Impact of Biochar Rate and Fertilizer Source on Root-Knot Nematodes, Southern Blight, and Tomato Yield in a Plasticulture Production System in Georgia, 2024

A field trial was conducted at the University of Georgia Hort Hill Farm in Tifton, GA, to examine the effects of biochar rate and fertilizer type on Meloidogyne incognita (root-knot nematode), Agroathelia rolfsii (southern blight), and yield in tomatoes during the 2024 growing season. Biochar significantly reduced nematode gall ratings, particularly at 20 tons/acre, while organic fertilizer lowered gall severity and increased yield compared with inorganic fertilizer. Biochar did not affect tomato yield, and southern blight mortality remained high across treatments, likely due to spring rainfall. These findings highlight biochar's potential for nematode suppression and emphasize the yield benefits of organic fertilizer in tomato production.