Evaluation of Pedotransfer Functions for Estimating Soil Moisture Constants: A Study on Soils in Dry Zone of Tropical Sri Lanka
Soil hydraulic parameters often play a key role in resource planning and management in agriculture and
environment. Hence, lack of reliable data on soil hydraulic parameters is one of the major drawbacks in resource planning in
tropical countries. Pedotransfer functions (PTF) can play a significant role in filling this data gap. Therefore, this study aimed
to evaluate the existing PTF developed for tropical soils to identify the potential use for dry zone soils of Sri Lanka. Twenty
two PTF developed by 9 research works were selected to find out the applicability of PTF to predict volumetric water content
(VWC) at -10, -33 and -1500 kPa for tropical soils in dry zone Sri Lanka. Further this study aimed to identify the potential
predictors to develop PTF for dry zone soils of tropical Sri Lanka. Out of the selected 22 PTF, three PTF developed by Botula
et al. (2013) showed better performances compared to other PTF. Sand and bulk density were identified as the probable
predictors to predict VWC at -10 and -33 kPa while Clay was identified as a probable predictor to predict VWC at -1500 kPa.
Keywords - Pedotransfer functions, Sri Lanka, tropical soils, volumetric water content.