Fertilizer N and P Effects on Root Mass of Bromegrass, Alfalfa and Barley

Abstract

ABSTRACT Roots play a major role in maintaining organic matter in soil. Six field experiments were conducted to evaluate the effects of fertilizer N and P rates, application times and placement methods on root mass of meadow bromegrass (Bromus biebersteinii Roam and Shultz), smooth bromegrass (Bromus inermis Leyss), alfalfa (Medicago sativa Leyss) and barley (Hordeum vulgare L.) in the surface 15 cm of Black Chernozemic (Udic Boroll) and Gray Luvisolic (Boralf) soils in central Alberta, Canada. Root mass of grasses and barley was markedly increased with N and P fertilization and increase in root mass was greater with band placement than broadcast N. Black Chernozemic soils produced more root mass than Gray Luvisolic soils. Root mass of bromegrass and alfalfa was many times greater than that of barley. Root mass was greater for alfalfa than smooth bromegrass, and for bromegrass-alfalfa mixture than their pure stands. In conclusion, use of N and P fertilizers and growing of bromegrass, alfalfa and bromegrass grass-alfalfa mixture could be employed to increase root mass and possibly increase C storage in soil.