Abstract
Two field experiments were conducted (a spring and an autumn) during 1996-97 to study the effect of application of two nitrification inhibitors (nitrapyrin and wax-coated CaC2) at two N rates (100 and 250 kg N ha-1) on fertilizer use efficiency (FUE), N recovery, yield of potato (Solanium tuberosum L.), and to compare it with split application of N. The results revealed that the treatment receiving inhibitors had more mineral N accumulation than the treatment receiving no inhibitors in the active root zone (0-30 cm) up to 65 days after sowing (DAS). Ammonium was a major fraction of mineral N in the treatments receiving inhibitors. At 95 DAS, the soil at 0-30 cm depth did not show major differences in the mineral-N status of treated and untreated plots. However, at 60-90 cm and 90-120 cm depths, the treatment receiving no inhibitors contained higher NO3-N indicating greater NO3 leaching from the active growth zone. Maximum tuber yield and N concentration was obtained at low N level treated with nitrification inhibitors followed by two split applications of 250 kg N ha-1.
