Research for Tropical Agriculture
Online ISSN : 2187-2414
Print ISSN : 1882-8434
ISSN-L : 1882-8434
Volume 8 , Issue 1
Showing 1-9 articles out of 9 articles from the selected issue
Original Article
  • Yui SUNANO
    2015 Volume 8 Issue 1 Pages 1-6
    Published: 2015
    Released: December 25, 2015
    Storage pits had been used worldwide to store grains and nuts during many centuries BC. Such storage pits prevented losses due to wind and rain, sparrows, mice, water, fire, and thieves. However, the level of humidity is very high inside the storage pits. Therefore, storage pits were substituted with aboveground storehouses for rice, wheat, and barley, which cannot be maintained in humid storage pits. The Dirasha who live in the Dirashe area in Southern Ethiopia use storage pits about 1.5 m in width and 2 m in depth that are called polota to store sorghum. Previous studies have shown that many types of storage pits display a low storage efficiency. However, polota can store sorghum for a maximum of 20 years. In the present report, I analyzed the structure and functions of polota and considered the reasons for its continual use in Dirashe area. Polota is dug in dense layer. It is produced by the action of chemical weathering of basalt layer. Therefore, air circulation is low inside the polota. In addition, low levels of oxygen and elevated levels of carbon dioxide were found inside the polota. This was caused by some seeds that used oxygen and exhausted carbon dioxide to germinate. Damage by pests to sorghum stored in polota is prevented by the low levels of oxygen. Long-term storage of sorghum in polota is possible because of the high levels of carbon dioxide. The Dirasha live in a semi-arid zone with recurrent low harvests; they prepare for a low harvest by storing sorghum in polota over a long period of time. Polota is preferred over other storage pits, insect repellents, and aboveground storehouses because the storage efficiency of polota is higher than that of other storage pits.
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