The underground foil system ("Subfolder System") is a sustainable ecological measure that establishes the most favorable water-air conditions in soil for its biological activity. It is applied in sandy soils witch are endangered by droughts, on which because of large water losses and spillage of nutrients, classic irrigation and fertilization is not sustainable. "Dry Lands" is the term that we call the land surface where the problem of drought is expressed, often involving whole regions of sand lands. They also appear on feritile land under the same ecological conditions of semi-arid and dry climate and production methods where they have a significantly lower yield, which can be observed on the same crop in one plot. These are poor humus, loamy-sandy soils on sandy pad grounds without the influence of undergroundwater. Due to the complexity of the problem, decline in fertility and productivity, sandy soils are neglected and abandoned.
The wealth of a community on long-term is based on productivity and fertility of the land, as well as on the water management capacity. Historically, these desertification processes have led to the shift of successful civilizations towards the north and migration of the population. Podfol is an innovative measure that in the exhausted soil repairs and increases water capacity, thus forming sustainable land.