QUALITE MORPHOLOGIQUE DE LA RACINE ET ETAT DU PROFIL CULTURAL
A survey was conducted of some twenty crop locations in three small regions of the "départment de la Manche" in northern France. For each plot, the physical obstacles to elongation or increasing thickness were listed. After defining a grid to describe the shape, roots were sampled when they were two or three months old.
In fact, the obstacles themselves can account for only a small part of the observed variability. As a corollary to this statement, an in-situ observation of the soil conditions surrounding the roots during the growth period does not provide a satisfactory basis for determining their shape. On the other hand, after having noted the relationship between the length of the root and the stage of foliar development of the plant, we indirectly hit upon the importance of the water supply to the soil during the downward growth of the root, which follows emergence.
- At the scientific level, there is a need for better understanding of the mechanical impedance of the soil and the root's ability to penetre the soil.
- At the technical level, soil water content under the seed bed must be maintained. Merely monitoring the average moisture content of the soil as a whole, as for irrigation purposes, may well be inadequate.