to increase the glucose content, so much so that in some varieties it actually doubles! Oca lends itself to a variety of cooking methods – steaming, boiling, frying. It can also be eaten raw or pickled, and is compatible with many spices and flavours (salt, sugar, vinegar, lemon, hot pepper), making it palatable to diverse cultures around the world. Oca has a high dry-matter percentage (approximately 20%) and could be investigated for the production of starch and alcohol. Conditions for growth Oxalis tuberosa is propagated by tubers and can mature in 6-9 months, depending on the variety. The lower temperatures of Europe could be compensated to some extent by altitude. In the area of origin, oca grows at 2500 m and higher, up to 4000 m, indicating it can withstand a reasonable degree of cold as long as it does not drop below 3 degrees Celsius. As for the high-temperature limit, it seems to tolerate values of 25-28°C but not more. Although this crop is very resistant and adaptable to harsh environments, it is necessary to select planting material adapted to Europe’s particularities, such as long day length. In its natural habitat in the high altitudes of the Andes at the equator, it enjoys 12 hour days. Oca’s cultivation range extends as far south as Southern Chile, justifying the belief that it is perfectly suitable for adaptation to other similar climates. In fact, oca has been successfully cultivated in France, Great Britain, New Zealand, and Oregon, USA and there are many indications that it can thrive just as well in other temperate zones such as the area extending from Holland to Poland with modest greenhouse protection against freezing temperatures…which would tend to cut the season short in the late fall before the crop has had a proper chance to mature. Regarding water needs, in the Andean region, oca grows in areas with between 600-2100 mm. of precipitation. In the cultivation zone we propose Northern Europe. There should be adequate rainfall, but considering that the crop will probably be grown semi-sheltered in greenhouses for part of its crop cycle, it will likely require some irrigation. Light, rich soil is ideal for oca plantings and the appropriate Ph is between 5.3 and 7.8. The harvesting procedure is similar to that of potatoes. The productivity ranges between 7 and 10 tons/ha under proper care. Some experiments conducted in Peru were reported to have given yields of 40 tons/ha. The size of the tubers ranges from 3 cm to approximately 20 cm, depending on the variety. As oca tubers are more “delicate’ than potatoes, it is generally safest to do the harvesting by hand in order to ensure maximum quality. It can be kept, like the potato, at room temperature but maintains better appearance and quality for marketability if kept cool. Most people who have cultivated oca concur that it is much more resistant to pests than the potato. It is known to have been affected by the following: a tuber-boring beetle (in the Andes), nematodes, mycoplasma-like organisms (Bolivia), and, on rare occasions, by fungi. 5 Pagina 14
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