Ecology, Environment and Conservation Paper

DYNAMICS OF SOIL ACIDITY IN THREE ACIDIC RED SOILS UNDER DIFFERENT LAND USE SYSTEMS

H.V. Rudramurthy and Y.P. Shilpashree

Abstract

In the soils under all the land use systems, the magnitude of different forms of soil acidity was in the order of total potential acidity >pH dependent acidity > total acidity > hydrolytic acidity > extractable acidity > exchangeable aluminum > exchangeable hydrogen > non-exchangeable aluminum. Solum weighted average indicated that the magnitude of different forms of soil acidity was more in the soil under paddy land use system than in the soils under current fallow and mixed forest land use systems. However surface horizon of mixed forest land use system recorded the higher amount of total potential acidity and pH dependent acidity than the surface horizons of soils under remaining land use systems. Positive and significant correlation among different forms of soil acidity with exception to non-exchangeable aluminium suggested the possible existence of a dynamic equilibrium among different forms of soil acidity and loss of one form of acidity would be replenished by other forms. In general different forms of soil acidity were negatively and significantly correlated with soil reaction, electrical conductivity and basic cations, while with acidic cations they were positively and significantly correlated. Soil under paddy land use system recorded the highest lime requirement and, the positive and significant correlation of lime requirement with all forms of acidity suggested that different forms of soil acidity must be considered in determining lime requirement of soil.