Jerusalem artichokes as dual-purpose crop?

Press, 14 February 1986, Page 12

Jerusalem artichokes as dual-purpose crop?

Jerusalem artichokes may have a future with, Canterbury irrigation farmers as a dual-purpose livestock fodder and feedstock for fructose sugar or alcohol production, according to a Christchurch company director and lawyer, Mr John Rutherford. His company, Chemical Technology, Ltd, of Clandeboye, near Temuka, has grown two new varieties of Jerusalem artichoke under quarantine for three years. These may be released to farmers for seed multiplication and contract growing in 198687.

The tubers of the Columbia and Mammoth French White varieties, at present growing on Mr Rutherford’s Moncks Spur farm on the Port Hills, can produce more sugar per hectare than sugar beet, he has claimed. The tubers are about 20 per cent carbohydrate, by weight, of which up to 80 per cent can be fructose sugar. This can be recovered by fermentation and ultrafiltration, processes that Chemical Technology Ltd is either involved with already in its production of alcohol from whey or can institute quickly. The contract growing for the future might be aimed at a continuity of feedstock for Chemical

Technology’s alcohol production when whey is not available during the winter. But as alcohol stores well and New Zealand already produces its requirement of industrial spirit, it seems more likely to be aimed at high fructose syrup. The New Zealand sugar industry will be deregulated in September and Mr Rutherford thinks this will open up opportunities for fructose production and sale. Fructose is claimed to have certain health advantages over sucrose, the main component of cane sugar. Many drinks and processed food overseas use fructose, produced from com in the United States.

“But that requires a multl-mllllon dollar plant,” said Mr Rutherford, “whereas the fermentation and ultrafiltration processes can be established very cheaply, perhaps even on a pilot scale on-farm.” Should farmers eventually be in charge of their own small fructose plants, Mr Rutherford believes the improved varieties of the common or garden Jeruselem artichoke will be very attractive as dualpurpose crops. Many gardeners will be familiar with this relative of the sunflower and in fact be not too happy with it, because it has a yam-

like persistence and a poor flower show for the feet of stalk and leaves that it produces every year. Still others may have memories of the flatulence caused by eating the tubers as a type of sweet potato. This is because the main carbohydratefraction, inulin, in which the fructose sugar is held, is indigestable by humans. The tubers have been eaten for centuries, however, when food was short or sometimes even out of preference. The name of the plant does not hark back to a Middle Eastern or Biblical origin but an etymological amusement whereby the Italian name of the plant, girasole articiocco, came into English as Jerusalem artichoke.

The soup made from the vegetable has been popularly known as Palestine soup — from its misnomer — but is probably never eaten in that region. However, Mr Rutherford is not suggesting that farmers will be reduced to eating the tubers, or even flooding the local produce market, but that cattle or goats could benefit from the high-sugar •dry matter production in spring and summer. The agronomic proposal is that farmers would sow seed tubers in early

spring and mound them up during growing much like potatoes. About the end of January the maximum above-ground growth has occurred and the stalks and leaves are very high in sugar. But given copious quantities of water, tubers then develop and the sugars migrate below ground. At flowering farmers could choose between feeding off the dry matter, or perhaps storing it as silage, or going for a big tuber production during winter. Under irrigation on light, free-draining soils, yields of up to 40 tonnes per ha of tubers have been grown in North America. Tubers can be lifted with a modified potato harvester but the sugar content deteriorates quickly after harvest. They will store very well under ground and even the tubers missed by the harvester will probably be enough to set a big crop next year.

Not much Is known about the crop’s fertiliser requirement or pest and disease potential. Agricultural and energy researchers in Canada have thoroughly investigated the Jerusalem artichoke but made little mention of crop problems in the literature that Mr Rutherford has collected.