In all treatments, soil non-exchangeable
K (Fig. 2b) remained stable above 40 cmand declined below 40 cm.
Generally, total K (Fig. 2c) in 0–100 cm soil depth remained stable
at approximately 20 g kg1 in the three treatments, though the
surface soil (0–10 cm) in the K225 treatment had a slightly higher
total K concentration than the other two treatments (P > 0.05).