Effects of lime and phosphate amendments on Alfisols of the Canary Islands

The effects of lime (Ca(OH)$) and disodium orthophosphate (Na$PO$H) added separately to selected Alfisols of the Acentejo Area (Tenerife, Canary Islands) have been studied. These soils have excessive acidity and a very high amount of exchangeable aluminium. Ca(OH)$ significantly (P = 0.01) increased soil pH (at 50% acid neutralization) and available P (at 100-200% acid neutralization), and decreased exchangeable Al (at 12.5% acid neutralization) white the addition of Na$PO$H did not significantly affect the available P, exchangeable Al, or the soil. It is recommended that Alfisol shouls be trated with lime to neutralize 100-200% of the acid using wetting and drying cycles during equilibration before adding P.