Abstract
In the study a hydroponic medium was prepared from black cotton soil and rice husks. The process involved mixing, moulding, firing and size reduction. The aggregates were prepared at 750°C, 30 minutes and 9:1 for firing temperature, time and ratio of black cotton soil to rice husk (on a weight basis) respectively. Size reduction was done to give a 90:5:5 composition of sand, silt and clay sized particles. The Hydrus 1D version 4.16.0110 model was used to estimate the hydraulic parameters. The results were 0.1 cm3 cm-3, 0.55 cm3 cm-3, 0.01, 1.91, 0.00368 cm s-1 and -1 for Өr, Өs, ά, n, Ks and l respectively. The goodness of fit (R2) and Root Mean Square error (RMSE) used to evaluate the model gave values of 0.83 and 0.0895 cm3 cm-3 respectively. This showed that the model estimations were within acceptable ranges and can be applied to determine the water retention and hydraulic conductivity of the expanded black cotton soil aggregates at varied saturation.
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