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 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 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.

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.

As pastagens formam a base da pecuária brasileira; essas sofrem degradação em larga escala por deficiência de nitrogênio (N). O consórcio com leguminosas, além de fixar N, pode apresentar outros efeitos na fertilidade do solo como acidificação ou retirada de nutrientes de camadas mais profundas para as mais superficiais. Este trabalho objetivou avaliar o estoque de serapilheira e a fertilidade do solo em pastagens degradadas de braquiária (Brachiaria decumbens), após implantar leguminosas arbustivas e arbóreas forrageiras. Para isso, uma amostragem foi realizada em março de 2010 em um experimento no campo, introduzindo pastagem degradada de Brachiaria decumbens, em julho de 2008, com sabiá (Mimosa caesalpiniifolia), leucena (Leucaena leucocephala), mororó (Bauhinia cheilantha) e gliricídia (Gliricidia sepium), além de braquiária adubada e não adubada com N. As amostras de solo e serapilheira foram coletadas aos 0-10, 10-20 e 20-40 cm de profundidade, em três transectos, alternando pontos cobertos por gramíneas e leguminosas, totalizando sete amostras compostas por parcela para determinar pH, P, K, Ca, Mg e Al no solo, enquanto SB, t e m foram calculados. A serapilheira foi separada visualmente em leguminosas, gramíneas e materiais não identificados, em que foram utilizados para quantificação de matéria seca, matéria orgânica, N, P, C, fibra detergente ácido e lignina. A introdução das leguminosas aumentou os teores de N total na serapilheira e reduziu as relações C:N, com destaque para gliricídia e sabiá; entretanto, essa última apresentou elevados teores de lignina. Houve efeito significativo da cobertura por leguminosas, sem diferenças entre essas, para pH e K, na profundidade de 0-10 cm, e para Al e m, aos 10-20 cm de profundidade.

Pastures are the fodder supply of Brazilian livestock, and are exhaustively degraded by nitrogen (N) deficiency. Intercropping with legumes, aside from nitrogen fixation, may have secondary effects on soil fertility, such as acidification or nutrient movement from deeper to the surface soil layers. This study evaluated the soil litter stock and fertility of degraded Brachiaria decumbens pastures after planting leguminous shrubs and forage trees. For this purpose, we sampled (March 2010) degraded Brachiaria decumbens pasture planted in July 2008 in an intercropping experiment with sabiá (Mimosa caesalpiniaefolia), leucaena (Leucaena leucocephala), mororó (Bauhinia cheilantha) and gliricidia (Gliricidia sepium), as well as N-fertilized and unfertilized brachiaria. Soil and litter was sampled (layers 0-10, 10-20 and 20-40 cm) in three transects, at alternating points covered by grasses and by legumes, totaling seven composite samples per plot to determine soil pH, P, K , Ca, Mg, and Al and calculate sum of bases, effective cation exchange capacity and aluminum saturation. Litter was visually separated in legumes, grasses and unidentified material to quantify dry matter, organic matter, N, P, C, acid-detergent fiber, and lignin. The use of legumes increased the levels of total N in litter and reduced the C: N ratios, especially of gliricidia and sabiá, although the lignin levels in the latter were high. There was a significant effect of legume soil cover, with no differences between them, on pH and K (layer 0-10 cm) and on pH, K and Al (layer 10-20 cm).

Ensiling warm-season grasses often requires wilting due to their high moisture content, and the presence of low-soluble sugars in these grasses usually demands the use of additives during the ensiling process. This study evaluated the bromatological composition of the fodder and silage from five Pennisetum sp. clones (IPA HV 241, IPA/UFRPE Taiwan A-146 2.114, IPA/UFRPE Taiwan A-146 2.37, Elephant B, and Mott). The contents of 20 Polyvinyl chloride (PVC) silos, which were opened after 90 days of storage, were used for the bromatological analysis and the evaluation of the pH, nitrogen, ammonia, buffer capacity, soluble carbohydrates, and fermentation coefficients. The effluent losses, gases and dry matter recovery were also calculated. Although differences were observed among the clones (p < 0.05) for the concentrations of dry matter, insoluble nitrogen in acid detergents, insoluble nitrogen in neutral detergents, soluble carbohydrates, fermentation coefficients, and in vitro digestibility in the forage before ensiling, no differences were observed for most of these variables after ensiling. All of the clones were efficient in the fermentation process. The IPA/UFRPE TAIWAN A-146 2.37 clone, however, presented a higher dry matter concentration and the best fermentation coefficient, resulting in a better silage quality, compared to the other clones.

Este estudo foi realizado com o objetivo de avaliar a dinâmica da associação capim-de-raiz (Chloris orthonoton Doell) e capim-milhã [Brachiaria plantaginea (Link) Hitchc] quanto à persistência e produção. Em pasto nativo diferido, foram realizadas a coleta do material botânico, avaliação da composição botânica e massa de forragem. Para estimativa da massa de forragem, utilizou-se delineamento de blocos ao acaso, com quatro tratamentos; 60, 90, 120 e 150 dias de diferimento; e cinco repetições. Na composição botânica, expressa em percentual do total, foram identificadas 10 famílias, 15 gêneros e 18 espécies. No período de maio a agosto de 2007, o capim-milhã foi o componente principal dos 60 aos 90 dias, correspondendo a 46,75 e 52,09%, respectivamente, da composição botânica total. Em agosto de 2007, outras espécies participaram com 57,75% da composição botânica. No ano de 2008, ao final do período de diferimento, outras espécies ocuparam 100% da composição botânica do pasto. As maiores massas de forragem (kg de MS/ha) para o capim-milhã (2.736) foram aos 90 dias, para outras espécies (3.141) e capim-de-raiz (2.701) aos 120 dias. O aproveitamento da forragem acumulada deve ocorrer preferencialmente dos 60 aos 90 dias. Após um ano sem interferência, o capim-de-raiz e o capim-milhã diminuem a participação na composição botânica do pasto.

This study aimed to evaluate the dynamics of the association of 'capim-de-raiz' (Chloris orthonoton Doell) and alexandergrass [Brachiaria plantaginea (Link) Hitchc], as for persistence and production. Gathering of botanical material, evaluation of botanical composition and forage mass were realized in deferred native pastures. To estimate forage mass, a randomized block design with four treatments was used, consisting of 60, 90, 120 and 150 days of deferring and five replications. The botanical composition was expressed as a percentage of the total. Ten families, 15 genera, and 18 species were identified. In the botanical composition from May to August 2007, alexandergrass was the main component from 60 to 90 days, corresponding to 46.75 and 52.09%, respectively. In August 2007, other species participated with 57.75% of the botanical composition. In the assessment of the year 2008, at the end of the deferring period, other species occupied 100% of the botanical composition of pasture. The highest forage mass (kg DM/ha) for alexandergrass (2,736) occurred at 90 days; for other species (3,141) and 'capim-de-raiz' (2,701), it was at 120 days. The use of stockpiled forage should preferably take place after 60 to 90 days of deferring. After a year without interference, 'capim-de-raiz' and alexandergrass decrease participation in the botanical composition of pasture.

Os objetivos neste trabalho foram estudar a associação entre características morfológicas e produtivas em clones de Pennisetum sp. e identificar as características morfológicas responsáveis pela produtividade em clones de Pennisetum sp. Foram avaliadas as correlações canônicas e feita análise de trilha a partir da matriz de correlações genotípicas simples entre características morfológicas e produtivas de oito clones de Pennisetum sp. (Taiwan A-146 2.37, Taiwan A-146 2.27, Taiwan-146 2.114, Merker México MX 6.31, Mott, HV-241, Elefante B e IRI-381). As correlações canônicas foram significativas a 1% de probabilidade pelo teste do qui-quadrado. O primeiro par de fatores canônicos, com correlação de 0,9999, associou plantas com maior teor de matéria seca a plantas com menores índices de área foliar, interceptação luminosa e ângulo foliar. O segundo par de fatores canônicos, com correlação de 0,9999, associou plantas com maior produção de matéria seca a plantas com maior densidade de perfilhos basais, altura, e menor número de folhas verdes por perfilho. Os resultados da análise de trilha indicaram que a interceptação luminosa é determinante na expressão do teor de matéria seca de clones de Pennisetum sp., enquanto a densidade de perfilhos basais e a altura da planta são responsáveis pela produção de matéria seca nesses clones.

The objectives in this work were to study the association between the morphological and productive characteristics in Pennisetum sp. clones, and to identify the morphological characteristics responsible for the productivity in Pennisetum cp. clones. The canonical correlations were evaluated and the path analysis was made from the simple genotypic correlation matrix between the morphological and productive characteristics of eight Pennisetum sp. clones (Taiwan A-146 2.37, Taiwan A-146 2.27, Taiwan-146 2.114, Merker México MX 6.31, Mott, HV-241, Elefante B and IRI-381). The canonical correlations were significant at 1% probability by the Chi-square test. The first pair of canonic factors, with correlation of 0.9999, related the plants with the highest dry matter content to plants with lower leaf area indexes, light perception and leaf angle. The second pair of canonic factors, with correlation of 0.9999, related the plants with the highest dry matter production to the plants with higher basal tiller density, height, and low green leaf number per tiller. The results of the path analysis indicated that the light interception is determinant in dry matter content expression of Pennisetum sp. clones, while the basal tiller density and plant height are responsible for dry matter production in these clones.

Considerando a importância do bioma Caatinga na pecuária da região semiárida brasileira, o presente trabalho objetivou apresentar informações sobre diferentes aspectos forrageiros de plantas da caatinga, com vistas à alimentação de ruminantes. A vegetação de caatinga é constituída por arbustos e árvores de pequeno porte, geralmente dotados de espinhos, sendo caducifólias, em sua maioria, perdendo suas folhas no início da estação seca. Complementam ainda a composição botânica desse bioma, cactáceas, bromeliáceas e um componente herbáceo, formado por gramíneas e dicotiledôneas, predominantemente anuais. Informações, principalmente sobre o aspecto quantitativo de plantas da caatinga, notadamente para o estrato herbáceo ainda são escassas. Dificuldades e desuniformidade de metodologias de avaliação, além de falta de detalhamento das metodologias utilizadas, dificultam a comparação de resultados quanto ao potencial forrageiro de algumas plantas. A fixação biológica de N atmosférico por espécies da caatinga até o momento foi pouco estudada, notadamente quanto aos aspectos quantitativos. Faz-se necessária uma avaliação mais profunda sobre a disponibilidade do nitrogênio, uma vez que parte deste pode estar ligado a parede celular (NIDA). A manipulação da caatinga é uma alternativa para modificar a quantidade e qualidade da forragem disponível aos animais, conseqüentemente modificar o desempenho animal. Estudos que mensurem as variações qualitativas e quantitativas das forrageiras nativas da Caatinga são primordiais para o manejo de suplementação alimentar, com vistas à sustentabilidade de produção animal em áreas de Caatinga.

Caatinga is the most important biome for the livestock in the Brazilian semi-arid region. This review paper aimed to present information on different forage aspects of caatinga vegetation for ruminant feeding. Caatinga vegetation is formed mainly by shrubs and small trees, usually presenting thorns, deciduous leaves, and leaf abscission occurring frequently at the onset of the dry season. Additional components of the botanical composition in this biome includes the families cactaceae, bromeliaceae, and a herbaceous component formed by grasses, legumes, and forbs, often presenting annual cycle. Quantitative information of caatinga vegetation is scarce in the literature, mainly for the herbaceous stratum. Methodological aspects such as lack of standardization across evaluations make comparison regarding forage potential of caatinga plant species difficult. Index species must be identified within each caatinga type. Quantitative aspects of biological N2 fixation by caatinga species have not been extensively studied. Regarding forage nutritive value, it is necessary to study N availability for ruminants in caatinga plants, since large proportion of this element may bind to fiber components (ADIN). Manipulation of caatinga vegetation is an alternative to change forage quantity and quality for grazing animals, affecting their performance as a result. Studies measuring qualitative and quantitative variability of native forage resources from caatinga are mandatory in order to improve animal feeding management, with the ultimate goal of creating sustainable animal production based on caatinga vegetation.