Mineral Accumulation by Perennial Grasses in a High-Rainfall Environment

Abstract

Mineral content affects the suitability of biomass for thermochemical conversion to bioenergy and represents macro- and micronutrients whose loss from the production system can impact subsequent regrowth and ecosystem services provided by perennial grasses. Genotypic differences in mineral content among cool-season grasses grown for seed are not well documented, and, consequently, the potential for genetic improvement of this trait is not known. This study compared the concentrations of carbon, nitrogen, potassium, phosphorus, chlorine, silicon, aluminum, boron, calcium, cobalt, iron, magnesium, manganese, sulfur, and zinc in leaves and stems from perennial ryegrass (Lolium perenne L.), orchardgrass (Dactylis glomerata), tall fescue (Schedonorus phoenix (Scop.) Holub), and Kentucky bluegrass (Poa pratensis L.) grown in the high-rainfall area of western Oregon. The concentration of C was similar in all grasses and in leaves and stems, but orchardgrass contained the greatest quantities of N, P, and K. The concentration of N was greater in leaf tissue, and similar among these grasses. There were differences in Cl, K, P, and Ca concentrations among these species and between leaf and stem tissues. Genotypic differences in the concentration of some of the minerals occurred among three varieties of tall fescue and among varieties of perennial ryegrass grown at two locations. Amounts of N, P, and K removed by harvest of 2.4 Mg ha − 1 of straw biomass of two perennial ryegrasses would range from 12 to 17, 3.4 to 3.8, and 40 to 47 kg ha −1 . Location had significant impact on mineral content, although plant mineral concentrations were not strictly correlated with soil composition.