With increasing frequency of dry and hot events, ryegrass-dominated grasslands become more vulnerable to infestation by the drought and heat resistant, but unpalatable C4 grass Setaria pumila. Grassland management must therefore be readjusted to strengthen resilience against weather hazards and resulting weed infestation. We investigated strategies to strengthen high quality forage grasses, as well as overseeding grass species more resistant to drought than ryegrass. The study involved a factorial experiment testing mowing height, time interval between harvests and overseeding, and an on-farm survey on the effects of farmers’ management practices on S. pumila abundance in 31 grasslands. Increasing mowing height from 3 to 8 cm or skipping one or two harvests during the summer months reduced S. pumila abundance during the years of strong infestation. These management options were also clearly beneficial for the abundance of forage grasses in the sward. A negative relationship between S. pumila abundance and mowing height was also observed in the on-farm survey. Overseeding cocksfoot significantly increased its abundance only by the fourth experimental year. We conclude that careful management focusing on the competitive ability of forage grasses is an important driver of grassland resilience against infestation by S. pumila.
