Degree of phosphorus saturation and soil phosphorus thresholds in an ultisol amended with triple superphosphate and phosphate rocks.
Soil phosphorus (P) release capability could be assessed through the degree of P saturation (DPS). Our main objective was to determine DPS and, hence, P threshold DPS values of an Ultisol treated with triple superphosphate (TSP), Gafsa phosphate rocks (GPR), or Christmas Island phosphate rocks (CIPR...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English English |
| Published: |
Scientific World
2011
|
| Online Access: | http://psasir.upm.edu.my/id/eprint/23698/ http://psasir.upm.edu.my/id/eprint/23698/1/Degree%20of%20phosphorus%20saturation%20and%20soil%20phosphorus%20thresholds%20in%20an%20ultisol%20amended%20with%20triple%20superphosphate%20and%20phosphate%20rocks.pdf |
| _version_ | 1848844831221088256 |
|---|---|
| author | Gikonyo, E.W. Abdul Rahman, Zaharah Musa, Mohamed Hanafi Abdul Rahim, Anuar |
| author_facet | Gikonyo, E.W. Abdul Rahman, Zaharah Musa, Mohamed Hanafi Abdul Rahim, Anuar |
| author_sort | Gikonyo, E.W. |
| building | UPM Institutional Repository |
| collection | Online Access |
| description | Soil phosphorus (P) release capability could be assessed through the degree of P saturation (DPS). Our main objective was to determine DPS and, hence, P threshold DPS values of an Ultisol treated with triple superphosphate (TSP), Gafsa phosphate rocks (GPR), or Christmas Island phosphate rocks (CIPR), plus or minus manure. P release was determined by the iron oxide - impregnated paper strip (strip P), while DPS was determined from ammonium oxalate - extractable aluminum (Al), iron (Fe), and P. Soils were sampled from a closed incubation study involving soils treated with TSP, GPR, and CIPR at 0-400 mg P kg-1, and a field study where soils were fertilized with the same P sources at 100-300 kg P ha-1 plus or minus manure. The DPS was significantly influenced by P source x P rate, P source x manure (incubated soils), and by P source x P rate x time (field-sampled soils). Incubated soil results indicated that both initial P and total strip P were related to DPS by exponential functions: initial strip P = 1.38exp0.18DPS, R2 = 0.82**and total strip P = 8.01exp0.13DPS, R2 = 0.65**. Initial strip P was linearly related to total P; total P = 2.45, initial P + 8.41, R2 = 0.85**. The threshold DPS value established was about 22% (incubated soil). Field soils had lower DPS values <12% and strip P was related to initial DPS and average DPS in exponential functions: strip P = 2.6exp0.44DPS, R2 = 0.77**and strip P = 1.1DPS2 - 2.4DPS + 6.2, R2 = 0.58**, respectively. The threshold values were both at ≈8% and P release was 11-14 mg P kg-1. Results are evident that DPS can be used to predict P release, but the threshold values are environmentally sensitive; hence, recommendations should be based on field trials. |
| first_indexed | 2025-11-15T08:37:10Z |
| format | Article |
| id | upm-23698 |
| institution | Universiti Putra Malaysia |
| institution_category | Local University |
| language | English English |
| last_indexed | 2025-11-15T08:37:10Z |
| publishDate | 2011 |
| publisher | Scientific World |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | upm-236982015-11-26T08:10:25Z http://psasir.upm.edu.my/id/eprint/23698/ Degree of phosphorus saturation and soil phosphorus thresholds in an ultisol amended with triple superphosphate and phosphate rocks. Gikonyo, E.W. Abdul Rahman, Zaharah Musa, Mohamed Hanafi Abdul Rahim, Anuar Soil phosphorus (P) release capability could be assessed through the degree of P saturation (DPS). Our main objective was to determine DPS and, hence, P threshold DPS values of an Ultisol treated with triple superphosphate (TSP), Gafsa phosphate rocks (GPR), or Christmas Island phosphate rocks (CIPR), plus or minus manure. P release was determined by the iron oxide - impregnated paper strip (strip P), while DPS was determined from ammonium oxalate - extractable aluminum (Al), iron (Fe), and P. Soils were sampled from a closed incubation study involving soils treated with TSP, GPR, and CIPR at 0-400 mg P kg-1, and a field study where soils were fertilized with the same P sources at 100-300 kg P ha-1 plus or minus manure. The DPS was significantly influenced by P source x P rate, P source x manure (incubated soils), and by P source x P rate x time (field-sampled soils). Incubated soil results indicated that both initial P and total strip P were related to DPS by exponential functions: initial strip P = 1.38exp0.18DPS, R2 = 0.82**and total strip P = 8.01exp0.13DPS, R2 = 0.65**. Initial strip P was linearly related to total P; total P = 2.45, initial P + 8.41, R2 = 0.85**. The threshold DPS value established was about 22% (incubated soil). Field soils had lower DPS values <12% and strip P was related to initial DPS and average DPS in exponential functions: strip P = 2.6exp0.44DPS, R2 = 0.77**and strip P = 1.1DPS2 - 2.4DPS + 6.2, R2 = 0.58**, respectively. The threshold values were both at ≈8% and P release was 11-14 mg P kg-1. Results are evident that DPS can be used to predict P release, but the threshold values are environmentally sensitive; hence, recommendations should be based on field trials. Scientific World 2011-07-28 Article PeerReviewed application/pdf en http://psasir.upm.edu.my/id/eprint/23698/1/Degree%20of%20phosphorus%20saturation%20and%20soil%20phosphorus%20thresholds%20in%20an%20ultisol%20amended%20with%20triple%20superphosphate%20and%20phosphate%20rocks.pdf Gikonyo, E.W. and Abdul Rahman, Zaharah and Musa, Mohamed Hanafi and Abdul Rahim, Anuar (2011) Degree of phosphorus saturation and soil phosphorus thresholds in an ultisol amended with triple superphosphate and phosphate rocks. The Scientific World Journal, 11 (-). pp. 1421-1441. ISSN 1537-744X http://www.hindawi.com/ 10.1100/tsw.2011.131 English |
| spellingShingle | Gikonyo, E.W. Abdul Rahman, Zaharah Musa, Mohamed Hanafi Abdul Rahim, Anuar Degree of phosphorus saturation and soil phosphorus thresholds in an ultisol amended with triple superphosphate and phosphate rocks. |
| title | Degree of phosphorus saturation and soil phosphorus thresholds in an ultisol amended with triple superphosphate and phosphate rocks. |
| title_full | Degree of phosphorus saturation and soil phosphorus thresholds in an ultisol amended with triple superphosphate and phosphate rocks. |
| title_fullStr | Degree of phosphorus saturation and soil phosphorus thresholds in an ultisol amended with triple superphosphate and phosphate rocks. |
| title_full_unstemmed | Degree of phosphorus saturation and soil phosphorus thresholds in an ultisol amended with triple superphosphate and phosphate rocks. |
| title_short | Degree of phosphorus saturation and soil phosphorus thresholds in an ultisol amended with triple superphosphate and phosphate rocks. |
| title_sort | degree of phosphorus saturation and soil phosphorus thresholds in an ultisol amended with triple superphosphate and phosphate rocks. |
| url | http://psasir.upm.edu.my/id/eprint/23698/ http://psasir.upm.edu.my/id/eprint/23698/ http://psasir.upm.edu.my/id/eprint/23698/ http://psasir.upm.edu.my/id/eprint/23698/1/Degree%20of%20phosphorus%20saturation%20and%20soil%20phosphorus%20thresholds%20in%20an%20ultisol%20amended%20with%20triple%20superphosphate%20and%20phosphate%20rocks.pdf |