Abstract
Labile forms of mineral phosphorus (P) strongly interact with solid phase of soil components. Therefore, soil characteristics may affect the chemical testing and interpretation to assess for the P availability for crops and fertilizer recommendation.
A glasshouse trial was conducted with several soil types using wheat as test crop. The soil P availability was estimated by Bray-P, Olsen-P AEM-P and Aslyng-P methods. Results indicated that chemical indices like Bray-P, Olsen-P and AEM-P, appropriately integrates soil factors related with P availability to plants so that its interpretation would not require additional information. However the soil capacity factor, is a key factor for making sound fertilizer recommendations. A quick test of the P adsorption power of soils allow to calculate more precise fertilizer requirements based on the soil sorption power and the P availability.