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 P i release into soil solution and thereby increases plant‐available Pi in soils. Low molecular weight organic acids may also induce organic P (P o ) 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 P o release is not well explained. This study used kinetic experiments to determine the concentrations and release rates of P i and P o induced by oxalic acid, citric acid, and malic acid in calcareous, neutral and acidic soils. Kinetic data were well described by Elovich ( r 2 = 0.801–0.993, P < 0.001) and power functions models ( r 2 = 0.721–0.977, P < 0.001). Low molecular weight organic acids at 10 mmol kg −1 soil induced the exponential release of both P i and P o , which reached a plateau approx. 480– 2,880 min after the start of the experiment. Cumulative P o 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 P o (NaHCO 3 ‐P o ) regardless of soil type. By contrast, oxalic acid was most effective in enhancing P i release from the HCl‐P i (Ca‐P i ) fraction of the calcareous soil, and citric acid was most effective in releasing P i from the NaOH‐P i (Fe/Al‐P i ) fraction of the neutral and acidic soils. Therefore, the mechanism for the kinetics of P o release induced by low molecular weight organic acids is ascribed to their ability to mobilize the labile P o (NaHCO 3 ‐P o ) rather than their ability to chelate cations ( i.e. , Fe 3+ , Al 3+ ) bound to P o in soil.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| 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 teacher head, 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".