Peppermint Productivity and Oil Composition as a Function of Nitrogen, Growth Stage, and Harvest Time
Bibliographic record
Abstract
The commercial production of peppermint (Mentha × piperita L.) is concentrated in more northern latitudes worldwide (north of the 41st parallel), including the United States. This 2‐yr field study in Mississippi evaluated the effect of N (0, 80, and 160 kg/ha), growth stage (bud formation and flowering), and harvest time or cut (first cut in mid‐July, second cut beginning of October) on peppermint yields, oil content, and composition. Biomass and oil yields were higher from the first cut than from the second. Overall, N increased biomass and oil yields. Contrary to literature reports that peppermint requires long days north of the 41st parallel to reach flowering, peppermint in Mississippi (at 34°43′22″ N lat) did reach flowering. The average oil yields at bud formation and at flowering were 165 and 122 kg/ha, respectively, and were greater than the average peppermint essential oil yields for the United States in 2008. Generally, (–)‐menthol concentration in the oil from the 2007 harvest was lower than in the oil from the 2008 harvest. The average (–)‐menthol concentration in the oil from the fertilized plots harvested at flowering in 2008 was 43 to 46%, but (–)‐menthol in the other treatments was below 37%. Our results suggest the first harvest in Mississippi should be delayed until the end of July to promote conversion of (–)‐menthone to (–)‐menthol. Peppermint could provide two harvests per growing season under the Mississippi climate, with oil yields and composition similar to those from other peppermint production regions.
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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 | 0.000 |
| 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".