Abstract Soil and water salinity are considered the main limiting factors of plant production. This work aimed to evaluate the influences of irrigation frequency and soil salinity on the development of cactus pear cv. Miúda (Nopalea cochenillifera Salm Dyck). The experiment was conducted in factorial arrangement of four salinity levels: 0.3 (control), 0.5 (low), 1.5 (medium) and 3.6 (high salinity) (ds m-1), associated with four irrigation frequencies (each 7, 14, 21 and 28 days) and two soil textures (sandy and sandy loam) in a randomized block design with four replicates. One cladode was planted in each polyethylene pot containing 10 kg of soil. The soil texture influenced some of the morphological characteristics of the cactus pear, so that plants grown in sandy loam soil yielded higher number of cladodes (9.47) and higher productivity (62.1 g plant-1). The sandy soil produced plants with fewer cladodes (4.50). Irrigation water with a salinity level of 3.6 ds m-1 and an irrigation frequency of 7 days showed higher soil electrical conductivity (48.65 dS m-1) and plants with a higher damage (5.0) and lower productivity (32.51 g plant-1), indicating a low tolerance of the cv. Miúda to salt stress.

Resumen En la región semiárida del nordeste de Brasil, las plantas nativas son una fuente importante de forraje. El objetivo de este estudio fue evaluar las características químicas de los henos de las leguminosas arbustivas nativas: sabiá (Mimosa caesalpiniifolia Benth.) y mororó [Bauhinia cheilantha (Bong.) Steud.], utilizando diferentes fracciones de las plantas: solo hojas y hojas más ramificaciones delgadas (<8 mm diámetro) de tallos. Los análisis incluyeron: concentraciones de materia seca (MS), proteína cruda (PC), fibra detergente neutra (FDN), extracto de éter (EE), ceniza, nutrientes digestibles totales (NDT) y carbohidratos no fibrosos (CNF). El heno de hojas de sabiá presentó mayor concentración de PC (182 g/kg de MS) que el heno de hojas de mororó (126 g/kg de MS); no obstante en ambas leguminosas las concentraciones de PC fueron similares cuando se analizaron hojas más ramificaciones de tallos (106 g/kg de MS en promedio). Las concentraciones de FDN (368 g/kg de MS), CNF (418 g/kg de MS) y NDT (481 g/kg de MS) del heno de hojas de mororó fueron superiores a las del heno de hojas de sabiá (465, 258 y 311 g/kg de MS, respectivamente). Los resultados sugieren que en la región semiárida de Brasil estas leguminosas nativas, conservadas como heno durante el período de crecimiento, pueden proporcionar un alimento suplementario de aceptable valor nutritivo durante el período de baja disponibilidad y calidad de forraje. Sin embargo, se necesitan muestreos adicionales de un rango de fases de crecimiento de las plantas y sitios tanto para confirmar estos resultados preliminares como para proporcionar datos sobre producción de MS. Además se requieren estudios de alimentación con rumiantes para evaluar el efecto de los henos en la producción animal.

Abstract Native forages are important feed sources in the northeastern semi-arid region of Brazil. The objective of this study was to evaluate the chemical characteristics of hays made from the native shrub legumes, sabiá (Mimosa caesalpiniifolia Benth.) and mororó [Bauhinia cheilantha (Bong.) Steud.], using different plant fractions: leaves only and leaves plus twigs. Analyses carried out were: concentrations of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), ether extract (EE), ash, total digestible nutrients (TDN) and non-fiber carbohydrates (NFC). Sabiá leaf hay contained greater CP concentration (182 g/kg DM) than mororó leaf hay (126 g/kg DM) but hay made from leaf plus twigs showed similar CP for both legumes (mean 106 g/kg DM). Concentrations of NDF (368 g/kg DM), NFC (418 g/kg DM) and TDN (481 g/kg DM) of mororó leaf hay were superior to those of sabiá leaf hay (465, 258 and 311 g/kg DM, respectively). The findings suggest that these native legumes can be conserved as hay during the growing season to provide a supplementary feed with acceptable nutritive value for feeding during the period of inadequate feed availability and quality in semi-arid Brazil. However, more samples from a range of growth stages and locations are needed to confirm these preliminary findings and to provide data on possible yields, while more feeding studies with ruminants are needed to confirm the preliminary data in terms of liveweight performance.