Environmental Engineering Reference
In-Depth Information
Maintenance
White yam is mainly maintained by yearly planting, but may also be retained in
the field as in the bush yam.
Special attributes and uses
White yams are palatable and are used for festivals such as the fetish yam festival.
They are also important for food security. The tubers are used in the preparation of
fried yam chips, ampesi , fufu , mashed yam, balls, and porridge.
Yellow yam (D. cayanensis)
Ecology
The yellow yam is grown in annual cropping systems. Field planting is normally
done between February and March, but it is sometimes planted as early as
January or late in April.
Land preparation and planting
Field planting is done on freshly cleared land or previously cropped fields. Usually
all tree cover is removed. Yellow yams are predominantly grown as a first crop.
Yam heads, cuttings or small whole tubers weighing 200-500 g are used for crop
establishment. The planting hole is dug to a depth of 30-60 cm and a width of
30-60 cm. The setts are planted in holes, mounds, or both. Depth of planting is
10-30 cm. Mound sizes are relatively large, varying from 50
30 cm. The setts may or may not be nursed. Nursery practices are the same as for
the other yams.
15 cm to 122
Staking
Mostly, non-live stakes are used. Where live stakes are used, they are managed by
coppicing. Leaders are also used to facilitate staking. The distance from the plant-
ing hole or mound to the live stake varies between 120 and 145 cm.
Harvesting and storage
The yellow yams produce tubers as early as four months after planting, but har-
vesting may be delayed till over nine months after planting. Harvesting may com-
mence between seven and eight months after planting. The tuber length varies
between 30 and 40 cm, but may be as long as 72 cm. The harvested tubers are
stored by tying them to posts, in barns, under trees, or on platforms. Staggered
harvesting is also sometimes practised as a way of increasing the storage period
through extension of harvest duration.
Maintenance
The crop is maintained by yearly planting or by retaining them on the field.
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