Kinetics of inorganic and organic phosphorus release influenced by low molecular weight organic acids in calcareous, neutral and acidic soils
Bibliographic record
Abstract
Abstract Low molecular weight organic acids exuded by plants roots enhance inorganic Pi release into soil solution and thereby increases plant‐available Pi in soils. Low molecular weight organic acids may also induce organic P (Po) release into soil solution, but kinetics of both Pi and Po displacement from the soil matrix into soil solution of agricultural soils is poorly understood, and the mechanism for Po release is not well explained. This study used kinetic experiments to determine the concentrations and release rates of Pi and Po induced by oxalic acid, citric acid, and malic acid in calcareous, neutral and acidic soils. Kinetic data were well described by Elovich (r2 = 0.801–0.993, P < 0.001) and power functions models (r2 = 0.721–0.977, P < 0.001). Low molecular weight organic acids at 10 mmol kg−1 soil induced the exponential release of both Pi and Po, which reached a plateau approx. 480– 2,880 min after the start of the experiment. Cumulative Po release induced by low molecular weight organic acids was ranked as oxalic acid (0.63–3.17 mg kg−1) > citric acid (0.61–2.82 mg kg−1) > malic acid (0.52–1.76 mg kg−1) and mainly resulted from the release of labile Po (NaHCO3‐Po) regardless of soil type. By contrast, oxalic acid was most effective in enhancing Pi release from the HCl‐Pi (Ca‐Pi) fraction of the calcareous soil, and citric acid was most effective in releasing Pi from the NaOH‐Pi (Fe/Al‐Pi) fraction of the neutral and acidic soils. Therefore, the mechanism for the kinetics of Po release induced by low molecular weight organic acids is ascribed to their ability to mobilize the labile Po (NaHCO3‐Po) rather than their ability to chelate cations (i.e., Fe3+, Al3+) bound to Po in soil.
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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 | 0.000 | 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".