In a normal planting operation, (when not using presswheels) the seed is normally covered by loose crumbly soil, only a small portion of the seed may be coming in direct contact with moist soil. Extending the germination time, the loose soil is also drying out quicker than if firmed.
When conventional planting not using Presswheels, you run the risk of the seed bed being compressed or smeared. By using incorrect or worn points resulting int he roots not being able to penetrat the compacted, smooth/glazed seed trench. (The root system will take the easy way out and send the roots along the seed trench rather sending out its laterals). This will potentially increase the risk of lodging and will also reduce the potential crop yield, though not maximizing the soil nutrients and moisture. By using a presswheel to firm the moist soil around the seed you are achieving a few important things. 1. By getting full seed/soil contact the seed will germinate 3 to 4 days quicker than conventional unpressed seed.
2. When using Presswheels you will always get a better root establishment ie. with the soil evenly firmed around the seed it allows the plant to get a better root establishment being able to send its roots out in all directions, optimising soil moisture hence better plant stand, better yield and less chance of crop lodging. 3. By getting a quicker germination the seed will also take more advantage of the moisture to get a better root/plant establishment.
