Successful biofumigation and green manuring from Caliente Brand Mustards requires a number of inputs, which will be repaid in following crops. Failure to treat Caliente Brand Mustards as a ‘crop’ may result in disappointment.
Seed placement
A reasonable seed bed is required, maximum seeding depth 5-10 mm. Seed should be shallow drilled and rolled, or broadcast (shallow harrowed) and rolled. Seed can be broadcast into cereal stubbles, rolling will improve germination. Fixed beds - reduce seeding rate/ha to take account for wheel tracks.
Crops grown on non-irrigated land should be timed to coincide with normal weather patterns. Crops will respond to irrigation during dry periods. Summer sown crops will respond well to irrigation throughout all crop stages to supplement rainfall.
Overwintering of crops is possible.
Soil moisture is essential at sowing and to establish the crop; lack of water will lead to premature flowering and reduced biomass production. The biofumigation reaction will only occur in the presence of moisture. Where irrigation is available, ensure crop is watered throughout germination and establishment, and as required to keep soil moist.
For maximum biomass production Caliente Brand Mustard crops require 120-140 kg/ha nitrogen, depending on soil type and previous cropping. Up to 90% of this nitrogen will be recycled and made available to following crops. Apply entire quantity of N at or immediately after sowing, except for overwintered crops where applications should be split into two; at sowing, and once growth restarts in early spring.
Time to crop maturity will vary with time of year and climatic conditions, but generally ranges from 60-100 days for a spring to late summer sown crop. Overwintered crops will take significantly longer. At maturity vertical growth will stop, and if grown to full potential will achieve a height of approx. 100-150 cm, producing 50-100 t/ha biomass (fresh weight), of which 15-20% constitutes dry matter. Aim to incorporate crop up to 2 weeks after first bloom for maximum biofumigation effect. Chop the crop using a flail mower with hammer blades for maximum cell destruction, immediately followed by cultivation equipment to incorporate to a depth no greater than 15cm, producing a fine tilth and rolled to seal the surface, trapping the ITC gas. In 20 minutes 80% of the ITC gas will be lost – it is therefore essential to incorporate the crop as quickly as possible after chopping. Use two pieces of equipment that closely follow each other, or large machinery that allows for one pass. Soil moisture at incorporation is essential for biofumigation, either irrigate or incorporate after rain.
Leave for 14 days after incorporation before planting subsequent crops. Crops grown as soon as possible after 14 day period will gain greatest benefit from green manure and biofumigation. Avoid ploughing and excessive cultivation before the following crop, subsequent cultivations should remain within the incorporated depth. All varieties are soft seeded and should not pose a volunteer problem providing seed is not allowed to ripen. As a guide, after first bloom, seed ripening takes 28-42 days. Any ripened seeds that do self-sow will germinate in one flush, enabling easy control by mechanical or chemical methods.