Auteur: Byrne N. , Berry D.P., Geoghegan A., Shalloo L., Gilliland T.J. and O’Donovan M.
Jaar van uitgifte: 2015
Increasing grass growth and utilisation on Irish dairy farms is shown to have a positive effect on farm profitability. This study was designed to establish the productivity of individual grass varieties under commercial conditions on-farms and compare this to their relative performance in recommended-list plot studies. The objective was to determine to what extent the plot tests are representative of on-farm performances. PastureBase Ireland (PBI) was established in Ireland as the national grassland database. 44 commercial dairy farms across different regions and soil types were selected to estimate grass yield using the PBI decision support tool. On these farms a number of grass varieties were sown as monocultures, each farm sowed the variety Tyrella (diploid ‘D’) (as a control), and a range of other varieties were also sown: AberGain (tetraploid ‘T’), Kintyre (T), AberChoice (D), Twymax (T), Drumbo (D), and Astonenergy (T). The range between the highest and lowest yielding varieties in the first full growing season was 1.6 Mg dry matter (DM) ha‑1, but the level of variability of the on-farm recordings meant that no significant differences were recorded. When the relationship between varieties under simulated grazing plots and on-farm evaluations was examined it was found that every additional Mg of DM ha‑1 in plot evaluations actually represented 0.64 Mg DM ha‑1 on-farm.