Just wanted to share something I came across that kind of goes with the whole "humid, not moist" ideology as it pertains to DSM's. Quite a few grammatical errors, but the message seems good. This is from Practical Farmer, by a guy named Wilbur Fisk Massey.
"THE roots of plants, if we except the aquatic plants of the swamps and marshes, do not need water in the soil, for standing water in the soil shuts out the air which is essential to the oxidation of plant food, and keeps the soil cold. What we need in the soil is moist air. We have seen in our first lesson that the percentage of moisture in the soil will depend largely on the size of the soil particles, each surrounded by its film of water. A soil that parts with this moisture rapidly by evaporation into the atmosphere will always be a colder soil than one which holds the moisture and evaporates it more slowly. So standing water is harmful, though moisture is necessary. It is essential that the soil be penetrated by air that the oxidation of matter in the soil may take place, and it is necessary that there be a due amount of moisture so that plant food may be dissolved for the roots since, as we shall see, no plant food is taken up until completely dissolved in the soil moisture. The rise of water in the soil to supply Supply of that taken by plant roots and by the evapo- oisture y rat;on into the air is caused by what is Capillary Attraction known as capillary attraction. Place a thick towel with one end in a pail of water and the other end resting on the ground and you will see that the water is taken up from the pail and transferredover the rim to the ground through the capillarity set up in the fine meshes of the towel. The samecapillarity occurs in the soil when left at rest, and in this rising water there is also brought to the surface soil much plant food that otherwise would be out of reach of the roots of crops."