Shifts in microbial communities following application of chloropicrin and 1,3-Dichloropropene in pineapple soils

Chloropicrin and 1,3-dichloropropene (1,3-D) are well-known soil fumigants. Their impact on microbiological communities and soil health is an important subject to understand. Increased crop production, decreased plant pests, and larger root systems are among the responses often observed with these chemicals. Microbial shifts in response to soil fumigation have been reported by other investigators, and significant detail and understanding have arisen recently due to studies utilizing culture-free genetic identification tools. The current study’s objectives were to: 1) Survey the soil biome in pre-plant-fumigated and non-fumigated soils in four pineapple fields located in Guatemala, the Dominican Republic, and Mexico; 2) Characterize trends and patterns, and quantify biome shifts which occur, including changes in biome diversity as well as the identification of prevalent species. The results point to a comparatively high degree of microbial diversity in fumigated soils and show fundamental shifts in bacterial and fungal species, including amplification of such functional groups as plant-growth-promoting rhizobacteria (PGPR) and the biocontrol fungus Trichoderma. Similarities and differences in the soil biome were discovered across the different sites and examples are presented. The data as a whole provide strong evidence that soil microbial shifts in response to soil fumigants are much more nuanced and complex compared to commonly perceived notions, and more importantly, the effects of fumigants on soil microbial health appear to be strongly positive.