Biofumigation is a method of pest control in agriculture, a variant of fumigation where the gaseous active substance—fumigant—is produced by decomposition of plant material freshly chopped and buried in the soil for this purpose.
[1][2][3] Plants from the Brassicaceae family (e.g., mustards, cauliflower, and broccoli) are primarily used due to their high glucosinolate content; in the process of decomposition, glucosinolates are broken down to volatile isothiocyanates which are toxic to soil organisms such as bacteria, fungi and nematodes, but less toxic and persistent in the environment than synthetic fumigants.
[3] The method consists of mowing and chopping the plants during flowering to ensure maximum glucosinolate content and speed up decomposition.
The ground needs to be irrigated to field capacity, after which the chopped material is incorporated into the top layer and covered with impermeable film to prevent the gas from escaping.
[3] On the other hand, it requires changes in cultivation practice due to the time needed for the method to take effect, can be costly if biofumigant-producing plants need to be brought from elsewhere (i. e. if they are not used in crop rotation to be chopped and buried on site), and is difficult to standardize due to varying active substance content in different cultivars.