Optimizing Available Phosphorus in Calcareous Soils Fertilized with Diammonium Phosphate and Phosphoric Acid Using Freundlich Adsorption Isotherm

Table 4

Quantities of P₂O₅ (kg ha⁻¹) required to achieve 0.2 mg L⁻¹ soil solution P.

CaCO3 level (%)	PA		DAP
	S-I	S-II	S-I	S-II
Native	98 ± 6.29*	78 ± 5.69	113 ± 7.94	99 ± 5.89
10%	302 ± 8.67	298 ± 12.49	317 ± 14.42	316 ± 9.50
20%	421 ± 14.65	419 ± 8.60	490 ± 20.13	483 ± 12.98

∗Means ± SE.