Effect of Mid-Summer Haying on Growth and Reproduction in Prairie Forbs

Abstract

Mid-summer haying is a common management practice for prairies; plant species could differ in the effect of haying on subsequent growth and reproduction. We examined the effect of haying on prairie species by performing a clipping experiment. For each of seven species, sixteen plants were chosen and half were randomly assigned to a clipping treatment and half to a control treatment. Experimental plants (and surrounding vegetation) in the clipped treatment were cut to a ten cm height in summer for two years. Measurements of plant height and the number of inflorescences were taken on all plants prior to clipping in June and in the fall each year. For many species, clipped plants were smaller than control plants in the fall after clipping. However, after overwintering, there were few significant differences in plant size or reproductive output between plants that were previously clipped and control plants. Some species, however, did show persistent effects of clipping. For example, both plant size and number of inflorescences were reduced by clipping in Lespedeza capitata. Similarly, clipped plants of Amorpha canescens had fewer inflorescences the year after clipping compared to control plants. Future studies should examine long-term effects of haying on plant growth and reproduction, and explore whether such effects depend on plant life forms or flowering phenologies.