Continuous Field Monitoring of Growth and Thickness Variation in a Potato Tuber Using a Strain-Gauge Sensor

Real-time measurement of belowground tuber growth has not been conducted in field crops. Here, a strain-gauge sensor was used to monitor the growth of a single potato tuber and estimate its daily water loss. Over the 11 days preceding harvest, tuber thickness increased by 0.80 mm, corresponding to a daily gain of 1.4 g, or a 4.2% increase. The greatest diurnal fluctuation was 0.439 mm, corresponding to a transpirational water loss of 9.1 mL, or 2.9% of the tuber’s water content. Daily estimated transpiration showed a positive correlation with estimated vapor pressure deficit. This sensor may enable more precise input control and higher temporal resolution than current methods for below-ground crops, supporting improved crop management, yield prediction, and harvest decisions.