Soil PH and Solubility of Aluminum, Iron, and Phosphorus in Ultisols: the Roles of Humic Acid
Bibliographic record
Abstract
Soil reaction (pH), aluminum (Al), iron (Fe) and phosphorus (P) are the soil properties that are related to each other. Their role on the growth and development of plant is very significant. Liming and organic mater are the soil amendments that are frequently used to increase soil pH and P solubility and to suppress the solubility of Al and Fe in the soil. Humic acid is one of the organic fractions which is presumed has a role and is closely related to the changes in the soil chemical properties as mentioned above. Information about the role of humic acid on the soil pH, the solubility of Al, Fe, and P, especially in upland acidic Ultisols is still limited. This study aimed to provide empirical data on the role of various humic acids to soil pH and the solubility of Al, Fe, and P, specifically in upland acidic Ultisols. The study was a laboratory experiment with a single factor which was set by a completely randomized block design and was conducted in two sets of experiments. The first experiment was intended to study the roles of various humic acids derived from several sources (commercial humic acid, humic acids extracted from composted chicken manure, humic acids extracted from composted cow manure, and humic acids extracted from composted goat manure) on the soil pH and solubility of Al, Fe, and P. The second experiment was aimed to study therelationship patterns between application of humic acid (sold commercially) on soil pH and solubility of Al, Fe, and P. The results showed that humic acid was able to increase the soil pH and solubility of phosphorus, while it suppressed the solubility of iron and aluminum with linear patterns of relationships. Humic acid that was sold commercially, at the same amount of C-organics, had greater in increasing the soil pH, solubility of phosphorus, and suppressing the solubility of iron and aluminum in the soil, roles than those derived from organic matter of compost extracts and from organic matter of compost.
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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".