Soil microbial biomass influenced by cover crop after fumigation of potato fields

Soil fumigation is commonly employed for pest control in potato production, although it can unintentionally harm non-target organisms in the soil. The presence of cover crops can significantly influence the abundance and composition of microorganisms. However, there is limited knowledge regarding the combined impact of soil fumigation and cover crops on soil health in potato fields. To address this knowledge gap, a field study was conducted at the Hermiston Agricultural Research and Extension Center, Oregon State University with a randomized split-plot design consisting of four fumigation treatments (no fumigation control, Telone, metam sodium, and co-applied Telone and metam sodium) as the main plots and five cover crop treatments [no cover crop, wheat (Triticum aestivum), mustard (Brassica nigra), radish (Raphanus sativus), and a mixture of winter pea (Pisum sativum) and faba bean (Vicia faba)] as the subplots. Compared to the control, microbial biomass carbon (MBC) in non-fumigated soils of pea+faba bean, wheat, and radish increased by 41 %, 37 %, and 31 %, respectively. In soils treated with metam sodium, pea+faba bean, wheat, radish, and mustard increased MBC by 30 %, 34 %, 41 %, and 40 % compared to the control. The results demonstrated the potential of cover crops to enhance MBC after fumigation. Both Fumigation and cover crop did not impact the total yield of potatoes, although fumigation increased the yield of tubers within 171-283 g size category compared to the control. However, the current data is not sufficient for making a conclusive remark. Further field studies should be conducted to understand the role of fumigation and cover crops on potato soil health and potato production.