Field experiment was conducted in 1980–81 on the alluvial soil of Ludhiana to study the effect of N and neem cake on potato. The vegetative growth exhibited a progressive increase with the increasing levels of N at all dates of observations (35, 55 & 75 days after planting). Higher levels of N (80 and 120 kg/ha) delayed the emergence and development of under ground parts but accelerated the rate of tuber formation later. The plant dry weight was largely the reflection of haulms and tubers dry weight at 35 and 75 days after planting, respectively. The N concentration in haulms, was directly related to the level of N and diminished with time. Same was true of N concentration of underground parts at first two observation dates through the treatment effects telescoped at the end. The N uptake by plant parts increased with time, but difference between levels of N became conspicuous after 55 days of planting. About 65 per cent of N remained in haulms under 120 kg N/ha at 75 days after planting. The yield of large tubers increased up to 120 kg N/ha whereas the medium and aggregate tuber yield increased up to 8 kg N/ha. Neem cake had little effect on any of the plant characters at any of the observation date or level of N.
