Fig. 1.
Precipitation and air temperature as recorded at Willard Airport Weather Station (http://mrcc.isws.illinois.edu/CLIMATE/, last accessed 2 August 2016) near the experimental site in 2013, 2014, and 2015. The sum of precipitation (in mm) is shown for individual days in (A) 2013, (B) 2014, and (C) 2015. Average daily air temperature (black line) and daily minimum and maximum temperature (gray shaded area) (in °C) is shown for (D) 2013, (E) 2014, and (F) 2015.