Comparative Effects of Wood Ash and Calcium Carbonate on the Physicochemical Properties of Soils

Abstract

Soil acidity is one of the soil degradation problems that affects the productivity of soils in Cameroon and Awing in particular and this has led to a steady decline in crop yields in such acid soils. This research aimed to evaluate the effects of two liming materials (wood ash and calcium carbonate) on the physicochemical properties of volcanic-influenced soils of Meupi-Awing, Northwest Cameroon. Two surface soil samples (0–30 cm) were collected and analysed for physicochemical properties before liming. Twenty-four sub-samples (six samples each) were limed separately with wood ash and calcium carbonate respectively for 3 and 6 weeks in a greenhouse incubator in the field and analysed for some physicochemical properties using international standard methods. Correlation analyses were done using SPSS version 20. The effects of liming materials on the soil physicochemical properties showed an increase in pH (from 5.0 to 9.1), electrical conductivity (from 0.03 to 0.60 mS/cm), sum of exchangeable bases (from 7.01 to 48.53 cmolc/kg), available phosphorus (from 5.81 to 86.11 mg/kg) and a decrease in the exchangeable acidity (from 0.26 to 0.00 cmolc/kg). Between the two liming materials, wood ash was generally more effective than calcium carbonate in the amelioration of soil properties, even though the differences were not significant (p > 0.05). This may be due to the fact that wood ash is natural lime that is rich in bases whereas CaCO3 contains only the Ca2+ and CO32- ions. Liming of these soils enhances the availability of nutrient anions and cations for plant uptake while trace elements reported in the study area are decreased from toxic to normal levels since their solubility in the soils is reduced at higher soil pH, hence reducing soil pollution. A minimum lime application rate of 2.70 g/kg soil for calcium carbonate and 7.72 g/kg soil for wood ash is recommended in the study area and in other areas with similar soil types