Assessment of Gypsum as a Soil Ameliorant on Salt-affected Soils in the Ho-Keta Plain of the Volta Region, Ghana

Abstract

Aims: To assess the effectiveness of Gypsum as a chemical ameliorant on three selected salt-affected soils of the Ho-Keta plain, in the Volta region of Ghana. Study Design:  Complete Randomized Design. Place and Duration of Study:  Soil Research Institute, Kwadaso, Kumasi between June 2014 and July 2019. Methodology: Soil sampling was taken in two forms. The initial sampling was taken at a depth of 0-30 cm from Anyako, Anyenui and Atiehife for the soil physical and chemical analysis. Samples were further taken from profiles, composited and sub-sampled for the leaching experiment. Approximately 2.6 kg of the soil samples from the different sites were taken, mixed thoroughly with different rates 0%, 25%, 50%, 75% and 100% of Gypsum, (CaSO4.2H2O) and filled into fifteen perforated polyvinyl plastic pots and replicated four times. The pots were saturated with water, incubated for 24 h and leached intermittently with 120 mL distilled water for a period of four weeks. Results: Significant displacement of Na+ by Ca2+ and subsequently leached became evident in the reduced values recorded for pH, EC and SAR. The applied gypsum reduced pH within a range of 4.0 to 4.2 compared to the original soil with no significant differences among the treatments at p = 0.05. Though a similar trend was observed for EC, significant difference at p = 0.05 was observed at gypsum level above 50%. Sodium adsorption ratio recorded a marked difference as gypsum level was varied with significant difference at p = 0.05 compare to the control.   Conclusion: The study revealed that gypsum rates at 75% and 100% Gypsum requirement were effective in improving the chemical properties of the soils with significant reductions in salinity, sodicity and pH. Atiehife soil performed better compared to Anyenui and Anyako soils.