Caliente Mustards are bred specifically for biofumigation, they contain very high levels of the correct glucosinolates (there are many different types, and some do not produce lots of ITC), and high levels of the myrosinase enzyme, in addition they have the potential to grow into large plants producing high levels of biomass and therefore more green tissue to produce ITC when chopped. Caliente Mustards have been developed over many years, with new blends and varieties developed for performing specific functions, and for growing in different climates and situations. They are not simple green manure or cover crops and should not be confused with fodder mustard which is commonly available as a green manure and will not generate the same biofumigation effect. When considering disease suppression, it is important to note that the biofumigation aspect is not the only important factor. It is a combination of the biofumigation plus the incorporation of green material into the soil which encourages beneficial microbe multiplication. These beneficial soil microbes play an important part in ‘out-competing’ pathogenic microbes for space in the soil profile, helping to keep soil disease levels down.
Caliente Mustards have been bred specifically for biofumigation and green manuring. The naturally occurring biofumigant gas (ITC) is produced by the plants when the crop is chopped, incorporating this compound and the green material into soil results in many benefits including improved soil structure, health and fertility, suppression of various soil-borne diseases and pests and increased soil microbial activity.
Biofumigation refers to the suppression of various soil borne pests and diseases by naturally occurring compounds. Caliente Mustard produces isothiocyanate (ITC) a natural gas released from all brassicaceous plant tissues. The gas is produced when plant cells are damaged (by crushing or chopping) and compounds called glucosinolates (present in all brassicas) come into contact with an enzyme (myrosinase) in the presence of water. It is believed that this mechanism was originally developed by the plant as a defence against sucking and chewing insects, but over time many of the glucosinolates (the compounds that make certain brassicas ‘hot’ e.g. radishes) have been bred out of brassica crops to make them more palatable for human and animal consumption e.g. cabbage and cauliflower, or to produce better quality oil e.g. oil seed rape.
To create the best biofumigation effect, Caliente Mustard plants must be chopped as finely as possible before immediately incorporating into soil, simply ploughing in the crop will not give the same effect.
There are a number of benefits common to all crop types, soil types, climate and situation: