Prediction of the Lifting Forces for Cassava Harvesting

An analytical model, based on knowledge in soil dynamics, is presented for predicting the lifting force requirement of a flat plate submerged in the soil. The input to the model includes soil mechanical properties namely, cohesion, angle of shearing resistance and unit weight, and also the size of plate and depth in the soil. Predictions of lifting force were in close agreement with those obtained from soil bin experiments. Furthermore, the model was modified to take into consideration the contribution of the roots to soil shear strength and then used to predict cassava lifting forces. A comparison between the predicted lifting forces of cassava were significantly higher than the values observed in a separate experiment.