Responses of Crested Wheatgrass to Various Clipping Treatments

Abstract

West, this species was selected for study. The investigations were designed to determine its response to various intensities, frequencies, and seasons of herbage removal under favorable (artificially watered) and unfavorable (arid) environment. The responses were evaluated on the basis of forage yield, chemical composition of herbage, apparent vigor, seed production, root yield, and root reserves. • REVIEW OR LITERATURE The effect of frequency and intensity of clipping on the yield and vigor of various pasture and range plants has received considerable study. These investigations have dealt with a great variety of conditions and methods and in general they show that yield and vigor decrease as frequency or intensity of clipping is increased (

Regrowth of crested wheatgrass (Agropyron cristatum [L.] Gaertn.) following defoliation

“…The GDD needed for regrowth to peak in crested wheatgrass appears to be affected by precipitation following grazing. Precipitation increases biomass production of desert wheatgrass after defoliation (Cook et al 1958); however, our findings suggest that it may take longer for crested wheatgrass to reach peak regrowth under moist conditions. When dry conditions prevail, regrowth may peak sooner, but yields will be less, as demonstrated in Lolium spp.…”

“…As with crested wheatgrass, late season defoliation of desert wheatgrass reduced herbage yield more in subsequent years than did early season defoliation (Cook et al 1958). Standing crop in early May 1991 of crested wheatgrass defoliated in 1990 was similar among treatments, likely because current photosynthesis in the spring offset reduced energy reserves or pools of carbon available for growth (Richards and Caldwell 1985).…”

“…Thus, even with relatively wet conditions after late season defoliation, regrowth of crested wheatgrass was minimal or nil. It is not clear whether this limited growth was caused by temperature or by water limitations; however, regrowth of desert wheatgrass following defoliation is limited by soil water deficits (Cook et al 1958;Mohammad et al 1982). When crested wheatgrass is grazed during later stages of vegetative growth, total annual biomass production is reduced compared with production from earlier or later grazing because growth is interrupted or cannot continue after defoliation, respectively.…”

“…When crested wheatgrass is grazed during later stages of vegetative growth, total annual biomass production is reduced compared with production from earlier or later grazing because growth is interrupted or cannot continue after defoliation, respectively. Biomass production by desert wheatgrass also is reduced when grazed in mid-season compared with early or late season defoliation (Cook et al 1958;Hyder and Sneva 1963).…”

“…Rest periods that plants require following grazing must be understood and controlled as overgrazing occurs when plants are grazed again before they have recovered from a previous grazing (Voisin 1959). Overgrazing of plants reduces above-and below-ground biomass (Cook et al 1958), carbohydrates (Buwai and Trlica 1977a,b;Stroud et al 1985), growth rates (Hume 1991;Willms 1991), and increases tiller mortality (McLean and Wikeem 1985), compared with plants receiving adequate rest between defoliations.…”