A comparative study of phosphorus availability in an acidic soil and an alkaline soil amended with organic and inorganic phosphorus sources
Bibliographic record
Abstract
An incubation study was conducted to investigate the effects of adding cow manure (CM), poultry manure (PM), city waste (CW) and triple super phosphate (TSP) on extractable P in a sandy loam acidic soil (Aquepts) and a silt loam alkaline soil (Fluvents).Phosphorus was added at a rate of 200 mg P kg -1 to the soil in the forms of CM, PM, CW and TSP.The soil was incubated at field capacity for 15, 30 and 60 days after which the P sources were extracted with Olsen, Kelowna, Mehlich-3, and Bray and Kurtz-II extractants.Regardless of the extractants and soils, after 15 days of incubation, the highest extractable P source was the TSP (88-97 mg kg -1 as Olsen P), and the lowest was the CW (11-15 mg kg -1 as Olsen P).The extractable P levels with the CM (41-48 mg kg -1 as Olsen P) and PM (71-73 mg kg -1 as Olsen P) were between the extractable P levels with the TSP and CW.Extractable P in the soils with the organic amendments increased slightly with increasing incubation time from 15 to 60 days.With the TSP, extractable P decreased sharply in the acidic soil, while it decreased gradually in the alkaline soil.In both soils, extraction efficiency was in the order of Bray and Kurtz-II> Mehlich-3> Kelowna>Olsen.The efficiency of the added P as measured by NaHCO 3 increased with the organic amendments, while the efficiency decreased with the TSP with days of incubation.This study indicates that soil samples taken 30 days after the addition of CM and PM in the soil might reflect the most plant-available P.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 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".