CALIENTE MUSTARD
Green manure & biofumigation

What is green manuring?

The incorporation of green plant tissue into the soil is known as ‘green manuring’, this plant tissue can be from any source, even weeds can count as green manure. It is an economical and practical method to improve soil structure and restore productivity to unused or overworked soil.

Benefits of green manuring:

1. Improves soil fertility and structure
2. Adds nutrients and organic matter
3. Improves soil aeration
4. Increases water infiltration and holding capacity
5. Reduced soil erosion from wind and water
6. Increases soil biodiversity by stimulating the growth of beneficial microbes and other soil organisms
7. Ideal for organic crop rotations and conventional systems where ICM (Integrated Crop Management) and reduced risk inputs are favoured

What is biofumigation?

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.

The following diagram simplifies the chemical reaction that takes place in a plant cell during biofumigation:

Click to enlarge

How is Caliente Mustard different?

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.

What are the benefits of Caliente Mustard?

There are a number of benefits common to all crop types, soil types, climate and situation:

1. Improvements to soil structure, fertility and biodiversity from the green manure effect
2. Provides a good source of nutrition to following crops, recycling nutrients like nitrogen
3. Encourages improved root systems and penetration (of following crop)
4. Measurable yield increases in following crops
5. Weed suppression, mainly of soft seeded annuals, most beneficial to crops following soon after Caliente Mustard incorporation

Benefits to potato and root crops:

1. Suppression of a range of soil-borne diseases, including Verticillium wilt, Rhizoctonia spp., Pythium spp., Fusarium spp., and Sclerotinia spp.
2. Suppression of a range of nematodes (eelworms) including some cyst, root knot and free living species. Trials are ongoing to determine the effectiveness of Caliente Mustard against Potato Cyst Nematode (eelworm) specifically
3. May improve skin finish
4. May deter wireworm populations

Benefits to vegetable and salad crops:

1. Suppression of a range of soil-borne diseases including Pythium spp., Sclerotinia spp., Fusarium spp., Rhizoctonia spp., and others
2. Suppression of a range of nematode species
3. Offers significant reduction in weeding costs, in terms of subsequent herbicide applications, and/or labour for hand/mechanical weeding. This is a particularly important benefit for organic systems

Benefits to soft and cane fruit crops:

1. Suppression of a range of soil-borne diseases including Verticillium wilt, Fusarium spp., and others
2. Suppression of a range of nematode species

Benefits to other crops/situations

Caliente Mustards and Nemat are suitable for a wide range of other applications and benefits have been seen in the following crops/situation:

1. Before replanting top fruit
2. In forestry and tree production
3. In protected cropping (soil grown) under glass and plastic
4. In ornamental plant and hardy nursery stock production, especially field grown plants where crop rotation is lacking and soil disease is present
5. In cut flower production
6. In bulb production
7. In viticulture (wine and table grape production) especially where nematodes are problematic

Caliente Mustard Products:

• Caliente Brand Mustard 119

Excellent all round variety with a proven track record in many cropping situations. Can be sown Spring or late Summer for quick crops, or mid-Autumn for overwintered crops in milder areas of the UK.
Best variety for organic systems

• Caliente Brand Mustard 99

Hottest variety, giving the best biofumigant action due to its very high levels of glucosinolates (30% more than variety 119). However it does require good growing conditions including additional fertiliser and irrigation in dry periods.

• Caliente Brand Mustard 61

Large leaved variety producing high levels of biomass under ideal conditions. Longer season and slowest to flower out of the varieties. Requires warmth so suitable for mid-summer UK growing and needs irrigation where soil moisture is low
Best variety for warmer climates (Spain, Portugal etc.)

• Nemat (Eruca sativa)

Not mustard but a white flowered rocket with biofumigant properties
Trap crop for various nematodes, including some root knot and cyst species
Plant roots contain highest levels of glucosinolates
Dense foliage produces good biomass although crop is shorter in height than the mustards
Mowing before flowering can extend the crops growing (and trapping) period
Tolerant to a range of temperatures, frost tolerant, and relatively drought tolerant once established

Caliente Mustards and Nemat are bred by the ISCI Institute, Bologna, Italy and all varieties are protected by plant breeder’s rights. Unauthorised multiplication or propagation is prohibited.

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