Modification of the productivity index model

A soil erosion-productivity model which considers the effect of soil water storage capacity, crop evapotranspiration, soil chemical and physical prope rties important for crop growth has been modified. The model is shown to gi ve good predictions and promises to be an improvement over the former produ ctivity index (PI) because it accounts for weather and cropping conditions. It also promises to give more reliable results than the currently used ins ufficient models which consider only soil water storage capacity and crop e vapotranspiration. (C) 1999 Published by Elsevier Science B.V. All rights r eserved.