Utilização racional da pastagem natural

04

Herbage Allowance and Nitrogen Fertilization Effects on Morphological Characteristics of \u3ci\u3ePaspalum notatum\u3c/i\u3e Flügge

The grazing study was conducted at the Estação Experimental Agronomica – UFRGS, 30o S, on a native pasture, to evaluate the leaf area index and structural morphological traits of bahiagrass (Paspalum notatum Fl.), within the requirements of a Central Composite Rotatable experimental design, providing for equal precision, with two blocks, encompassing two factors at five levels each, namely: Herbage Allowance (HA) = 4.0; 5.5; 9.0; 12.5 and 14.0 kg green dry matter per 100 kg liveweight per day (% LW), in association with Nitrogen (N) fertilization levels of 0; 30; 100; 170 and 200 kg ha-1 as urea, The leaf length and leaf area index (LAI) were increased as HA and N levels increased. The tiller density was increased at higher HA where the N contribution showed to be more effective. More lenient grazing also increased leaf life span and leaf lamina length, while N promoted canopy density and reduced leaf life span and number of leaves per tiller. The higher LAI values developed were accomplished by reduced tiller densities that supported small number of leaves per tiller, with increased leaf sizes

Livestock Farmers and Researchers Perceptions about Ecosystem Services Provided by Rio de la Plata Grasslands

The perception and valuation that livestock farmers have about ecosystem services provided by natural pastures is of fundamental importance to their management decisions and the conservation of this resource. This work aims to reveal results of a project carried out in Brazil, Paraguay, Argentina and Uruguay using the TESSA (Toolkit for Ecosystem Service Site-based Assessment) methodology to compare the perceptions of different ecosystem services among livestock farmers and researchers. The methodology was participatory workshops, two by country, one with livestock farmers participating in the Grassland Alliance (at least 50% of natural grassland in the livestock production system) and another with researchers working in grassland based livestock production. Main services targeted by producers were their way of life, water quality, water regulation, scenic beauty, meat quality, and fodder production. On the other hand, the researchers target ecosystem services related to forage production (food and fiber), water regulation, erosion control, carbon sequestration, soil fertility, and tourism. Farmers value their habitat in a more sensitive way and place more importance to intangible services that benefit their well-being and future generations. At the same time, researchers mainly point to quantitative benefits of pasture, soil and water as well as the potential for tourism

Application of the TESSA Methodology in a Pilot Protocol for Participatory Evaluation of Ecosystem Services and Agents of Change in the Pampa Grasslands. Method Description and Lessons Learned

The Toolkit for Site-Based Assessment (Landscape) of Ecosystem Services (TESSA) is intended to be an accessible guide for low-cost methods to assess the benefits that people receive from nature at particular sites in order to generate information that can be used to influence decision-making (Pehl et al 2015). However, TESSA does not have defined protocols for grasslands ecosystems. This article focuses on the description and discussion of the lessons learned in the participatory workshops that include engaging with policy and decision-making actors. The work consisted of identifying 1) the area occupied by each coverage or use, 2) the threats and agents of change, 3) the ecosystem services and 4) a detailed description of the most important services in the area. The methodology was applied in the grassland ecosystems in the countries of Brazil, Argentina, Uruguay, and Paraguay (Schossler et al 2016). A total of 54 livestock farmers, 56 researchers and more than 22 institutions were involved with this study. Results involve the perceptions of the actors involved with the topic of interest in the four countries of interest, in addition to the potential changes and trends presented by the agents of change that most affect the ecosystem. In this paper we discuss the initial steps of the TESSA methodology. The protocols used at the field level and their results will be published as self contained articles within the doctoral thesis of the primary author

Evaluation of the legumes from genus Trifolium

De março de 1984 a novembro de 1985, na Estação Experimental Agronômica da Universidade Federal do Rio Grande do Sul (EEA-UFRGS), Guaíba, RS, avaliou-se o potencial das espécies nativas T. riograndense Burkart e T. polymorphum Poir., em relação ao trevo-branco (Trifolium repens), cultivares BR- 1-Bagé, Regal, Jacuí e Guaíba. Foram avaliadas as seguintes variáveis: rendimento de matéria seca (MS), conteúdo de ácido cianídrico (HCN), nodulação, persistência, rendimento, percentagem de proteína bruta (PB) e digestibilidade "in vitro" (DIV) da MS e matéria orgânica (MO). As cultivares de trevo-branco apresentaram variação entre si, enquanto as cultivares novas mostraram-se promissoras. As espécies nativas T. riograndense (2x e 4x) e T. polymorphum apresentaram produções baixas de MS; entretanto, exibiram boa qualidade e, conforme os teores de HCN obtidos, mostraram que, provavelmente, não são cianogênicas. A forma autotetraplóide de T. riograndense não foi significativamente superior à forma diplóide da mesma espécie para nenhuma das variáveis estudadas.From March 1984 to November 1985, in the Agricultural Experiment Station of the Federal University of Rio Grande do Sul, Guaíba, RS, Brazil, the potential of the native species T. riograndense Burkart and T. polymorphum Poir., were evaluated in comparison with white clover (Trifolium repens L). cultivars BR-1-Bagé, Regal, Jacuí and Guaíba. The variables dry matter yield (DM), HCN content, nodulation, persistence, yield, crude protein (CP), percentage and in vitro dry matter digestibility (IVOMD) and in vitro organic matter digestibility (IVOMD) were evaluated. The white clover cultivars showed variations and the new cultivars presented very promising. The native species T. riograndense (2x and 4x) and T. polymorphum presented low DM yield, but showed good quality and, according to the contents of HCN achieved, showed that probably are not cyanogenic. The autotetraploid form of T. riograndense was not significantly superior to the diploid form of the some specie for none of the variables studied

Avaliação do potencial de produção de sementes de espécies, formas e cultivares de trevo-branco

From March 1984 to November 1985, the potential seed yield of the native species of white dover T. riograndense Burkart and T. polymorphum Poir. was evaluated in comparison to the BR-1-Bagé, Regal, Jacuí and Guaíba cultivars of white dover (T. repens L.). The experiment was performed at the Agricultural Experiments Station of the Federal University of Rio Grande do Sul, Guaíba, RS, Brazil. The variables regarding to the seed yield and the components of the seed yield, DM yield of forage residue, percentage of crude protein (CP) and in vitro dry mater digestibility (IVOND) of the forage residue after seed harvest were evaluated. The cultivars of the white dover present differences. Rega) showed to have no adaptation for seed yield in this place. The native species T. polytnorphuni and T. riograndense (2x and 4x) showed significantly lower seed yield than the cultivars of the white dover. The autotetraploid form of T. riograndense showed no differences between variables, except for number of inflorescences/m 2 and weight of 1000 seeds, that were superior to those of the diploid form.De março de 1984 a novembro de 1985, foi avaliado o potencial de produção de sementes das espécies nativas Trifolium riograndense Burkart e Trifolium polytnorphum Poir. em relação às cultivares BR-1-Bagé, Regal, Jacuí e Guaíba de trevo-branco (Trifolium repens L.). O experimento foi realizado na Estação Experimental Agronômica da Universidade Federal do Rio Grande do Sul (EEA-UFRGS), Guaíba, RS. Foram avaliadas as variéveis referentes aos componentes do rendimento de sementes, além do rendimento de MS do resíduo, teor de proteína bruta e digestibilidade in vitro da MS e MO desse resíduo. As cultivares de trevo-branco apresentaram variação entre si e a cultivar Regal mostrou-se sem adaptação para a produção local de sementes. As espécies nativas T. po!yrnorphurn e T. rio-grandense (2x e 4x) mostraram produções de sementes significativamente menores que as das cultivares de trevo-branco. A forma autotetraplóide de T. riograndense não apresentou diferenças signiíicativas entre as variáveis, com exceção do número de inflorescências/m 2 e peso de 1.000 sementes, que foram superiores às da forma diplóid

Variação morfológica em acessos de Paspalum nicorae Parodi, forrageira promissora

Paspalum nicorae Parodi é uma forrageira perene, apomítica, tetraplóide, nativa no Rio Grande do Sul, com tolerância ao pastejo e adaptada a solos arenosos e a secas moderadas. Como passo inicial para o melhoramento, uma caracterização morfológica considerando pilosidade da folha, cor da bainha, da folha e da nervura central, hábito de crescimento, altura da planta, número e comprimento de racemos, comprimento e largura da folha foi realizada em 53 acessos coletados no Rio Grande do Sul, Brasil, que são parte de um programa de melhoramento de espécies de Paspalum. Os resultados mostraram que 35,84% dos acessos tinham folhas completamente pilosas, 73,58% tinham bainha verde, 54,71% venação central esbranquiçada e 50,94% hábito decumbente. A cor da folha foi estimada por dois métodos, cartela de cores e colorímetro Os acessos foram classificados como 76,92% verdes, 13,45% amarelo esverdeados e 9,62% como verde acinzentados pelo primeiro, e 59,62% acinzentados, 32,69% amarelo acinzentados, 5,77% amarelos e 1,92% cinza escuros pelo segundo método. O comprimento do racemo variou de 9,40 a 1,30 cm, o número de racemos de um a seis (sendo que 48,73% dos acessos tinham quatro racemos), o comprimento e a largura da folha de 36,13 a 13,06 cm e 0,67 a 0,36 cm, respectivamente e a altura da planta de 115,70 a 29,00 cm. Portanto, grande variação morfológica foi detectada entre os acessos, sem relação com localização geográfica, mas indicando alta potencialidade de utilização em programas de melhoramento.Paspalum nicorae Parodi is a perennial, apomictic tetraploid forage species, native in the state of Rio Grande do Sul, Brazil, with grazing tolerance and adapted to sandy soils and moderate droughts. As a first step to future breeding, a morphological characterization regarding leaf hairiness, sheath, leaf and central venation color, growing habit, plant height, raceme number and length, and leaf length and width was performed in 53 accessions from Rio Grande do Sul that are part of a Paspalum species breeding program. 35.84% of the accessions had completely hairy leaves, 73.58% had green sheath, 54.71% whitish central venation, 50.94% decumbent habit. Leaf color was estimated by two methods, color chart and colorimeter. The accessions were classified as 76.92% green, 13.45% greenish yellow and 9.62% as grayish green by the first, and 59.62% grayish, 32.69% grayish yellow, 5.77% yellow and 1.92% dark grayish by the second method. Raceme length ranged from 9.40 to 1.30 cm, number of racemes from one to six (48.73% of the accessions had four racemes), leaf length and width from 36.13 to 13.06 cm and 0.67 to 0.36 cm, respectively, and plant height from 115.70 to 29.00 cm. Therefore, a large morphological variation among accessions was detected, with no relation to geographical location but indicating a high potential use in plant breeding programs

Morphological Acclimatation and Canopy Structure Characteristics of \u3cem\u3eArachis pintoi\u3c/em\u3e under Reduced Light and at Full Sun

The canopy structure is a key variable to determine the adaptive potential of forages and it influences the radiation use efficiency (RUE) under different light conditions. The light extinction coefficient calculated from the Beer-Lambert formula (k) shows the canopy architecture and light interception patterns of plants and thus their potential ability to convert light energy (photosynthetically active radiation-PAR) into plant biomass (Hirose 2005). Under shade, forages may experience changes in plant morphology and canopy structure. Many authors reported those changes and relate them to modifications in light quantity and quality (Varella et al. 2010). The magnitude of these morphological changes may be determinant to screen forages for shaded environments such as silvopastoral systems. The objective of this study was to determine the light interception patterns and extinction coefficients of Arachis pintoi under two artificial shading levels (50% and 80%) and in full sunlight and relate them to adaptive potential of this legume for silvopastoral systems