Phosphorus Release Dynamics in Sweet Potato Production

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.