Thus, the decrease order of P fraction at the beginning
of composting was labile Pi>Ca+Mg-bound
P>Fe+Al-bound P>microbial P>residue P>humic
P>moderately labile Po>labile Po, while in the mature
compost the order was Ca+Mg-bound P>labile
Pi>Fe+Al-bound P>microbial P>residue P>moderately
labile Po>humic P>labile Po. The composting process
allowed the transformation of labile Pi and labile Po
to more recalcitrant forms such as Fe+Al-bound P,
Ca+Mg-bound P and residual P.