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Helianthus tuberosus L.

Asteraceae
Jerusalem artichoke, Girasol, Gerasole

Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.

  1. Uses
  2. Folk Medicine
  3. Chemistry
  4. Description
  5. Germplasm
  6. Distribution
  7. Ecology
  8. Cultivation
  9. Harvesting
  10. Yields and Economics
  11. Energy
  12. Biotic Factors
  13. References

Uses

Jerusalem artichoke is grown primarily for tubers which can be eaten fresh or raw, cooked in appetizing ways similar to Irish potatoes, or pickled. Tubers are used to fatten cattle, sheep and hogs. Stems and leaves are rich in fats, protein and pectin, and make good forage and silage. The alcohol fermented from the tubers is said to be of better quality than that from sugar beets. It is good weed eradicator, as it makes so dense shade that few other plants can compete. It is good in ridding fields of quackgrass.

Folk Medicine

Reported to be aperient, aphrodisiac, cholagogue, diuretic, spermatogenic, stomachic, and tonic, Jerusalem artichoke is a folk remedy for diabetes and rheumatism (Duke and Wain, 1981).

Chemistry

Since the food reserves are stored in the form of inulin, the tubers serve as substitutes for potatoes and starches in diabetic diets. They are a potential source of levulose for use in sweetening by diabetics. One report notes that Jerusalem artichokes contain about 80% water, the remainder made up of about 15% protein, 1% fat, 75% nitrogen-free extract with 60% inulin, 4% fiber and 5% ash. A different report cites 80% water, the remainder being 10% protein, 76% starch, 1% oil, 6% fiber, 5% ash. Phosphorus is about 0.099%; calcium, 0.023%, iron 3.4 mg/100 g with traces of aluminum, chlorine, iodine, magnesium, potassium, solium, sulphur, and zinc. Small amounts of Vitamins B, and C; purine bases arginine, histidine, betaine, choline, and hemagglutinin are present.

Description

Perennial herb often cultivated as an annual, with tubers produced on the ends and branches of underground stems or rootstocks as well as midway on the rootstocks, tubers knobby, white, red or purple skinned, ranging in size from 7.5–10 cm long, 3–5 cm thick; stems erect 1.5–3 m tall, hirsute; leaves opposite or the upper ones alternate, ovate to ovate-oblong, serrate-dentate, rough above, with winged petiole; heads 5–7.5 cm across, few to many, terminal on the branches; rays 12 to 20, light yellow, conspicuous, disk yellow, seeds pubescent. Fl. July–Aug.

Germplasm

Thousands of forms, stocks and strains but no well-defined cvs. 'Jerusalem White', Veitch's Improved Long White', 'Sutton's New White', 'Mammoth French White' and 'French White Improved' are a few selected types propagated vegetatively. In USDA experiments where 1300 seedlings from selected plants were grown, 1300 varieties resulted, and each plant grown to maturity was recognizably different. Only high yielding strains of acceptable color and shape should be cultivated. From the North American Center of Diversity, Jerusalem artichoke is reported to tolerate bacteria, frost, high pH, laterite, low pH, photoperiod, sand, shade, slope, virus, waterlogging, and weeds (2n = 102) (Duke, 1978).

Distribution

Native to North America, and long used by the American Indian for food. Has been introduced and become naturalized in all temperate regions in the Northern and Southern Hemispheres.

Ecology

Jerusalem artichoke is a suitable crop in any soil and climate where corn will grow. It survives in poor soil and in areas as cold as Alaska. It tolerates hot to sub-zero temperatures. The first frost kills the stems and leaves, but tubers withstand freezing for months. It grows best in a loose circumneutral loam, and in full sun, but can tolerate some shade. Plants do not flower in northern Europe. Plants are sensitive to day-length, requiring longer periods from seedling to maturation of plant, and shorter periods for tuber formation. They do not grow where day-lengths vary little. Ranging from Cool Temperate Steppe to Wet through Tropical Dry to Moist Forest Life Zones, Jerusalem artichoke is reported to tolerate annual precipitation of 3.1 to 28.2 dm (mean of 40 cases = 10.1), annual temperature of 6.3 to 26.6°C (mean of 40 cases = 13.3), and pH of 4.5 to 8.2 (mean of 37 cases = 64) (Duke, 1978, 1979).

Cultivation

Jerusalem artichoke is propagated by tubers, which should be planted as early as possible in the spring when the soil can be satisfactorily worked. Late planting usually reduces tuber yields and size seriously. Whole tubers or pieces about 50 g (2 oz.) should be planted like potatoes and covered to a depth of 10 cm. Pieces larger than 50 g do not increase the yield, though those smaller will decrease it. Deeper planting may delay emergence, weaken the sprouts, and cause the tubers to develop deeper, making harvest more difficult. Seed pieces should be planted 60 cm apart in rows which are 90–110 cm apart. Average yields per hill may be much greater at wider spacings, up to 120 cm apart, in rows to 6 m apart. Cultivation should be shallow, not more than 3.5–5 cm deep, to avoid damaging the stolons and tubers. Tubers begin to form in August. The crop should be cultivated or hoed only sufficiently to control the weeds thoroughly. Little cultivation is required after stolon formation is well under way, since by that time the plants have met in the rows, and shade out weeds. Fertilizer helps produce a better crop, 500 to 750 kg/ha of a complete fertilizer (4-8-4 or 4-12-4) generally recommended.

Harvesting

Either a crop of forage or a crop of tubers can be harvested from a planting, but not both. The maximum yield of green tops for forage is available at or just before flowering. Then the yields of green tops and dry matter decline rapidly, due to movement of food materials from tops to tubers. At this stage of maximum top yield, the tuber yield would be about 40%–60% of the normal yield of tubers. Tops left undisturbed until frost to obtain the maximum yield of tubers are of little or no value for forage. The first freeze blackens the leaves, which soon dry out and fall. The large woody tops must be removed first from the plants. The conventional potato-harvesting machinery is inadequate and no efficient harvesting on a commercial scale at low cost has been devised yet. Turning out the tubers with a plow leaves many in the soil. Hand-digging with forks yields the largest percentage of the tubers in the soil but is laborious and expensive. Tubers are small, and picking proceeds slowly. Tubers are difficult to store because of the thin skin which permits shrinkage and injury that leads to decay. They keep perfectly if left in the soil until needed, freezing does no damage. Although they cannot be harvested from frozen soil, tubers for spring planting are best left in place until spring. They should then be harvested and handled promptly before they sprout appreciably. Tubers should not be left in poorly drained soil. Good, sound, diseasefree tubers can be successfully kept several months in cold storage at a high humidity and a temperature of 0°C. After harvesting in the spring, volunteer growth should be discouraged by deep plowing in late spring, and the crop followed with a late-sown, quick-growing hay crop or a cultivated crop, or rotated as in France with oats, clover and wheat, but corn, rye, potatoes, or turnips may also be used.

Yields and Economics

Average tuber yields of 16,000–20,000 kg/ha may be expected from crops grown under ordinary farm conditions. Production costs, except for harvesting, should not be greatly different from those for potatoes. In France, alcohol yields are placed at 60–100 liters/MT of tubers. Yields of tops for forage average 18,000–28,000 kg/ha green weight. "Fuseau", a garden vegetable in France, is grown and recommended as producing a very heavy yield of forage. Pigs foraging in artichoke have produced 800 kg meat per hectare.

Energy

For alcohol production, chicory and Jerusalem artichoke, which both have a high content of easily hydrolysed inulin, may have a technical advantage over cellulose feedstocks that could be derived from perennial energy plantations. However, as cellulose hydrolysis methods improve, alcohol from cellulosic feedstocks may well become comparable in cost to that from grains and sugary, inuliferous, or starchy feedstocks. In Europe, sugarbeet is likely to be preferred among noncellulosic crops for alcohol production because the carbohydrate is in an immediately fermentable form, whereas the starchy crops like potato and Jerusalem artichoke do not offer better yields, yet require hydrolysis as an extra step (Palz and Chartier, 1980). Recently (acc. to press release March 25, 1983), a Minnesota firm sold more than $19 million in the US, partly by a sales pitch indicating that growers could make as much as $90,000 per ha growing artichokes. In Montpelier, France, fresh stem biomass was highest in September (51.4 MT/ha), gradually decreasing as the reserves were transferred to the tubers. In October, total DM yields were ca 9.5 MT/ha, but in November, tuber DM was at 11 MT, stem DM at 8 (46–54 around Montpelier, France). Tuber yields can reach 90 MT/ha and their polyfructosan (inulin - ca 80% of DM) can be used as a fermentation substrate. During the last two world wars, the tubers were used for ethanol production applying a water extraction technique followed by a hot acid hydrolysis step and fermentation with distiller's yeast. The energy-intensive hydrolysis step can be bypassed using yeast strains with good alcohol-producing and inulinase activity. Kluyveromyces marxianus can produce 12% alcohol from extracts containing 200 g sugar/liter. In a continuous production system with non-sterile medium at pH 3.5 (Chabbert et al, 1983).

Biotic Factors

Jerusalem artichoke is attacked by many fungi including: Acrochyta helianthi, Cercospora bidentis, C. helianthi, Coleosporum helianthi, Corticium rolfsii, C. solani, Erysiphe cichoracearum, Fusarium sp., Macrophomina phaseoli, Myrothecium roridum, Oidium helianthi, Phymatotrichum omnivorum, Plasmopora halstedii, Puccinia helianthi, Rhizopus nodosus, Rh. stolonifer, Sclerotinia fuckeliana, S. libertiana, S. rolfsii, Septoria helianthi, Sphaerophoma brenchklei, Sphaerotheca fuligines, Uromyces junci, Verticillium dahliae. It is also attacked by: Agrobacterium tumefaciens, Pseudomonas helianthi, Tobacco mosaic virus and the following nematodes: Caconema radicicola, Ditylenchus dipsaci (stem nematode), Aphelenchoides ritzemabosi (leaf nematode), Heterodera marioni, Het. schachtii, and Meloidogyne sp. (root-knot nematode). Puccinia helianthi is the most serious pest; burning the tops and a change of locality is recommended.

References

Complete list of references for Duke, Handbook of Energy Crops
Last update Wednesday, January 7, 1998 by aw