Cover crops for early season weed suppression in corn
Bibliographic record
Abstract
Integrated weed management is becoming more important to prevent herbicide-resistant weeds from reducing corn yield.This study examined the influence various combinations of cover crop species, termination timing, and N rate had on early-season weed suppression and corn yield at Manhattan and Ottawa in 2019 and 2020.Fall cover crops of triticale (x Triticosecale Wittm.), pea (Pisum sativum L.), and triticale + pea (mixed) were sown in November 2018 and 2019, with the exception of pea sown in spring 2019.Two cover crop termination timings, three weeks before (3WBP) or at corn planting (AP), were subplot factors.The sub-subplot factor was N broadcast applied as urea at rates of 100 or 168 kg N ha -1 within two weeks after planting in both years.Cover crops were terminated and no-cover treatments were treated with glyphosate and 2,4-D.Cover crop biomass was collected at termination and weed density was counted regularly from 3WBP through the POST herbicide application of atrazine, glyphosate, and mesotrione at three weeks after planting.Weed density and biomass were collected in August 2020 to quantify control by the POST application.Cover crop biomass production ranged from 2,500 to 7,600 kg ha -1 in the mixed and triticale treatments when terminated AP in both years.Weed density was influenced by cover crop species and termination time at Manhattan with reductions of 51 to 59% by using cover crops compared to no cover and 44% when terminated AP compared to 3WBP.There was no reduction in weed density at Ottawa by delay in termination timing, likely due to little cover crop biomass production.Yield was variable between the two locations.Delay in termination timing and the triticale cover crop reduced yield at Manhattan in both years by 14 to 19%.At Ottawa, a 15% increase in yield was observed when termination timing was delayed from 3WBP to AP, and yield increased by 11% with increased fertilizer applied from 100 to 168 kg N ha -1 , regardless of cover crop type.Results indicated that cover crops generated varying results over different regions, soil types, and field management histories, as was exemplified by the locations of this study.Data from this study suggest that using a cover crop species that has high biomass production and corn fertilization with a minimum of 168 kg N ha -1 will result in greater weed suppression and less corn yield loss than cover crop treatments fertilized with 100 kg N ha -1 .v Table of Contents List of Figures ........
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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".