Waldssimiler Teixeira de Mattos

Boron nutrition and yield of alfalfa cultivar crioula in relation to boron supply

O cultivar Crioula de alfafa (Medicago sativa cv. Crioula) e utilizado no Sul do Brasil e existem poucos estudos referentes a sua exigencia em boro. Foi conduzido um experimento com alfafa cultivada no inverno, com o objetivo de avaliar a quantidade de boro absorvido pelas plantas, o efeito de doses de boro na producao de massa seca, a distribuicao do boro nas plantas e obter informacoes relacionadas a diagnose de boro nessa forrageira. As doses de 0; 0,0625; 0,125; 0,25; 0,50; 1,00 e 2,00 mg L-1 foram aplicadas no substrato, colocando-se 1 L de solucao nutritiva em cada recipiente. As plantas foram cortadas aos 46 dias apos o transplante. A massa seca da forrageira foi influenciada pelas doses de boro e foi insignificante quando a solucao nutritiva apresentava a mais baixa concentracao de boro. A concentracao de boro nas folhas foi mais elevada que nas hastes e nas raizes. A utilizacao de boro da solucao atingiu 90% na dose de 0,0625 mg L-1 e decresceu acentuadamente com o incremento das doses de boro. A concentracao e o conteudo de boro nas folhas e na parte aerea da planta foram mais elevados quando o boro se encontrava na solucao nutritiva entre 1,5 e 1,6 mg L-1. O nivel critico de boro foi de 61 mg kg-1 nas folhas e 39 mg kg-1 na planta para este cultivar de alfafa.

Crescimento de raízes dos capins aruana e tanzânia submetidos a duas doses de nitrogênio

ABSTRACT - The root system (pre and post grazing) characteristics of aruanagrass and tanzaniagrass under two nitrogen rates (150and 300 kg ha -1 N year) grazed by sheep in variable rotational stocking (three to seven grazing days) and variable rest period were evaluatedin this study. The treatments were assigned to a complete randomized block (two) design with two replicates (plots = grasses an d split-plots = nitrogen rates)within repeated measures. In the pre-grazing tanzaniagrass, averages within nitrogen rates and grazing p eriod showedhigher amount of dry matter of organic matter (DMOM) (1.7 mg cm -3 of soil) than aruanagrass (1.2 mg cm -3 of soil) and greater root length(119.1 cm cm -3 of soil x 68.7 cm cm -3 of soil). The 300 kg ha -1 N rate contributed to a higher root system length (107.1 cm cm -3 of soil)than the 150 kg ha -1 N rate (80.7 cm cm -3 of soil). Post-grazing root growth showed similar behavior among the variables measured andwas more evident after the second regrowth week. Considering averages within grasses, nitrogen rates and growth age, in the periodequivalent to Autumn/Winter, the DMOM growth root was of 3.9 mg 100 cm

In situ degradability and selected ruminal constituents of sheep fed with peanut forage hay.

Because legumes are a very important feed source for ruminants, the aim of this study was to evaluate the ideal inclusion level of hay Arachis pintoi cv. Belmonte in sheep diets by measuring the dry matter intake (DMI), concentration of volatile fatty acids, ammonia–nitrogen concentration, ruminal pH and the in situ degradability of dry matter (DM) and crude protein (CP). In the experiment with four sheep, a 4 × 4 Latin Square design was used with four periods and four treatments (0%, 30%, 60% and 100% Arachis replacing grass hay). Significant interactions were observed between treatments and sampling times for ammonia–nitrogen and acetate, propionate and butyrate concentration and the acetate:propionate ratio. The ruminal pH and total volatile fatty acids concentration were not affected by interaction between treatments and sampling time. The degradation of DM and CP was similar, rising with the increasing content of Arachis, showing a linear effect. The treatment containing 60% of Arachis showed best results, with good levels of daily weight gain and higher ruminal concentrations of volatile fatty acids. The legume showed high levels of CP, high digestibility and appropriate levels of fibre, with excellent standards of degradation and ruminal characteristics. The use of the legume Arachis for ruminants is a promising option of nutrient supply to meet production demands of these animals.