Figure 3.

Sequentially extracted soil P fractions of the manure-treated flooded soil samples after 50 days (a) and 120 days (c) of incubation and the manure-treated upland soil samples after 50 days (b) and 120 days (d) of incubation. PM, pig manure; CM, chicken manure; DM, dairy manure; and OM, commercial organic compost. The value was the average value, and the error bar (n = 3) represents the standard deviation. The asterisk symbols denote significant differences in CK and animal manures. A-P = available P = Resin-P + NaHCO₃-Pi; M-Pi = moderately inorganic P = NaOH-Pi + HCl-P; Po = Organic-P = NaOH-Po + NaHCO₃-Po; O-P = Occluded-P = Residual-P. *p < 0.05.