scholarly journals Metolachlor and Simazine Leaching through Horticultural Substrates

1994 ◽  
Vol 12 (1) ◽  
pp. 55-58
Author(s):  
G.E. Mahnken ◽  
W.A. Skroch ◽  
T.J. Sheets ◽  
R.B. Leidy
Keyword(s):  
Herbicide Application ◽  
Over Time ◽  
Container Production

Abstract This study was designed to determine whether differences existed in the amount of Derby (metolachlor and simazine) leached through four substrates used in container production. Substrate compositions (by vol) used in this study were 3:1 redwood bark:sand, 2:1:1 redwood bark:Yolo loam:sand, 3:1 pine bark:sand, and 1:1 composted hardwood bark:pine bark. Substrates were packed into #3 containers, and 4.5 kg ai/ha (4 lb ai/A) of metolachlor and 1.1 kg ai/ha (1 lb ai/A) of simazine were applied to the containers as a granular formulation. Containers were leached with 2.7 cm (1.06 in) of water per day, and leachate samples were collected 0, 1, 2, 4, 8, and 16 days after herbicide application. Both herbicides were detected in the redwood bark:sand leachate on the day of herbicide application, and concentrations increased over time but appeared to level off between day 8 and day 16. Metolachlor and simazine were detected in the redwood bark:Yolo loam:sand leachate 4 days after application, and concentrations of both herbicides increased over time. Metolachlor and simazine were detected in a few leachate samples from the hardwood bark:pine bark and pine bark:sand substrates. Substrate ranking based on the amount of herbicide lost was 3:1 redwood bark:sand >2:1:1 redwood bark:Yolo loam:sand >1:1 hardwood bark:pine bark >3:1 pine bark:sand.

scholarly journals Soil Microbial Community Changes in a Field Treatment with Chlorotoluron, Flufenacet and Diflufenican and Two Organic Amendments

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1166
Author(s):  
María José Carpio ◽  
Carlos García-Delgado ◽  
Jesús María Marín-Benito ◽  
María Jesús Sánchez-Martín ◽  
María Sonia Rodríguez-Cruz
Keyword(s):  
Microbial Community ◽  
Microbial Biomass ◽  
Microbial Activity ◽  
Soil Microbial Community ◽  
Organic Amendments ◽  
Herbicide Application ◽  
Amended Soils ◽  
Soil Microbial ◽  
Unamended Soil ◽  
Over Time

The soil microbial activity, biomass and structure were evaluated in an unamended (S) and organically amended soil treated with two commercial formulations of the herbicides chlorotoluron (Erturon®) and flufenacet plus diflufenican (Herold®) under field conditions. Soils were amended with spent mushroom substrate (SMS) or green compost (GC). Soil microbial dehydrogenase activity (DHA), biomass and structure determined by the phospholipid fatty acid (PLFA) profiles were recorded at 0, 45, 145, 229 and 339 days after herbicide treatment. The soil DHA values steadily decreased over time in the unamended soil treated with the herbicides, while microbial activity was constant in the amended soils. The amended soils recorded higher values of concentrations of PLFAs. Total soil microbial biomass decreased over time regardless of the organic amendment or the herbicide. Herbicide application sharply decreased the microbial population, with a significant modification of the microbial structure in the unamended soil. In contrast, no significant differences in microbial biomass and structure were detected in S + SMS and S + GC, untreated or treated with herbicides. The application of SMS and GC led to a significant shift in the soil microbial community regardless of the herbicides. The use of SMS and GC as organic amendments had a certain buffer effect on soil DHA and microbial biomass and structure after herbicide application due to the higher adsorption capacity of herbicides by the amended soils.

scholarly journals Efficacy of preemergence herbicides over time

2019 ◽  
Vol 37 (2) ◽  
pp. 55-62
Author(s):  
James E. Altland
Keyword(s):  
Weed Control ◽  
Effective Control ◽  
Seed Density ◽  
Herbicide Application ◽  
Weed Seed ◽  
Cardamine Flexuosa ◽  
Nursery Crops ◽  
Seed Application ◽  
Preemergence Herbicides ◽  
Over Time

Abstract Preemergence herbicides are applied to container-grown nursery crops repeatedly throughout the year, often in 8 to 10 week intervals. Preemergence herbicide efficacy may decline over time, resulting in reduced weed control several weeks after application if weed seed density remains high. The objective of this research is to evaluate efficacy of preemergence herbicides on creeping woodsorrel (Oxalis corniculata L.) and flexuous bittercress (Cardamine flexuosa With.) by applying weed seed from 0 to 10 weeks after herbicide application. Granular formulations of pendimethalin, prodiamine + isoxaben, oxyfluorfen + pendimethalin, and flumioxazin were applied at their maximum labeled rates to separate groups of containers every two weeks for ten weeks. After the herbicide application at 10 weeks, 40 seeds of creeping woodsorrel and flexuous bittercress each were applied to all containers. All herbicides provided effective control when seed were applied within 2 weeks of herbicide application. Herbicides containing oxyfluorfen or flumioxazin provided effective preemergence bittercress and creeping woodsorrel control when seed were applied up to 8 to 10 weeks after herbicide application. Other herbicide products resulted in reduced control as the time between herbicide and seed application increased. Index words: weed control, container crops, substrates. Species used in this study: flexuous bittercress (Cardamine flexuosa With.), creeping woodsorrel (Oxalis corniculata L.). Chemicals used in this study: pendimethalin (Pendulum 2G), prodiamine + isoxaben (Gemini G), pendimethalin + oxyfluorfen (OH2), and flumioxazin (BroadStar).

scholarly journals Residual activity of sulfentrazone and its impacts on microbial activity and biomass of Brazilian Savanna soils

2021 ◽  
Vol 51 ◽  
Author(s):  
Virgínia Damin ◽  
Bruno da Silva Carrijo ◽  
Nathalia Almeida Costa
Keyword(s):  
Microbial Biomass Carbon ◽  
Residual Activity ◽  
Clay Content ◽  
Brazilian Savanna ◽  
Herbicide Application ◽  
Soil Attributes ◽  
Microbiological Parameters ◽  
Urochloa Decumbens ◽  
Savanna Soils ◽  
Over Time

ABSTRACT Soil attributes may affect the residual activity and impacts of herbicides on non-target organisms. This study aimed to evaluate the residual activity of the sulfentrazone herbicide and its impacts on microbiological parameters of Brazilian Savanna soils, as well as to identify soil attributes that can be used to predict the residual activity of the herbicide in these soils. The experimental design was completely randomized, in a 6 x 5 factorial scheme, with 4 replications, being 5 soil types (Rhodic Acrustox; Typic Quartzpsamment; Rhodic Haplustox; Typic Humaquepts; Fluventic Dystrustepts) and 6 periods (0, 15, 30, 45, 60 and 90 days after herbicide application - DAA). The residual activity of the sulfentrazone herbicide is dependent of the soil type, and the time that the herbicide can control at least 80 % of Urochloa decumbens plants ranges from 0 (Typic Humaquepts) to 38 days (Rhodic Haplustox). The bases saturation is the only soil attribute correlated with the herbicide efficacy over time, in the Brazilian Savanna soils, showing a moderate correlation up to 90 DAA. The pH, organic matter and clay content are not correlated with the herbicide efficacy over time in these soils. Sulfentrazone reduces the microorganisms activity from 45 to 90 DAA in all the studied soils. However, it does not affect the microbial biomass carbon.

Social transmission bias and the cultural evolution of folk-economic beliefs

2018 ◽  
Vol 41 ◽  
Author(s):  
David Hirshleifer ◽  
Siew Hong Teoh
Keyword(s):  
Cultural Evolution ◽  
Social Transmission ◽  
Cognitive Approach ◽  
Economic Problems ◽  
Economic Attitudes ◽  
The Social ◽  
Economic Beliefs ◽  
Over Time

AbstractEvolved dispositions influence, but do not determine, how people think about economic problems. The evolutionary cognitive approach offers important insights but underweights the social transmission of ideas as a level of explanation. The need for asocialexplanation for the evolution of economic attitudes is evidenced, for example, by immense variations in folk-economic beliefs over time and across individuals.

Articulatory Generalization in Two Word-Medial, Ambisyllabic Contexts

1988 ◽  
Vol 19 (3) ◽  
pp. 251-258 ◽  
Author(s):  
Virginia I. Wolfe ◽  
Suzanne D. Blocker ◽  
Norma J. Prater
Keyword(s):  
Common View ◽  
Perceptual Salience ◽  
The Common ◽  
Unitary Concept ◽  
Over Time

Articulatory generalization of velar cognates /k/, /g/ in two phonologically disordered children was studied over time as a function of sequential word-morpheme position training. Although patterns of contextual acquisition differed, correct responses to the word-medial, inflected context (e.g., "picking," "hugging") occurred earlier and exceeded those to the word-medial, noninflected context (e.g., "bacon," "wagon"). This finding indicates that the common view of the word-medial position as a unitary concept is an oversimplification. Possible explanations for superior generalization to the word-medial, inflected position are discussed in terms of coarticulation, perceptual salience, and the representational integrity of the word.

Treatment Fidelity Procedures for an Aphasia Intervention Within a Randomized Controlled Trial: Design, Feasibility, and Results

2020 ◽  
Vol 29 (1S) ◽  
pp. 412-424
Author(s):  
Elissa L. Conlon ◽  
Emily J. Braun ◽  
Edna M. Babbitt ◽  
Leora R. Cherney
Keyword(s):  
Randomized Controlled Trial ◽  
Controlled Trial ◽  
Treatment Protocol ◽  
Treatment Fidelity ◽  
Protocol Adherence ◽  
Study Condition ◽  
Randomized Controlled ◽  
Aphasia Therapy ◽  
Percent Accuracy ◽  
Over Time

Purpose This study reports on the treatment fidelity procedures implemented during a 5-year randomized controlled trial comparing intensive and distributed comprehensive aphasia therapy. Specifically, the results of 1 treatment, verb network strengthening treatment (VNeST), are examined. Method Eight participants were recruited for each of 7 consecutive cohorts for a total of 56 participants. Participants completed 60 hr of aphasia therapy, including 15 hr of VNeST. Two experienced speech-language pathologists delivered the treatment. To promote treatment fidelity, the study team developed a detailed manual of procedures and fidelity checklists, completed role plays to standardize treatment administration, and video-recorded all treatment sessions for review. To assess protocol adherence during treatment delivery, trained research assistants not involved in the treatment reviewed video recordings of a subset of randomly selected VNeST treatment sessions and completed the fidelity checklists. This process was completed for 32 participants representing 2 early cohorts and 2 later cohorts, which allowed for measurement of protocol adherence over time. Percent accuracy of protocol adherence was calculated across clinicians, cohorts, and study condition (intensive vs. distributed therapy). Results The fidelity procedures were sufficient to promote and verify a high level of adherence to the treatment protocol across clinicians, cohorts, and study condition. Conclusion Treatment fidelity strategies and monitoring are feasible when incorporated into the study design. Treatment fidelity monitoring should be completed at regular intervals during the course of a study to ensure that high levels of protocol adherence are maintained over time and across conditions.

Percutaneous Tracheostomy: A Multidisciplinary Approach

2008 ◽  
Vol 18 (2) ◽  
pp. 87-98 ◽  
Author(s):  
Vinciya Pandian ◽  
Thai Tran Nguyen ◽  
Marek Mirski ◽  
Nasir Islam Bhatti
Keyword(s):  
Health Care ◽  
Quality Assurance ◽  
Data Collection ◽  
Health Care Professionals ◽  
Multidisciplinary Approach ◽  
Percutaneous Tracheostomy ◽  
Johns Hopkins Hospital ◽  
Prospective Data ◽  
Comprehensive Service ◽  
Over Time

Abstract The techniques of performing a tracheostomy has transformed over time. Percutaneous tracheostomy is gaining popularity over open tracheostomy given its advantages and as a result the number of bedside tracheostomies has increased necessitating the need for a Percutaneous Tracheostomy Program. The Percutaneous Tracheostomy Program at the Johns Hopkins Hospital is a comprehensive service that provides care to patients before, during, and after a tracheostomy with a multidisciplinary approach aimed at decreasing complications. Education is provided to patients, families, and health-care professionals who are involved in the management of a tracheostomy. Ongoing prospective data collection serves as a tool for Quality Assurance.

High-Risk Youth Behaviors Decreasing Over Time

2008 ◽  
Vol 42 (7) ◽  
pp. 26-27
Author(s):  
MARY ELLEN SCHNEIDER
Keyword(s):  
High Risk ◽  
High Risk Youth ◽  
Over Time ◽  
Youth Behaviors
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