Roots
One last structure we need to talk about with grasses is the roots. Grasses have a fibrous root structure that functions to absorb water, take up nutrients, and anchor the plant. In perennial grasses, roots often account for up to 80 percent of total plant weight. When subject to heavy defoliation and disturbance, root mass can be reduced by as much as 50 percent. The following pictures demonstrate roots developing on a perennial grass seedling (Exhibit 29) and fibrous roots extracted from a mature grass plant (Exhibit 30).
Exhibit 29. Fibrous roots forming on a switchgrass (Panicum virgatum L.) seedling. Photo credit: John Guretzky, University of Nebraska-Lincoln
Exhibit 30. Fibrous roots extracted from a section of soil 24 inches wide, 30 inches deep, and 3 inches thick below a mature stand of big bluestem (Andropogon gerardii Vitman). Photo credit: John Guretzky, University of Nebraska-Lincoln