Rooting Characteristics of Native Grassland Species in Saskatchewan

Abstract

The nature and extent of underground parts of the principal species of native grassland were examined to discover the extent of variation in root development caused by differences in climate and microclimate and to relate these differences to relative competitive ability of species. The root systems of 914 plants of 56 species were examined in 27 excavations along a 300-mile transect. The nature of the root system of 33 species is reported for the first time. Agropyron smithii and A. dasystachyum were the only major graminoids commonly rooted deeper than 1.2 m, Koeleria cristata, Bouteloua gracilis and Carex eleocharis were 40-90 cm deep, while Stipa comata, S. spartea var. curtiseta and Festuca scabrella were intermediate in depth. Bunch grasses extended 15-30 cm laterally and produced 4 to 5 times as many main roots as shoots. No differences are shown in depth of the dominant grasses of different soil zones (climates). However, when the same species occurs along a climatic gradient, there is a definite trend among both grasses and forbs for deepest penetration in the drier climate. On tops of knolls many species are more shallowly rooted than on protected slopes. No difference is shown between the depth of the same species on mesic and xeric slopes in the same locality, but the species associated with them (but not present in both habitats) tend to be deeper in the xeric position. In sand mesophytic species develop more deeply than in loam, while xerophytic species tend to have superficial development. Lateral roots of forbs are more abundant and longer in sandy soil than in loam, while no such difference is shown for grasses.