CONTRIBUTIONS OF SHOOT N, P AND K TO SWEET POTATO (Convolvulus arvensis L.)
Publication Date : 31/03/2015
Trials were conducted during the dry seasons of 2013/2014 at the Irrigation Farm, Institute for Agricultural Research, Samaru to test the response of four varieties of Sweet potato((PR-6, TX PR, LA 07-146 and B-14) to four rates of NPK fertilizer (0, 300, 600 and 900 kg/ha), two forms of seed tuber (whole and cut-tubers). Positive and highly significant correlation (P = 0.01) was observed between tuber yield and shoot N (r = 0.47, 0.74 and 0.57), P (r = 0.51, 0.41 and 0.57) and K (r = 0.33, 0.48 and 0.47) during the dry seasons of 1998/99 and 1999/2000 and the combined of the two seasons, respectively. A strong and positive relationship (P = 0.01) was also found when shoot N, P and K contents were correlated among each other during the two seasons and the two year combined except in 1998/99 dry season when a positive though non significant correlation was observed between shoot N and shoot K (r = 0.15). The direct contributions of shoot N and P to tuber yield were generally much higher than the indirect contributions except for shoot K whose indirect contribution to tuber yield out weighed that of the direct contributions in most cases.