Fig. 2.
(a) The ionic products of some ions which may form precipitates in the solution; and (b) relation between P release from biochar and time. The equilibrium pH was 8.0–9.0. (O-P, orthophosphate; T-P, total phosphorus; Py-P pyrophosphate). Error bars represent ± SE (SE is the standard error of estimate). The experiments were conducted in duplicate (n = 2).