Research at Grasslands into earthworm activities dates from September 1947, when Sears and staff did a determination of the weight and number of earthworms per square foot in a series of 24 grass and clover plots at Palmerston North. Since then these; 24 plots under mowing have been sampled twice more, a series of 36 similar plots under grazing once, a corresponding 24-plot series at Gore once, and a corresponding 36-plot series at Gore once.
