Exploring a soil fumigation strategy based on ammonium bicarbonate to control Fusarium wilts of cucurbits

• Ammonium bicarbonate was applied as a fumigation agent to control Fusarium.
• The fumigant ammonium bicarbonate (AB) can inhibit the growth of pathogens.
• AB mixed with lime had a stronger antifungal effect in soil with pH less than 7.
• Fumigation altered the soil culturable microflora.
• This study provided a potential strategy for controlling Fusarium.

Fusarium wilt diseases, caused by formae speciales of the fungus Fusarium oxysporum are a serious problem for the production of cucumber, watermelon, melon and other plants around the world. In this study, the possibility of applying a novel fumigation agent to the soil was investigated as a strategy for controlling F. oxysporum f. sp. cucumerinum (FOC), F. oxysporum f. sp. niveum (FON), and F. oxysporum f. sp. melonis (FOM). The fumigation agent ammonium bicarbonate, which releases ammonia, was investigated when applied alone and with lime as a direct soil amendment under sealed conditions. For the FOC, FON and FOM, the suitable additive concentrations of ammonium bicarbonate were 2, 2 and 1.5 g kg−1 soil dry weight (DW), respectively, when applied alone. These concentrations produced the best effects when short processing times, broad temperature ranges and wide soil moisture contents were used. Ammonium bicarbonate had a stronger antifungal effect when mixed with lime than when applied alone in the pot experiments. In the field experiment, stronger antifungal effects were observed when the pH value of the soil was less than 7, and no significant difference between the two treatments was observed in alkaline soil. This study explored a novel fumigation agent for controlling F. oxysporum that was based on ammonium bicarbonate and provided a potential strategy for ensuring healthy cucumber, watermelon and melon crops and supporting the worldwide development of these cropping industries.