In both experiments, each plot was composed of five
10 m long rows with a spacing of 1.5 m between rows.
Experimental data were collected only from the three central
lines of each plot. Soil samples were collected 6-mo after
ratoon plants started to sprout in both experiments. These
samples were taken from 10 randomly chosen points next
to the three central rows of each plot at depths between 0-20
and 20-40 cm. Exchangeable K in the soil was determined
according to procedure reported by Raij et al. (2001).