Root-depth profiles of important agricultural crops

Based on a literature review we describe root density profiles in terms of a logistic dose-response function for important global agricultural crops (wheat, maize, rice, barley, soybean, pulses, cotton, potato, sunflower, rye, rapeseed, and sugarbeet). These root density profiles can be used in 1-D macroscopic root water uptake models. For use in 1-D microscopic root water uptake models, we analyze root density data in terms of the half mean distance between roots. Based on the database there is little support for a predictive relationship between parameters of the root density distribution of agricultural crops and climate or management factors. Constancy of the shape of the root density distribution with time is shown not to hold in some experiments, but evidence is anecdotical. At present the basis to describe rooting profiles with depth only seems to allow profiles which are constant in time and with depth. The correlation between half mean distance and drought sensitivity is investigated and conclusions will be presented.