Uptake of Selected Nutrients by Temperate Grasses and Legumes

Abstract

Temperate forages are used throughout the southeastern USA to provide feed for livestock when tropical and subtropical grasses are dormant and as a hay source. Long‐term utilization of broiler litter as a fertilizer in some areas of the region has elevated soil levels of P and micronutrients. Our objective was to compare P, Cu, and Zn uptake among temperate forage species from a Savannah fine sandy loam soil (fine‐loamy, siliceous, semiactive, thermic Typic Fragiudult) amended with litter under a single‐harvest system. Dry weight of ryegrass (Lolium multiflorum Lam.) herbage was greater than all other species except ball clover (Trifolium nigrescens Viv.) in 1997 and oat (Avena sativa L.) in 1998. Clovers were susceptible to Sclerotinia crown and stem rot (Sclerotinia trifoliorum Erikss.) that reduced plant density, vigor, and dry herbage weight. Although forage P concentration of all species was similar to or greater than ryegrass, only crimson clover (T. incarnatum L.) had P uptake equal to ryegrass during both years (mean of 23.4 kg ha−1). This was attributed to the high correlation between dry herbage weight and P uptake (r = 0.95 and 0.89 in 1997 and 1998, respectively). Legumes typically had greater Cu and Zn concentrations than ryegrass, but only crimson clover and hairy vetch (Vicia villosa Roth) had comparatively greater Cu and Zn uptake during both years. The combination of desirable agronomic traits and nutrient uptake capacity make annual ryegrass a superior temperate forage species for use in southeastern pastures fertilized with broiler litter.