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How cover crops and crop residue affect soil water Covering the Bases How you manage your soil today could have impacts on the productivity of your soil in the near and distant future. Water infiltration and plant-available water are two important soil hydraulic properties to manage in regions where rainfall is supplemented using irrigation to meet plant production goals. Both water infiltration and plant-available water are affected by plant residue management, cover crop use and tillage. wHy are water inFiltration and plant-aVailaBle water important? Plant-available water is the volume of water that is held against gravity but can be removed from the soil by plants. Water infiltration is the rate or amount of water that enters the soil. Any water that does not infiltrate into the soil is lost from a field as runoff or evaporation. Managing both water infiltration and plant-available water Diggin' In SOIL HEALTH| By Michael Sindelar, Humberto Blanco, Virginia Jin & Richard Ferguson will be key to keeping fields productive, mitigating drought and floods, and reducing soil loss due to water erosion. This will be accomplished by increasing the rate at which water enters the soil and the amount of water the soil can store, thereby decreasing runoff. Plant-available water can be thought of as a water tank from which plants can remove water. The larger the volume of plant-available water stored by your soil, the more water is available for plant use through the growing season. How Can we inCrease water inFiltration and plant- aVailaBle water? We can do this by improving or maintaining soil structure and soil organic carbon. Soil organic carbon functions as a binding agent for soil particles to hold together as aggregates. Previous research suggests that soil structure can be managed through managing surface plant residues and/or planting cover crops after harvest. How does plant residue management aFFeCt soil struCture, plant- aVailaBle water, and water inFiltration? Research from Ohio State University and the University of Nebraska–Lincoln has found that when removing high amounts of residue (more than 50 percent), plant- available water was decreased in as little as one year when all residue is removed and within four years when about 60 percent is removed. Additionally, after removing approximately 60 percent of the corn residue for six years, plant-available water decreased from 1.61 inches to 1.21 inches per 4 inches of soil in south-central Nebraska. Aggressive residue removal decreased plant-available water in the 0-to-2-inch and 2-to-4-inch soil depths. This research comes Rain clouds move over a corn residue and cover crop management experiment located at the UNL South Central Agriculture Laboratory in south-central Nebraska. A view of all four experiment treatments from a corn residue and cover crop experiment in south-central Nebraska. Clockwise from top left are cereal rye with 60 percent corn residue removal; cereal with corn residue; no cover crop with corn residue (control); and no cereal rye with 60 percent corn residue removal. 42 POTATO GROWER | DECEMBER 2018