VARIOUS FORMS OF NITROGEN FERTILIZER FOR BROMEGRASS ON A SOLONETZ SOIL

Abstract

Ammonium nitrate, ammonium sulfate and urea, applied to provide nitrogen at a rate of 112 kg/ha annually, were compared as fertilizers for bromegrass on a Solonetz soil. All were equally effective in increasing yield except in the drought year, 1966, when urea was less effective than the others. About 45% of the nitrogen applied as urea was recovered in the crop, compared with over 55% from the other forms. This difference was most pronounced in the driest year. The reduction in soil pH from 5.3 to 4.0 with the use of ammonium sulfate indicated that this was an undesirable source of nitrogen for these soils that are already high in sulfur. Nitrate levels in the crops were highest in the years of adequate rainfall and were generally increased about equally by each fertilizer. However, all crops contained well below recognized toxic levels.