Plastic mulches and row covers for early and midseason crisphead lettuce produced on organic soils
Bibliographic record
Abstract
Plastic mulches and row covers for early and midseason crisphead lettuce (Lactuca sativa L. ‘Ithaca’) grown on organic soils were investigated over 2 yr. For early production, four mulch treatments (infrared transmitting, silver-on-black co-extruded polyethylene, white-on-black co-extruded polyethylene and a bare soil control) with and without an agrotextile low tunnel were tested. For midseason production, the same mulch treatments were evaluated in combination with normal and high planting densities (54 400 plants ha-1 and 65 200 plants ha-1). Low tunnels combined with mulches accelerated early growth and maturity by 10 d for infrared-transmitting mulch, 7–8 d for silver mulch and 3–5 d for white mulch, relative to production on bare soil control without a low tunnel. Infrared-transmitting mulch alone increased plant biomass early in the season and produced a lettuce head of heavier or similar weight relative to that from bare soil, even if harvested 3–4 d earlier. Lettuce heads grown on silver and white mulches were harvested 1–3 d earlier, and were 22% heavier in the first year and 29% heavier in the second year than when grown on bare soil. Head weights of lettuce under the low tunnels were higher than those from control plots in the first year only, and head size was similar in both years. For midseason production, infrared-transmitting and silver mulches accelerated the early growth of lettuce, but resulted in heads with long cores at maturity, particularly with infrared-transmitting mulch. Silver mulch increased the percentage of marketable heads in the first year and head weight and size at maturity in the second year, and reduced the incidence of aphids in both years, relative to plots without mulch. White mulch resulted in larger and heavier heads than those produced without mulch in the second year, and produced heads with shorter cores than those produced with other mulches in both years, even during particularly hot growing conditions. The percentage of marketable heads was similar for both the high- and low-density plantings and, as a result, the former produced more marketable heads per hectare. However, lettuce plants grown at the higher density were smaller in the second year. During conditions conducive to disease development in the first year, higher density plantings were more susceptible to downy mildew. Key words: Lactuca sativa, iceberg lettuce, muck soils, plasticulture, mini-tunnel, physiological disorder, planting densities
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 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".