Abstract
Several studies have indicated that clipping or grazing reduces root weights, whereas other studies have indicated little or no change in root weights after defoliation. Root production and carbohydrate reserve stores are important in maintaining forage production after defoliation. Therefore, the effects of intensive defoliations on root weights and carbohydrate reserves of blue grama [Boutelotta gracilis (H.B.K.) Lag.] and western wheatgrass (Agropyron smithii Rydb.) were studied on a shortgrass prairie range. Small differences in root weights among undefoliated and heavily defoliated blue grama and western wheatgrass plants were found. However, undefoliated western wheatgrass plants had significantly more carbohydrate reserves than did the defoliated plants. Resistance of blue grama to grazing may be related to its ability to maintain a vigorous root system and carbohydrate reserve levels after defoliation.