Five grams of air-dried soil was placed in a glass bottle and incubated
at field capacity at 24 ± 2 °C for 14 days prior to the sequential extraction
in order to reach equilibrium after sampling, drying and sieving disturbances
(Hedley et al., 1982). After the incubation, soils were stored at
4 °C and equilibrated at room temperature overnight prior to P sequential
fractionation analysis.