Economic trade-offs with canola-based crop rotations in the presence of clubroot (Plasmodiophora brassicae)
Bibliographic record
Abstract
Clubroot (Plasmodiophora brassicae) is a soil-borne disease of Brassica crops, including canola (Brassica napus) on the Canadian Prairies. Intensive canola cropping can expedite disease severity, leading to escalated yield loss and lost profits. This study examined the long-term economic implications for two canola-based crop rotations in the presence of clubroot in the Edmonton, Alberta area. Clubroot disease severity was modelled over time to incorporate rotation and clubroot resistance effects on canola yield. The first part of the analysis compared annual returns from hard red spring wheat production to canola with different disease severity index levels. Clubroot disease severity index levels of 35% or more resulted in wheat having higher returns than canola. The second part of the analysis used a bio-economic model with a clubroot sub-model to compare crop rotations. The two-year rotation of canola-wheat was optimal if clubroot disease was low, otherwise canola-wheat-field pea had higher long-term net returns. With a susceptible cultivar, annual net returns averaged $140 ha-1yr-1 higher for the three-year than the two-year rotation. When a clubroot resistant cultivar was introduced, but resistance broke over time, the three-year rotation had higher annual returns of $56ha-1yr-1. Pre-emptive and early use of more break-years between canola crops was critical whether growing susceptible or clubroot resistant cultivars to maintain profitable canola production over time. This result is consistent with agronomic recommendations for canola production.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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".