Phosphorus Releasing Characteristics of Ogun Phosphate Rock Acidulated with Cashew Nutshell Liquid

The phosphorus (P) release characteristic of Ogun rock phosphate (OPR) acidulated with cashew nutshell liquid (CNSL), an industrial waste, was studied under laboratory conditions for ten weeks. The results showed that the acidulation of phosphate rock with cashew nutshell liquid at a ratio of 4 to 1 released the highest quantity of available P. There was a general increase in the amount of P extracted from the phosphate rock under the influence of cashew nutshell liquid and this was more spontaneous in alkaline media. The peak of phosphorus release occurred at the 56 days of incubation following a form of stoichiometric order. We found the use of the cashew nutshell liquid in this regard as a win-win approach to not only recycle a major waste of cashew processing industries, which will help to maintain a healthy environment, but to deploy the complementary use of this waste in crop production.