Effects of Metam Sodium Fumigation on Soil Microbial Activity and Community Structure

Abstract

Metam sodium (MS) is a widely used soil fumigant with broad biocidal activity. The impact of MS on soil microbial community structure and function is largely unknown. We investigated the effects of fumigation with field‐relevant doses of MS in soil microcosms using traditional heterotrophic activity measures (C and N mineralization), a substrate‐utilization assay, and fatty acid analysis. Our results suggest that fumigation with MS results in persistent changes (at least 18 wk) in heterotrophic activity and fatty acid composition of the microbial biomass. Lack of recovery of heterotrophic activity and changes in fatty acid composition after fumigation suggest that MS has the potential to alter important microbially mediated functions such as nutrient cycling and pollutant degradation. Preliminary fatty acid data suggest that actinomycetes and other gram‐positive organisms may recover preferentially after fumigation with MS. Although community fatty acid analysis shows promise as a screening tool in soil microbial toxicity studies, more detailed information can be obtained from analysis of phospholipid fatty acid (PLFA) and other specific lipid fractions.

Enzyme activities in agricultural soils fumigated with methyl bromide alternatives

“…The latter may feed on cell debris, leading to restructuring of soil microbial populations as indicated elsewhere (Macalady et al, 1998;Ibekwe et al, 2001;Orosco et al, 2001). …”

“…Previous studies on the effects of potential MeBr alternatives on the size, composition and activity of soil microorganisms are limited to one or a few fumigants, a relative short time period, and/or the laboratory (Miller et al, 1997;Macalady et al, 1998;Ibekwe et al, 2001). Recovery of microbial processes in the laboratory compared to the field may be reduced due to the absence of re-colonization by nonfumigated soils (Macalady et al, 1998).…”

“…Previous studies on the effects of potential MeBr alternatives on the size, composition and activity of soil microorganisms are limited to one or a few fumigants, a relative short time period, and/or the laboratory (Miller et al, 1997;Macalady et al, 1998;Ibekwe et al, 2001). Recovery of microbial processes in the laboratory compared to the field may be reduced due to the absence of re-colonization by nonfumigated soils (Macalady et al, 1998). Furthermore, the effect of alternative fumigants on soil microbial processes was studied on soils with a 10-year history of 13 fumigation with MeBr + CP combinations (history soils) followed by a 2 to 3 year break prior to the initiation of these field experiments at Watsonville and Oxnard, respectively.…”

Impacts of Soil Type on Microbial Community from Paddy Soils in Gyeongnam Province

“…이러한 토 양 미생물의 다양성을 평가하고 유지하는 것은 친환경농업 을 추진하기 위한 기본적인 요건이라 할 수 있다 (Lee et al, 2011a;Lee et al, 2011b). 최근 미생물의 다양성을 쉽 게 분석하고 평가할 수 있는 방법으로 Fatty acid methyl ester (FAME) 방법이 주목받고 있다 Lee and Ha, 2011;Lee and Zhang, 2011;Lee et al, 2011c;Macalady et al, 1998;Schutter and Dick, 2000).…”

Impacts of Soil Texture on Microbial Community from Paddy Soils in Gyeongnam Province

“…토양환경이 외부로부터 급격한 변화를 받게 되면 미생물의 군집은 영향을 받게 된다 Lee and Yun, 2011). 미생물의 군집 비율은 fatty acid methyl ester (FAME) 방법을 사용하여 분석할 수 있다 Macalady et al, 1998;Schutter and Dick, 2000). 으로 미사질양토 135 mg kg -1 보다 유의적으로 높다고 하였다 (Lee and Ha, 2011a …”