Conversion of metam sodium and emission of fumigant from soil columns

Zheng, Wei; Yates, Scott R.; Papiernik, Sharon K.; Nunez, Joe

doi:10.1016/j.atmosenv.2006.06.009

Cited by 24 publications

(14 citation statements)

References 21 publications

(33 reference statements)

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“…The degradation behavior of dazomet is described by a first‐order kinetic model (Zheng et al, 2006):

C_{t} = C_{0} \exp (- k t)

where t (h) is the incubation time, k (h −1 ) is the first‐order rate constant, and C t and C 0 (mg kg −1 ) are the dazomet concentrations in soil at incubation time t (h) and time 0.…”

Section: Methodsmentioning

confidence: 99%

“…Studies have shown that metam sodium is rapidly converted to MITC by an abiotic decomposition process, usually within 1 to 24 h after application (Gerstl et al, 1977; Wales and Helliker, 2000). The rate of decomposition depends strongly on soil temperature, soil texture, and soil moisture (Zheng et al, 2006). However, dazomet is a solid (metam sodium is a liquid), which makes the decomposition of dazomet to MITC more dependent on environment conditions.…”

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confidence: 99%

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Environmental Factors and Soil Amendment Affect the Decomposition Rate of Dazomet Fumigant

et al. 2018

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Dazomet (3,5‐dimethyl‐1,3,5‐thiadiazinane‐2‐thione) is widely used as a soil fumigant for controlling soil‐borne diseases and pests in China and other agricultural countries. The active ingredient of dazomet is its degradation product, methyl isothiocyanate. Little is known about the environmental conditions that affect the degradation of dazomet in soil. In this study, we conducted laboratory incubation experiments to test the effects of several environmental factors, including soil texture, water content, temperature, pH, and soil amendments, such as chicken manure or urea fertilizer, on the decomposition of dazomet. Results showed that dazomet degradation in soil is an abiotic process strongly dependent on soil texture, water content, temperature, and pH. Decomposition rates differed greatly in various soils, depending mainly on soil physicochemical properties such as pH and organic matter content. The degradation rate increased by 15 to 24 times and by 16 to 37 times when soil temperature increased from 5 to 45°C, and water content increased from 10 to 30%, respectively. Dazomet degraded faster in alkaline versus acidic soil. Both chicken manure and urea fertilizer moderately slowed dazomet degradation. Dazomet was degraded in soil mainly by hydrolysis. The results of our study contribute to a better understanding of the environmental behavior of dazomet, potentially leading to its more efficient, safe, profitable, and effective use by farmers. Core Ideas Dazomet dissipation is highly dependent on soil type. Temperature and soil water content had a large impact on the degradation of dazomet Dazomet degraded faster in an alkaline soil than in acidic soil. Chicken manure and urea fertilizer moderately slowed dazomet degradation. Dazomet degradation is an abiotic process.

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“…The degradation behavior of dazomet is described by a first‐order kinetic model (Zheng et al, 2006):

C_{t} = C_{0} \exp (- k t)

where t (h) is the incubation time, k (h −1 ) is the first‐order rate constant, and C t and C 0 (mg kg −1 ) are the dazomet concentrations in soil at incubation time t (h) and time 0.…”

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

Environmental Factors and Soil Amendment Affect the Decomposition Rate of Dazomet Fumigant

et al. 2018

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“…In an effort to reduce fumigant off‐gassing and subsequent atmospheric emission, several techniques have been utilized, such as improved plastic barrier films 12–16. Alternative preplant fumigant application and soil management procedures have also been explored, such as drip application,17, 18 modified chemical injection methods,19 soil solarization20 and soil surface water sealing 15, 21–23…”

Section: Introductionmentioning

confidence: 99%

“…They found that intermittent water sealing significantly reduced MITC off‐gassing when used in combination with standard shank and chemigation practices. Zheng et al 22 found that the cumulative emission loss of MITC could be reduced by up to 66% in soil columns with a surface water sealing application relative to soil columns without a surface treatment.…”

Section: Introductionmentioning

confidence: 99%

Surface water seal application to minimize volatilization loss of methyl isothiocyanate from soil columns

Simpson

Nelson

Stratmann

et al. 2010

Pest Management Science

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“…The simulation was conducted only for MITC. No attempt was made to simulate Met‐Na transformation because it efficiently (e.g., >92%) and quickly converts to MITC (tens of minutes) under the study conditions (Zheng et al, 2006). …”

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confidence: 99%

Water and Methyl Isothiocyanate Distribution in Soil after Drip Fumigation

Nelson

Ajwa

Trout³

et al. 2013

J. Environ. Qual.

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Methyl isothiocyanate (MITC) generators, such as metam sodium (Met-Na), are used for soil fumigation of agricultural land. The ban on the fumigant methyl bromide has resulted in greater use of MITC generators. To understand the efficacy of MITC, it is necessary to assess its generation and disappearance kinetics when Met-Na is applied to soil. This study evaluated the movement of water and distribution and dissipation of MITC in soil after application of Met-Na through surface drip irrigation systems. The effects of varying water application volume (25, 50, and 75 mm) and rate (1.9, 5.0, and 7.5 L h m) were evaluated in a sandy loam soil. Good fumigant distribution within the sandy loam soil was observed under medium water application amount (50 mm) with slow to intermediate drip application rates (1.9-5.0 L h m). Low water application amount (25 mm) or high application rate (7.5 L h m) did not provide adequate MITC distribution throughout the soil bed width and rooting depth. Dissipation patterns of MITC in soil in all water application amounts and rates followed first-order kinetics, with a rate constant of 0.025 ± 0.004 h and a half-life of 27 ± 3 h. Simulated water distribution through the soil profile using HYDRUS 2D/3D fitted measured field data well, and the model accurately simulated MITC fumigant distribution in the soil.

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Conversion of metam sodium and emission of fumigant from soil columns

Cited by 24 publications

References 21 publications

Environmental Factors and Soil Amendment Affect the Decomposition Rate of Dazomet Fumigant

Environmental Factors and Soil Amendment Affect the Decomposition Rate of Dazomet Fumigant

Surface water seal application to minimize volatilization loss of methyl isothiocyanate from soil columns

Water and Methyl Isothiocyanate Distribution in Soil after Drip Fumigation

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