Effectiveness of Extractants for Bioavailable Phosphorus in Tropical Soils Amended with Sewage Sludge

Table 4

Correlation matrix for phosphorus extracted from soils at depths of 0–10, 10–20, and 20–40 cm and phosphorus levels in diagnostic leaves of maize plants grown in the long-term experiment ().

	Mehlich-I	H2SO4	Resin	Plant
	0–10 cm
Mehlich-I	—	0.99^**	0.92^**	ns
H2SO4		—	0.90^**	ns
Resin			—	ns
Plant				—
	10–20 cm
Mehlich-I	—	0.99^**	0.94^**	ns
H2SO4		—	0.94^**	ns
Resin			—	ns
Plant				—
	20–40 cm
Mehlich-I	—	0.98^**	0.95^**	ns
H2SO4		—	0.93^**	ns
Resin			—	ns
Plant				—

ns: not significant at 5%; ^**significant at 1%.