How to put plant root uptake into a soil water flow model: A documentation with complete computer code.

Abstract

The need for improved crop water use efficiency calls for flexible modelingplatforms to implement new ideas in plant root uptake and its regulation mechanisms. Thispaper documents the details of modifying a soil infiltration and redistribution model to include(a) dynamic root growth, (b) non-uniform root distribution and water uptake, (c) the effect ofwater stress on plant water uptake, and (d) soil evaporation. The paper also demonstratesstrategies of using the modified model to simulate soil water dynamics and plant transpirationconsidering different sensitivity of plants to soil dryness and different mechanisms of rootwater uptake. In particular, the flexibility of simulating various degrees of compensateduptake (whereby plants tend to maintain potential transpiration under mild water stress)is emphasized. The paper also describes how to estimate unknown root distributionand rooting depth parameters by the use of a simulation-based searching method. Thefull documentation of the computer code will allow further applications and new development.