Management impacts to soil microbial communities in Maine potato production

Authors: ASHLEY, KATHERINE - University Of Maine; HAIN, ANDREA - University Of Maine; Larkin, Robert; HAO, JIANJUN - University Of Maine

Submitted to: PhytoFrontiers
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/20/2025
Publication Date: 3/20/2025
Citation: Ashley, K.A., Hain, A., Larkin, R.P., Hao, J. 2025. Management impacts to soil microbial communities in Maine potato production. PhytoFrontiers. https://doi.org/10.1094/PHYTOFR-02-25-0015-R.
DOI: https://doi.org/10.1094/PHYTOFR-02-25-0015-R

Interpretive Summary: Soil health is critical for agricultural productivity and sustainability and soil microbial communities are a major component of soil health. This study investigated the impacts of a variety of different management practices in potato production on soil microbial communities, including rotation length, rotation crops, green manures, compost amendments, and a soil fumigant using two different potato varieties. DNA collected from soil samples were used to identify and characterize the impacts of the management practices on potato soil bacterial and fungal communities over a 4-yr period. Overall, fungi were more sensitive to the management practices than bacteria. Fumigation and compost had the greatest impacts on microbial communities. Fumigation resulted in a decrease in the abundance of certain fungal groups. Compost amendment led to substantial increases in fungal diversity, with many more different types of fungi compared to soils without compost, as well as substantially lower numbers of fungi identified as plant pathogens. In general, compost appeared to positively impact soil microbial communities and fumigation appeared to negatively impact them. This research is useful for scientists, extension personnel, growers, and consumers in developing crop management decisions which improve soil health, reduce disease, and increase yields.

Technical Abstract: Agricultural management is impactful to soil health. Potato production can be particularly taxing through intensive tillage and typically short crop rotations. This study investigated the impacts of management practices on soil microbial communities, including rotation length, rotation crops, green manures, compost amendments, and a soil fumigant using two potato varieties ‘Caribou Russet’ and ‘Russet Burbank.’ Soil samples were collected, and bacterial and fungal communities were characterized using amplicon sequence variants (ASVs) of the 16S rRNA and ITS rDNA regions, respectively. Initially, no significant differences were detected between microbial communities, however, after four years significant differences were found. Overall, fungi were more sensitive to the management practices than bacteria. Of the practices, fumigation and compost had the largest impacts to microbial communities. Fumigation resulted in a decrease in the abundance of certain fungal groups, particularly saprotrophs or unidentified functional fungi. Two largest groups of fungi that were more abundant in fumigated soils were saprotrophs or plant pathogens. Compost amendment led to substantial increases in fungal diversity, with over 3.5 times more differentially abundant fungal ASVs found compared to soils without compost. Within these more abundant fungal ASVs in compost-amended soils, plant pathogens made up only 4% versus 25% in soils without compost. In general, compost appeared to positively impact soil microbial communities, whereas fumigation appeared to negatively impact them. The results of this study could aid farmers in crop management decisions which improve soil health, reduce disease, and increase yields.