ABSTRACT
This chapter focuses on the relation between root traits and root surrounding soil fractions affecting the water supply of crops and thus salt tolerance under saline soils conditions. In saline soils, the availability of soil water to roots is the most limiting growth factor to plants. Thus the basis of salt tolerance rating in irrigated agriculture focuses on soil water salinity in the root zone, with respect to plant growth. The objective of controlled irrigation management using saline waters is to achieve crop specific root zone salinity levels through optimal watering. The transpiration demand of growing plants is primarily met by root water uptake from the soil fraction nearest to the roots, the rhizocylinder. Thus, plant transpiration and salt exclusion by the roots produce increasing soil water salinity at simultaneously decreasing soil water content. Growing roots can expand into the soil fraction outside the rhizocylinder and, thereby increase rhizospheric soil volume.
