Soil moisture and nutrient variation within an undulating Manitoba landscape
Bibliographic record
Abstract
The use of discrete management units for variable-rate N fertilization requires that factors influencing grain yield response to N fertilizer are adequately characterized by delineating landscapes into such management units. The objective of this study was to compare the use of topographically derived landform element complexes (LEC) and the use of individual soil series as management units. Soil volumetric moisture content, nitrate-N, exchangeable ammonium-N, extractable phosphorus, exchangeable potassium, and sulphate-sulphur were studied in 10 intensively sampled transects in an undulating glacial till landscape near Miniota, Manitoba. The study site was delineated into upper, mid and lower LEC using a digital elevation model derived from relative elevation data. The LEC were useful in capturing gross variability at a manageable landscape scale. Among LEC there was a general trend of lower > mid > upper for median values of soil moisture, nitrate, phosphate, potassium and sulphate, as these attributes generally increased with convergent landscape character. Differences among LEC were often statistically significant, and relative distributions exhibited temporal persistence. The site was also stratified by soil series, including Newdale, Varcoe and Angusville soils (Black Chernozems), which were identified by examination of individual soil cores at each sample point. Stratifying the site into management units using soil genetic information, which is reflective of historical moisture conditions and biomass production, was expected to be superior. There was little advantage, however, in using soil series rather than LEC. Spatial distributions of the most agronomically relevant attributes (soil moisture and nitrate) were expressed at a landscape scale broader than that at which soil series occurred within the site. While there were important differences among soil series with respect to nutrients such as phosphate and sulphate, the site was better stratified by LEC with respect to soil moisture and nitrate. Key words: Soil-landscape, soil series, soil moisture, soil residual nitrate, extractable phosphorus
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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 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 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".