Measurements were repeated at 15 sites randomly distributed in
each plot. The readings of resistance force were used to calculate
sinkage resistance by dividing the plate surface area and to calculate
penetration resistance by dividing the maximum area of the cone.
The readings of 15 replicates were averaged for each depth. The
measurement using penetrometer can only be carried out without
interference of crop. Therefore, this method was not applied during
the rice growth period