EM071 High Residue Farming Under Irrigation: What and Why provides an overview of high residue farming (HRF), including its benefits and challenges. It also discusses some special considerations for high residue farming in the irrigated agriculture regions of the far western United States.
If you want your soil to take water faster, protect the surface with crop residues. This was shown in a classic study from 1940.
F.L. Duley took a sandy loam, covered it with straw, and then applied a simulated rainfall to it for five hours at a rate higher than what it could take, resulting in runoff. He measured the rate of water entering the soil (infiltration) which settled to a nearly constant 1.2 inches per hour (click on graph below). After 40 minutes of this, he removed the straw. The infiltration rate of the now bare soil dropped rapidly, then leveled off at just 0.25″ per hour.
Farmers wanting to maintain more crop residue cover on their fields are often prevented from doing so by previous dammer diking. While dammer diking controls runoff under center pivot systems, it also leaves large holes in the field, making it impossible to plant a following crop without tillage. The tillage required to smooth the soil surface for planting also buries most of the previous crop’s residues. The bare soil is then susceptible to surface crusting, poor infiltration, and runoff. To fix this, farmers dammer dike their fields, continuing the dammer-diking – tillage cycle. The way out of this cycle is to maintain a crop residue cover on the soil surface. » More …