Effects of UV Degradation of Biodegradable Mulches On Soil Temperature, Moisture, and Evaporation.

The use of plastic sheet mulches has resulted in a major disposal problem for both the farmers and the community at the end of the growing season.  The disposal problem has initiated an effort in recent years toward the development of biodegradable plastic mulches that can be tilled into the soil or composted onsite after crop production. Studies have addressed mechanical aspects of various biodegradable mulch materials yet there is still a knowledge gap in the literature specifically dealing with how the soil warming and evaporation performance of these materials are affected by photo degradation from exposure to UV light.  This study addresses the questions of how exposure to UV light over time affects both the evaporation rates and the soil temperature response of various biodegradable and traditional plastic mulches.  Four different mulches will be exposed to UV light at a controlled rate and over different times of exposure.  Repacked soil columns covered by the mulch materials will be used to monitor changes in both evaporation rates and soil temperature response in the laboratory at each time period by monitoring changes in soil temperature at multiple depths and changes in soil moisture content by changes in column weight. The results will be used to create a regression relationship between total UV exposure and temperature and evaporation rate response for each mulch material.