The DRIGrass facility (Drought and Root Herbivore Impacts on GRASSlands) was established in 2013 to investigate the impacts of changes in the frequency and size of rainfall events on a mesic grassland, and the role of root herbivory as a modifier of plant and ecosystem responses. Rainfall treatments include an ambient control, a 50% reduction and a 50% increase in ambient rainfall, a reduced frequency treatment which receives control rainfall amounts in a single event, once every three weeks, and a summer-long rainfall exclusion. Grassland functioning is strongly influenced by rainfall amount and, to a lesser extent, frequency, with the biggest effects associated with summer drought. Ongoing research is evaluating the effects of altered rainfall regimes on plant community diversity, plant-microbial interactions and key ecosystem processes including nutrient and carbon cycling.