Submitted to: Strategies for No Till
Publication Type: Popular Publication
Publication Acceptance Date: January 15, 1996
Publication Date: N/A
Technical Abstract: The effect of crop residue on the soil surface is poorly understood and the changes during the year are even less understood. This prevents farmers from being able to manage the soil effectively under no-till systems and acts as a barrier to adoption. A study was developed on both a Nicollet and Monona soil to evaluate the effect of fresh corn residue, weathered corn residue and weathered residue arranged in a strip with a 10 cm band of bare soil between the residue. These soils were placed as undisturbed monoliths in a controlled environment chamber with the environmental conditions set to simulate both warming and cooling trends typical of spring and fall, respectively. Each monolith was instrumented with soil temperature and time domain reflectometry probes and each block was placed on load cells to measure the rate of soil water evaporation. Placing corn residue on the surface decreased the soil water evaporation rate by 40%. The largest suppression of evaporation was caused by the fresh residue followed by weathered and then strip residue. The Monona soil had greater evaporation than the Nicollet because of the internal water vapor movement at the soil surface residue layer interface. The wetter soils in the residue-covered monoliths were cooler because of the effect of wet soil on thermal conductivity. Residue-covered soil is more water conserving and has a stable microclimate near the soil surface, which affects the potential soil biological activity. Residue management decisions can be used to improve water storage in the Midwest.