CLIPPING DISPOSAL INVESTIGATIONS WITH ROTARY LAWN MOWERS

Traditionally the homeowner has removed clippings when mowing lawns. The removal of clippings is a time-consuming process. In the 1960's a number of professional turfmen questioned this practice, although very little research existed to substantiate this position. Clipping return has been reported to increase the infiltration rate of water into the soils (3). Noer (4) measured the amount of nutrients removed in the clippings from a creeping bentgrass (Agrostis palustris Huds.) green in Milwaukee, Wisconsin. He reported 4.8 pounds of nitrogen, 0.7 pound of phosphorus, and 2.6 pounds of potassium removed annually per 1,000 square feet. Such data indi cate the benefi ci al effects of clippi ng retu rn, particularly the value of nutrient recycling. One objection some homeowners have to clipping return is the residue of brown dead clippings that is sometimes left on the surface of the lawn which creates an objectionable appearance. Under infrequent mowing the resulting layer of clippings can be so thick that light is excluded causing yellowing and weakening of the turf. Unsupported statements can also be found in the literature indicating that clipping return contributes to thatch accumulation. The objective of this investigation was to study the disposition and potential problems associated with clipping return as it relates to non-mulching versus mulching type rotary mowers