Comparison of Soil Phosphorus Tests for Assessing Plant Availability of Phosphorus in an Ultisol Amended with Water-Soluble and Phosphate Rock Sources

• Main Authors: Gikonyo, Esther Wakiuru, Abdul Rahman, Zaharah, Musa, Mohamed Hanafi, Abd Rahim, Anuar
• Format: Article
• Language: English; English
• Published: 2010
• Online Access: http://psasir.upm.edu.my/id/eprint/11708/1/Comparison%20of%20Soil%20Phosphorus%20Tests%20for%20Assessing%20Plant%20Availability%20of%20Phosphorus%20in%20an%20Ultisol%20Amended%20with%20Water.pdf; http://psasir.upm.edu.my/id/eprint/11708/

This work reports on soil phosphorus (P) test calibrations in triple superphosphate (TSP)– and phosphate rock (PR)–fertilized soils for cost-effective fertilizer recommendations. Results showed that separate calibrations are required for TSP and PR fertilizers for conventional soil tests. Use of critical P levels (CPLs) established for TSP in PR recommendations leads to erroneous application of PR while it incurs unnecessary application costs. The iron oxide–impregnated paper was insensitive to P sources and would be the most appropriate soil test in integrated nutrient systems