFS1 - 279 g/kg of buffelgrass; TFS2 - 240 g/kg of buffelgrass and 17 g/kg of wheat bran; TFS3 - 198 g/kg of buffelgrass and 34 g/kg of wheat bran; TFS4 - 108 g/kg of buffelgrass and 74 g/kg of wheat bran; TFS5 - 118 g/kg of wheat bran. The lowest NDF intake was found in lambs that consumed TFS5 (402 g/d). The non-fibrous carbohydrates apparent digestibility was higher for TFS5, while the NDF apparent digestibility of TFS5 and TFS4 was higher than TFS1. Diets promoted an average daily weight gain of 180.8 g/d. Under experimental conditions, the use of forage cactus pear and concentrate in the form of total mixed rations silage leads to greater intake of crude protein, non-fibrous carbohydrates, ether extract and greater digestibility of non-fibrous carbohydrates and neutral detergent fiber, however, all diets were viable in the feed of confined sheep, providing gains of up to 198 g/d according with the formulation of the diet.

Na Mata Fresca, área situada na divisa dos Estados do Rio Grande do Norte e Ceará, pequenos agricultores têm como fonte de renda a obtida com a produção de raízes de mandioca, usando densidades de plantio em torno de 5.000 plantas ha-1. Esse procedimento pode estar limitando a obtenção de maiores rendimentos de raízes, pois alguns trabalhos demonstraram que é possível a obtenção de rendimentos maiores da mandioca, com maiores densidades. O objetivo do trabalho foi avaliar o rendimento de raízes e outras características da mandioca em resposta à densidade de plantio. A cultivar Vermelhinha foi submetida às densidades de plantio de 5.000 a 21.000 plantas ha-1, com intervalos de 2.000 plantas ha-1, em experimento irrigado. Utilizou-se o delineamento de blocos completos casualizados com quatro repetições. As densidades de plantios ideais para maximizar a obtenção de matérias frescas de folhas, caule + ramos, total de raízes, de raízes comercializáveis, número de raízes comercializáveis, e de matérias secas de raízes comercializáveis e da parte aérea foram de 17.800; 17.077; 14.416; 13.594; 16.436; 12.361 e 18.149 plantas ha-1, respectivamente. Com a adoção da densidade de plantio usada pelos agricultores, obtiveram-se 15.837 kg ha-1 de raízes comercializáveis. Com o uso da densidade ideal encontrada no presente trabalho (13.594 plantas ha-1), o rendimento foi mais do dobro do rendimento do agricultor. O aumento da densidade de plantio reduziu o comprimento das raízes comercializáveis e o índice de colheita (relação entre a matéria seca das raízes comercializáveis e a matéria seca total da planta).

In Mata Fresca, an area located on the border of the states of Rio Grande do Norte and Ceará, in Brazil, small farmers have a source of income from the production of cassava roots, using planting densities of around 5,000 plants ha-1. This procedure might be helping to limit higher yields of the roots, since some studies have shown that it is possible to obtain higher yields of cassava using higher densities. The objective of this study was to evaluate the root yield and other characteristics of the cassava, as a response to planting density. The Vermelhinha cultivar was submitted to planting densities of from 5,000 to 21,000 plants ha-1, at intervals of 2,000 plants ha-1, in an experiment under irrigation. A completely randomized block design with four replications was used. The ideal planting densities in order to maximise leaf green matter, stems and branches, total roots, total marketable roots, number of marketable roots, marketable-root dry matter and stem dry matter, were 17,800; 17,077; 14,416; 13,594; 16,436; 12,361; and 18,149 plants ha-1 respectively. When adopting the planting density used by the farmers, a yield for marketable roots of 15,837 kg ha-1 was obtained. By using the optimal density as found in this work (13,594 plants ha-1), the yield was more than double that of the farmers. Increasing planting density reduced both the length of the marketable roots and the harvest index (the ratio of marketable-root dry matter to total plant dry matter).