RESPONSE TO MICRONUTRIENT ON CARROTS GROWN ON A VIRGIN SPHAGNUM PEAT

Field studies were conducted over a period of years on a virgin sphagn um peat bog in St. Charles, New Brunswick to determine the effect of t race elements on carrot (Daucus carota L.) root yield and nutrient con centration. Addition of the trace elements, boron (B), molybdenum (Mo) , copper (Cu), and zinc (Zn), did not affect the marketable carrot roo t yields, although yields differed significantly from year to year. Ad dition of B at 10 kg/ha resulted in leaf tissue B concentrations as hi gh as 75 mg/kg. Addition of foliar Mo at 0.14 kg/ha and soil Mo at 0.5 6 kg/ha raised the leaf tissue Mo concentrations to 3 to 4 mg/kg. Copp er applications at 30 kg/ha raised the leaf tissue Cu concentration to 12 mg/kg. Zinc addition at 10 kg/ha did not increase the leaf Zn leve ls which ranged from 44 to 58 mg/kg. The leaf tissue B, Mo, Cu, and Zn levels as low as 29, 0.17, 4, and 44 mg/kg, respectively, were not re lated to deficiency of these elements. Such leaf tissue concentrations of B, Mo, and Cu are marginal for optimum crop production on this bog and should be monitored periodically to detect any significant trends through continuous use of this bog in crop production.