Nitrogen fertilization of smooth bromegrass in Interior and Southcentral Alaska

Abstract

Although forage crops occupy the majority of agricultural land in Alaska, best fertilizer management practices to maximize forage yield and quality in Alaska are not well established. The objective of this study was to determine optimum time and rate of nitrogen (N) fertilizer applications to produce high yields of high quality forage in interior and Southcentral Alaska from smooth bromegrass (Bromus inermus). Nine N fertilization treatments, differing in rate and time of application, were applied at four sites. Forage samples were harvested twice per season in 1999 and 2000 to obtain yield and quality values. Nitrogen applied at 225 kg ha⁻¹ produced greater yields than N applied at 125 kg ha⁻¹, but there were no significant differences between single and split applications. Yield and crude protein content of the control were significantly lower than plots receiving N treatment. Midseason application of N increased crude protein percentages in second cuts at most sites. Acid and neutral detergent fiber were not affected by N treatment. N fertilizer use appeared to be more efficient for split applications, but no significant differences were found. This study showed potential for the production of high yielding, good quality grass forages in Alaska under a variety of N fertilizer strategies.