Effect of Biodegradable Mulches on Environmental Data Collected from High Tunnel and Open Field Settings

High tunnels are used to protect crops from severe weather events and extend the growing season while mulches are commonly used for weed control in specialty crop production. Our USDA-funded trans-disciplinary research project evaluated conventional plastic mulch, four biodegradable mulches (BioTelo, BioAgri, WeedGuard, and an experimental spunbond PLA), and a no-mulch control in high tunnel and open field production with tomato ('Celebrity') as the test crop. The study was conducted at three locations, Mid-South (Knoxville, TN), High Plains (Lubbock, TX), and Pacific Northwest (Mount Vernon, WA), for three growing seasons (2010, 2011, and 2012). Environmental data collection by mulch treatment included soil and air temperatures (5 cm depth, and top of crop canopy, respectively), relative humidity (RH), and photosynthetically active radiation (PAR). Data were collected using a Hobo U30-NRC weather station installed in the center of one high tunnel and one open field plot at each location. Results showed distinct environmental differences among the three locations. The average soil temperature at Mount Vernon was 10 to 12 °C lower than at Knoxville and Lubbock throughout the three growing seasons. Soil temperature in the high tunnel was 1 to 2 °C higher than in the open field for all three location to -3 °C higher than under paper mulch. At Lubbock, soil temperature under conventional plastic mulch was 3 to 6 °C higher than under spunbond PLA and the no-mulch treatment. The average RH at Lubbock was 40% lower than at the other two locations. RH in the open field was 2% to 5% higher than in the high tunnel at Knoxville and Mount Vernon, but at Lubbock RH did not differ between the high tunnel and open field. As expected, the monthly average PAR was 200–300 µE higher in the open field than in the high tunnels at all three locations. The greatest difference in PAR between the high tunnel and open field was at Lubbock, followed by Knoxville and Mount Vernon. These environmental data provide useful information for interpreting findings from concurrent studies on crop production (e.g., yield, disease incidence, and weed control) and degradation of different mulch treatments.