Effects of Clipping on Carbohydrate Reserves in Basin Wildrye1

Abstract

AbstractBasin wildrye (Elymus cinerus Scribn. and Merr.) plants are difficult to maintain under spring grazing conditions. The objective of this study was to determine whether an association between carbohydrate reserve depletion and regrowth following clipping occurs in basin wildrye.After establishment, individual, spaced basin wildrye plants were clipped to 10 or 30 cm at three developmental stages in 1971. Total nonstructural carbohydrates (TNC) were measured on these plants 1, 2, 3, and 10 weeks following the initial clipping, and on additional plants, TNC was measured on regrowth of 3 weeks after each initial clipping. Seasonal TNC trends of undipped plants were also determined.Seasonal TNC levels of undipped plants declined rapidly during June. After this time, TNC levels increased through the summer, except for a decline in mid‐August associated with the following year's tiller development. Carbohydrate reserves (TNC) of plants clipped once or twice to 10 cm were significantly lower than for plants clipped to 30 cm at all three developmental stages at all dates. The greatest decline was associated with plants clipped twice to 10 cm. Within 3 weeks TNC was restored with plants clipped to 30 cm, but only slight restoration occurred with plants clipped to 10 cm. Ten weeks after the initial clipping, TNC levels of plants clipped to 10 cm were significantly lower than those of plants clipped to 30 cm.These results indicate that a severe depletion of carbohydrate reserves occurs following clipping. This may be associated with lack of resistance to spring grazing of basin wildrye.