Tiller Dynamics of Two Grasses--Responses to Grazing, Density and Weather

The tiller dynamics of the two dominant species in a grassland, Agrostis stolonifera and Lolium perenne, were followed for two years in a field grazing experiment. Sheep grazing was applied in three seasons at two grazing intensities; winter, spring (in both seasons grazed or ungrazed) and summer (hard or light grazed). Tiller densities of both species showed peaks in late summer and troughs in spring due to variation in tiller birth rates. Tiller death rates were not seasonal. Year-to-year weather variation also arected the dynamics. Harder summer grazing increased tiller birth and death rates of both species, increasing tiller turnover, but did not affect tiller densities (...)