Seasonal patterns of grass production under cutting or continuous stocking managements

Abstract

A comparison was made between the seasonal pattern of net herbage accumulation under cutting and the pattern of intake under continuous variable stocking on a Lolium perenne sward, which was well supplied with nitrogen fertilizer and irrigated to minimize moisture stress.The seasonal pattern of production under monthly cutting showed characteristic asymmetry with a marked peak in production in late May/early June, a rapid decline in June followed by an increase in rate in August and the total amount harvested over the season was 9-28 t organic matter ha"'.By contrast, the seasonal patterns of production on swards grazed by ewes to maintain sward surface heights of 30, 50 and 70 mm all differed fundamentally from that observed under cutting. Production was more evenly distributed throughout the season under these grazing treatments which, it has been proposed, should optimize performance. Total amounts harvested by grazing were 10-84, 1012 and 8-51 t OM ha"', respectively. The different patterns of production under cutting and grazing were considered to be associated with differences in the expression of reproductive development in the grass crop and the maintenance of a smaller leaf area per unit ground area under grazing.The results of the study suggest thai it is not appropriate to regard the seasonal pattern of net Correspondence: R. J. Orr, AFRC Instiiuie for Grassland and Animal Production, Hurley, Maidenhead, Berks SL6 5LR. UK.accumulation under a standard cutting regime as representing the potential production of grass under continuous stocking. Moreover, in practice, the more uniform seasonal pattern of production seen in swards maintained on the basis of a controlled sward surface height makes it easier to match the supply of herbage to the appetite of grazing animals as the season progresses.

Effects of Biosolids-Derived Organomineral Fertilizers, Urea, and Biosolids Granules on Crop and Soil Established with Ryegrass (Lolium perenne L.)

“…The timing of fertilizer application influenced yieldto-nitrogen responses. In Y2 and Y3, fertilizer application was relatively late (Table 1) compared with the characteristic pattern of seasonal rate of growth (i.e., peak growth) of grass crops (Orr et al 1988). To some extent, this explains the overall decline in responses and DMY observed in Y2 and Y3 compared with Y1.…”

“…This is explained by late timing of N application relative to maximum rate of growth of ryegrass (Orr et al 1988), and combined effects of high temperatures around the time of fertilizer application with surface-application of fertilizers leading to losses of N by volatilization of NH 3 . The latter is recognized to be the main reason for inefficiency of urea-based fertilizers compared with other straight N fertilizers such as ammonium nitrate (Watson et al 1990).…”

Field studies on the value of organomineral fertilisers as amendments for perennial ryegrass (Lolium perenne L)

“…Differences between-fertilisers were smaller in 2010 which responded to the combined effect of drier soil conditions in the early part of the spring (Figure 1) and the surface application of the fertilisers. This effect was observed despite that the timing of fertiliser application matched, approximately, the expected peak of growth of the grass crop which under the UK conditions typically occurs around May (Orr et al, 1988). The relatively dry and warm conditions recorded in April 2010 (Figure 1) support the possibility of N losses by volatilisation of NH 3 after the fertiliser application.…”

“…For subsequent cuts, N should be applied immediately after the previous cut but because the N rates are usually lower than 120 kg ha -1 , the full dressing may be applied. Because of the characteristics patterns of growth of grass swards under the UK conditions (Orr et al, 1988), this fertilisation strategy will maximise the response of the grass to the application of fertiliser-N, including OMF-N, and will minimise the opportunities for N losses to the environment (DEFRA, 2010;Antille et al, 2013a). In 2009, the recommendations regarding the timing of fertiliser application could not be strictly followed because it was the year of grass establishment and emergence was recorded on 11 April.…”

Características Estruturais De Cultivares De Azevém Perene Como Critério De Seleção Para Maximizar O Consumo De Vacas Leiteiras Em Pastejo

“…Ao mesmo tempo as tradicionais avaliações em pequenos canteiros submetidas a intervalos de cortes, que tem como objetivo representar o efeito do pastejo animal, vem sendo fortemente repudiada por alguns pesquisadores (Jones, 1984;Orr et al, 1988 No entanto, voltamos a enfatizar que praticamente não existe nenhuma correlação de produção entre cultivares avaliada sob pastejo e cultivares avaliados sob corte (Orr et al, 2000). É muito comum encontrarmos na literatura diferenças em digestibilidade medidas na forragem com diferentes metodologias, seja em material coletado em fistulas esofágicas ou simulações do pastejo através da colheita à mão, corte rentes ao solo e ou estas alturas variando de 2, 5 ou 7 cm, apresentado respostas animais indiferentes.…”