Foliar-Applied Urea and Ammonium Nitrate Fertilizers on Shortgrass Range

Abstract

Liquid foliar applications of urea-N fertilizer were compared with dry and foliar applications of ammonium nitrate-N fertilizer for 3 years, 1969-71. The fertilizers were applied in December, May, June, and July each year on separate plots. Treatments were repeated each year on the same plots. The source of N was far more important than method of application. Whether applied in dry form or as foliar application, the ammonium nitrate-N was superior to urea-N for increasing herbage yields, crude-protein content, and protein yields when applied in December, June, or July. When applied in May, both sources of N were equally effective, regardless of method of application. Ammonium nitrate-N in water solution may be applied as late in the growing season as early July with favorable results. The ammonium nitrate-N applied in July increased nitrate-N in herbage in the third year, although not to toxic levels.