Field Comparisons of Formamide, Urea‐Ammonium Nitrate Solution, and Ammonium Nitrate as Nitrogen Sources for Grasses and Wheat1

Abstract

AbstractFormamide, HCONH2, closely related to urea, is a clear liquid containing about 31% N. It is a solvent for many fertilizer salts, lowers the salting‐out temperature of urea ammonium nitrate solutions (UANS) and makes possible higher concentrations of soluble N, and has a low vapor pressure and a high boiling point. Pot tests have indicated its possible utility as nitrogenous fertilizer but no reports of field plot tests were found. In this study it was compared with UANS and prilled ammonium nitrate (PAN) in 13 field plot experiments. Five of these were on established stands of grasses [(tall fescue (Festuca elatior var. arundinaceae), smooth bromegrass (Bromis inermis Leyss.), orchardgrass (Dactylis glomerata L.), reed canary‐grass (Phalaris arundinacea L.) and eight were on winter wheat (Triticum aestivum L.). All materials were surface‐applied in early April when grasses and wheat were approximately 8 to 13 cm tall, at rates of 28, 56, and 112 kg N/ha. Formamide and UANS were applied as sprays and PAN was surface‐applied in bands 30 cm apart. Observations were made on leaf tip‐burning and lodging. Yields and N contents of grasses and grain were determined. Formamide was an effective source of N but, in general, somewhat less effective than UANS or PAN, as evidenced by lighter green color of plants, lower yield of grasses, less lodging of wheat, and lower N content of wheat grain. Some early leaf tip‐burning on grasses resulted from formamide; no such effects of UANS or PAN were observed.