Despite extraordinary progress, no-tillage is still awaiting the discovery of a “silver bullet” before it will become cemented as the irreversible replacement for conventional tillage on a global scale. 

This “silver bullet” is recognizing the importance of soil pore space humidity (or the vapor water content of the soil air in the pore spaces) between soil particles in undisturbed soils.

This important largely-unrecognized fact (any soil physicist will confirm this) is that this soil pore space vapor water needs to remain at 100% relative humidity. This is true even when undisturbed soils otherwise dry down to what is called their permanent wilting point (PWP). Actually the pore space relative humidity at PWP is 98.8%).

Importance of PWP

Pore space humidity is not an available resource in tilled soils (including those that are tilled in strips) because all soil disturbance allows it to evaporate. But if retained in the soil during no-tillage, it is capable of both germinating seeds sown into it and energizing the soil microbes that live within it. 

Unfortunately, no-tillage will never fully energize soil biology and regenerate soil health on a long-term basis until no-tillers learn how to priorities the retention of this precious pore space humidity at seeding time. This should be ,one of no-till’s most important objectives.

Soil Disturbance vs. Soil Biology

Most soil disturbance affects soil biology negatively. Conversely, the avoidance of soil disturbance affects soil biology positively. If no-tillage is done properly, it is capable of retaining the pore space humidity within the seeded rows as well as perform all of the other things that are essential for making no-tillage more “fail-safe” than conventional tillage ever was.

Growers need to learn which no-tillage drill designs retain soil water vapor and which designs do not! It is as simple as that.