Rain infiltration in dry soil
Improve the chances of moisture getting into the ground with proper soil practices
Radio interview source: Mark McFarland, Extension Soil Fertility Specialist, Texas Agrilife Extension
There's nothing better than a gentle, long-duration rain that you know is seeping deep into the soil and nourishing the plants. If it comes too fast and exceeds the soil infiltration rate, there will be surface runoff.
Mark McFarland is a soil fertility specialist with Texas Agrilife Extension. He says some runoff is desired because it refills our lakes and streams. However, for maintaining ground water and plants, soil texture and porosity is important. This is often determined by whether you have sandy or clay soil.
"Typically sands are going to have larger pore spaces and so the movement of water into the soil is much more rapid, and it can move down into the soil more quickly," he says. "Clays on the other hand are fine-textured soils and in other words the particles are much smaller and typically the pore space is considerably smaller. The rate of infiltration and the conductivity of water down into the soil are going to be slower."
Soil structure is defined as the formation of small clods. The granular-type structure of clay soil allows water to seep in more effectively. A thick, rock-hard crust on the surface where nothing seems to get through needs to be broken up by tilling. McFarland also encourages adding organic matter and mulch.
"When the rain drops are coming down and striking the soil surface, those rain drops have a lot of power," says McFarland. "You've heard them hit the hood of your car before, right? They'll make a thump. When they hit the soil, they will actually damage and destroy those aggregates. So by putting a mulch on the soil, we will allow it to absorb the impact of the rain drop as it comes to the ground, and then the water moves through that mulch down to the aggregates, to the soil, and can infiltrate."
Wood chips, compost, even cover crops will help direct the water down to thirsty plants.
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