Transformation of 1,3‐Dichloropropene in Soil by Thiosulfate Fertilizers

Abstract

Abstract The pesticide 1,3‐dichloropropene (1,3‐D) is considered to be the most promising alternative to methyl bromide for soilborne pest control. The high volatility of 1,3‐D, however, has been shown to result in excessive atmospheric emissions that may impose toxicological effects on workers or residents. This study demonstrated that 1,3‐D was rapidly transformed to nonvolatile products by thiosulfate fertilizers in soil, and that thiosulfate‐facilitated fumigant transformation may be used to reduce 1,3‐D emissions. Transformation of 1,3‐D by thiosulfate was chemically based, and 1,3‐D degradation in soil accelerated proportionally as thiosulfate level in soil increased. At a 4:1 thiosulfate to fumigant molar ratio, the half‐life of 1,3‐D was reduced to only a few hours, as compared with >10 d for nonamended soils. The rate of thiosulfate‐facilitated 1,3‐D transformation was independent of soil types and was higher in moist soils and at high soil temperatures. Transformation occurred at a similar rate for ammonium, calcium, and sodium thiosulfates. As these thiosulfate compounds are commercial fertilizers, amendment of these products at the soil surface during 1,3‐D fumigation may offer an effective and inexpensive approach for reducing 1,3‐D emissions.