OCR Text |
Show Unfavorable Soils. Clay soils are unfavorable to vegetation vege-tation because the soil is too close and adhesive to allow the free passage of air or water to the roots of the plants. It also obstructs the expansion of the fibers of the roots. Sandy soils are unfavoravle because they consist of particles that have too little adhesion to each other. They do not retain sufficient moisture for the nourishment nourish-ment of the plants. They allow too much solar heat to pass to the roots. Chalk soils are unfavorable because they do not absorb the solar heat, and are, therefore, cold to the roots of the plants. |