SIMULATING ROOT-GROWTH DYNAMICS

We present a simple root-growth model that is capable of reproducing r oot distribution patterns as conditioned by varying soil conditions. T he model assumes that the lateral growth of roots at any depth is gove rned by two factors: (i) the current root mass or root-length density at a given depth, and (ii) an environmental factor that may limit the further growth of roots at that depth. Using the relative soil-water c ontent as the environmental factor, it is shown that an exponentially declining root distribution, commonly observed under wet soil profiles , can be reproduced by the model. Other non-exponentially declining ro ot profiles observed under spatially varying soil-water contents can b e simulated. The results indicate that the simple root model is capabl e of predicting differing root growth and distribution patterns, consi stent with empirical observations under varying soil conditions. Copyr ight (C) 1996 Published by Elsevier Science Ltd