Cauliflower and Compost
By Neville Passmore
One of the healthiest groups of vegetables we can put on the table to feed our families is the cabbage family. The list of health benefits would take an article of this length in its own right. It would include cancer fighting, bad cholesterol lowering as well as the supply of significant quantities of vitamins and minerals. In short these vegetables, including cauliflower, are true superfoods.
Cauliflower has been cultivated since the time of the ancient Greeks and Romans. It can trace origins to the eastern end of the Mediterranean and into Asia Minor. This curious vegetable, which in fact is consumed as an unopened flower bud, is a sought after stir fry ingredient in South East Asia. Singapore is the major market for cauliflower growers in Western Australia.
The quality of vegetables for export is at the top of the tree for any crop. The Department of Agriculture and Food in WA has developed a standard for assessing cauliflowers which is based on a scale of 1 to 7. Six to seven is export quality, three to five is suitable for the domestic market and one to two means it's unsaleable; in other words a reject.
Sam Calameri is a highly respected vegetable grower in Baldivis and has been using compost amendments for more than a decade to boost quality and financial returns. The cauliflower trial he conducted with C-Wise convinced him of the value of building up our sandy soils for commercial vegetable growing.
The trial compared a part of the farm which had been treated with 1.5 litres of compost per lineal metre of bed, with an area of no organic amendments. The high maturity compost was inserted into the sandy bed into grooves that had been specially cut to concentrate the treatment. Cauliflower seedlings were planted directly into the compost at the astounding rate of 25,600 plants per hectare. That's a lot of cauliflowers.
At the end of the harvest the results were quite astounding. Fifty seven percent of the curds grown with compost were of export quality versus fifty one percent in the control batch. The average weight showed an even greater increase with 981 grams as against 700 grams from the control area.
Of the remainder, 43% of the compost grown crops fell into the domestic quality range with no rejects, while 32% of the control crop was of domestic market quality and 17% were rejects.
Export cauliflowers pay considerably more than those for local markets and when the final accounting was completed the value of the compost amended crop was $24,071 compared to $13,899 for the control, a difference of $10,172. When you look at the cost of supplying and applying the compost at a rate of $1000 per hectare there is a real economic case for these additions.
When you talk about unexpected outcomes its usually something bad. In this case, the uniformity of the compost crop meant that it could be harvested in 3 picks compared to 5 picks of the others. This represented a saving in labour costs amounting to $900 per hectare.
Clubroot is a common disease in all members of the cabbage family and the most damaging effect is that it attacks the roots of the plant reducing its growing potential and increasing its vulnerability to drought, particularly associated with irrigation system problems.
Clubroot damage was not observed in the plants grown in the compost mix but was evident in the control group. Sam noticed that there was little wilting between irrigation cycles with the compost crop compared to the control and this he attributed to a more robust root system.
This natural suppression of the disease is probably a major factor in the improvement seen between the two crops as the increased uptake of nutrient and moisture fostered heavier more uniform curds.
The exciting result shows that incorporating a high humus compost (this product is now available in bags under the name of Humicarb) to vegetable growing can reduce pesticide use and water requirements; at the same time as growing higher quality, more uniform crops.