A Simple, Semi-Automated, Gravimetric Method to Simulate Drought Stress on Plants

Drought is a major constraint of global crop production. Given that drought-induced crop losses can threaten world food security, it has been and continues to be the focus of a large body of interdisciplinary research. Most drought experiments are conducted under controlled environmental conditions, where maintaining accurate soil moisture content is critical. In this study, we developed a simple, Arduino microcontroller-based, semi-automated, lysimeter that uses the gravimetric method to adjust soil moisture content in pot experiments. This method employs an Arduino microcontroller interfaced with a balance as part of a portable lysimeter and irrigation system which can weigh and record the mass of plants growing in pots, determine water loss due to evapotranspiration, and adjust soil moisture automatically to a desired relative soil water content. The system was validated with a greenhouse pot experiment using a panel of 50 early-maturity Canadian soybean varieties. Drought was induced in the experiment by adjusting soil moisture content to 30% field capacity while maintaining control pots at 80%. Throughout the experiment, the two moisture levels were efficiently maintained using the Arduino-based lysimeter. Plant physiological responses confirmed that plants in the drought treatment were under physiological stress. This semi-automated lysimeter is low-cost, portable, and easy to handle, which allows for high-throughput screening.