ARS | Publication request: Nitrogen Rates for Dryland Triticale Hay

Submitted to: Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: January 15, 2010
Publication Date: March 2, 2010
Citation: Vigil, M.F., Poss, D.J., Halvorson, A.D. 2010. Nitrogen Rates for Dryland Triticale Hay. Great Plains Soil Fertility Conference. Pages 189-194. March 2-3, 2010. Denver, CO.

Interpretive Summary: Fertilizer costs have increased nearly 70% in the last 7 years. This increase in cost has coincided with a decrease in dryland crop yields due to drought. The question then becomes “should optimal N fertilizer rates be less in dry years with low yields” and if so, “how much less”? Another consideration is “how does optimum fertilizer N rate change with commodity price and N cost”? Dryland farmers/ranchers in the CGPR have recently taken an interest in triticale as a hay crop. Triticale is well adapted and its forage is palatable and nutritionally competitive with other annual forages grown in the region. On deficient soils, triticale’s forage-yield response to applied fertilizer-N is impressive. Our objective here was to quantify the response of dryland triticale to applied N and to residual soil inorganic N. Winter triticale was planted into either wheat or millet stubble over three site years at the USDA-ARS Central Great Plains Research Station. In three experiments (1995, 2007, and 2009) just prior to planting, the crop was top-dressed with 0, 20, 25, 40, 50, 60, 75 80, 100 and 120lbs of fertilizer N as urea or ammonium nitrate in a typical replicated randomized complete block design field experiment. Forage yield was harvested and quadratic N response equation was fitted to the measured yield response and economically optimum N rates (EONR) tables were generated using the fitted N response equations. These tables can be used by producers to select optimal N rates for triticale hay based on hay price, N price and expected hay yield for dry years, average years and wet years.

Technical Abstract: Dryland farmers/ranchers in the CGPR have recently taken an interest in triticale as a hay crop. Triticale is well adapted and its forage is palatable and nutritionally competitive with other annual forages grown in the region. On deficient soils, triticale’s forage-yield response to applied fertilizer-N is impressive. Our objective here was to quantify the response of dryland triticale to applied N and to residual inorganic N. Winter triticale (cultivar NE422T) was planted into either wheat or millet stubble over three site years at the USDA-ARS Central Great Plains Research Station. In two experiments (2007-2009) just prior to planting, the crop was top-dressed with 0, 25, 50, 75 or 100 lbs of fertilizer N as urea or ammonium nitrate in a typical replicated randomized complete block design field experiment. In an earlier (1995) experiment, using similar design and methods, winter triticale (NE422T) was fertilized at 0, 20, 40, 60, 80 and 120 lbs of fertilizer N per acre. Forage yield was harvested just as the awns were beginning to emerge from the boot. A quadratic N response equation was fitted to the measured yield response and EONR tables were generated using the fitted N response equations.