Alexandre Carneiro Leão de Mello

Produtividade e composição química de gramíneas tropicais na Zona da Mata de Pernambuco

This work was carried out to evaluate the productive potencial and chemical composition of five grasses (Pennisetum purpureum Schum. cv. Pioneiro, P. purpureum Schum cv. Mott; Panicum maximum Jacq. cv. Mombaca, P. maximum Jacq cv. Tanzânia, e Brachiaria brizantha (Hochst) Stapf. cv. Marandu). The cuts were performed at 35 days of intervals and 40 cm above ground. Pioneiro showed higher DM yield (7.35 t DM/ha/35 days) when compared to the Dwarf Elephantgrass (5.28 t DM/ha/35 days) and Tanzânia grass (5.23 t DM/ha/35 days), being similar to the others. Brachiaria brizantha presented the highest total tillering (538.72/m²) however the aerial tiller weight was the lowest for this species. The cultivars of P. purpureum showed higher aerial tillering and lower basal tillering, when compared to the cultivars of P. maximum. The CP concentration ranged from 6.96 to 10.20% and the cultivar Pioneiro presented the highest value. No difference was found among the forages for NDF and ADF, and the mean values were 73.83 and 39.20%, respectively. At the evaluated cut interval, the forages presented a high proportion of leaves (> 80%), showing potential to be used on livestock pasture-based operations in the Forest Zone of Pernambuco.

Respostas morfológicas do capim-Tanzânia (Panicum maximum Jacq. cv. Tanzânia-1) irrigado à intensidade de desfolha sob lotação rotacionada

Objetivando quantificar respostas morfologicas de dosseis de capim-Tanzânia (Panicum maximum Jacq. cv. Tanzânia-1) sob tres intensidades de pastejo, lotacao rotacionada e irrigacao, foi conduzido um experimento em delineamento experimental de blocos completos casualizados com quatro repeticoes. Os tratamentos foram tres intensidades de pastejo, representados pelas quantidades de massa seca verde residual pos-pastejo (T1=1000; T2=2500 e T3=4000 kg MSV/ha). Durante oito ciclos de pastejo (rebrotas de 33 dias apos tres dias de pastejo em cada ciclo), foram realizadas avaliacoes de altura media do dossel, indice de area foliar (IAF), interceptacao luminosa (IL) e ângulos foliares medios, em quatro dias dentro do periodo de rebrota (1, 11, 22 e 33 dias apos a saida dos animais). A analise de correlacoes parciais indicou correlacoes entre altura e IL, bem como entre IAF e IL. Com o progresso da estacao de pastejo, da primavera-verao para outono-inverno, houve reducoes nos valores de IAF medio. Valores medios de IAF critico (95% IL) de 3,6 (T1), 4,0 (T2) e 4,5 (T3), foram alcancados por volta do 22o dia das rebrotas. A maior intensidade de pastejo (menor residuo) alterou a estrutura da pastagem no que diz respeito a arquitetura do dossel, evidenciada pela reducao nos ângulos foliares medios (folhas mais horizontais) ao longo das estacoes, com plantas passando a interceptar mais luz por unidade de area foliar. Os IAFs criticos medidos sugerem a necessidade de periodos de descanso menores que 33 dias em pastos de capim-Tanzânia, quando submetido a pastejo intensivo sob lotacao rotacionada e irrigacao.

Potential of Caatinga forage plants in ruminant feeding

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.

Caracterização e Seleção de Clones de Capim-Elefante (Pennisetum purpureum Schum.) na Zona da Mata de Pernambuco

This work aimed to characterize an elephantgrass collection (Pennisetum purpureum Schum.) comprising 71 clones and selecting the best ones to be tested later under grazing conditions. It was carried out at Cedro Experimental Station - IPA, located in Vitoria de Santo Antao, forest zone of Pernambuco State. The period of evaluation included both the raining and the dry season. Each clone was represented by a non-replicated plot of 10 m2. According to linear correlation analysis, the more productive clones also showed highest plant height and highest growing point height, greatest stem diameter, highest stem/leaf ratio, highest basal and total tiller numbers and greatest leaf lenght. The same characteristics above were also positively correlated with the leaf blade yield, except stem/leaf ratio. There was a high correlation coefficient (r = 0.9517) between dry matter yield and leaf blade yield. The selection of clones to be tested under grazing conditions was based on the materials that showed the highest leaf blade yield. These materials were: Mineirao/IPEACO, Hexaploide, Mole de Volta Grande, King Grass, 591-76 or Cameroon, CE 5 AD, Gigante de Pinda, CE 4 AD, Elefante da Colombia and Vrukwona

Fotossíntese e taxa diária de produção de forragem em pastagens de capim-tanzânia sob lotação intermitente

The objective of this study was to evaluate the effects of grazing intensity on forage accumulation rate and on net leaf photosynthesis of Tanzania guinea grass (Panicum maximum Jacq.) pastures under rotational stocking. The experiment was carried out from November 1999 to October 2000, in a randomized complete block experimental design, with four replications. Treatments were three levels of residual green forage biomass (1,000, 2,500, and 4,000 kg ha -1) in grazing cycles of 36 days (33 days of rest and 3 days of grazing). Forage accumulation rate was not affected by grazing intensities, and it was highest in the first 11 days of regrowth during the periods of the highest temperatures. Net leaf photosynthesis was not affected by grazing intensity (mean 23.2 µmol m -2 s -1 CO2) and increased during regrowth with the highest values between the 11th and the 22nd days of rest, depending on the season of the year. Net leaf photosynthesis was correlated with sward structure changes, during leaf development. The use of fixed rest periods avoided alterations of forage accumulation rate caused by grazing intensity.

Relação entre características morfológicas e produtivas de clones de palma-forrageira

This research evaluated the relationship among the morphological and productive characteristics of clones of cactus forage for identification of those that directly contribute to the production. It was evaluated 50 clones of cactus forage planted five years ago and submitted to the first cut two years before the evaluation. Characteristics of the plant and of the cladode were evaluated and data were analyzed by descriptive characteristics, Pearson correlation and by path analysis of the explanatory independent variables on the dry matter production in t/ha/2 years (main dependent variable). Production varied among clones and it was the highest in clones 8, 782 e 418 whose dry matter production was of 40.8; 18.1 and 12.1 tMS/ha/2 years, respectively. There was a low correlation among almost all the explanatory variables and the production considered main variable, so, association of characteristics was needed. Characteristic height associated with plant width explained better the potential of dry matter production in t/ha/2 years because they presented a high correlation with production (r = 0.71) and the highest direct effect (0.69). Indirect and non destructive selection for production have to be based on higher and larger plants.

Elephant grass clones for silage production

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.

Association between the morphological and productive characteristics in the selection of elephant grass 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 Mexico 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.

Soil characteristics under legume and non-legume tree canopies in signalgrass (Brachiaria decumbens) pastures

Tree canopies can change soil environments. Our study looked at soils 10%, 50%, 100% and 150% the distance from tree trunk to canopy edge of leguminous sabiá (Mimosa caesalpiniifolia Benth.) and espinheiro (Machaerium aculeatum Raddi) and non-legume cajueiro (Anacardium occidentale L.) and jaqueira (Artocarpus integrifolia L.) in a signalgrass (Brachiaria decumbens Stapf) pasture. Composite soil samples were collected from the 0 to 10 cm soil layer. Clay concentration increased (P ≤ 0.05) with distance from tree trunk to full sunlight, whereas CO2 emission, phosphorus, and organic matter from soil collected under tree canopies were inversely proportional (P ≤ 0.05) to distance from the tree trunk. Soil under the canopy of espinheiro had greater (P ≤ 0.05) concentrations of exchangeable cations than the non-legume trees. Pearl millet [Pennisetum americanum (L.) Leeke] grown in soils collected under tree canopies had 24% greater (P ≤ 0.05) dry matter (DM) yields than those grown in full sunlight. Soil collected under cajueiro grew 100% greater (P ≤ 0.05) pearl millet DM yields than jaqueira, whereas soil collected under sabiá produced the least (P ≤ 0.05) pearl millet DM. Tree canopy had a positive effect on soil fertility and leguminous tree canopies tended to improve soil properties more than non-legumes.

Repetibilidade e respostas de características morfofisiológicas e produtivas de capim-elefante de porte baixo sob pastejo

The objective of this study was to estimate the coefficients of repeatability and determination (R2) and the minimum number of measurements necessary to predict the real value of morphophysiological and yield variables, as well as the responses to sheep-grazing of dwarf elephant grass pasture. The experiment was carried out in a randomized block design with five treatments - Taiwan A-146 2.27, Taiwan A-146 2.37, Taiwan A-146 2.114, Merker Mexico MX 6.31 and Mott - and four replicates, over five grazing cycles, between September 2008 and April 2009. Mean sward height, leaf area index (LAI), light interception (LI), mean leaf angles (MLA), silage accumulation (SA) and silage accumulation rate (SAR) were evaluated. For the variables LAI, IL and mean sward height of plants, in long cycles, only one measurement was necessary (R2 = 80%) to place them among the most predictable characteristics in the evaluation of elephant grass clones. Assessments for SA and SAR need longer experimental periods for greater reliability in the estimation of response variables. In dwarf elephant grass, light interception increases with sward height and LAI.