NUTRIENT CONCENTRATIONS IN GRASS AND LEGUME FORAGES OF NORTHWESTERN MANITOBA

Abstract

Concentrations of Mo, Cu, Zn, Mn, Fe, N, Ca, P, Mg and K were determined in native and introduced grasses and legume forages from throughout northwestern Manitoba. Nutrient concentrations were compared with minimum requirements of cattle suggested by the Agricultural Research Council and the National Academy of Sciences–National Research Council. Differences in Mo concentrations were noted in forages between two geologic subareas within the study area. Cu and Mo concentrations suggested potentials for primary Cu deficiency in grasses throughout the region, and for Mo-induced Cu deficiency with grasses west of the Swan River formation and with legumes from all areas within the region. Throughout the study area, concentrations of Zn and Mn were found to be at deficient levels while those of Fe and Ca were found to be at adequate to excessive levels for cattel production. N and P concentrations in all forages were borderline to adequate, while Mg and K concentrations of grass forages were deficient to borderline with relation to the requirement of cattle.