Effect of the diameter of cuttings in the establishment of gliricidia (Gliricidia sepium)

This study aimed to evaluate the effects of diameter of Gliricidia sepium cuttings (6, 8 and 10 cm) on the number, diameter, and length of sprouts, 2 mo after planting in plants grown in nursery condition. These same attributes and plant survival rate were used in the evaluation conducted 4 mo after planting both in nursery and in the field. The experimental design was a randomized blocks with ten replicates. Results of the initial evaluation in the nursery showed that the cuttings of the largest diameter (10 cm) gave sprouts with the largest diameter and length in their upper 30 cm portion. At 4 mo, under field conditions the largest total number of sprouts was obtained with cuttings of 10 and 8 cm planted directly in the soil. A positive correlation (r = 0.99; P< 0.0001) was found between the number of sprouts located in the top 30 cm and plant survival rate (%) in the field. Independent of planting conditions, the survival rate of plants in the field was not affected by diameter of the cuttings and averaged 90%. In conclusion, gliricidia cuttings can be used for vegetative propagation by planting directly in the field without the nursery stage provided that the minimum cuttings diameter of 8 cm is observed

Shading effects on establishment of stylosanthes Campo Grande

There is increased interest in shading effects on establishment of forages, especially with regard to associations of forage species and trees in sylvopastoral systems. The object of this study was to evaluate the influence of four levels (0, 25, 50, and 75%) of artificial shading on the 16 variables: plant height (PH), root dry matter (RDM) , stem dry matter(SDM) , leaf dry matter (LDM), aerial parts dry matter (APDM), total plant dry matter (TPDM), nodules dry matter (NDM), aerial parts: root ratio (AP/R), leaf:stem ratio (L/S), number of leaves (NL), leaf area (LA), specific leaf area (SLA), leaf area ratio (LAR), root matter ratio (RMR), stem matter ratio (SMR), and leaf matter ratio (LMR), in the establishment phase of stylosanthes Campo Grande plants (seed mixture of 80% Stylosanthes macrocepha and 20% S. capitata). The experimental design was a randomized blocks with three replications. The highest values for PH, SDM, LDM, APDM, TPDM, NL, and LA of stylosanthes Campo Grande were obtained with 75% shading and this level is recommended for use in pastoral-forest and agropastoral-forest systems

Effect of shading on the initial growth of Massaigrass (Panicum maximum)

The objective of this research was to evaluate the influence of four levels (0, 25, 50, and 75%) of artificial shading on 12 attributes (plant height - PH, number of tiller – NT, number of leaves – NL, leaf area – LA, root dry matter – DMR, leaf dry matter – DML, total dry matter – DMT, ratio of aerial part: root – AP/R, specific leaf area - SLA, ratio of leaf area – RLA, ratio of root matter – RRM, and ratio of leaf matter – RLM), in the establishment phase of Massai grass plants. The experimental design was randomized blocks with three replications. The highest values for PH, NT, DMR, DML, DMT and RRM of Massai grass were obtained at the level of 75% of shading, indicating suitability of its use in pastoral-forest or agropastoral-forest systems

Effect of shading on the establishment of Panicum maximum cv. Mombaça

Interest in studying forage establishment in the shade has increased, principally when the intention is to associate forage species and trees to constitute sylvopastoral systems. The objective of this research was to evaluate the influence of four levels (0, 25, 50, and 75%) of artificial shading on 12 variables: plant height (PH), number of tiller (NT), number of leaves (NL), leaf area (LA), dry matter of roots (DMR), dry matter of leaves (DML), dry matter total (DMT), leaf area (LA), specific leaf area (SLA), ratio of leaf area (RLA), of root matter (RRM) and of leaf matter (RLM), in the establishment phase of Mombaça grass. The experimental design was randomized blocks with three replications. The results showed that the highest values for PH and DML (by univariate analysis of variance and regression analysis), LA, and DMT (by regression analysis) and NT and DMR (by high tendency) of Mombaça grass were obtained at the level of 75% of shading. Thus the authors recommend this level of shading to be used in pastoral-forest or agropastoral-forest systems

Estabelecimento de leguminosas arbóreas em pastos de capim-marandu e tanzânia

The objective of this work was to evaluate the performance of nonprotected (by fences or pickets) seedlings of leguminous tree species and an equitable mix of these species, introduced in pastures of Brachiaria  brizantha cv. Marandu and Panicum maximum cv. Tanzânia, in the presence of cattle. The experimental design was a completely randomized one, in a 2x5 factorial arrangement, with two grasses (marandu and tanzânia) and four leguminous species (Mimosa artemisiana, Pseudomanea guachapele, Enterolobium contortisiliquum,Acacia  farnesiana), and a mix of these species, with three replicates. Evaluations were made for: seedling height, stem diameter, canopy diameter, seedling survival, pasture frequency and ant occurrence. The statistical difference between the means of the main canonical variable, by the test of Scott-Knott, indicated the formation of three groups, standing out the one formed by M. artemisiana and mixture of leguminous in the two pastures, plus E. contortisiliquum and A. farnesiana in pastures of marandu and tanzânia grass, respectively. Differences between the means of treatments for each variable, calculated by means of Bonferroni’s intervals of confi dence,showed that M. artemisiana presented the greatest height and seedling survival in the pasture of marandu grass. This leguminous seedlings, without protection, are indicated to be introduced in pastures of marandu grass in the region, in the presence of cattle.O objetivo deste trabalho foi avaliar o desempenho de mudas sem proteção (de cercas ou estacas) de quatro espécies de leguminosas arbóreas e uma mistura eqüitativa dessas espécies, introduzidas em pastagens de Brachiaria brizantha cv. Marandu e Panicum maximum cv. Tanzânia, na presença de gado. O delineamento experimental foi o inteiramente ao acaso, em esquema fatorial 2x5, duas gramíneas (marandu e tanzânia) e quatro espécies de leguminosas (Mimosa artemisiana, Pseudosamanea guachapele, Enterolobium contortisiliquum, Acacia farnesiana e uma mistura dessas espécies), com três repetições. Avaliaram-se: altura da muda, diâmetro do caule, diâmetro da copa, sobrevivência da muda, freqüência de pastejo e ocorrência de formigas. As diferenças estatísticas entre as médias da variável canônica principal, pelo teste de Scott-Knott, indicaram a formação de três agrupamentos, tendo-se destacado o grupo formado pelos tratamentos M.  artemisiana e mistura de leguminosas, nos dois pastos, mais E.  contortisiliquum e A.  farnesiana, nos pastos dos capins marandu e tanzânia, respectivamente. Diferenças entre as médias dos tratamentos relativas a cada variável, calculadas por meio de intervalos de confi ança de Bonferroni, mostraram que mudas de M. artemisiana apresentaram maior altura e sobrevivência em pasto de capim-marandu. Mudas dessa leguminosa, sem proteção, são indicadas para ser introduzidas, nas pastagens de capim-marandu da região, na presença do gado

Evaluation of thermal comfort in a silvipastoral system in a tropical environment

The use of trees in silvipastoral systems can improve quality of the microclimate and thermal comfort of animals. The object of this research was to compare differences in microclimatic conditions in three environments (under the canopy of trees of the species Acacia holosericea, in the space between rows of trees and in full sunlight in monoculture grass) of a sylvopastoral system, at three hours of the day (9:00, 12:00, and 15:00), in two seasons of the year (dry = winter and wet = summer), in the municipality of Seropédica, RJ. The statistical design was randomized complete blocks in which environment represented the main plots and hour of day and season of year were split plots, with four replications. The nine microclimatic variables studied were: black globe temperature (bgt), dry bulb temperature (dbt), humid bulb temperature (hbt), maximum daily temperature (MaxT), minimum temperature (MinT), air velocity (av), temperature humidity index (THI), black globe humidity index (BGHI), and radiant thermal load (RTL). Results showed that the values of bgt, hbt, THI, and BGHI were lower in the dry than the wet season. BGHI was lower in the morning and afternoon than at noon, correlated with THI (r = 0.85) and was shown to be more precise than the latter as an indicator of thermal comfort. The tree canopy reduced the heat load that the animal would feel by 26% compared with the full sunlight environment

Diurnal ingestion behavior of crossbred heifers in a sylvanpastoral system in a tropical region

Knowledge of the ingestive habits of animals enables better adjustment of their management, resulting in enhanced production. The objective of this research was to compare the effects of two pastoral systems (sylvanpastoral and monocultural) in Brachiaria brizantha cv. Marandu forage, two seasons of the year (rainy summer and dry winter), and two diurnal periods (morning and afternoon). Five parameters of diurnal behavior were observed (grazing, standing rumination, decumbent rumination, standing at rest, and decumbent rest) in ¾ Holstein-Zebu heifers. The results showed that grazing and rumination and rest while standing were more frequent during the dry season; grazing of the Marandu grass was more frequently observed under the sylvanpastoral system compared to the monoculture pasture without shade, whereas the opposite was true of rumination and rest while standing; finally standing and decumbent rumination were more frequent in the afternoon than in the morning. The sylvanpastoral system and the dry season promoted more frequent grazing and also better quality of the grass forage, while improving the thermal comfort of the animals, which are positive effects from the standpoint of livestock production and pasture sustainability

Seleção de acessos de tomateiro resistentes à pinta-preta pela análise de agrupamento das curvas de progresso da doença

O objetivo deste trabalho foi selecionar acessos resistentes à pinta-preta (Alternaria tomatophila) por meio da análise de agrupamento das curvas de progresso da doença em tomateiro (Solanum lycopersicum). Foram avaliados 134 acessos de tomateiro do Banco de Germoplasma de Hortaliças da Universidade Federal de Viçosa (BGH-UFV), no delineamento de blocos ao acaso, além das testemunhas suscetíveis 'Débora' e 'Santa Clara'. As plantas foram inoculadas com uma mistura de conídios de diferentes isolados de Alternaria spp. e avaliadas regularmente quanto à severidade da doença a cada três dias após a inoculação, no total de seis avaliações. Ajustou-se o modelo logístico aos dados de severidade da pinta-preta, e as estimativas obtidas para a incidência final da doença (B1) e a taxa de progresso da doença (B3) foram submetidas à análise de variância multivariada (Manova). As médias dessas estimativas, para cada acesso, foram submetidas à análise de agrupamento. Foram formados 24 grupos distintos com base no agrupamento das curvas de progresso da doença, o que possibilitou identificar os acessos BGH-2143, BGH-2235, BGH-2270 e BGH-2118 de tomateiro como potenciais fontes de resistência à pinta-preta

Óleo essencial de alecrim no controle de doenças e na indução de resistência em videira

O objetivo deste trabalho foi determinar as características químicas do óleo essencial de alecrim e o seu efeito na produtividade, no controle da mancha da folha e do míldio, e na indução de resistência em videira 'Isabel'. O experimento foi realizado em vinhedo comercial, em dois ciclos consecutivos. Os tratamentos consistiram das doses do óleo essencial: 0, 500, 1.000, 2.000 e 4.000 µL L-1, além dos tratamentos Tween 80%, calda bordalesa, acibenzolar-S-metil e mancozebe. Foram avaliados a severidade da mancha da folha e do míldio, a atividade das enzimas quitinase e catalase, a massa e o número de cachos e as características químicas das uvas. Houve efeito quadrático das doses do óleo essencial de alecrim, para severidade da mancha da folha e do míldio da videira, nos dois ciclos, com resultados semelhantes aos dos tratamentos com calda bordalesa, acibenzolar-S-metil e mancozeb. Também houve aumento no número e na massa dos cachos, bem como na produtividade. O óleo essencial não interferiu nas características químicas das uvas. Observaram-se aumento na atividade da enzima quitinase e redução na atividade da catalase nas folhas. O óleo essencial nas doses de 500, 1.000 e 2.000 μL L-1 é uma alternativa para o controle de doenças da videira 'Isabel'