Irrigation rate should correspond to the effective root depth, however, crop root growth
is influenced by a number of factors, and little data is available on the impact of irrigation. This
contribution presents the results of several experiments in which the influence of sprinkler or drip
irrigations on root density distribution of shallow, medium and deep rooted crops within the soil
profile were studied. Irrigation significantly increased the root density of potato, celery, and
wheat in the topsoil zone. On the contrary, at most cases there was only a slightly reduced root
density in the subsoil layers. Total root length, to maximum root depth, only increased
significantly with drip irrigation in potato. The root depths of these crops were not significantly
modified by irrigation. The results suggest that the use of a constant value for the calculation of
maximum irrigation depth in a specific crop may not correspond to the variability of root depth
nor the distribution in different years or fields
