High Rates of Nitrogen Fertilization Influence Coastal Prairie Range

Abstract

Nitrogen at four rates, 100, 300, 600, and 900 lb/acre, and a combination of 900 lb N, 100 lb P2O5/acre were applied to a bunchgrass-annual forb community in a randomized complete block design in 1965. Fertilization with nitrogen and nitrogen with phosphorous increased the total production in all cases, although grass production decreased in 1967. Nitrogen content and protein content of forage increased with all rates of fertilization. Phosphorous content increased only when phosphorous was added to the nitrogen fertilizer. There was no change in potassium content with any treatment. Residual amounts of phosphorous occurred in the soil one year after fertilization. Cattle grazed fertilized strips more heavily than the control plots. Both the percent utilization and pounds of herbage increased with fertilization rate. There was no difference in the amount of residual material left after grazing.