Investigating factors impacting phosphorus dynamics and phosphate sorption capacity of manure amended soils of Ontario
Bibliographic record
Abstract
Phosphorus (P) in agricultural soil is an essential nutrient for plant growth. Manure application as an organic phosphorus fertilizer improves P supply to plants. Labile P from manure can be easily transported from agricultural fields through surface runoff. Excessive P fertilizer in amended soils change into more stable forms. These processes cause eutrophication of lakes. Understanding P dynamics and P compositions in manure and soils is important. This study analyzed how do the total P and bioavailable P fraction in manure-amended agricultural soils change over seasons, as well as what factors may contribute to these changes. Additionally, we tested P sorption capacity in two soils. This study was conducted with agricultural soils from Bay of Quinte area, Ontario, Canada. Our results showed that the total phosphorus (TP) amount tend to decline with aging of applied manure. Soils amended by manure in 2019 summer have around 1.17 mg TP g-1 in average, while soils with manure application more than 6 years ago have approximately 0.97 mg TP g-1 in average. Compared to manure with 4.19 mg TP g-1, the TP in soils was much less indicating low P fertilization efficiency. Comparing the concentration of TP and bioavailable P among seasons, both parameters showed an increasing trend with decreasing temperature. Reduced uptake of P by plants, the limitation of mineralization, and less rain events in winter contribute to the high values of P in winter. P sorption were examined by soil incubation experiments on two soil samples with potassium dihydrogen phosphate (KH2PO4) as inorganic fertilizer. Results indicated a negative correlation between adsorbed P and added P. Even with additional geothite as an extra iron oxide-hydroxide source, the same relation was observed. It signifies that these soils have low P-sorption capacity. The abundant amount of OM and Ca from manure and soils negatively correlated to P adsorption onto iron oxide-hydroxides. The degree of phosphorus saturation (DPS) of these two soils (95.78 and 82.46%) exceeded the threshold of P saturation level in agricultural soils (80%) and explained the release of P from solid phase.
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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| 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".