Department of Soils, Punjab Agricultural University, Ludhiana, 141004, Punjab
In a field experiment conducted on a Fatehpur loamy sand (Fluventic Ustipsamment) alkaline, non-calcareous soil at the Punjab Agricultural University farm, four levels of N from calcium ammonium nitrate (CAN) and urea were applied with or without farmyard manure (FYM). Compared with urea, CAN was found to be superior source of fertilizer N for potato. FYM increased the potato yield irrespective of the source of nitrogen. Maximum response dose in the presence of FYM was 198 kg N/ha from CAN and 174 kg N/ha from urea whereas without FYM the respective values were 194 and 137 kg N/ha. The critical nitrogen concentration in potato leaves at pre-bloom stage was 5.35 per cent.
Leaf analysis, nitrogen dose, critical level, potato
