ABSTRACT: Short-term grazing behavior variables are sensitive to the canopy structure and have an impact on daily forage intake. This study evaluated the effect of pre- and post-grazing canopy heights on the forage harvesting process at a patch scale in a mixture of Brachiaria brizantha (Hochst. ex A. Rich.) Stapf. syn. Urochloa brizantha R.D. Webster cv. Marandu (palisade grass) and Arachis pintoi Krapov. & W.C. Greg. cv. Belomonte (forage peanut). Treatments were allocated to a split-plot arrangement in a completely randomized design. The plots, in their entirety, consisted of two pre-grazing canopy heights: 25 cm (CH25) and 35 cm (CH35); subplots consisted of three levels of defoliation severity: no defoliation (DS0); 20% depletion of pre-grazing canopy height (DS20); and 40% depletion of pre-grazing canopy height (DS40), with eight replications. Heifers were allowed to graze the patches (0.7 × 0.7 m) and their grazing behavior was recorded. Canopy structure measurements were taken both before and after grazing. Patches from CH35 presented greater stem mass for grass (p = 0.001) and legume (p = 0.002) than did patches from CH25. Bite rate, bite mass and instantaneous intake rate were greater for CH25 than for CH35 (p < 0.001, p = 0.068, and p = 0.074), and bite mass and instantaneous intake rate were lower for DS20 compared to DS0 (p = 0.032 and p = 0.016). Greater stem mass in the grazing strata negatively influenced the instantaneous intake rate.

ABSTRACT Integrating warm-climate forage legumes into grass monocultures has received significant research attention during the past 70 years, but widespread adoption by end users has been elusive. The objectives of this review are to provide historical context regarding legume use in warm-climate grasslands; synthesize the current literature addressing contributions to grassland ecosystem services of warm-climate, grass-only vs. legume-grass mixed swards; and consider how to achieve more widespread adoption of legume technology in warm climates. For this review, warm-climate grasslands are considered those in areas between latitudes 30° N and 30° S, where C4 perennial grasses dominate. The literature suggests measurable advantages in animal performance, soil carbon accumulation, and nutrient cycling of legume-grass mixtures are most likely when grass-only swards receive little or no N fertilizer. Advantages are less or may disappear when mixtures are compared with grasses receiving high N fertilizer rates. In contrast, amelioration of greenhouse gas emissions is often most pronounced for mixtures when compared with grass-only swards receiving high rates of N, because of the magnitude of N fertilizer effects on emissions. Going forward, there is need to focus on selecting for, and thoroughly documenting legume persistence, achieving low-risk and affordable legume establishment methods, assessing compatibility of legumes in mixture with grasses prior to legume cultivar release, emphasizing adoption of both legume species and optimal management practices, and recognizing scientists must assume a larger and more intentional role in encouraging adoption by end-users of research innovations, in addition to our traditional role in technology and product development.

RESUMO Devido às previsões de mudanças climáticas, é necessário identificar plantas forrageiras que sob estresse hídrico possam manter a produtividade e o valor nutritivo. O objetivo foi avaliar a biomassa e as respostas químicas de três acessos de Desmanthus spp. em dois regimes de privação de água (7 e 21 dias). O delineamento experimental foi em blocos ao acaso em esquema fatorial 3 × 2 (acesso e privação de água), com quatro repetições. Houve redução da biomassa de folha e caule de 64% e 51%, respectivamente. O 43F apresentou maior biomassa de folha (1,86 g.planta-1) e caule (1,97 g.planta-1) que os acessos 89F e AusT, na privação de água de 21 dias. Nas folhas dos acessos 43F e 89F, os carboidratos acumularam em torno de 28% e 51%, respectivamente, sob privação de 21 dias, enquanto o AusT diminuiu 38% no intervalo de 7 dias. A privação de água afetou as características químicas dos acessos. A prolina livre foi semelhante entre os acessos e acumulou 463% a mais nas folhas de plantas com 21 dias de privação de água (90,22 mg.kg-1) em relação às submetidas a 7 dias (16,03 mg.kg-1). O acúmulo de prolina e carboidratos solúveis totais em 43F e 89F foram insuficientes para regular a proteína bruta, o teor de C e a relação C:N. Há variabilidade na tolerância à seca entre espécies e acessos. Os acessos 43F e 89F foram mais suscetíveis à privação de água por 21 dias, enquanto AusT mostrou maior tolerância à seca.

ABSTRACT Due to the predictions of climate change, there is a need to identify forage plants that can keep their productivity and nutritive value under hydric stress. The objective of this study was to evaluate the biomass and chemical responses of three Desmanthus spp. accessions under two water deprivation regimens (7 and 21-day). The experimental design used was randomized blocks in a 3 × 2 factorial arrangement (access and water deprivation) with four replications. There were reductions in the biomasses of leaf and stem fractions of 64% and 51%, respectively. The 43F accession showed greater leaf (1.86 g.plant-1) and stem (1.97 g.plant-1) biomasses under a total water restriction of 21 days, compared to the 89F and AusT accessions. In accessions 43F and 89F, there were carbohydrate accumulations in the leaves of 28% and 51%, respectively, under the 21-day water restriction, while AusT decreased 38% within a 7-day interval. Water deprivation affected the chemical characteristics of the accessions. Free proline was similar among accessions and accumulated 463% more in the leaves of plants submitted to 21-day water deprivation (90.22 mg.kg-1) compared to those subjected to water deprivation for 7 days (16.03 mg.kg-1). Proline and total soluble carbohydrate accumulation in 43F and 89F were insufficient to regulate crude protein, C content, and C:N ratios. These results demonstrate the variability in drought tolerance among accessions. Accessions 43F and 89F were more susceptible to 21-day water deprivation, while AusT showed greater drought tolerance.

Resumo: O objetivo deste trabalho foi avaliar a divergência entre genótipos de Desmanthus sp. quanto a características morfológicas, produtiva e qualitativa, bem como estimar o número de observações necessárias para predizer o valor real destas características. O experimento foi conduzido no semiárido do estado de Pernambuco, Brasil, com uso de 26 genótipos de Desmanthus sp. de diferentes localidades nessa região. Foram realizadas sete avaliações de julho de 2013 a julho de 2014. Utilizou-se o método de agrupamento de Tocher e a distância euclidiana média padronizada. Os coeficientes de repetibilidade (r) e determinação (R2) foram estimados por dois modelos de análise de variância, componentes principais baseados na matriz de correlação ou covariância, e análise estrutural baseada na matriz de correlação. As variáveis com maiores pesos foram diâmetro do caule (DC), índice de área foliar e produção de forragem, com frequências de 22,05, 17,57 e 14,58%, respectivamente. Observou-se variabilidade morfológica, produtiva e qualitativa entre os genótipos de Desmanthus sp. Todas as características apresentaram r e R2 de alta magnitude nos métodos de análise. Até quatro ciclos de avaliação são necessários para prever (R2=95%) o valor real de diâmetro do caule, comprimento do pedúnculo, altura da planta, comprimento e largura da folha, número de folhas e comprimento da vagem.

Abstract: The objective of this work was to evaluate the divergence among genotypes of Desmanthus sp. regarding morphological, productive, and qualitative characteristics, as well as to estimate the number of observations necessary to predict the real value of these characteristics. The experiment was conducted in the semiarid of the state of Pernambuco, Brazil, using 26 genotypes of Desmanthus sp. from different locations in the region. Seven evaluations were carried out from July 2013 to July 2014. Tocher’s grouping method and standardized average Euclidean distance were used. The coefficients of repeatability (r) and determination (R2) were estimated using two models of the analysis of variance, principal components based on the correlation or covariance matrix, and structural analysis based on the correlation matrix. The variables with the greatest weights were stem diameter, leaf area index, and forage yield, with frequencies of 22.05, 17.57, and 14.58%, respectively. Morphological, productive, and qualitative variability was observed among the genotypes of Desmanthus sp. All characteristics presented r and R2 of high magnitude in the methods of analysis. Up to four evaluation cycles are required to predict (R2=95%) the real value of stem diameter, peduncle length, plant height, leaf length and width, number of leaves, and pod length.

ABSTRACT Soil quality indicators may have different seasonal trends during the year. The hypothesis of this study was that sowing maize and marandu palisadegrass with the presence of grazing animals might cause short-term changes in soil indicator responses. We compared four intercropping techniques: ICLS-1: maize plus marandu palisadegrass sown simultaneously, without herbicide; ICLS-2: maize plus marandu palisadegrass sown simultaneously, with herbicide; ICLS-3: maize plus marandu palisadegrass in lagged sowing (i.e., marandu palisadegrass sown 20 days after maize sowing); ICLS-4: maize plus marandu palisadegrass sown simultaneously (palisadegrass on the rows and inter-rows, with herbicide). Two control treatments in monoculture (i.e., grass and maize monocultures) represented the conventional systems. The soil was sampled three times over a one-year period, for the evaluation of carbon and nitrogen fractions as affected by seasonal variability. Results indicated that ICLS-1 and ICLS-4 enhanced soil quality more quickly during the seasonal variation. The ICLS-2 negatively affected microbial biomass (22%), resulting in reduced labile carbon (43%), carbon management index (33%), and potentially mineralizable nitrogen (20%). Labile carbon and the carbon management index were more sensitive and efficient indicators for verifying soil quality changes in the short-term. Results indicated that there is large variability in these soil indicators during the annual cycle, and further studies are needed to verify the effects of the tested systems on different soil nitrogen fractions and how they affect available nitrogen in the short-term. However, potentially mineralizable nitrogen can provide positive insights for short-term changes in the soil.

ABSTRACT This study evaluated soil chemical and isotopic changes in soils of a chronosequence rainforest-sugarcane-pasture in the Atlantic Forest biome, Brazil. Soil samples were collected (0-20 cm) in areas of native Brazilian Atlantic rainforest, sugarcane plantation and pastures of Brachiaria decumbens. The soil analyses performed were: pH (water 1:2.5), P (Mehlich-I), (Al+3, H+Al, K+, Ca+2, Mg+2 and Na+), soil organic matter (SOM), N, organic carbon and δ13C and δ15N stable isotopes. The conversion of rainforest to sugarcane and pastures resulted in a reduction of the soil natural acidity. Forest areas had greater Al+3 and H+Al concentrations than cultivated areas. The conversion from forest to agricultural soil reduced Al+3 (44%) and H+Al (11%), approximately. Soils from pasture had a greater percentage of base saturation (37.3%) than forest soils (25.4%). Cation exchange capacity was strongly influenced by concentrations of K+, Ca+2 and Mg+2, but not by Na+. Carbon stable isotope (δ13C) was more depleted in forest areas (-28.14‰), followed by sugarcane (-21.33‰), and pastures (-19.54‰). The greatest δ15N values were found in sugarcane areas. The short chronosequence studied, had a strong influence of the conversion of the forest on the decrease of the natural acidity and modifications of the isotopic profile. The enrichment of soil δ13C was attributed to the changes from predominant C3 vegetation to C4 grasses.

Abstract In order to evaluate, among clones of the Oreja de Elefante Mexicana nopal cultivar (Opuntia stricta Haw), the one that indicated agronomic and zootechnical characteristics to be considered with forage potential, an experiment was carried out at the Agronomic Institute of Pernambuco (IPA), located at coordinates 08° 25’ 15’’ south latitude and 37° 03’ 41’’ west longitude, at 663 meters above sea level, with a precipitation of 692 mm. The experimental period was from January 2014 to July 2015 and the clones used were Lisa 1, Lisa 2, Seg CV, mãe plant, Seg 1, Seg 2, Seg 3, Seg 4, Seg 5 and Seg 6. The variables evaluated were production (t DM ha-1), number of cladodes in plant (NC), plant height (PH), plant width (PWI), amount of thorn (AT), size of thorn (ST) and amount of gloquide (AG); within each plant it was measured in cladodes, perimeter (P), length (LC), width (WID) and thickness (TH), number of lines (NLI) and number of buds (NBU). The experimental design was completely random and the test of comparison of means with Tukey (p≤ 0.05). There were differences between clones (p≤ 0.05); Lisa 2, showed the lowest AT, ST, AG, and the lowest production (6.45 t DM ha-1), the Seg CV clone, showed higher production (67.41 t DM ha-1), NC, PH, and PWI, without However, it also presented higher AT, ST and AG, so despite its yield it does not show the best agronomic and zootechnical characteristics.

Resumen Evaluar clones del cultivar de nopal Oreja de Elefante Mexicana (Opuntia stricta Haw), con el objetivo de encontrar el que mostrara características agronómicas y zootécnicas para ser considerado con potencial forrajero, se llevó a cabo un experimento en el Instituto Agronómico de Pernambuco (IPA), localizado en las coordenadas 08° 25’ 15’’ latitud sur y 37° 03’ 41’’ longitud oeste, a 663 msnm, con una precipitación de 692 mm. El periodo experimental comprendió de enero 2014 a julio de 2015 y los clones utilizados fueron Lisa 1, Lisa 2, Seg CV, Planta mãe, Seg 1, Seg 2, Seg 3, Seg 4, Seg 5 y Seg 6. Las variables evaluadas fueron producción (t MS ha-1), número de cladodios en planta (NC), altura de la planta (AP), ancho de la planta (ANP), cantidad de espina (CE), tamaño de espina (TE) y cantidad de gloquidio (CG); dentro de cada planta se midió en cladodios, perímetro (P), longitud (LC), ancho (ANC) y grosor (GC), número de líneas (LCP) y número de yemas (YCP). El diseño experimental fue completamente al azar y la prueba de comparación de medias con Tukey (p( 0.05). Se presentaron diferencias entre clones (p≤ 0.05) lisa 2, mostró la menor CE, TE, CG, y la menor producción (6.45 t MS ha-1), el clon Seg CV, presentó mayor producción (67.41 t MS ha-1), NC, AP, y ANP; sin embargo, también presentó mayor CE, TE y CG por lo que pese a su rendimiento no muestra las mejores características agronómicas y zootécnicas.

Abstract In forage crops such as cactus morphological characteristics respond to management practices such as fertilization. An evaluation was done to determine if organic matter (OM) fertilization (0, 10,000, 20,000 and 30,000 kg OM ha-1 yr-1 bovine manure), mineral fertilization (0, 120, 240 and 360 kg N ha-1 yr-1, using urea) and cut frequency (annual and biennial) influenced cladode length, width and perimeter, and Cladode Area Index (CAI) values in Nopalea cochinillifera Salm Dyck cv. Miúda, and how these variables related to productivity. The experimental design was random blocks, using a sub-sub-plot arrangement with four replicates. Fertilization with 30,000 kg OM ha-1 year-1 increased cladode width by 9.8 % and length by 17.8 % compared to the control. Cladode perimeter increased proportionally to OM fertilization level. At the optimum fertilization level (25,970 kg ha-1) the CAI value was 68.29 % higher than the control. Mineral fertilization only affected cladode perimeter at 120 kg ha-1 and only with an annual cut; however, at this fertilization level the CAI value was higher with a biennial cut. Organic matter fertilization increased cladode width and length, and CAI values in N. cochenillifera cv. Miúda, while mineral fertilization had only a minimal effect. Biennial cutting frequency results in higher CAI values. Correlations were high between the evaluated variables and dry matter production, highlighting the utility of morphological variables in evaluating productivity.

Resumen Las características morfológicas de las plantas forrajeras como el nopal, son influenciadas de acuerdo al manejo recibido, prácticas como la fertilización son importantes; debido a lo anterior el objetivo de esta investigación fue evaluar el efecto de la fertilización con materia orgánica (MO) (0, 10,000, 20,000 y 30,000 kg MO ha-1 año-1 con estiércol bovino) o mineral (0, 120, 240 y 360 kg de N ha-1 año-1 utilizando urea) y la frecuencia de corte (anual y bianual) en la longitud, ancho, perímetro, e Índice del Área de Cladodio (IAC) en cladodios de nopal forrajero cv. Miúda (Nopalea cochenillifera Salm Dyck), y su relación con la productividad. El diseño experimental fue de bloques al azar, con el arreglo de parcelas sub-sub-divididas con cuatro repeticiones. La fertilización con 30,000 kg MO ha-1 año-1 incrementó el ancho y longitud de cladodio de 9.8 a 17.8 % respecto al tratamiento testigo. El perímetro de cladodio se incrementó proporcionalmente cuando aumentó la MO. El IAC fue 68.29 % mayor (con 25 970 kg ha-1) respecto al tratamiento testigo. La fertilización mineral sólo afectó el perímetro de cladodio en el corte anual con dosis de 120 kg ha-1 y el IAC fue mayor en el corte bianual. Se concluyó que la fertilización con MO aumentó el ancho, longitud e IAC en cladodios de nopal forrajero cv Miúda (Nopalea cochenillifera Salm Dyck), mientras que la fertilización mineral tuvo bajo impacto en el ancho, longitud e IAC, el corte bianual favorece el IAC. Se presentó una alta correlación entre las variables evaluadas y la producción de materia seca.

ABSTRACT The objective was to evaluate the effect of three stocking rates (2, 3.9, and 5.8 animal units ha−1) and three fertilization levels (0, 150, and 300 kg N ha−1 yr−1) on herbage mass and nutritive value of elephantgrass (Pennisetum purpureum Schum.) cv. IRI-381. The experiment was conducted from May to August of 2009 and 2010 in Itambé, PE, Brazil, during the rainy season. Treatments were allocated in a split-plot arrangement in a completely randomized block design. The variables measured included leaf mass (pre- and post-grazing), botanical composition, soil cover, leaf area index, light interception, leaf angle, and concentrations of dry matter, organic matter, N, and in vitro digestible dry matter. When fertilized with 300 kg N ha−1 yr−1, leaf mass reached 18,560 kg ha−1. Leaf area index decreased with increasing stocking rate. The relationship between sward height and light interception was R2 = 0.0126. Increased stocking rate resulted in greater contribution of signalgrass [Brachiaria decumbens (Stapf.) R.D. Webster] in the botanical composition, with a contribution up to 29% in 2010. Elephantgrass nutritive value is directly affected by the fertilization levels and stocking rate, with highest nutrient concentrations observed with 2 AU ha−1 and 300 kg N ha−1 yr−1.

RESUMO: Objetivou-se avaliar o potencial produtivo e a composição mineral da palma forrageira IPA-Sertânia (Nopalea cochenillifera Salm Dyck), em cultivo isolado e consorciada com leucena [Leucaena leucocephala (Lam.) de Wit.] ou gliricídia [Gliricidia sepium (Jacq.) Steud.], e adubada com as fontes de esterco bovino, ovino, caprino e cama de frango. O experimento foi conduzido na Estação Experimental do Instituto Agronômico de Pernambuco - IPA, em Caruaru. O delineamento foi casualizado em blocos, em parcelas subdivididas, com quatro repetições. As parcelas foram representadas pelos sistemas de cultivo e as subparcelas pelas fontes de esterco. A colheita da palma foi realizada aos dois anos de crescimento e analisada quanto à produção e aos teores de nitrogênio (N), fósforo (P), potássio (K), cálcio (Ca) e magnésio (Mg). Não foram observadas diferenças de produção da palma entre os sistemas de cultivo, atingindo valor médio de 22,1t ha-1 2 anos-1 de matéria seca (MS). Nos sistemas consorciados, a maior proximidade com as leguminosas incrementou a produção da palma, nos tratamentos com os estercos bovino e ovino, e elevou os teores de P, K e Mg, mas não os teores de N. A introdução de leguminosas arbóreas, juntamente com a aplicação dos estercos, contribui para elevar a produção e os níveis de nutrientes da palma IPA-Sertânia.

ABSTRACT: The objective of this study was to evaluate the productive potential and mineral composition of the forage cactus IPA-Sertânia (Nopalea cochenillifera Salm Dyck). This species was analyzed both in monoculture and intercropped with leucaena [Leucaena leucocephala (Lam.) De Wit.] and gliricidia [Gliricidia sepium (Jacq. Steud.], and was assessed with different sources of manure (cattle, sheep, goat, and broiler litter) serving as fertilizer. The experiment was conducted at the Experimental Station of the Instituto Agronômico de Pernambuco in Caruaru, PE, Brazil. Treatments were allocated in a split-plot arrangement in a randomized complete block design, with four replications. Main plots consisted of cropping systems, while the split-plots were dedicated to manure sources. Cactus harvest was carried out after two years of regrowth. Response variables included both production and nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg) concentrations. No differences were observed for cactus production between the cropping systems, with an average value of 22.1Mg dry matter ha-1 2 years-1. In the intercropped systems, greater proximity to the legumes increased the production of the cactus in the treatments with the cattle and sheep manure, and increased the concentrations of P, K, and Mg, but not of N. The introduction of tree legumes, along with the application of manure, contributes to an increase in production and nutrient concentration of IPA-Sertânia cactus.

Resumo: O objetivo deste trabalho foi caracterizar morfologicamente genótipos de capim-elefante (Pennisetum purpureum) e estimar as proporções de tecido de suas lâminas foliares, sob pastejo. Duas variedades altas (Elefante B e IRI-381) e três baixas (Mott, Taiwan A-146 2.37 e Taiwan A-146 2.114) foram avaliadas sob pastejo intermitente de ovelhas quanto às seguintes variáveis morfológicas: altura de planta, comprimento de entrenós e razão entre lâminas foliares e colmos. Além disso, foram estimadas as proporções dos seguintes tecidos da lâmina foliar: esclerênquima, epidermes adaxial e abaxial, células buliformes, feixes vasculares, floema, bainha vascular, xilema e mesófilo. As variedades baixas foram 28,6% menores do que as altas e apresentaram maiores razões entre lâminas foliares e colmos; Mott e Taiwan A-146 2.114 tiveram os menores entrenós de 3,9 e 4,7 cm, respectivamente, ao longo de dez ciclos de pastejo. Os clones diferiram quanto às proporções de tecidos da sua lâmina foliar, exceto para epiderme abaxial, floema e xilema. As diferenças nas características morfológicas indicam que os clones baixos Mott e Taiwan A-146 2.114 são melhores adaptados ao pastejo por ovelhas e, portanto, podem ser recomendados para o melhoramento de pastagens.

Abstract: The objective of this work was to characterize morphologically elephant grass (Pennisetum purpureum) genotypes and to estimate their proportions of leaf blade tissues under grazing. Two tall varieties (Elephant B and IRI-381) and three short ones (Mott, Taiwan A-146 2.37, and Taiwan A-146 2.114) were evaluated under intermittent sheep grazing as to the following morphological characteristics: plant height, internode length, and leaf blade/culm ratio. Moreover, the proportions of the following leaf blade tissues were estimated: sclerenchyma, adaxial and abaxial epidermis, bulliform cells, vascular bundles, phloem, vascular sheath, xylem, and mesophyll. The short varieties were 28.6% shorter than the tall ones and showed higher leaf blade/culm ratio; Mott and Taiwan A-146 2.114 had the shortest internodes of 3.9 and 4.7 cm, respectively, over ten grazing cycles. The clones differed regarding their proportions of leaf blade tissues, except for abaxial epidermis, phloem, and xylem. The differences in morphological characteristics indicate that the short clones Mott and Taiwan A-146 2.114 are better adapted to sheep grazing, and, therefore, may be recommended for the improvement of pastures.

Resumo: O objetivo deste trabalho foi caracterizar taninos condensados de seis leguminosas forrageiras e determinar sua atividade biológica. Os monômeros propelargonidina, prodelfinidina e procianidina foram analisados, assim como taninos condensados extraíveis (TCE), taninos condensados ligados a proteínas (TCLP) e ligados a fibras (TCLF), massa molecular, grau de polimerização, índice de polidispersão e atividade biológica, por meio de proteínas precipitadas por fenóis (PPF), em folhas das leguminosas Cajanus cajan, Gliricidia sepium, Stylosanthes capitata x Stylosanthes macrocephala (estilosantes), Flemingia macrophylla, Cratylia argentea e Mimosa caesalpiniifolia, e na casca desta última espécie. Foram observadas diferenças nas concentrações de TCE, TCLP, PPF e total de taninos condensados entre as espécies, mas não na de TCLF. O maior valor de TCLP ocorreu em F. macrophylla. O total de TC variou de não detectável em C. argentea à maior concentração em folhas de M. caesalpiniifolia, que contêm os maiores níveis de PPF. Não se observaram diferenças quanto ao grau de polimerização em estilosantes, F. macrophylla e M. caesalpiniifolia. Folhas de estilosantes, C. cajan e G. sepium, todas com total de TC entre 20 e 50 g kg-1, poderiam ser fontes benéficas de TC, se oferecidas como única fonte de alimentos em dietas de ruminantes. A proporção prodelfinidina:procianidina variou de 10:80 (stylo) a 65:35 (F. machrophylla), e a propelargonidina é determinada somente em C. argentea.

Abstract: The objective of this work was to characterize condensed tannins (CT) from six tropical forage legumes and to determine their biological activity. The monomers propelargonidin, prodelphinidin and procyanidin were analyzed, as well as extractable condensed tannin (ECT), protein-bound CT (PBCT) and fiber-bound CT (FBCT), molecular weight, degree of polymerization, polydispersity index, and biological activity by protein precipitate by phenols (PPP) of leaves of the legumes Cajanus cajan, Gliricidia sepium, Stylosanthes capitata x Stylosanthes macrocephala (stylo), Flemingia macrophylla, Cratylia argentea, and Mimosa caesalpiniifolia, and of the bark of this latter species. Differences were observed in the concentrations of ECT, PBCT, PPP, and total condensed tannin among species, but not in that of FBCT. The highest value of PBCT occurred in F. macrophylla. Total CT varied from nondetected concentration in C. argentea to the highest concentration in M. caesalpiniifolia leaves that contain the greatest levels of PPP. No differences were observed for polymerization degree in stylo, F. macrophylla, and M. caesalpiniifolia. Leaves of stylo, C. cajan, and G. sepium, all containing between 20 and 50 g kg-1 total CT, should be beneficial CT sources, if offered as sole feeds in ruminant diets. The ratio of prodelphinidin:procyanidin varies from 10:80 (stylo) to 65:35 (F. machrophylla), and propelargonidin is only determined in C. argentea.

Objetivou-se avaliar características morfológicas de clones de Panicum maximum durante o período de rebrota após a interrupção da irrigação. Os clones de Panicum foram coletados em Sergipe e em três locais de Pernambuco ("São Bento do Una", "Itambé" e "São João da Coroa Grande"), além das cultivares 'Mombaça', 'Tanzânia' e 'Massai'. Os tratamentos consistiram de sete clones submetidos a 7, 14, 21 ou 28 dias de suspensão da irrigação. O delineamento utilizado foi o inteiramente casualizado em arranjo fatorial 7 × 4 com quatro repetições. Foram avaliados o número de perfilhos, altura da planta, comprimento da lâmina foliar, número de folhas verdes por perfilho e número de folhas mortas por perfilho. O fator clone afetou significativamente o número de perfilhos por vaso e o número de folhas mortas por perfilho (P≤0,05). O clone de Sergipe produziu mais perfilhos (8.39) que os demais após 28 dias de interrupção da irrigação, enquanto a cultivar 'Mombaça' apresentou mais folhas mortas (5.39) após 7 dias sem irrigação. Em geral, a interrupção da irrigação por 28 dias resultou em plantas mais altas com lâminas foliares maiores e com número superior de folhas verdes por perfilho.

This study aimed to evaluate the morphological characteristics of Panicum maximum clones during the regrowth period following cessation of irrigation. Panicum clones were collected in Sergipe and in three Pernambuco locations (‘São Bento do Una’, ‘Itambé’ and ‘São João da Coroa Grande’), in addition to ‘Mombaça’, ‘Tanzânia’ and ‘Massai’ cultivars. The treatments consisted of seven clones, which were subjected to either 7, 14, 21 or 28 days of water suspension. The experimental design was completely randomized in a factorial 7 × 4 design, with four replicates. The morphological characteristics evaluated included the number of tillers, plant height, leaf blade length, number of green leaves per tiller and number of dead leaves per tiller. The clone factor significantly affected the number of tillers per pot and the number of dead leaves per tiller (P ≤ 0.05). The clone from Sergipe produced a greater number of tillers (8.39) than the other clones following 28 days of water suspension, while the ‘Mombaça’ cultivar had a greater number of dead leaves (5.39) after 7 days of water suspension. In general, the 28-day cessation of irrigation period resulted in taller plants with larger leaf blades and a greater number of green leaves per tiller.

Resumo: O objetivo deste trabalho foi estimar a repetibilidade (r) e o número de amostragens necessárias para mensurar o valor nutricional de quatro gramíneas forrageiras tropicais numa região semiárida. As gramíneas avaliadas foram Urochloa mosambicensis, Cenchrus ciliares, Digitaria pentzii e Megathyrsus maximus. As avaliações ocorreram sob duas condições de manejo da forragem: diferimento e pastejo. Amostras de forragem coletadas por pastejo simulado foram analisadas para matéria seca (MS), proteína bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), lignina e digestibilidade in vitro da MS (DIVMS). Para a análise de r e número de amostragens necessárias, utilizaram-se quatro métodos: análise de variância, componentes principais da matriz de covariância (CPCOV) e de correlação (CPCOR), e análise estrutural (AECOR). As espécies foram comparadas pela probabilidade da diferença, tendo-se utilizado o teste t. Para o método CPCOV, observa-se maior coeficiente de r, portanto, menor número de amostragens necessárias. A lignina é a característica que apresenta o maior número de amostragens necessárias. Em termos qualitativos, D. pentzii e M. maximus mostram melhores características entre as espécies forrageiras avaliadas.

Abstract: The objective of this work was to estimate the repeatability (r) and the number of samples required to measure the nutritional value of four warm-season forage grasses growing in a semiarid region. The grasses evaluated were Urochloa mosambicensis, Cenchrus ciliaris, Digitaria pentzii, and Megathyrsus maximus. Evaluations occurred under two forage management conditions: stockpiling and grazing. Hand-plucked forage samples were analyzed for dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, and in vitro DM digestibility (IVDMD). Four methods were used to estimate r and the number of samples required: analysis of variance, method of principal components based on the covariance (PCCOV) and the correlation (PCCOR) matrices, and structural analysis (EVCOR). Species were compared by the probability of the difference using the t-test. The method PCCOV presents the highest coefficient of repeatability and, therefore, a lower number of samples required. Lignin is the trait that have the highest number of samples required. In terms of qualitative traits, D. pentzii and M. maximus show the best forage qualities among the species evaluated.

ABSTRACT Tree legumes are an underexploited resource in warm-climate silvopastures. Perceived benefits of tree legumes include provisioning (browse/mast, timber, fuel, human food, natural medicines, and ornamentals), regulating (C sequestration, greenhouse gas mitigation, soil erosion control and riparian buffers, shade, windbreaks, and habitat for pollinators), supporting (biological N2-fixation, nutrient cycling, soil fertility and soil health, photosynthesis, and primary productivity), and cultural ecosystem services. Tree legumes, however, have not been assessed to the same extent as herbaceous legumes. Once tree legumes are established, they are often more persistent than most herbaceous legumes. There are limitations for extended research with tree legume silvopastures, but extensive research has been done in Africa and Australia and recent efforts have been reported in South America. Economic benefits must be demonstrated to land managers to increase adoption. These benefits are apparent in the research and successes already available, but more long-term research, including the livestock component is necessary. Other factors that reduce adoption include paucity of domesticated germplasm, lag in research/technology, challenges of multipurpose trees and management complexity, challenges to mechanization, dangers of invasive weeds, and social and cultural barriers. In the current scenario of climate change and the need to increase food security, tree legumes are a key component for the sustainable intensification of livestock systems in warm-climate regions.