Fig. 4
From: Benchmarking electrical methods for rapid estimation of root biomass
Growth media used in root biomass estimation found in related literature and in our study. The size of the circles is proportional to the coefficient of determination r 2 found in each study. When more than two studies involved the same growth media, the mean (in black ring), the minimum (in grey circle) and the maximum (dashed circle) of coefficient of determination r 2 were plotted