
%0 Journal Article
%A Passioura, JB 
%A Frere, MH 
%T Numerical analysis of the convection and diffusion of solutes to roots
%J Soil Research
%D 1967/12/01
%V 5
%N 2
%P 149-159
%K 
%R https://doi.org/10.1071/SR9670149
%U https://www.publish.csiro.au/paper/SR9670149 
%X A numerical method is given for solving a partial differential equation describing the radial movement of solutes through a porous medium to a root. Computer programmes based on the method were prepared and used to obtain solutions of the equation for an idealized root-soil system in which a solute is transported to the root by convection but is not taken up by the root. Various patterns of water uptake were considered, the most complex being a diurnally varying uptake from soil in which the water content is decreasing. The solutions suggest that the maximum build-up of solute at the surface of a root is trivial if the root is growing in a medium such as agar, in which the diffusion coefficient of the solute is high, but may be considerable, with a concentration up to 10 times higher than the average concentration in the soil solution, when the root is growing in a fairly dry soil. The application of the method to systems other than the one considered in detail is discussed. 
