Grazing management strategies for massaigrass-forage peanut pastures: 2. productivity, utilization and sward structure

Abstract

-This study was carried out to evaluate the productivity, utilization and sward structure of a mixed massaigrass (Panicum maximum x P. infestum, cv. Massai) and forage peanut (Arachis pintoi Ac 01) pasture, intermittently stocked at three daily herbage allowance levels (9.0, 14.5 and 18.4% of live weight). In each grazing cycle, dry matter (DM) accumulation rates, defoliation intensity (%), grazing depth (%) and grazed horizon (cm) were evaluated. The structure of massaigrass tussocks was characterized in both dry and rainy seasons by measuring its pre-grazing morphological composition and postgrazing height and density (tussocks/m). Pastures submitted to higher herbage allowance (HA) levels showed higher productivity, but were less efficiently utilized. On average, over the experimental period, DM accumulation rates increased linearly from 56.8 to 81.3 kg/ha/day as HA levels increased from 9.0 to 18.4% of live weight. However, defoliation intensity and grazing depth declined linearly with increasing HA levels. During the dry season, pre-grazing morphological composition of massaigrass was characterized by 41% of green leaf blades, 10% of pseudostems and 49% of dead material, irrespective of HA levels. In the rainy season, however, it showed higher percentage of green leaf blades and lower percentage of pseudostems when submitted to lower HA levels, although there were not differences in relation to percentage of dead material. The structure of massaigrass tussocks tended to deteriorate at high HA levels.Key Words: Arachis pintoi, defoliation intensity, grazing depth, legume, morphological composition, Western Amazon Estratégias de manejo do pastejo para pastos consorciados de capim-massai e amendoim forrageiro. 2. Produtividade, utilização e estrutura do pasto RESUMO -Este estudo foi realizado para avaliar a produtividade, utilização e estrutura de uma pastagem consorciada de capim-massai (Panicum maximum x P. infestum, cv. Massai) e amendoim forrageiro (Arachis pintoi Ac 01), submetida a três níveis de oferta diária de forragem (9,0; 14,5 e 18,4% do PV), sob lotação rotacionada. A cada ciclo de pastejo, avaliou-se a taxa de acúmulo de matéria seca (MS), a intensidade de desfolha (%), a profundidade de pastejo (%) e o horizonte pastejado (cm). A estrutura das touceiras do capim-massai foi caracterizada nos períodos seco e chuvoso quanto à composição morfológica pré-pastejo e à altura e densidade (touceiras/m) pós-pastejo. Pastagens submetidas a maiores níveis de oferta de forragem (OF) apresentaram maior produtividade, porém foram utilizadas com menor eficiência. Na média do período experimental, a taxa

Biomass accumulation and chemical composition of Massai grass intercropped with forage legumes on an integrated crop-livestock-forest system

“…A. pintoi survives in well-drained areas, even though there is a severe leaf loss during the dry season, but resprouting is strong with the warmer temperatures of spring (Andrade et al, 2006). This work also found that weather conditions directly affected the production of this legume in the dry season of 2010.…”

“…This is probably due to excessive shading during the growth period with maize. When assessing the dynamics and botanical composition of a Massai grass + Arachis pintoi pasture intercropping, Andrade et al (2006) also observed that the participation of Arachis increased throughout the experimental period, particularly in pastures with a lower and more open canopy. The authors concluded that Arachis can be successfully intercropped with Massai grass if the pasture height in the pre-grazing condition is kept below 60 cm to prevent excessive shading of legumes.…”

Productivity, utilization efficiency and sward targets for mixed pastures of marandugrass, forage peanut and tropical kudzu

“…Amarillo (21.7 to 29.3 t/ha of DM), in Costa Rica, where annual rainfall is twice that recorded in Rio Branco-Acre, besides being better distributed along the year. Values of annual DM production in this study are also inferior to those reported by Andrade et al (2006a) for swards of massaigrass and forage peanut in Acre (20.4 to 29.2 t/ha of DM). This is probably due to the higher production potential of massaigrass in comparison with marandugrass, and also due to the soil waterlogging during part of the rainy season, which affected negatively the growth of marandugrass.…”

“…In the present study, grazed horizon was similar (mean of 17.1 cm) in the different treatments ( Figure 2E), an expected result in swards managed under different forage allowances, since higher swards are less intensively grazed and lower swards are more intensively grazed (Andrade et al, 2006a). Grazed horizon presented seasonal variation ( Figure 2F) similar to pre-grazing sward height (Andrade et al, 2012), with high correlation between the two variables (r = 0.96), a result similar to that reported by Brâncio et al (2003), evaluating three P. maximum cultivars and by Andrade et al (2006a) in a study with a mixed pasture of massaigrass and forage peanut. Grazed horizon was bigger during the January-March period (mean of 26 cm), as a result of plant lodging, decreasing to 14 cm in the AprilJune period, and to only 9 cm in the July-September period.…”

“…Over the experimental period, average DM accumulation rates increased linearly from 40 to 53 kg/ha/day as forage allowance increased from 6.6 to 17.9% LW ( Figure 1A). Similar responses were observed in mixed pastures of massaigrass and forage peanut under rotational stocking in Acre (Andrade et al, 2006a) and of marandugrass and forage peanut cv. Belmonte under continuous stocking in Paraná (Silva, 2008).…”