An Investigation Into the Simulation of Nutrient Returns by the Grazing Animal in Grassland Experimentation

An experiment is described that examined mowing with the return of excreta and mowing with the return of clippings as methods of simulating the return of nutrients by grazing animals in experiments where grazing is impracticable. These treatments were applied to a pure grass and to a grass/clover sward. Both methods gave herbage nearer in yield and composition to that resulting from natural grazing than did mowing with no return, but neither was suitable for use on sites outside experimental stations. Although the nitrogen returned in excreta was rather inefficiently used, it appeared to be the major factor in increasing yield on the grass sward and in changing the grass/clover balance on the mixed sward. The return‐treatments had a marked effect on the potassium nutrition of both swards and the results suggest that omitting the grazing animal from trials assessing potassium fertilizer requirements may invalidate the results.