Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/6/2000
Publication Date: N/A
Interpretive Summary: Cool-season forage crops are utilized throughout the southeast USA as feed for livestock in the fall and winter when warm-season pasture grasses are dormant, and to produce hay in the spring. Broiler litter, a mixture of chicken manure, feathers, feed, and bedding material that is abundant in many areas of the region, often serves as a fertilizer source for these forages. Long-term application of broiler litter has led to high soil levels of some nutrients that act as potential pollutants of surface water. We conducted this study to evaluate the uptake of these nutrients by cool-season forages commonly used by farmers. Annual ryegrass, one of the most widely-used cool-season forages, usually yielded more hay and took up more phosphorus, copper, and zinc than the other species despite having a lower concentration of these nutrients in the hay. Clovers were susceptible to a fungus that killed plants and reduced plant vigor. Our results suggest that annual ryegrass has the greatest potential among cool-season forage species as a tool to reduce soil nutrient levels.
Technical Abstract: Temperate forages are utilized throughout the southeast USA to provide feed for livestock in the fall, winter, and spring when tropical grasses are dormant. Broiler litter, produced in abundance in many areas of the region, often serves as a fertilizer source for these forages. Our objective was to determine nutrient uptake of commonly available temperate forage species. Single-harvest P, Cu and Zn uptake of annual ryegrass (Lolium multiflorum Lam.) was compared with three small grains, ten annual legumes, and three perennial legumes on a Savannah loam (fine-loamy, siliceous, thermic Typic Fragiudult). Ryegrass yielded greater dry weight than all other species except ball clover (Trifolium nigrescens Viv.)in 1997 and oats (Avena sativa L.)in 1998. Clovers were susceptible to Sclerotinia crown and stem rot (Sclerotinia trifoliorum Erikss.)that reduced plant density, vigor, and yield. Although forage P concentration of all species was similar to or greater than that of ryegrass both years, ryegrass usually had greater P uptake (mean of 23.4 kg ha-1). This was attributed to the negative or low correlation between P concentration and P uptake R=0.12 and -0.11 in 1997 and 1998, respectively), and the high correlation between dry weight and P uptake r = 0.95 and 0.89 in 1997 and 1998, respectively). Although legume Cu and Zn concentration often exceeded that of ryegrass, ryegrass Cu and Zn uptake was greater than that of all legumes except crimson clover (T. Incarnatum L.) and hairy vetch (Vicia villosa Roth).