| dc.description.abstract | Soil phosphate (P) exists in various
chemical forms, including inorganic P (Pi) and organic
P (Po), which differ widely in their behavior and fate
in soils. Some fractions of soil P are insoluble forms
and each concentration depends on soil types. The
problem of P deficiency in Andisol and Oxisol can
potentially be solved by the progressive return of
organic materials to soil. However, the quantity,
quality, and management of this practice are
fundamental factors that affect the availability of P
from residues. The objectives of this research are to
evaluate: (1) the changes of fractions of soil P in
Andisol and Oxisol by adding organic acid and organic
matter, and (2) enhancement of available soil P in
Andisol and Oxisol. Four treatments have been done
i.e: (1) control, (2) citric acid, (3) oxalic acid, and (4)
soybean biomass. Soil was incubated for 30 days. The
results show that application of soybean biomass
increases the total P and the availability of P in both
soil types. Furthermore, model of changes of soil P
fractionation are different between Andisol and Oxisol.
In addition, 30 days incubation does not influence the
decreased of P retension in Andisol; it shows that
adsorption site of Andisol is higher than Oxisol. | en_US |
