Microbial Response to Bensulfuron-Methyl Treatment in Soil

El-Ghamry, A. M.; Xu, JM; Cy, Huang; Gan, Jianying

doi:10.1021/jf010756x

Cited by 34 publications

(20 citation statements)

References 18 publications

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“…Marsh and Davies (1981) observed long-term strong inhibition of nitrification in dichlorprop-and mocoprop-treated soils. Moreover, nitrification was suppressed significantly by bensufuron-methyl applied at concentrations of 0.1 and 1.0 μg g −1 soil (El-Ghamry et al 2002). It seems reasonable to assume that the chemical nature of herbicides is responsible for their effects on this process.…”

Section: Nitrification and Ammonification Ratesmentioning

confidence: 99%

Linuron effects on microbiological characteristics of sandy soils as determined in a pot study

2010

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The aim of this study was to find what dosages of linuron introduced into soil can be tolerated by microorganisms, and whether a dosage equal to 100-times higher than the predicted environmental concentration (PEC) is harmful. A pot study was performed to determine the effects of the herbicide at PEC (4 mg kg −1 ), 5 times PEC (20 mg kg −1 ), and 100 times PEC (400 mg kg −1 ) on substrate-induced respiration (SIR), four enzyme activities (dehydrogenase, acid and alkaline phosphatases, and urease), ammonification and nitrification rates, plate counts of total bacteria, fungi, N 2 -fixing bacteria, nitrifiers and denitrifiers, and distribution of r-and K-strategists in sandy soils of different texture throughout 28 days of incubation. Linuron increased SIR and ammonification, especially at 100 times PEC. In contrast, a decrease in nitrate concentrations was detected in both soils treated with the highest dosage of linuron. Although some changes in microbial numbers were ascertained, they were transient (i.e. total bacteria, N 2 -fixing bacteria and nitrifiers) or not significant (i.e. total fungi and denitrifiers). Among the enzymes tested, dehydrogenase was the most sensitive to linuron, showing decreased activity for all treatments and two higher dosages in the loamy sand (LS) and sandy loam (SL) soils, respectively. The addition of 100 times PEC of linuron to LS resulted in the domination of slow-growing K-strategists on days 1 and 14. However, r-strategists dominated on both days 1 and 28 in SL. Our results indicate that linuron may disturb indigenous soil microorganisms, especially when released at high concentrations.

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Section: Nitrification and Ammonification Ratesmentioning

confidence: 99%

Linuron effects on microbiological characteristics of sandy soils as determined in a pot study

2010

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“…Studies have shown that there was no discernable effect, an increase or decrease in measures of microbial activity or biomass carbon (Ahtiainen 2003;Anderson 1992;Chen et al 2001;Duah-Yentumi & Johnson 1986;El-Ghamry et al 2002;Haney et al 2002;Hart & Brookes 1996;Martikainen et al 1998;Prado & Airoldi 2001;Voets et al 1974). The conclusion of several researchers has been that although an effect might be measurable in the short term, long-term effects of pesticide applications to soils are transient (El-Ghamry 2002;Greaves 1979;Hart & Brooks 1996). Several studies have also found that that total soil respiration measures in particular may not be affected by pesticide treatments (Ahtiainen et al 2003;Hart & Brooks 1996).…”

Section: Introductionmentioning

confidence: 99%

Accelerated degradation of N, N? (DBU) upon repeated application

2005

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In a recent study on the degradation of N,N'-dibutylurea (DBU), a breakdown product of benomyl [methyl 1-(butylcarbamoyl)-2-benzimidazole carbamate], the active ingredient in Benlate fungicides, degradation half-lives of 1.4-46.5 days were observed across several soils incubated at various combinations of soil moisture potential (-0.03 and -0.1 MPa) and temperature (23, 33, and 44 degrees C) for a single DBU application of 0.08 and 0.8 microg g(-1) (Lee et al. 2004). However, Benlate can be applied as often as every 7 days resulting in the repeated application of DBU likely to be present in the Benlate over a growing season. In this study, the effect of seven repeated DBU applications on mineralization rate was investigated in two soils, which encompass the range in rates previously observed. For the slower degrading soil, repeated DBU application increased mineralization from 0.029 to 0.99 day(-1) at the 0.08 microg g(-1) rate, and 0.037 to 0.89 day(-1) at the 0.8 microg g(-1) rate. For the faster degrading soil, effects on mineralization of repeated DBU applications were small to negligible. For the latter soil, the effect on mineralization of applied DBU concentrations from 0.0008 to 80 microg g(-1) was also investigated. Mineralization rates decreased from 0.43 to 0.019 day(-1) with increasing DBU concentrations. However, the amount of DBU mineralized by day 70 was similar across concentrations and averaged 83% of applied. Microbial respiration was not affected by increasing DBU concentrations. These findings support the supposition that DBU is readily degraded by soil microorganisms, thus unlikely to accumulate in agricultural soils.

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“…Until now there are some reports about the influences of sulfonylurea herbicides on soil microorganisms (microbial biomass, soil respiration, soil enzymes activity, and nitrogen and carbon metabolism) by conventional culture methods (Gigliotti et al 1998;Yamamoto et al 1998;El-Ghamry et al 2002). Nevertheless, only a few researches have done on the influences of sulfonylurea herbicides on the soil microbial community structure diversity, especially the effects of BSM let alone bioremediation.…”

Section: Discussionmentioning

confidence: 99%

“…El-Ghamry et al (2002) reported that microbial biomass and nitrogen mineralization were not affected with the application of BSM at the field rate, and that the microbial biomass was inhibited only on the first few days after BSM application. Yamamoto et al (1998) reported a negative effect on nitrification, microbial biomass, and nitrogen mineralization in their work with BSM in flooded conditions.…”

Section: Introductionmentioning

confidence: 99%