Grasses and field crops reduce the concentration of resting spores of <i>Plasmodiophora brassicae</i> in soil under controlled conditions
Bibliographic record
Abstract
Abstract Clubroot, caused by Plasmodiophora brassicae , dramatically reduces yields of brassica crops, and once present in a field, can persist in the soil for many years via long‐lived resting spores. Some nonhost crops can stimulate the germination of resting spores, which reduces clubroot inoculum because the pathogen cannot complete its life cycle in the absence of a living host. The effect of selected grasses and other field crops on the concentrations of spores in soil was assessed in two replicated and repeated short‐duration (8‐week) studies under controlled conditions. The spore concentration declined precipitously in the bare soil control relative to the initial spore concentration over the course of both studies. Cultivars of meadow bromegrass, smooth bromegrass and one cultivar of perennial ryegrass reduced the spore concentration compared to the bare soil control in both repetitions of one study, while two cultivars of perennial ryegrass did not reduce the spore concentration. In a second study, spring wheat, perennial ryegrass, barley and field pea reduced spores compared to the bare soil control, but soybean did not. Our hypothesis that larger root systems would produce larger reductions in spore numbers was not supported; there was no correlation between root weight and reduction in spore concentration. We conclude that perennial grasses, spring cereals and field pea can contribute to the reduction of clubroot spores in soil. The advantage of grass crops over annual crops for clubroot management is that movement of infested soil is minimized over the entire duration of the grass stand.
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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) | 0.000 | 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 | 0.001 |
| 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".