Studies were carried out in 2000–2002 on the soil of light loamy sand type. The reproduction material – seedlings of cv. Canuana produced due to in vitro micropropagation – originated from Western Guinea. The biological value of Ipomoea batatas tubers was great. It much
exceeded tuber plants cultivated in Poland such as potato or Jerusalem artichoke as regards dry matter, starch, sugars, total and specific protein levels. Fertilization of sweet potato with nitrogen dose 100 kg ha-1 appeared to be profitable and sufficient considering the content of: dry mass, starch, total and specific protein, vitamin C, nitrate and ash in tubers.