Seasonal Fluctuations of Blue Grama Roots and Chemical Characteristics

Root collections of blue grama (Bouteloua gracilis (H.B.K.) Lag.) were made at intervals near Manyberries, Alberta, over a 3-year period. Root samples, after being weighed, were analyzed for C,N, ethanol/benzene-extractable C, methoxyl groups, lignin, soluble and structural carbohydrates, and calorific value. Significant fluctuations occurred over the seasons for all characteristics. Over 50% of the root mass was lost between October and May. This occurred regardless of soil moisture levels. The relationship of (C:N)(% lignin)/(% carbohydrate^-0.5) showed significant differences between the roots collected in the fall and those collected in spring and early summer. The chemical composition of the roots in the fall may have to be considered in explaining root mass losses between October and May.