Response of potato to nitrogen application at different growth stages*

Field studies undertaken on loamy soil of Shimla with 4 potato (Solanum tuberosum L.) cultivars to evaluate response of potato to N application at various growth stages revealed that the optimum doses for N in Great Scot, Kufri Chandramukhi, Kufri Jyoti and SLB/Z-405(a) were 150,88,93 and 150 kg N/ha, and the yield ranged from 462 q in Kufri Jyoti to 328 q/ha in SLB/Z 405(a). N recovery varied from 17% at tuber initiation to 41% at tuber bulking stage. There was positive interaction between N application rate and hauhns yields. N applicaton tended to increase N and P content in haulms and tubers but decreased K content. Nutrient accumulation in different plant parts was in order of Great Scot, Kufri Chandramukhi, Kufri Jyoti, SLB/Z-405(a) and was maximum at 115 days.