Under P-deficient acid soil conditions in South Kalimantan, significant positive responses to phosphate rock application
were observed for Maize. The significant increase in the maize yield was found when phosphate rock was combined with
organic material such as manure for 1 or 2 ton ha-1. This study suggests that phosphate rock could be an effective and
efficient P source of fertilizer especially its residual effects. Morocco phosphate rock appears to be an effective source of P
in this regard.