Introduction a. Are needed in very small quantities b. Cation exchange the ability of clay and humus to attract and exchange positive ions 2. Clay and humus are negatively charged 3. Opposites Attract 4. Higher the cation exchange capacity the more closely the nutrients are held and the less likely they are to be lost to leaching 5.
Acid soils promote club root disease of cabbage Table.
Lime is used to raise the pH i.