**Pathankot (Punjab).
***Haryana Agricultural University, Hissar.
Punjab Agricultural University, Ludhiana
Present Address: *Professor and Head, Department of Vegetable Crops, Haryana Agricultural University, Hissar.
In the field having low content of available nitrogen (210 kg N/ha) four levels of nitrogen (0, 80, 120 and 160 kg) applied through poultry manure, farm yard manure and their combination with fertilizer, showed significantly increasing response to each addition. A combination of 80 kg N through poultry manure and 80 kg N through fertilizer gave maximum yield. Crude protein and phosphorus concentration in the tubers increased considerably with the increasing levels of nitrogen while water soluble carbohydrates and starch contents were found to increase only upto 120 kg N level and declined with the higher application of nitrogen.
