Hog‐Manure‐Recovered Struvite: Effects on Canola and Wheat Biomass Yield and Phosphorus Use Efficiencies
Bibliographic record
Abstract
Core Ideas Struvite recovered from liquid hog manure is a slow‐release P source. Recovered struvite produced yields that matched or exceeded those from MAP fertilizers. Despite its slow‐release properties, struvite supplied adequate P to the crops. Recovery of manure P as magnesium ammonium phosphate hexahydrate (MgNH 4 PO 4 ∙6H 2 O), commonly known as struvite, can mitigate the risk of P contamination of surface water bodies from hog operations. The slow release of P from struvite may help improve crop P use efficiency. This greenhouse bioassay evaluated the agronomic effectiveness of liquid hog manure recovered struvite. Struvite, monoammonium phosphate (MAP), and polymer‐coated MAP (CMAP) were evaluated for canola ( Brassica napus L.) grown in rotation with spring wheat ( Triticum aestivum L.) in two low soil test P (Olsen P < 6 mg kg −1 ) soils: a sandy Gleyed Regosol (Typic Haplaquent) and a clay loamy Orthic Black Chernozem (Udic Boroll). The fertilizers were applied either in the seed row or in a sideband at 1.1 and 2.2 g P m −2 rates. In both soils, struvite produced canola dry matter (DM) yield (DMY, 2.4 g kg −1 soil), P uptake (5.9 mg P kg −1 soil), P recovery efficiency (43%), and agronomic efficiency (0.15 g DM mg −1 P) that were similar to those of MAP and CMAP in the first crop phase. Moreover, at the 2.2 g P m −2 rate, struvite produced significantly greater canola DMY than MAP in the second crop phase and both MAP and CMAP in the third crop phase. Overall, wheat did not produce significant responses to P fertilization. These results indicate that struvite recovered from liquid hog manure can supply sufficient P to sustain yields and P use efficiency matching or exceeding those for MAP.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".