Effects of Applied Nitrogen and Phosphorus on Native Grasslands in the Northern Great Plains

The majority of the grazing lands in the Northern Great Plains are native grasslands. In some areas profits derived from these grasslands may best be increased by complete renovation and reseeding. However, many of these grasslands can be improved by practices such as deferred grazing, interseedings, rotational grazing and fertilization. This study involves the evaluation of one of these practices, nitrogen and phosphorus fertilization. It is a study that is to provide basic information which can be used to determi.ne the economic feasibility of grassland fertilization. The purpose of this study was (1) to determine whether significant yield increases could be obtained from nitrogen fertilizer application on native grassland in the Northern Great Plains climate, (2) to determine the extent to which residual nitrogen increases yields in succeeding growing seasons, (3) to determine whether the application of a light rate of phosphorus could produce significant yield increases in soils that are very low in soil test phosphorus levels, (4) to determine the effects of date of nitrogen application on yield and ·(5) to determine the effects of various nitrogen and phosphorus levels and the effects of varying dates of nitrogen application on the content of protein phosphorus, calcium, magnesium: sulfur, potassium, and nitrates in the forage