By increasing aeration water holding capacity, and nutrients. They loosen up compacted, hard pan and clay soils and release locked up nutrients.Soil conditioners can also raise or lower pH levels depending on what they are made of. Good soil for plants is usually comprised of 50% organic or inorganic material, 25% air space and 25% water space Clay, hard pan and compacted soils lack the necessary space for air and water. Beneficial microorganisms make up a portion of the organic matter in good soil. Without proper air and water, many microorganisms can’t survive