Je-ar M. Colipano, Luz G. Asio and Nello D. Gorne
Sweetpotato yield may be increased through effective crop management practices including plant spacing and fertilization. This study was conducted in an alluvial soil (Inceptisol) to evaluate the effects of plant spacing and rates of NPK application on the growth and yield of NSIC Sp30 sweetpotato. The experiment was laid out in a split plot arranged in RCBD with three replications. Three plant spacing treatments were designated as the main plot D1(75cmx25cm), D2(100cmx25cm), and D3(100cmx50cm). The rates of NPK application were designated as the subplot: F0(no NPK), F1(40-40-60kg ha-1 NPK), F2(60-60-90kg ha-1 NPK), and F3(80-80-120kg ha-1 NPK).
Plant spacing significantly affected the number of lateral vines, weight of marketable roots, number of marketable roots, root length, and the total root yield of NSIC Sp30 sweetpotato. An interaction effect was observed between the plants spaced at 100cmx50cm with NPK application resulting in more medium-sized roots. Plants spaced at 75cmx25cm produced the highest total root yield of 7.67t ha-1.
Application of NPK significantly influenced the length of main vines, fresh herbage yield, the weight of marketable roots, number of marketable roots, root length, root diameter, total root yield, LAI and HI. A higher yield of marketable roots 7,208.85kg ha-1 and a total root yield of 8.51t ha-1 were observed for plants applied with 40-40-60 kg ha-1 NPK. The growth and yield performance of NSIC Sp30 is better when plants are spaced at 75cmx25cm with 53,333 plants ha-1 and fertilized with 40-40-60kg ha-1 of NPK.
Keywords:NPK fertilization, NSIC Sp30, plant spacing, plant population