Primary Functions -- Increase soil tilth, aeration, and porosity and reduce compaction, dustiness and water run-off
Secondary Functions -- increase plant vigor, color, appearance, rooting depth and emergence of seeds while decreasing water requirements, diseases, erosion and maintenance expenses
Unless cultivated soils have their crumbs stabilized with mucilaginous materials such as humic acids and other cements, tilled soils usually revert to the prior untilled condition with irrigations and drying.
Soil Drain/P.A.M. is a water soluble mucilage which functions like organic matter except that it lasts for several decades and is required in small quantities only.
The space between soil crumbs become the major channels for air exchange, water movement into the soil and root growth. Water is still absorbed by the soil particles but the water moves into the soil avoiding its waste and the lack of aeration which occurs when soils are flooded.
Soil Drain/P.A.M. can be applied either as a dry granular powder or dissolved in water. Applications of dissolved Soil Drain/P.A.M. is normally used for transplants and for hydroseeding.
Since the action is to stabilize tilled soils and not to break up compaction, soils need to be tilled before treatment. After tillage, soils can be amended with low rates of organic amendments which can supply nutrients. Since low rates are used, burning of plant foliage is greatly lessened for most products. Gypsum is normally applied also to promote better soil conditioning.
Rates of application per 1,000 square feet are 6 to 9 pounds for sandy soils, 12 to 16 pounds for loamy soils and 20 pounds for clayey soils.
For transplants, the rate per cubic yard is about 1/4 pound if applied with water. For hydroseeding, the rate per 1,000 gallons is 1 to 4 pounds.
Treated soil becomes a mulch of soil which reduces evaporative water loss. Water infiltration is increased with better movement of salts thorough the soil profile. Salinity is reduced. The rate that sodium can be leached increases.
Some plant nutrients such as iron and potassium are more available in well aerated soil. With an increased rooting depth, the frequency of fertilizations is reduced. Also, healthier and more vigorous plants have less diseases and much better appearance and coloration.