raw and processed data Hunnekens et al 2021
Thermal insulation capacity of grasses, herbs and combinations thereof were assessed. It is shown that soil covered with plants provide a better thermal insulation when compared to bare soil. At the same time, soil covered with monocultures of herbs provide a better thermal insulation when compared to soil covered with monocultures of grasses. No differences were observed in thermal insulation within the group of herbs and within the groups of grasses. In addition, it is shown that mixtures of grasses and herbs have thermal insulation properties similar to that of monocultures of grasses. The indigenous herbs Veronica chamaedrys, Prunella vulgaris, Origanum vulgare and Knautia arvensis were used as well as the grasses Holcus lanatus, Festuca rubra, Anthoxanthum odoratum and Arrhenatherum elatius (Medigran; www.medigran.nl). A total of 1800 seeds were sown in 30 x 30 x 30 cm (height / width / depth) boxes using biological duplicates. The same total amount of seeds was used in a 1:1 ratio in combination treatment that consisted of both herbs and grasses. The boxes were covered at the bottom and the sides with a 10 cm-thick panel of expanded polystyrene. Plants were grown in a greenhouse at the Utrecht Botanical Gardens for a period of 15 weeks without temperature management. During the following 11 weeks, plants were grown at 10 °C between 07.00 and 21.00 and at 5 °C between 21.00 and 07.00. In weeks 2, 6 and 10 of this 11-week period, temperature in the greenhouse was 23 °C during the day and 20 °C at night from Monday to Sunday. The greenhouse was actively heated, while cooling was done passively via hatches in the roofing of the greenhouse. Plants were watered on Monday, Wednesday and Friday. Temperature was monitored for seven days in week 4 (V. chamaedrys, O. vulgare, F. rubra and K. arvensis) or week 9 (P. vulgaris, A. odoratum, H. lanatus and A. elatius) in the 11-week-period of temperature management (see above) at the moment the boxes had been fully covered with the plants. Boxes without plants were used as a control. Temperature was measured every 5 min with temperature sensors (DS18B20, Aideepen; www.aideepen.com) connected to a bespoke Arduino network (based on Arduino Mega 2560, RobotDyn; www.robotdyn.com). The sensors had been placed at and 10 cm below the surface of the potting soil. Increase in temperature was determined between 7.00 and 21.00, while decrease in temperature was quantified between 21.00 and 7.00. The minimum and maximum temperatures between these two time periods were taken and divided by the number of hours to reach this change in temperature, resulting in a Δtemp (°C h-1). The Δtemp was averaged over the 7-days-measurement for each replicate. Statistical analysis was performed with SPSS Statistics 26.
Steps to reproduce
see description of the dataset