Organic Phosphorus Forms in Agricultural Soils under Mediterranean Climate
Bibliographic record
Abstract
Core Ideas Monoesters were the dominant OP form. Their degradation occurs under conditions of P limitation. Fe oxide type was crucial for explaining the stabilization of different organic P forms in soils. Inositol hexakisphosphate was mainly related to poorly crystalline Fe oxides. Monoesters different from inositol‐6‐phosphate were related to crystalline Fe oxides and carbonates. Future sustainable phosphorus (P) management in agriculture will require a full understanding of the effects of agricultural practices on soil organic P (OP) speciation in different regions. This work studied the effects of land use, available P status, and soil properties on OP forms in Spanish agricultural soils under Mediterranean climate. We used 31 P nuclear magnetic resonance spectroscopy to characterize P in eight soils under two types of land use (field crops and olive or vine orchards), using two samples with different soil Olsen P status (“low” and “high” P samples) per soil type. Orthophosphate monoesters dominated OP in these soils, and inositol hexakisphosphates (IP 6 ) were the most abundant identified group of monoesters. Land use affected total OP concentrations mainly through crop residue incorporation. The contribution of monoesters, including myo ‐IP 6 , to total OP increased with higher Olsen P concentrations, but only in soils from orchards. Degradation of monoesters including IP 6 occurred under conditions of P limitation, suggesting some contribution of these OP forms to the plant P supply. Total IP 6 was mainly related to poorly crystalline iron (Fe) oxides, whereas other monoesters were related to crystalline Fe oxides and to active Ca carbonate equivalents. The dominant Fe oxide type, carbonates, and the low accumulation of crop residues explained the relative contents of different OP forms in these Spanish soils compared with soils from other geographical areas. The effect of oxides in the accumulation of different OP forms was attributed to the affinities of these forms for oxides and to differences in the density of binding sites depending on the oxide type.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".