Effect of Nitrogen and Potassium Fertilizers on Root Growth of Sweet Potato Intercropped with Maize

Abstract

The experiment was carried out at the Bangabandhu Sheikh Mujibur Rahman Agricultural University in order to evaluate root growth of sweet potato intercropped with maize at different application levels of nitrogen and potassium fertilizer. Sweet potato at 100% population density was intercropped with maize at 50% population density at four nitrogen fertilizer levels (0, 50, 100, 150 kg N ha^-1) and four potassium levels (0, 40, 80, 120 kg K₂O ha^-1). Nitrogen and potassium fertilizers were applied in combination in order to observe their individual and combined effect on intercropped sweat potato root growth. Nitrogen and potassium fertilizers did not interact significantly with intercropped sweet potato root growth, yet increased N levels independently increased thickened root number but not tuberization index, tuber diameter or tuber fresh weight. However 100 kg N ha^-1 had the best indices of intercropped sweet potato root growth parameters. Potassium had no effect on tuber initiation although it had a great effect on intercropped sweet potato tuberization index, tuber diameter and tuber fresh weight, Sweet potato without intercropping had the highest tuber diameter and tuber fresh weight. However 100 kg N ha^-1 and 120 Kg K₂O ha^-1 produced the highest number of tuberous roots and a higher tuberization index. ‘These growth parameters narrowed the difference in root growth between sole and intercropped sweet potato.