EFFECT OF NITROGEN FERTILIZER AND CLIPPING FREQUENCY ON THE DRY MATTER YIELD AND PERSISTENCY OF INTERMEDIATE WHEATGRASS
The effects of six rates of N fertilizer and five frequencies of clipping on the dry matter yield and persistency of irrigated intermediate wheatgrass, Agropyron intermedium (Host.) Beauv., were studied during 1961–62 at one site, and 1963–65 at a second site.The dry matter yield increased with increasing rates of N fertilizer, and with longer intervals between clippings. Highest yields were obtained with the 375-kg/ha rate of N fertilizer and the 8-week clipping interval.Fertilizer level did not have a significant effect on either the basal ground cover of grass or the degree of winter injury suffered by intermediate wheat-grass. However, clipping frequency was closely related to both of these factors.Application of a regression analysis to the study of significant interactions among management factors proved to be a very useful statistical approach.