Effects of soil type, temperature, moisture, application rate, fertilizer, and organic amendments on chemical properties and biodegradation of dimethyl disulfide in soil

Authors: HAN, DAWEI - Chinese Academy Of Agricultural Sciences; YAN, DONGDONG - Chinese Academy Of Agricultural Sciences; WANG, QIUXIA - Chinese Academy Of Agricultural Sciences; FANG, WENSHENG - Chinese Academy Of Agricultural Sciences; WANG, XIANLI - Chinese Academy Of Agricultural Sciences; LI, JUN - Chinese Academy Of Agricultural Sciences; Wang, Dong; LI, YUAN - Chinese Academy Of Agricultural Sciences; OUYANG, CANBIN - Chinese Academy Of Agricultural Sciences; CAO, AOCHENG - Chinese Academy Of Agricultural Sciences

Submitted to: Land Degradation and Development
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/25/2018
Publication Date: 10/22/2018
Citation: Han, D., Yan, D., Wang, Q., Fang, W., Wang, X., Li, J., Wang, D., Li, Y., Ouyang, C., Cao, A. 2018. Effects of soil type, temperature, moisture, application rate, fertilizer, and organic amendments on chemical properties and biodegradation of dimethyl disulfide in soil. Land Degradation and Development. 29(12):4282-4290. https://doi.org/10.1002/ldr.3177.
DOI: https://doi.org/10.1002/ldr.3177

Interpretive Summary: Pre-plant soil fumigation with methyl bromide has been the most direct and effective method for controlling plant parasitic nematodes, soil-borne pathogens, and weeds for production of high-valued crops. However, methyl bromide soil fumigation has been banned world-wide, and new chemicals or methods of soil treatment are sorely needed. Dimethyl disulfide is a naturally occurring compound and has the potential for killing soil pests. Little is known about the environmental fate and behavior of this chemical. Laboratory tests were carried out to determine the rate of degradation and transformation pathways of the chemical under different soil, temperature, moisture, dosage, and amendment conditions. Results showed that soil pH and organic amendment were major factors controlling the degradation, and the main pathway of transformation was by biodegradation. This information will be valuable for developing effective strategies for controlling soil pests and reducing fumigant environmental impact.

Technical Abstract: Dimethyl disulfide (DMDS) is a potential alternative to methyl bromide for soil fumigation to control soil-borne pests. However, its degradation in soil is not fully understood. Laboratory experiments were conducted to investigate the effects of combinations of soil and environmental factors on DMDS degradation in soil. The results showed that soil pH and soil organic matter content are the major factors influencing the degradation of DMDS in soil. Generally, DMDS degradation was significantly slower in acidic and high organic content soils. The results of studies on five types of sterilized soil showed that biodegradation is the main pathway for DMDS removal in soil. In general, the degradation rate increased with temperature and water content. However, when the temperature exceeded 35°C the degradation rate decreased with temperature, and when the soil water content rose to 10% the change in DMDS degradation was not significant in Fangshan soil. The degradation of DMDS in soil depended on the initial application rate. In general, degradation slowed down as the fumigant application rate increased. DMDS degradation in soil was restrained by the addition of organic matter to soil, and the effect was enhanced by increased dosage. DMDS degradation in soil was also restrained by the use of chemical fertilizers except when amended with sodium dihydrogen phosphate and sodium thiosulfate. The impact of fumigant application rates and chemical fertilizers on bacterial communities in soil was determined by 16S rRNA gene amplicon Illumina pyrosequencing. The results showed that bacterial diversity was affected by different treatments. Our study provides a theoretical basis for developing effective DMDS application strategies for achieving good pest-control efficacy, and reducing atmospheric volatilization.