Tiago Luis da Ros de Araújo

Forage mass and stocking rate of elephant grass pastures managed under agroecological and conventional systems

The objective was to evaluate elephant grass (Pennisetum purpureum Schum.) pastures, under the agroecological and conventional systems, as forage mass and stocking rate. In the agroecological system, the elephant grass was established in rows spaced by 3.0 m from each other. During the cool season ryegrass (Lolium multiflorum Lam.) was established between these rows, which allowed the development of spontaneous growth species during the warm season. In the conventional system the elephant grass was established singularly in rows spaced 1.4 m from each other. Organic and chemical fertilizers were applied at 150 kg of N/ha/year with in the pastures under agroecological and conventional systems, respectively. Lactating Holstein cows which received 5.0 kg/day supplementary concentrate feed were used for evaluation. The experimental design was completely randomized, with two treatments (agroecological and conventional systems) two replications (paddocks) and independent evaluations (grazing cycles). The pastures were used during the whole year for the agroecological system and for 195 days in the conventional year. The average values of forage mass were 3.5 and 4.2 t/ha and the stocking rates were 2.08 and 3.23 AU/ha for the respective systems. The results suggest that the use of the elephant grass under the agroecological system allows for best distribution of forage and stocking rate to be more uniform throughout the year than the use of elephant grass in conventional system.

Produtividade e valor nutritivo de pastos consorciados com diferentes espécies de leguminosas

The objective of this research was to evaluate the productivity and nutritive value of two pasture-based systems (PS) with elephant grass (EG) + ryegrass (RG) + white clover (WC) + spontaneous growing species (SGS), for PS1; and EG + RG + forage peanut (FP) + SGS, for PS2. EG was established in rows spaced by four meters. Ryegrass was seeding in the space between rows during cool-season and development of SGS was permitted in the warm-season. Holstein cows under rotational grazing were used in the evaluation. The initial forage mass (IFM), the botanical composition and the structural components were evaluated. Samples from hand-plucking method were collected to analyze neutral detergent fiber (NDF), acid detergent fiber (ADF), crude protein (CP), in vitro dry matter digestibility (IVDMD) and in vitro organic matter digestibility (IVOMD). The experimental design used was completely randomized with two treatments, two repetitions in complete split-plot time. The mean values of initial forage mass and stocking rate were similar among PS. Superior results were found for mean of CP in PS2. The use of ryegrass, legumes and spontaneous growing species mixed to EG allow the forage mass to be uniform during the grazing pastures.

Produtividade e proteína bruta de pastagens de capim elefante manejadas sob os sistemas agroecológico e convencional

O objetivo desta pesquisa foi avaliar a massa, o teor de proteina bruta da forragem e a taxa de lotacao em pastagens de capim elefante em dois sistemas de producao. No sistema convencional, o capim elefante foi plantado em linhas afastadas a cada 1,2m. No sistema agroecologico, o capim foi plantado em linhas afastadas a cada 3m; no espaco entre as linhas, no periodo hibernal, foram semeados o azevem anual e o trevo vermelho e, no periodo estival, permitiu-se o desenvolvimento de especies de crescimento espontâneo. Foram utilizados 150kg de N ha-1 com fertilizantes quimico e orgânico para os respectivos sistemas forrageiros. Foram usadas vacas em lactacao que receberam complementacao a razao de 0,9% do peso vivo. Para determinacao do teor de proteina bruta, foram retiradas amostras simulando o pastejo. Valores similares foram observados quanto a composicao estrutural do capim elefante em ambos os sistemas. Durante o periodo experimental, foram conduzidos oito e sete pastejos para os respectivos sistemas. Os valores medios de massa de forragem de pre-pastejo e da taxa de lotacao foram de 3,7 e 4,8t ha-1 e de 2,10 e 2,51UA ha-1 dia-1. A pastagem sob sistema agroecologico apresenta melhor distribuicao de forragem ao longo do ano. Teores elevados de proteina bruta foram observados no periodo hibernal, em ambos os sistemas forrageiros.