Performance of Low‐Cost Open‐Top Chambers to Study Long‐Term Effects of Carbon Dioxide and Climate under Field Conditions
Bibliographic record
Abstract
The increase in atmospheric carbon dioxide concentration ([CO 2 ]) and consequent increase in air temperature is expected to have significant effects on plant growth and nutritive value. Studies examining the effects of elevated [CO 2 ] on plants under field conditions have been limited by the inherent difficulty to modify air composition in open air. Here we describe an efficient and inexpensive open‐top chamber (OTC) system designed to study the effects of elevated atmospheric [CO 2 ] and temperature on perennial alfalfa–timothy ( Medicago sativa L.)–( Phleum pratense L.) mixture. The design and construction of these OTCs are described in detail, along with cost estimation for each component. Eight OTCs, each with 1.2 m 2 of ground area (four with elevated [CO 2 ] and four with ambient [CO 2 ]) were fabricated and four control plots of the same dimension were established to assess the chamber effects on plant responses to CO 2 . The [CO 2 ] in elevated‐CO 2 chambers fell 93% of the time within ±20% of the targeted 600 µmol mol −1 CO2, based on 10 min averages. The CO 2 consumption in elevated‐CO 2 chambers averaged 3.0 kg CO 2 m −2 d −1 . To ensure that the environment within OTCs was similar to the surrounding field, growing conditions were determined in all chambers and control plots. Adequate light transmission was observed compared to control plots (93%) and the temperature increase was 0.7°C on average. After two growing seasons of continued use, this system has proven its effectiveness for studying the effects of CO 2 and climate change in the field at low cost.
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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 | 0.000 | 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) | 0.000 | 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".