Soil Acidity and its Distribution in Laterite Soils of Northern Kerala: A Descriptive Analysis

Soil acidity is one of the major constraints of crop production in tropical soils. A study was conducted to examine different forms of soil acidity, contribution of each fraction to total acidity and distribution of exchangeable Al+3, exchangeable H+ detrital laterite rice wetlands of Kerala. Among the series, the Kalikkadavu series reported the highest exchangeable acidity with a mean of 1.66 ± 0.23 meq/100g at a depth of 0-15 cm. Soils from Angadipuram series showed high values for exchangeable hydrogen with a mean of 0.71 ± 0.87 meq/100g and a range of 0.2- 3 meq/100g. Kalikkadavu series reported a high value for exchangeable hydrogen with a mean value of 1.29 ± 0.23 meq/100 g. Regarding potential acidity, Nanminda series reported the highest with a mean value of 40.2 meq/100g. Descriptive statistics of pH dependent acidity data revealed highest acidity for Nanminda series in surface layer with a mean value of 39.27 ± 1.77 meq/100g while in subsurface soils, Arathil series has reported the highest with a mean value of 32.21 ± 3.28 meq/100g. From the paired t-test analysis, significant variations of potential acidity and pH-dependent acidity were observed across surface and subsurface while exchangeable acidity, exchangeable Al+3, exchangeable H+ have shown non-significant variation.Hence, we recommend a proper soil management system that lowers the surface and subsoil acidity in low-pH soil. Again, for best effects in terms of biomass production and economic crop yields, amelioration of soil acidity should be followed by optimum plant nutrient inputs.