Spatial Distribution and Chemical Speciation of Soil Phosphorus in a Band Application
Bibliographic record
Abstract
There is limited information on how manure and inorganic fertilizer application in a concentrated band impacts the solubility, mobility, and transformation of the phosphate compounds in Canadian prairie soils. A combination of resin membrane probes, sequential chemical extraction, and synchrotron based techniques were used to reveal the spatial distribution and chemical speciation of soil phosphorus (P) when inorganic fertilizer P or manure is placed in the soil in a band under field conditions. This study was performed at Central Butte and Dixon, SK, Canada. Monoammonium phosphate blended with urea was applied at a rate of 54 kg N ha −1 and 12 kg P ha −1 at Central Butte (Brown Chernozem) and solid cattle manure was applied at rate of 60 t ha −1 yr −1 at Dixon (Black Chernozem). Fertilizer application increased the total and labile P supply at the center of the band and was mainly confined to a relatively small area within about 5 cm of band regardless of slope position. The X‐ray absorption near edge structure (XANES) spectroscopy directly identified different forms of soil P, while chemical extraction results provided indirect support that there are differences in the forms of P in the band center as related to in the landscape position and fertilization type. The XANES analysis results showed that different P retention mechanisms take place depending on both landscape position and fertilizer type. For the inorganic fertilizer application made in calcareous upslope positions, a significant amount of apatite and adsorbed P species were observed at center and near‐band and only apatite was present at large distances from the band; adsorbed P species dominated at all distances from the band at downslope positions. The solid cattle manure applied soil contained dicalcium phosphate (DCP) and organic P at center and near‐band at both slope positions but adsorbed P and calcium phosphate further away at upslope positions and adsorbed P further away at downslope positions. The XANES results also indicated that the movement of organic P was limited as this species was always localized near the band.
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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 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| 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".