Evaluation of Three Soil Test Kits for the Determination of Soil pH of Cacao Plantations in Nigeria

Abstract

pH of soils planted to cocoa in Nigeria ranged between slight acidity to near neutral. Soil fertility management of such plantations should ensure no further decrease in the pH of the soil, hence the need to monitor the soil pH. Conventional analytical laboratory methods of soil analysis are presently being used for soil analysis on limited scale in Nigeria. These methods employ mostly imported sophisticated, electricity dependent and expensive equipment which makes soil testing quite expensive. Most of the cocoa farmers in Nigeria are resource limited small holders who cannot afford the cost of conventional soil analytical methods hence there is an urgent need to explore the use of affordable quick soil test kits for soil testing. Three soil test kits (LaMotte, Rapitest, Hanna soil test kits) and conventional analytical methods were evaluated at the Department of Soil and Water Science Laboratory, Tropical Research and Education Center, University of Florida for the determination of soil pH of soils collected from different cocoa plantations in Nigeria. The results from the kits were compared with those obtained by means of conventional analytical method. The t- test values of 0.091 and 0.483 obtained when comparing conventional analytical methods with each of LaMotte and Hanna test kits at p=0.05 indicated that there was no significant difference between each of these two test kits and the conventional method for pH determination. Rapitest kit could not detect pH values below 5. It was an indication that Rapitest might not be good for determination of soil pH of acidic soils with pH values below 5.