Enhanced degradation of some soil‐applied herbicides

Walker, A.; Welch, Sarah J.

doi:10.1111/j.1365-3180.1991.tb01742.x

Cited by 45 publications

(20 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Beneficial microbes that are sensitive to allelochemicals will likely develop resistance over time, and the indirect inhibitory effects on the plants associating with them will, therefore, decline. Likewise, microbes that act to reduce allelopathic effects by degrading allelochemicals will likely become more efficient as they adapt to the novel allelochemicals (Blum and Shafer, 1988;Walker and Welch, 1991). Conversely, microbial enhancement of allelopathic effects through increased toxicity of microbial degradation products is predicted to increase as the time since invasion increases.…”

Section: Discussionmentioning

confidence: 93%

Microbes as Targets and Mediators of Allelopathy in Plants

2012

View full text Add to dashboard Cite

Studies of allelopathy in terrestrial systems have experienced tremendous growth as interest has risen in describing biochemical mechanisms responsible for structuring plant communities, determining agricultural and forest productivity, and explaining invasive behaviors in introduced organisms. While early criticisms of allelopathy involved issues with allelochemical production, stability, and degradation in soils, an understanding of the chemical ecology of soils and its microbial inhabitants has been increasingly incorporated in studies of allelopathy, and recognized as an essential predictor of the outcome of allelopathic interactions between plants. Microbes can mediate interactions in a number of ways with both positive and negative outcomes for surrounding plants and plant communities. In this review, we examine cases where soil microbes are the target of allelopathic plants leading to indirect effects on competing plants, provide examples where microbes play either a protective effect on plants against allelopathic competitors or enhance allelopathic effects, and we provide examples where soil microbial communities have changed through time in response to allelopathic plants with known or potential effects on plant communities. We focus primarily on interactions involving wild plants in natural systems, using case studies of some of the world's most notorious invasive plants, but we also provide selected examples from agriculturally managed systems. Allelopathic interactions between plants cannot be fully understood without considering microbial participants, and we conclude with suggestions for future research. Allelopathy and Soil MicrobesAllelopathy, generally, is considered as a form of negative chemical communication between organisms, whereby one participant (the donor) in an interaction produces a compound(s) that is released in the environment in ecologically relevant quantities that negatively impacts the fitness of other participants (the receivers); the effect presumably benefits fitness of the donor. While the concept of allelopathy extends back to at least Theophrastus in the third century B.C., who invoked this phenomenon as an explanatory mechanism of plant growth, abundance, or community structure in natural systems, the concept has fluctuated in popularity over time (see Willis, 2007 for review). Allelopathy often has been subjected to criticisms of ecological relevance that other phenomena, such as resource competition, have not, thus explaining why it has fallen out of favor during certain time periods. However, studies of allelopathy in terrestrial systems have experienced a tremendous "rebirth" in the last 20 years as interest has risen in describing biochemical mechanisms responsible for structuring plant communities, determining agricultural and forest productivity, and explaining invasive behaviors in introduced organisms. More rigorous observational and experimental approaches, along with better analytical techniques, have

show abstract

Section: Discussionmentioning

confidence: 93%

Microbes as Targets and Mediators of Allelopathy in Plants

2012

View full text Add to dashboard Cite

show abstract

“…Its vapor pressure is 2.1 × 10 −3 Pa at 20°C and its water solubility is 242 mg L −1 at 25°C (Tomlin, 1997). Its half‐life at 20°C in soil is 20 to 40 d (Pothuluri et al, 1990; Walker and Welch, 1991) and its adsorption coefficient ( K oc ) is 170 L kg −1 (Tomlin, 1997). Bentazone is a colorless crystalline powder.…”

Section: Methodsmentioning

confidence: 99%

Alachlor and Bentazone Losses from Subsurface Drainage of Two Soils

Dousset

Babut²,

Andreux

et al. 2004

J of Env Quality

View full text Add to dashboard Cite

Atrazine (6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine) is frequently detected at high concentrations in ground water. Bentazone [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] plus alachlor (2-chloro-2',6'-diethyl-N-methoxymethylacetanilide) is a potential herbicide combination used as a substitute for atrazine. Thus, the objective of this study was to assess the environmental risk of this blend. Drainage water contamination by bentazone and alachlor was assessed in silty clay (Vertic Eutrochrept) and silt loam (Aquic Hapludalf) soils under the same management and climatic conditions. Drainage volumes and concentrations of alachlor and bentazone were monitored after application. Herbicides first arrived at the drains after less than 1 cm of net drainage. This is consistent with preferential flow and suggests that about 3% of the pore volume was active in rapid transport. During the monitoring periods, bentazone losses were higher (0.11-2.40% of the applied amount) than alachlor losses (0.00-0.28%) in the drains of the silty clay and silt loam. The rank order of herbicide mass losses corresponded with the rank order of herbicide adsorption coefficients. More herbicide residues were detected in drainage from the silty clay, probably due to preferential flow and more intensive drainage in this soil than the silt loam. Surprisingly, herbicide losses were higher in the drains of both soils in the drier of the two study years. This could be explained by the time intervals between the treatments and first drainage events, which were longer in the wetter year. Results suggest that the drainage phases occurred by preferential flow in the spring-summer period, with correspondingly fast leaching of herbicides, and by matrix flow during the fall-winter period, with slower herbicide migration.

show abstract

“…Degradation of herbicides in soil is an important aspect 402 C. Accinelli et al to consider in the prediction of their environmental fate. Degradation of metolachlor, linuron and isoproturon in unsaturated soil has been studied by numerous authors (Walker et al, 1991;Dinelli et al, 2000;Accinelli et al, 2001;Walker et al, 2001), but little is known about their degradation in flooded soils.…”

Section: Introductionmentioning

confidence: 99%

Influence of flooding on the degradation of linuron, isoproturon and metolachlor in soil

Accinelli

Screpanti

Vicari

2005

Agron. Sustain. Dev.

View full text Add to dashboard Cite

-Degradation of pesticides in soil usually refers to normally aerated conditions. However, considering that under some circumstances, fields treated with pesticide can be subject to flooding phenomena, more information on pesticide persistence under these conditions is needed. The main objective of the present study was to investigate the persistence of linuron, isoproturon and metolachlor in soil samples incubated under flooding conditions. During the whole incubation period, changes in soil Eh, pH and microbial C were measured. Flooding conditions produced different effects on the persistence of the three herbicides. More specifically, flooding conditions led to a significant increase in linuron and isoproturon persistence. The half-lives of linuron and isoproturon in flooded soil were 1.8 and 1.4 times higher than in nonflooded soil, respectively. An opposite phenomenon was observed with metolachlor. The half-life of metolachlor was reduced from 32.2 to 24.1 days in nonflooded and flooded soil, respectively. Soil Eh rapidly decreased in soil samples incubated under flooding conditions, passing form 368.0 mV to -225.5 mV within the first week of flooding. No significant changes in soil microbial C in soil samples incubated under the two water regimes were observed. The results obtained from the present experiment showed that information from normally aerated soil conditions is not correctly applicable to predict herbicide persistence under flooding conditions. herbicide persistence / linuron / isoproturon / metolachlor / flooding conditions

show abstract

Enhanced degradation of some soil‐applied herbicides

Cited by 45 publications

References 16 publications

Microbes as Targets and Mediators of Allelopathy in Plants

Microbes as Targets and Mediators of Allelopathy in Plants

Alachlor and Bentazone Losses from Subsurface Drainage of Two Soils

Influence of flooding on the degradation of linuron, isoproturon and metolachlor in soil

Contact Info

Product

Resources

About