A look at food security issues relevant to Africa: Part I


system and the quality of the water distributed is poor. There are several ways of conserving rainwater. A common method is the collection of water running from the roofs of houses by channeling to a reservoir. In East Africa for example, the levels of rainfall range from 60mm to 2300mm of rainfall per annum. The pattern of rainfall is that of heavy downpour for short periods, followed by long dry spells. Harvesting rainwater is therefore beneficial in these conditions. Rainfall of 100mm per annum means that 100L of water falls on one square meter per year. From this data, the amount to be harvested can be calculated as follows:

Wc=RxAxP (Where Wc is water collected in liters, R is Rainfall in mm A is the catchments area such as a house roof in square meters and P is the efficiency of collection. P is about 50%). Using the above formula, at 50% efficiency and 150 square meters of collecting surface (e.g. a house roof) the level of rainfall and harvested water is as shown on table 1.

The collected amount of water in areas with 250mm of rainfall and above may be significant. The collected water can be used for sustaining small vegetable gardens, with improvement in household food level.

Water is also collected using contour ridges, with an upslope furrow that accommodates runoff from catchments between the ridges that are constructed along growing crops. The furrows that collect and direct water have shown to reduce the risk of crop failure due to drought by concentrating the runoff water. This technology has been used with millet, cowpeas and sorghum in countries like Kenya, Niger and Zimbabwe. (4)

The way forward: In Part II of this article attention will drawn on how food security could be influenced by exploiting the available and abundant natural resources like energy sources, bioactive chemicals and naturally occurring chemical processes.

References:

1a-http://www.un.org/esa/population/publica...

or

1b-http://esa.un.org/unpp/ United nations population statistics

2-FAO accessed via www.fao.org (Food and Agriculture Organization)

3-Sullivan, P. NCAT Agriculture Specialist 2000 http://attra.ncat.org/attra-pub/PDF/drou...

4-Critchley, W., C. Reij, and A. Seznec 1992. accessed: www.unep.org Water Harvesting for Plant Production. Volume II: Case Studies and Conclusions for Sub-Saharan Africa. World Bank Technical Paper No. 157,A look at food security issues relevant to Africa ,A look at food security issues relevant to Africa

The copyright of the article A look at food security issues relevant to Africa: Part I in Canning & Preserving is owned by Paul Vincent Mroso. Permission to republish A look at food security issues relevant to Africa: Part I in print or online must be granted by the author in writing.

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