YAM 

Yams have a general botanical name Dioscorea spp  - require well-drained loamy soils, rich in humus. Yams like high temperature direct simple sunshine and rainfall of about 75cm.

Land Preparation:

Land clearing followed ridging is advisable.

There are different species:

I.     Dioscorea rotundata (White Yam)

ii.    D. cayensis (Yellow Yam)

iii,   D. alata (WaterYam)

iv.    D. dumentorum (Three-leaf Yam)

v.     D. bulbifera (Aerial Yam)

vi.   D. esculena (Chinese Yam)

Sowing: Early planting is around November to December, and Late planting is from February to March. Planting can be with yams sett or seed yams. Seeds rate should be about 2.5 tones -5 tonnes per hectare with each yam sett weighing 0.8kg -1kg. The sett can be treated against yam beetle by rolling them in Aldrin 2.5% dust before planting. Yam is propagated by vegetative means using tuber.

Weeding

Weeding is done 2 to 4 times.

Staking: 

This is the provision of support for the yam vines. Stems of bamboos, raffia, and palm fronds and erect plants are used. These are tied to trees and the vines directed to trail up the ropes. Yield can be reduced by about 50% if there is no staking.

Fertilization Application: 

Apply 10, 10:20 mixed fertilizer at the rate of 260kg -500kg per hectare. Apply 10cm away from the stand and 10cm deep around each stand at 2-3 months of planting.

Harvesting: 

Early harvested yam cannot be stored for it contains too much water so that it is eaten or sold for money. The process of early harvesting, while tuber is still growing, is call detuberisation of topping. The main harvest starts when leaves begin to -wither and the vines also begin to turn yellow.

Storage: Harvested crops are tied in a barn. In tying the tubers, space is left at the base to keep off rodents and contact with other tubers. Sometimes harvested yams may be buried for before tying in barns.

Pests of Yam: 

The most important are the yam beetle (hetroligus sp.)

Importance: Yam is the cue of the most important root crops. It is the staple food for many Nigerians.