PERFORMANCE OF WATER CHARACTERISTICS MODEL IN SELECTED WETLAND SOILS IN ZARIA, NIGERIA

PERFORMANCE OF WATER CHARACTERISTICS MODEL IN SELECTED WETLAND SOILS IN ZARIA, NIGERIA

Abstract:

The performance of Soil Water Characteristic Hydraulic Properties Calculator (SWC-HPC) model to predict soil water characteristic of some wetlands in Zaria, Nigeria, was evaluated and reported herein. The objective of the study was to establish the predictability and reliability of the SWC-HPC model, and hence it use in determining water characteristic of wetland soils in the study area. Ninety soil samples collected in August, 2013 from three wetland sites were used in the evaluation. The wetland sites include Hayin Agoi in Giwa local government area along Shika Road, Rafin yerima in Basawa local government area and Kubani multipurpose Maje road in Tudunwada local government area. The soils particle size distribution (specifically percent clay and sand), organic matter contents and salinity were inputted into the model to simulate soil moisture status at saturation, field capacity, wilting point, and soil bulk density. The model outputs were statistically compared with observed parameters from laboratory tests using Root Mean square Error (RMSE), Coefficient of Variation (CV), Modeling Efficiency (EF) and Coefficient of Residual Mass (CRM). The model was able to predict the bulk densities of the soil tested and also was able to predict the soil moisture content at field capacity and wilting point. The coefficient of residual mass (CRM) revealing that the model under predicted moisture content at saturation with 0.26 (26 %), 0.26 (26 %) and 0.24 (24 %). Moisture content at field capacity under predicted at 0.01 (1 %), 0.26 (26 %), 0.24 (24 %) moisture content at wilting point was under predicted with 0.04 (4 %), 0.07 (7 %). The model under predicted bulk density at 0.2 (2 %), 0.52 (52 %) and 0.24 (24 %). The SWC-HPC may therefore be used only to simulate soil bulk densities and moisture status at field capacity and wilting point in the study locations.

PERFORMANCE OF WATER CHARACTERISTICS MODEL IN SELECTED WETLAND SOILS IN ZARIA, NIGERIA