The interface between the soil surface and the atmosphere above it is a critical juncture. Both vital air and water must cross this boundary to supply the root system beneath the soil. Numerous measurements have indicated that 60% of the roots are within 4 inches of this zone. Raindrops strike this interface with the force of little bombs, exploding the soil surface into tiny particles that then plug the porosity of the interface and stop air and water from crossing. If this wasn’t bad enough, most tillage systems are designed to pulverize the soil surface to kill emerged weeds and to provide a fine seed/soil contact for rapid germination. This makes the soil skin more susceptible to sealing of the surface pores. Except for semi-aquatic plants, oxygen at the root surface is critical for roots to use plant energy to grow and absorb nutrients. Air moves through the pores in the soil unless they are plugged.