Determination of optimum NPK level for cultivation of sweet potato cultivars in Samoa

Siose, Taniela K. and Kader, Md. Abdul (2019) Determination of optimum NPK level for cultivation of sweet potato cultivars in Samoa. Advances in Horticultural Science, 33 (2). 00-00. ISSN 0394-6169 (Unpublished)

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Abstract

Establishment of a sound fertiliser dose is necessary in achieving higher yield, soil fertility management and environmental sustainability. Currently, there is no available data pertaining to the optimum fertiliser requirement in sweetpotato under Samoan conditions. To achieve this, a preliminary experiment was conducted to determine the optimum NPK levels in three sweetpotato cultivars under both screen house and field conditions of Samoa. Treatment combinations including four levels of NPK in kg/ha equivalent (control, 30:30:30, 60:60:60, and 90:90:90) and three improved sweetpotato cultivars (IB/PH/03, IB/PR/12, and IB/PR/13). Results revealed that each cultivar exhibited remarkably varied responses to NPK levels. Yield of IB/PH/03 increased consistently with increasing NPK levels indicating that the applied NPK levels was insufficient to determine optimum NPK level. Cultivar IB/PR/13 followed a typical crop response curve, however, IB/PR/12 failed to produce significantly higher yield with increased level of NPK. Based on a quadratic model, the putative optimum NPK level for IB/PR/13 and IB/PR/12 was determine 49-49-49 and 54-54-54 kg/ha respectively, however, the most profitable levels for both cultivars was 30-30-30 kg/ha. Although the profitable level was the highest NPK level for IB/PH/03, its optimum NPK was not correctly determined in this study. Further studies are recommended on wider soil conditions including higher dose for the high yielding IB/PH/03 to verify the result obtained in this study before establishing a sound fertiliser recommendation.

Item Type:	Journal Article
Uncontrolled Keywords:	Crop response curve, Fertiliser, Nutrient utilisation, Sweetpotato, Samoa
Subjects:	S Agriculture > S Agriculture (General)
Divisions:	Faculty of Business and Economics (FBE) > School of Agriculture and Food Technology
Depositing User:	Md. Abdul Kader
Date Deposited:	30 Jul 2025 00:58
Last Modified:	30 Jul 2025 00:58
URI:	https://repository.usp.ac.fj/id/eprint/11715

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