Construction, calibration and field use of a rapid-reading viscous flow porometer.
Abstract
Comparisons made over a wide range of soil matric potentials showed minimum resistance of 0.5 s/cm for cotton and 1.0 s/cm for maize. Readings made in the field with maize indicated that, because of variability between plants, large numbers of readings were required to obtain acceptable accuracy. The instrument used is described and illustrated; it had the advantage that readings could be taken at a rate of 120/h.