Reguladores de crescimento no desenvolvimento de diferentes espécies de grama

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desenvolvimento de grama-esmeralda, grama-bermudas 'Tifway 419' e 'Celebration' submetidas a aplicação de reguladores de crescimento

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Determinação da fase lactente-ruminante de cordeiros pela técnica do delta 13C

This study was conducted at University of Marília, São Paulo State, Brazil, aiming to determine the phase of intake transition between exclusively liquid diet (milk) and diet based on milk, grass and/or ration by lambs by δ13C technique. Six Suffolk crossbreeding lambs were distributed in a totally random design (3x2), with two experimental groups and three replications. At the first one, lambs were penned and sucked milk from dams fed with C4 diet. besides, they had access to C3 ration in creep feeding, since their birth. At the second group, lambs were kept on a paddock with Tifton – 85 grass (C4 photosynthetic way) as well as their dams and had access to C3 ration in creep feeding, since their birth. The C3 ration contained soybean meal, ground oat grains, lucerne hay and also mineral salt. The penned lambs’ ration consumption overcame the milk intake at 30-35 days after birth; however, grazing lambs ingested more milk and pasture than ration until 40 days after birth. The δ 13C technique was considered effective on studies of lambs feeding behavior.

Efficiency of nitrogen sources and rates on growth and dry matter yield of tifton 85

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Condições de luminosidade e substratos no desenvolvimento de grama bermuda

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Condições de luminosidade e substratos no desenvolvimento de grama bermuda

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comparative in vitro evaluation of forage legumes (prosopis, acacia, atriplex, and leucaena) on ruminal fermentation and methanogenesis

Two experiments in vitro were conducted to evaluate four Egyptian forage legume browses, i.e., leaves of prosopis (Prosopis juliflora), acacia (Acacia saligna), atriplex (A triplex halimus), and leucaena (Leucaena leucocephala), in comparison with Tifton (Cynodon sp.) grass hay for their gas production, methanogenic potential, and ruminal fermentation using a semi-automatic system for gas production (first experiment) and for ruminal and post ruminal protein degradability (second experiment). Acacia and leucaena showed pronounced methane inhibition compared with Tifton, while prosopis and leucaena decreased the acetate:propionate ratio (P<0.01). Acacia and leucaena presented a lower (P<0.01) ruminal NH3-N concentration associated with the decreasing (P<0.01) ruminal protein degradability. Leucaena, however, showed higher (P<0.01) intestinal protein digestibility than acacia. This study suggests that the potential methanogenic properties of leguminous browses may be related not only to tannin content, but also to other factors.

Soil compressibility and least limiting water range of a constructed soil under cover crops after coal mining in Southern Brazil

The use of cover crops affects the support capacity of soil and least limiting water range to crop growth. The objective of this study was to quantify preconsolidation pressure (sigma(p)), compression index (CI) and least limiting water range (LLWR) of a reclaimed coal mining soil under different cover crops, in Candiota, RS, Brazil. In the experiment, with randomized blocks design and four replicates, the following cover crops (treatments) were evaluated: Hemarthria altissima (Poir.) Stapf & C.E. Hubbard, treatment 1 (T1), Paspalum notatum Flugge, treatment 4 (T4), Cynodon dactilon (L) Pers., treatment 5 (T5), control Brachiaria brizantha (Hochst.) Stapf, treatment 7 (T7) and without cover crop treatment 8 (reference treatment, T8). Soil compression and least limiting water range were evaluated with undisturbed samples at a depth of 0.00-0.05 m. In order to evaluate parameters of soil compressibility, the soil samples were saturated with water and subjected to -10 kPa matric potential and then submitted to a uniaxial compression test under the following pressures: 25, 50, 100, 200, 400, 800 and 1600 kPa. Cover crops decreased the preconsolidation pressure of constructed soils after coal mining and the greatest soil reclamation was obtained with the H. altissima cover crop, where the lowest degree of soil compactness and soil load capacity were observed. Soils cultivated under H. altissima or B. brizantha presented the highest least limiting water range and these two cover crops generated similar soil critical bulk density obtained by least limiting water range and soil load support capacity. (C) 2012 Elsevier B.V. All rights reserved.

Responses of transplanted native tree species to invasive alien grass removals in an abandoned cattle pasture in the Lacandon region, Mexico

We tested the early performance of 16 native early-, mid-, and late-successional tree species in response to four intensities of grass removal in an abandoned cattle pasture dominated by the introduced, invasive African grass, Cynodon plectostachyus, within the Lacandon rainforest region, southeast Mexico. The increase in grass removals significantly improved the performance of many species, especially of early-and mid-successional species, while performance of late-successional species was relatively poor and did not differ significantly among treatments. Good site preparation and at least one additional grass removal four months after seedling transplant were found to be essential; additional grass removals led to improved significantly performance of saplings in most cases. In order to evaluate the potential of transplanting tree seedlings successfully in abandoned tropical pastures, we developed a "planting risk index", combining field performance measurements and plantation cost estimations. Our results showed a great potential for establishing restoration plantings with many early-and mid-successional species. Although planting risk of late-successional species was considered high, certain species showed some possibilities of acclimation after 18 months and should be considered in future plantation arrangements in view of their long-term contributions to biodiversity maintenance and also to human welfare through delivery of ecosystem services. Conducting a planting risk analysis can help avoid failure of restoration strategies involving simultaneous planting of early-, mid-, and late-successional tree species. This in turn will improve cost-effectiveness of initial interventions in large-scale, long-term restoration programs.

Different herbage allowances and milk yield in crossbred Holstein x Gir

The objective of this study was to evaluate different herbage allowances in stargrass (Cynodon nlemfuensis Vanderyst var. nlemfuensis), on the herbage disappearance rate (HDR) and milk yield in crossbred Holstein x Gir cows. Thirty animals were assigned to three different herbage allowances (HA), ranging from 10.0, 12.5 and 15.0% BW. There was effect of HA on the HDR ( P<0.001). Increasing the HA in one unit had effect on the HDR increasing by 140.0kg ha(-1) day(-1). There was effect of leaf: stem ratio on milk yield (P<0.05). The increasing in supplying herbage allowances did not resulted in increased milk yield because the management for herbage allowance and herbage growth.

Testing the Performance of Fourteen Native Tropical Tree Species in Two Abandoned Pastures of the Lacandon Rainforest Region of Chiapas, Mexico

The rainforest of Mexico has been degraded and severely fragmented, and urgently require restoration. However, the practice of restoration has been limited by the lack of species-specific data on survival and growth responses to local environmental variation. This study explores the differential performance of 14 wet tropical early-, mid- or late-successional tree species that were grown in two abandoned pastures with contrasting land-use histories. After 18 months, seedling survival and growth of at least 7 of the 14 tree species studied were significantly higher in the site with a much longer history of land use (site 2). Saplings of the three early-successional species showed exceptional growth rates. However, differences in performance were noted in relation to the differential soil properties between the experimental sites. Mid-successional species generally showed slow growth rates but high seedling survival, whereas late-successional species exhibited poor seedling survival at both the study sites. Stepwise linear regressions revealed that the species integrated response index combining survivorship and growth measurements, was influenced mostly by differences in soil pH between the two abandoned pastures. Our results suggest that local environmental variation among abandoned pastures of contrasting land-use histories influences sapling survival and growth. Furthermore, the similarity of responses among species with the same successional status allowed us to make some preliminary site and species-specific silvicultural recommendations. Future field experiments should extend the number of species and the range of environmental conditions to identify site generalists or more narrowly adapted species, that we would call sensitive.

Diferentes ofertas de forragem e a produção de leite em vacas mestiças Holandês x Gir

Objetivou-se avaliar o efeito de diferentes ofertas de forragem em pastagem de estrela africana (Cynodon nlemfuensis Vanderyst var. nlemfuensis), sobre a taxa de desaparecimento de forragem (TDF) e a produção de leite de vacas mestiças Holandês x Gir. Trinta animais foram submetidos a três ofertas de forragem (OF) distintas, sendo 10,0 12,5 e 15,0% do peso corporal. Houve influência da OF sobre a TDF (P<0,001). Para cada unidade de acréscimo da OF, a TDF aumentou 140,0kg ha-1 dia-1. Houve efeito da relação folha:colmo sobre a produção de leite (P<0,05). O aumento da oferta não refletiu em incremento da produção de leite em função do manejo empregado para obtenção das ofertas e estádio de crescimento das plantas.

Parches de vegetación arvense en una toposecuencia de altos y bajos en cultivos de manzanos : Mendoza (Argentina)

En un cultivo de manzanos en la provincia de Mendoza, Argentina, se observó la presencia de las comunidades dominadas por Cynodon dactylon y Galinsoga parviflora localizadas entre y bajo las copas de los árboles frutales, en coincidencia con una toposecuencia de relieves de altos y bajos, respectivamente. Ante el hecho de estar frente a un interesante ejemplo agronómico de establecimiento de comunidades arvenses se las analizó fisonómica, florística y sociológicamente, relacionándolas con las condiciones ecológicas, físico-químicas de los suelos y bioclimáticas de los sitios que las contienen. Mientras la comunidad de Cynodon dactylon presente en los altos o entre plantas resultó más luminosa, cálida, seca y menos fértil, la de Galinsoga parviflora en los bajos fue más sombría, fría, húmeda y más fértil. En esta última, la alta concentración de materia orgánica, nutrientes minerales y humedad de los suelos parece estar relacionada con la presencia de plantas anuales bajo las copas. Los resultados obtenidos muestran la importancia de las toposecuencias de relieves de altos y bajos en la distribución, estructura y composición florística de las comunidades vegetales arvenses, las cuales pueden resultar potenciadas con las coberturas de las copas de los árboles frutales.

Flora y vegetación de céspedes de parques públicos : Mendoza (Argentina)

Se analizó la flora y la vegetación de céspedes de parques públicos de Mendoza (Argentina) a fin de aportar información para su manejo. Se registraron 73 especies, incluidas en 65 géneros y 24 familias. Las Poaceae, Asteraceae, Fabaceae y Brassicaceae representaron el 58,9 % de la flora de los céspedes. El 67,1 % de las especies son introducidas; el resto son nativas. Dominaron las perennes: 54,8 %, sobre las anuales: 42,5 % y bienales: 2,7 %, así como las estivales: 75,3 % sobre las invernales. Estructuralmente también lo hicieron las terófitas: 42,5 %, sobre las hemicriptófitas: 27,4 %, geófitas: 21,9 %, caméfitas: 5,5 % y helófitas: 2,7 %. Se determinaron 33 comunidades y se identificaron las clases fitosociológicas Molinio- Arrhenatheretea R. Tx. 1937 (campos húmedos y pisoteados, con vegetación subnitrófila e higrófita) y Stellarietea mediae R. Tx. 1950 (vegetación arvense de los cultivos). Las comunidades vegetales de Trifoliun repens más Cynodon dactylon, Lolium multiflorum más Cynodon dactylon y Cynodon dactylon fueron las de mayor extensión y coberturas de los céspedes.

Céspedes de estadios de fútbol : Mendoza (Argentina)

Se considera los estados de desarrollo de los céspedes de estadios de fútbol en Mendoza (Argentina). Desde un punto de vista fitosociológico se determinan dos grupos de plantas: Molinio-Arrhenatheretea R. Tx. 1937 (campos húmedos y pisoteados, con vegetación subnitrófila e higrófita) y Stellarietea mediae R. Tx. 1950 (vegetación arvense de los cultivos). Se indican las etapas dinámicas que se producen por sobrepisoteo y labores culturales. Del análisis se desprende que: 1. El sobrepisoteo y falta de cuidados culturales conducen a la pérdida de la cubierta vegetal y a la formación de peladeros sin vegetación. 2. La comunidad de Cynodon dactylon L., junto con elementos de la Molinio-Arrhenatheretea, es la más aceptada. Su cobertura representa el mejor estado del campo. 3. Adecuadas prácticas culturales asegurarían el mantenimiento y/o conservación de los céspedes favoreciendo la práctica del deporte y aportando belleza escénica.