Defoliation patterns and tillering dynamics in Italian ryegrass under different herbage allowances
This work was carried out in order to generate information on the tillering process and to contribute for the understanding of the defoliation process on Italian ryegrass (Lolium multiflorum Lam.) grazed by lambs under different herbage allowances: 6, 8 and 12 kg of dry matter per 100 kg of animal live weight per day. The grazing method was intermittent. The experimental design was completely randomized following a repeated measure arrangement, with three treatments and two area replications. The intensity of defoliation is greater at 6 and 9% herbage allowances. The defoliation interval is higher at 12% herbage allowance, intermediate at 9% and lower at 6%. The rates of tiller emergence, survival and death, stability index the tiller population are similar for the different herbage allowances and differ according to the phenological stage of ryegrass. Structural changes caused by canopy management with low herbage allowance and/or due to the advance in developmental stage of ryegrass alter defoliation strategies, with more intense and frequent grazing.
INTENSIDADE E FREQUÊNCIA DE DESFOLHAÇÃO EM AZEVÉM
Foram avaliadas a intensidade e frequencia de desfolhacao em azevem ( Lolium multiflorum Lam.) pastejado por borregas, em duas intensidades de remocao da biomassa: 36% (“baixa”) e 52% (“alta”).   O metodo de pastejo foi intermitente e o intervalo entre pastejos foi determinado pela soma termica acumulada de 313 graus-dia, resultando em quatro ciclos de pastejo. O delineamento experimental foi inteiramente casualizado, com duas repeticoes de area. A intensidade de desfolhacao de lâminas foliares (%) foi semelhante em ambas as intensidades de remocao da biomassa, em media 85%. A frequencia de desfolha de lâminas foliares (no de desfolhacoes lâmina -1 dia- 1 ) aumentou de 0,14 para 0,78 no inicio do florescimento do azevem.  Na intensidade “baixa” de remocao da biomassa as lâminas foliares em expansao tiveram maior frequencia de desfolha, 0,41 (no de desfolhacoes lâmina -1 dia -1 ), enquanto em “alta” as lâminas foliares em expansao e expandidas foram pastejadas com a mesma frequencia, em media 0,66 (no de desfolhacoes lâmina -1 dia -1 ). As intensidades de remocao da biomassa alteram a estrutura do dossel e as perdas de forragem dependendo dos estadios fenologicos do azevem. Palavras-chave: Lolium multiflorum , pastejo intermitente, soma termica ABSTRACT The intensity and frequency of defoliation in Italian ryegrass ( Lolium multiflorum Lam.) grazed by ewe lambs in two intensity of biomass removal: 36% (“low”) e 52% (“high”) were evaluated. The grazing method was intermittent and the interval between grazing was determined by accumulated thermal sum of 313 degree day, resulting in four grazing cycles. The experimental design was completely randomized, with two treatments and two area replicate. The leaf defoliation intensity (%) was similar in both intensity of biomass removal, on overage 85%. The frequency of defoliation of leaf blades (no of defoliation blade -1 day -1 ) increased from 0.14 to 0.78 at the beginning of flowering of ryegrass. The expanding leaves had higher frequency of defoliation in the "low " intensity of biomass removal, 0.41 (no of defoliation blade -1 day -1 ) while in "high" the expanded and expanding leaves were grazed with the same frequency of defoliation, on overage 0.66 (no of defoliation blade -1 day -1 ) . The intensities of removing the biomass change the canopy structure and forage losses depending on the phenological stages of Italian ryegrass. Key words : Lolium multiflorum, intermittent grazing, thermal sum.
The Determination of Physicochemical Characteristics of Biodiesel and Its Blending Oils
The viscosity,combustion heat,sulfur content,carbon residue,ash,flash point,moisture and cetane value of biodiesel and its blending oils with diesel were determined.The influence of temperature on the viscosity was studied,and the physicochemical characteristics of biodiesel and its blending oils were compared with diesel.The results indicated that biodiesel and its blending oils had some superior performances and good application prospect.