CHARACTERISTICS AND PERFORMANCE OF Aeschynomene spp. IN THE TROPICS AND SUBTROPICS

Aeschynomene is a principally tropical genus with native American species distributed from 40°N to 35° along the Atlantic coast and from 28°N to 17°S on the Pacific coast. There are about 160 species but cultivars have been released only from americana (Aa; 'Glenn') and falcata (»Bargoo'). Bargoo is a spreading, prostrate, perennial adapted to infertile, well-drained sites. Glenn and Florida common Aa are upright annuals adapted to seasonally-flooded areas. Aa has been evaluated and used commercially to a greater degree than other species. Studies have shown that Aa plant hight at first defoliation is critical, and plant should be clippled or grazed when 30 to 40 cm tall to increase vigor, leafiness, and nutritive value of regrowth. Crude protein and in vitro digestibility of 20 and 70% have been observed for the grazed portion of well-managed Aa swards. Over 3 yr in Florida, steers gained 0.7 kg d- 1 on grass-Aa pastures. Although used commercially in Florida, major limitations of Aa are that it is an annual and drought-induced stand failures are common

Component Yield and Tissue Composition of Carpon Desmodium- Bahiagrass Pasture as Influenced by Fertilizer Treatment

This research was conducted to determine fertilizer requirement for maintaining a stable bahiagrass (Paspalum notatum Flügge) and Florida carpon desmodium (.Desmodium heterocarpon (L.) DC cv. 'Florida') mixed pasture. Four replicates of seven fertilizer treatments: 56 kg Ν ha"1; 29 kg Ρ ha*1; 56 kg Κ ha'1; 22 kg S ha"1; 45 kg ha"1 of a micronutrient mix containing 24 g Β kg"1, 24 g Cu kg"1, 144 g Fe kg" \ 60 g Μη kg"1, 6 g Mo kg"1, and 56 g Zn kg"1; 29 kg Ρ ha"1 + 56 kg Κ ha"1 + 22 kg S ha"1 + 45 kg micronutrient mix ha*1 (mixed fertilizer); and no fertilizer (control) were randomly assigned to the same 7.6-m by 15.2-m plots in June 1996 and 1997. Metal exclosure cages (2 m by 2 m) were used to protect forage from cattle between June and November. Forage was harvested once in November 1996 and 1997 and separated into grass and legume components. Tissue mineral composition (Ν, Ρ, K, Ca, Mg, Cu, Fe, Μη, Zn, and Β) was analyzed separately for each component. Total (grass + legume) forage dry matter yield (DMY) ranged from 6.3 to 7.8 Mg ha"1, but there was no fertilizer treatment effect. The bahiagrass: carpon desmodium ratio for control DMY averaged 58:42 each year. Relative to the control, Ν application increased the bahiagrass:carpon desmodium DMY ratio to 79:21, whereas the mixed fertilizer treatment decreased the ratio to 44:56. Of the major nutrients, Ρ and Κ fertilizer increased carpon desmodium concentrations for each respective element, Κ fertilizer increased bahiagrass tissue K, and Ν fertilizer had no effect on tissue Ν concentration of either forage. Bahiagrass Ν was increased by the mixed fertilizer. Besides Mg and Β in bahiagrass and Mn and Cu. .in carpon desmodium, no other tissue macro- or micronutrients were altered by fertilizer treatments. The study has demonstrated a need for periodic application of Ρ, K, and micronutrients fertilizer to maintain productivity of grass-legume systems in sub-tropics

Espécies forrageiras para produção de leite em solos de várzea Forage species for milk production in lowland soil

Objetivou-se com este trabalho avaliar a disponibilidade de forragem, a composição morfológica e química do pasto, a capacidade de suporte do pasto e a produção de leite de vacas em três gramíneas forrageiras sob lotação contínua e taxa variável em solo de várzea. O delineamento experimental foi inteiramente casualizado com três tratamentos e três repetições. Os tratamentos constituíram-se das gramíneas Paspalum atratum cv. Pojuca, Brachiaria humidicola cv. Llanero e capim-tangola, híbrido natural de Brachiaria arrecta e Brachiaria mutica. A taxa de lotação foi ajustada para manter a forragem disponível entre 2.000 e 3.000 kg de massa seca por hectare. O período avaliado foi de novembro de 2003 a maio 2004. Não houve diferença significativa entre as espécies quanto à disponibilidade de massa seca de forragem verde, com valor médio de 2.902 kg/ha. O capim-pojuca apresentou 62% de lâminas foliares e 38% de colmo + bainha na massa seca de forragem verde, seguido pelo capim-humidícola com 49 e 51% e o capim-tangola com 18 e 82%, respectivamente. O capim-tangola apresentou teor mais alto de proteína bruta na lâmina foliar (15,41%) que os capins humidícola (9,98%) e pojuca (8,74%) e menores de fibra (FDN e FDA). A produção individual das vacas refletiu o melhor valor alimentício do capim-tangola, cuja média diária (10,27 kg/vaca) foi maior que no capim-pojuca (7,80 kg/vaca) e semelhante ao obtido com capim-humidícola (9,16 kg/vaca). A produção de leite por área não foi afetada pela gramínea forrageira, com média de 27,8 kg/ha × dia-1, uma vez que a taxa de lotação um pouco mais alta no capim-pojuca, apesar de não apresentar diferença significativa, compensou a menor produção individual das vacas.<br>The objective of this study was to evaluate the forage availability, pasture morphological and chemical composition, pasture carrying capacity and the milk production of cows on three forage grasses under continues stocking and the variable rate on lowland soil. The experimental design was completely randomized with three treatments and three replicates. The treatments were the Paspalum atratum cv Pojuca grass, Brachiaria humidicola cv Llanero grass and tangola grass (natural hybrid of Brachiaria arrecta and Brachiaria mutica). The stocking rate was adjusted to maintain the forage available between 2.000 and 3.000 kg dry matter per hectare. The period evaluated was from November 2003 to May 2004. There was no significant difference between the species when the dry matter availability of green forage was evaluated, with mean value of 2.902 kg/ha. The pojuca grass had 62% of leaf blade and 38% of stem + sheath in green forage dry mass, followed by humidícola grass with 49 and 51% and tangola grass with 18 and 22%, respectively. The tangola grass showed higher level of crude protein on the leaf blade (15.41%) than humidícola (9.98%) and pojuca (8.74%) grasses and lower levels of fiber (NDF and ADF). The individual production of cows was affected by the better nutritional value of the tangola grass. The average daily production of this grass was higher (10.27 kg/cow) than the pojuca grass (7.8 kg/cow) and had similar value to humidícola grass (9.16 kg/cow). The milk production per area, with had mean of 27.8 kg/ha × day-1, was not affected by the forage grasses because the more high stocking rate of pojuca grass, although not significant, compensated the lower individual production