A whole-plant bioassay system for the detection of residues of ALS/AHAS inhibiting herbicides in soils and determination of safe planting intervals for sensitive crops
Notice bibliographique
Résumé
In Ontario, the ALS/AHAS herbicides, including the sulfonylureas, imidazolinones and triazolopyrimidines, are used to control a wide range of weeds in many crop species. These herbicides have very high biological activity (i.e. dose ranges of g ai ha-1 vs. kg ai ha-1 for older generation chemistries) which has potential to cause significant negative impact to non-target plants or subsequently planted sensitive crops such as ' Beta vulgaris' (sugar beet), and 'Brassica spp.' (canola and cole crops) among others. The injury to sensitive crops varies with herbicide type as well as climatic and edaphic factors. Sulfonylurea herbicides degrade primarily by chemical hydrolysis and tend to persist in alkaline soils. Imidazolinone herbicides degrade primarily by microbial activity and are more persistent in acidic soils. This research was conducted to develop a whole-plant bioassay system to detect injurious concentrations of these herbicides in different soil types across southern Ontario. A loam soil was fortified with 0.0, 0.01, 0.05, 0.1, 0.5, 1, 2.5, 5 and 10 [mu]kg-1 of each herbicide into which indicator crops of sugar beet, canola, rutabaga and sweet corn were seeded and grown for 30 days under optimized growth room conditions. Plant dry weight data were subjected to a log-logistic regression analysis to determine the I50 concentrations of each herbicide by indicator species combination. I50 values for chlorimuron were 0.11 (se<0.005), 0.09 (se<0.004), and 0.10-0.11 (se<0.009) [mu]g kg-1 for canola, rutabaga and sugar beet, respectively. For flumetsulam the I 50 values were 0.95-1.10 (se<0.075), 0.69-0.85 (se<0.062), and 0.67-1.76 (se<0.139) for canola, rutabaga and sugar beet, respectively while I'50' values for imazethapyr were 0.42-0.65 (se<0.057), 0.54-0.91 (se<0.071), and 0.30-0.46 (se<0.032) [mu]g kg-1 respectively, for canola, rutabaga and sugar beet. The whole-plant bioassay system was utilized to determine the in situ concentration of chlorimuron and imazethapyr in field samples collected at various intervals following field application to a soybean crop in 1998 or 1999 in four-replicate RCBD experiments at five sites across Ontario. Each of the sites differed in soil pH and other edaphic factors. Growth response of sugar beet in herbicide-treated field soil samples was compared to general and soil-specific dose-response curves developed by spiking untreated site-specific soil with 0.0, 0.05, 0.1, 0.5, 1.0, 2.5 [mu]g kg-1 of each herbicide. The results indicate that the degradation rate of chlorimuron and imazethapyr varied by site but were similar within a site, reflecting differences in soil conditions among sites (pH, texture, OM, etc). However, three years following herbicide application there was no difference in herbicide concentration detected by bioassay among the sites. I10 values would be a more appropriate economic indicator of acceptable crop injury for these herbicides and were estimated to be 0.005-0.090 and 0.067-0.405 pg kg-1 for chlorimuron and imazethapyr, respectively, using sugar beet as the indicator species. The whole-plant bioassay system was developed and validated across a range of southern Ontario soils and was able to detect injurious concentrations of chlorimuron and imazethapyr that were at levels less than the detection limits of liquid chromatography and capillary electrophoresis. This bioassay system can be used to determine when sensitive crop species can safely be seeded into sites previously treated with the ALS/AHAS herbicides.
Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.
Comment cette classification a été obtenuedéplier
Prédiction machine sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Le volet Gemma est une étiquette directe du modèle pour chaque travail de la base, lue sur la notice réduite au titre. Le volet Codex est un classifieur appris des 10 348 étiquettes directes de Codex et calibré sur les taux pondérés de l'échantillon; les champs sans appui suffisant ne portent aucun appel Codex. Le mode candidate est l'union des deux volets; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont pas des étiquettes humaines.
Scores du classifieur distillé par catégorie (deux têtes)
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,001 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,001 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,001 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule source (Gemma direct ou Codex distillé), pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».