Predicting crop water uptake under full and deficit irrigation: An example using pea (Pisum sativum L. cv. Puget)

Abstract

The traditional reference evaporation with empirical crop factor approach to irrigation scheduling can now be improved upon (due to the accessibility of personal computers) by using a more dynamic description of the factors affecting crop water uptake. The soil–water balance (SWB) model, which quantifies water uptake as a water-supply- or evaporative-demand-limited process, was successfully adapted to estimate the water-use of pea (Pisum sativum L. cv. Puget) under both well-watered and water-stressed conditions. A growth analysis experiment in Pretoria, South Africa, provided the necessary crop input parameters to the model. Simulations of soil water deficit and canopy growth compared well with independent data sets in a water-stress field trial. The model, developed in a user-friendly format, can be used as a generic crop irrigation scheduling tool, for full or deficit irrigation conditions, provided that specific crop growth parameters are known.