Yield and N Uptake by Seven Perennial Grass Species as Affected by High Rates of N Fertilizer

Abstract

Seven species of grass were grown on plots to which N had been applied at progressively increasing rates (0 to 775 kg N/ha) to reach and exceed those required for maximum yields. Yield of hay and protein in all seven grasses increased with N fertilizer. Recoveries of N were only 12 to 31% when applied once, and 8 to 14% when applied every year. Because these recoveries are considered to be uneconomical, massive rates of N fertilizer are not recommended. Intermediate wheatgrass produced the most hay and protein. All seven grasses responded most to applied N in the first 2 years after application, regardless of age of stand.