Nutrient and Biomass Allocation in Five Grass Species in an Oklahoma Tallgrass Prairie

Abstract
Partitioning of biomass, N, P and K between various parts of the plant was analyzed to determine if differences exists between Andropogon gerardii, Schizachyrtum scoparium, Sorghastrum nutans, all C4 perennials; Dichanthelium oligosanthes, a C3 perennial and Aristida oligantha, a C4 annual. The C4 annual allocated 15.6% of its plant biomass and 28.0% of its total plant N to reproduction, whereas the C4 perennials allocated < 2.7% total plant biomass and 5.0% total plant N to reproduction. Total plant N in the C4 perennials remained relatively constant after an initial spring uptake. N was conserved by being translocated belowground in the C4 perennials during the autumn and into overwintering leaves in the C3 perennial. Unlike N, P was not efficiently conserved in any species while K was not conserved at all. The difference in the degree of conservation is related to the form in which these elements are found in the plant and the availability of these elements in the soil.