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close this bookPrimary School Agriculture Volume II: Background Information (GTZ, 1985, 190 p.)
close this folderPart III: Crop storage
close this folder10. Tuber preservation
View the document10.1 Present state of tuber storage
View the document10.2 What happens to tubers in storage
View the document10.3 Preparing Tubers for Storage
View the document10.4 General storage principles
View the document10.5 Tuber stores
View the document10.6 Storage pests of tubers

10.4 General storage principles

In general, all tubers store best under similar conditions. However, there are a few differences which should be noted. Therefore tuber storage principles will be talked about under three groups. The first group will be sweet and Irish potatoes, the second group will be yams and cocoyams, and finally, cassava storage will be discussed.

a) Sweet Potatoes and Irish Potatoes

Once the curing and selection process is finished the. potatoes should be kept under the following conditions:

- dark,
- dry,
- cool,
- ventilated.

Sweet potatoes do not store as well as Irish potatoes. Many people leave sweet potatoes in the ground until they wish to eat them. This does not work very well during the rainy season. The Sweet Potato Weevil is a serious pest in some areas which makes it difficult to follow the practice of leaving the potatoes in the ground until they are needed.

In the store the potatoes should not be piled too high on top of each other. One meter is the limit. Potatoes can be stored in cold storage or refrigerators.

The store should be dark, dry, and cool because it is hard for fungus to live in these conditions. Also, the tuber respirates in dry, cool, dark places. The store should be ventilated so that when the tuber gives off heat and moisture during respiration the air can pass and carry it away. The potatoes should not lie directly on the earth floor - water can come and spoil them.

b) Yams and Cocoyams

The main principles to maintain in yam storage are the same as for potatoes. The store should be:

- dark,
- dry,
- cool,
- ventilated.

Such a store keeps the yams and cocoyams respirating slowly and it makes it difficult for fungus and disease to enter. The ventilation makes it possible for the air to keep moving away any heat which is given off during respiration.

Whereas potatoes can be laid on top of each other up to one meter, yams do not store well when they are touching each other. Yams should not touch or lie on each other in storage. They do not dry evenly and air does not pass as well when the yams are piled like this. Yams and cocoyams should not lie directly on dirt floors.

In most cases cocoyams do not store as well as yams. However, this varies as to the locality and the species of cocoyams and yam.

Yams are also left in the ground in many areas and harvested upon need. However, the success of this method depends on the local problems with pests in the field: monkeys, insects, rats, and termites. This practice apes not succeed during the rainy season once the tubers are mature.
Usually yams which take the longest time to mature and are harvested late have the strongest flesh and seem to store better. The white yam and the yellow yam store better than the water yam and the Chinese yam.

c) Cassava

Cassava is very difficult to store. Cassava tubers generally cannot last more than a few days once they are harvested. It should be left in the ground and harvested as it is needed. The best way to preserve cassava is in the form of gari.