Agronomic Evaluation of Alfalfa Cultivars in Rio Grande do Sul, Brasil

From April 1995 to June 1998, thirty five alfalfa (Medicago sativa L.) cultivars (cvs.) were evaluated in a field trial at the “Depressão Central” ecoclimatic region, in southern Brazil. Two years after sowing, 30 cultivars were excluded from the test due to their poor overall agronomic performance, mainly low forage DM yields. The remaining cultivars: Crioula (local genotype used as a check), Victoria, Rio and P 30 are hay-type cultivars while Alfagraze is a grazing-tolerant type. Twenty-two harvests were made and no significant differences were found for total DM yields among cvs. Crioula, Victoria, Rio and P 30; however, cv. Crioula yielded 25,854 kg.ha-1, showing a significant (P\u3c 0.05) superior performance compared to cv. Alfagraze (17,478 kg.ha-1). The highest average annual and seasonal DM yields were obtained by cv. Crioula and spring was the best growing season. Cv. Alfagraze showed the highest crude protein content and leaf to stem ratio. Incidence of foliar diseases was low, affecting all cultivars similarly. Cv. Victoria showed the lowest stand persistence. Alfalfa root density did not differ among cultivars and the highest average value was found at the 0-10 cm topsoil layer. Results indicate that cvs. Crioula and Alfagraze are well-adapted, productive and persistent alfalfa genotypes for hay production and grazing, respectively, under the soil and climatic conditions of the “Depressão Central” region

Morphological acclimation and canopy structure characteristics of Arachis pintoi under reduced light and at full sun.

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Direct Drilling of Soybean in a Pensacola Bahiagrass Pasture in the Northwest Region of Rio Grande Do Sul, Brazil

The response of methods of soil preparation (M1=conventional tillage, and with notillage using the following herbicides M2=50% Paraquat plus 50% Orizalin; M3=50% Paraquat plus 50% Diquat and M4=Paracol (20% Paraquat plus 20 Diuron)) and row spacing (E1=17 cm, E2=24 cm, E3=51 cm and E4=68 cm) on soybean grain yield direct drilled in an eight-year-old grazed sward of Bahiagrass cv. Pensacola (Paspalum notatum var. saurae Parodi) were studied in southern of Brazil. The results showed that direct drilling of soybean on Pensacola accompanied by desiccant herbicides is a viable agronomic practice. The narrow row spacing is beneficial to this agronomic practice resulting in higher grain yields. The relationship between soybean grain yield and Pensacola dry matter yield was expressed by a negative linear regression. In spite of the damage to the Pensacola caused by herbicides and by soybean competition the sward recovered immediately after the soybean maturation and harvest

Manejo de animais e pastagens em sistemas de integração silvipastoril

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Silvopastoral systems in the cold zone of Brazil.

The cold zone of Brazil occupies approximately 6 % of the national territory and is located between latitudes 24° S and 33° S. In this area, extensive cattle and sheep farming systems and conventional cropping and forestry are predominant. With the end of government subsidies by the decade of 1980s, an increase in farming production costs, a decrease of native forest covering, an increase of degraded areas in agriculture and livestock farming systems and a mismatch between timber national supply and demand after 1990s, an opportunity arises for integrate forestry with livestock and agriculture activities in Brazil, particularly in the southern. This chapter initially reports key events over the last three decades that have supported the increasing interest of farmers and enterprises on agroforestry activities, with focus on silvopastoral systems in the cold area of Brazil. Then, relevant advances on silvopastoral systems from research and extension services were reported, highlighting the screening of shaded adapted forage plants and management, trees species screening for silvipastoral systems and animal performance and behaviour under trees. Finally, the chapter analyses the existent opportunities to increase silvopastoral areas in southern Brazil and future challenges for research, development and technology transfer.bitstream/item/175986/1/Jamir-Luis-Silva-Book-Silvopastoral-Systems-in-South-America-Springer-2016-1.pd

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

Eficiência de uso da radiação fotossinteticamente ativa de três forrageiras nativas dos campos sulinos sob dois níveis de sombra e a pleno sol.

Este trabalho teve como objetivo determinar a eficiência de uso da radiação fotossinteticamente ativa (EUR) de Paspalum notatum, Paspalum regnellii e Paspalum dilatatum sob 50% e 80% de sombra artificial e a pleno sol, buscando avaliar o potencial de uso destas espécies em sistemas silvipastoris na região sul do país e a utilização de forrageiras nativas nestes sistemas integrados