Why do fruit trees need deep and well-drained soil?

Most fruit trees require deep, well-drained soil to achieve their highest productivity because they must root extensively to a depth of three feet (one metre) or more.1

When subsoil is heavy or internal drainage is imperfect, trees often develop shallow, weak root systems. These compromised root structures are unable to efficiently absorb the necessary water and nutrients from the soil, which can ultimately limit the tree's health and reduce overall yields. While techniques such as tiling and surface ditching can help mitigate water accumulation in poorly drained areas, sites that naturally allow for deep, unobstructed root growth remain the most desirable for successful fruit-growing enterprises.1