EFFECTS OF NITROGEN NUTRITION OF POTATOES ON MARKET QUALITY REQUIREMENTS
Yield of 80–450g tubers increased 5.7 to 17.1 t/ha as the rate of applied nitrogen increased from 0 to 80 kg/ha. Specific gravity was depressed by rates of applied nitrogen above 80 kg/ha and petiole nitrate-nitrogen concentrations greater than 1.6%. Increasing rates of applied nitrogen were positively correlated in the experiment reported with crisp darkening however this was not substantiated in a further 4 experiments conducted. Significant changes in crisp colour occurred during storage for 2 and 4 months.