Phosphorus Release Dynamics in Sweet Potato Production
Isiaka Kareem *
Department of Agronomy, University of Ilorin, P.M.B. 1515, Ilorin, Nigeria
E. A. Akinrinde
Department of Agronomy, University of Ibadan Ibadan, Nigeria
O. F. Adekola
Department of Agronomy, University of Ilorin, P.M.B. 1515, Ilorin, Nigeria
T. B. Salami
Department of Agricultural Education, Emmanuel Alayande College of Education Oyo, Oyo State, Nigeria
Yusuf Oladosu
Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400 Serdang, Selangor, Malaysia
*Author to whom correspondence should be addressed.
Abstract
Soil phosphorus (P) toxicity in tuber production is a significant issue and to solve this problem and have optimum tuber yield at a lesser cost of P-fertilization, knowledge in depth on the dynamics of phosphorus release in sandy loamy soil is necessary. Therefore, the present work was carried out to assess the trend of P-release from the application time to the period of its optimum release along with its effects on sweet potato growth and tuber production. For obtaining so, a 5-week incubation study under laboratory conditions was performed to study P-release dynamics using different P sources. Another similar field experiment was concurrently conducted using the same P sources and application rates to monitor the influence of P-release rate on sweet potato production. Various parameters, namely leaves, vine length, tuber yield, soil extractable phosphorus and leaf phosphorus uptake were taken into consideration. Relationships were also established between P-uptake and tuber yield, number of leaves and vine length. The curve of the trend of the phosphorus release was S-shaped. Also, P-application improved the production of leaf and vine length while tuber yield was suppressed. The study recommended that P-fertilizer should not be applied at close intervals even if its effects are yet to be felt on plants.
Keywords: Incubation, phosphorus sources, phosphorus uptake, P-release dynamics and tuber yield