Herbage accumulation, tiller population density, and sward components of prairie grass under different nitrogen levels

Abstract

Two trials were performed to study the effect of nitrogen fertilisation on prairie grass (Bromus catharticus) sward characteristics, and to compare the agronomic performance of this species with that of Italian ryegrass (Lolium multiflorum). Both trials were carried out in the Humid Pampa in Argentina. In both trials, annual herbage accumulation depicted a linear model with increasing nitrogen levels. Increases in tiller population densities due to nitrogen fertilisation were more evident in late winter. Tiller categories and sward components were relatively unaffected by nitrogen fertilisation. Until mid spring, prairie grass and Italian ryegrass accumulated similar total herbage masses, but Italian ryegrass exhibited earlier growth than prairie grass and the latter was superior from late spring onwards. Dry matter digestibility was higher in Italian ryegrass than in prairie grass from early to mid spring. It was concluded that prairie grass could be a complementary annual crop in the Humid Pampa in Argentina.