Deposition and transformation of nitrogen after soil fumigation with ethanedinitrile

Abstract

A novel methyl bromide alternative, ethanedinitrile (EDN), has been reported to be efficacious against soil-borne pathogens, weeds, and plant-parasitic nematodes. Degradation products of EDN include NH4+and NH3, but it is currently unknown at what quantities these degradation products are being released into the soil at a given use rate of EDN. To address this issue, field studies were performed using the raised-bed plasticulture system. Deposition of NH4+ and NO3L in top 0-15-, 15-30-, and 30-45-cm soils were evaluated 3 weeks after fumigation with EDN applied at 336, 448, and 560 kg·haL1. Change of pH and transformation of NH4+ to NO3L in top 0-15- and 15-30-cm soils were tracked weekly after fumigation with EDN at 448 kg·haL1 for 10 weeks. This study found that fumigation with EDN significantly increased soil pH of the top 0-15-cm soil and soil NH4+ in top 0-15- and 15-30-cm soils, but soil NO3L was unaffected. Nitrification process in top 0-15-cm soil was inhibited by fumigation with EDN for at least 7 weeks. These results indicate that N deposited by fumigation with EDN could be an important preplant N source for crop production, and the inhibition of nitrification could help mitigate nitrate leaching. This study provides helpful information for quantification of N deposited from fumigation with EDN.