Multiyear changes in snowmelt phosphorus runoff with soil P drawdown or application of struvite to an organic forage crop
Bibliographic record
Abstract
Abstract In this study, changes in P runoff losses from three field‐scale small watersheds in the Northern Great Plains region (Manitoba, Canada) under organic management were evaluated over a 7‐year period (2017–2023). A perennial forage crop was grown through this time period, either with biennial addition of a slow‐release fertilizer to maintain soil fertility (struvite, 4 site‐years) or without P amendment (drawdown, 8 site‐years). Annually measured soil P (Olsen P) strongly correlated with mass balance of P added as struvite or removed by crops and surface runoff. As a result, P limitation of forage yield was observed in the later years of the drawdown treatment. P loads and flow‐weighted mean concentrations (FWMCs) measured in snowmelt runoff after struvite application were compared to predicted values using published regional models developed with 82 site‐years of data from field‐scale small watersheds, with Olsen P, water yield, and percent surface cover as predictors. To evaluate response to struvite over a wider range of conditions, P runoff was measured in two additional watersheds under conventional annual grain production following struvite application (2 site‐years). Higher risk of P loss was observed with higher Olsen P. However, following struvite applications, the risk of P loss to snowmelt was consistently lower than predicted (between −0.13 and −0.85 mg L −1 for FWMC of total dissolved P) suggesting that the solubility of struvite in runoff water may be lower than for other forms of soil P also extractable as Olsen 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 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 | 0.001 | 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 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".