Case Study: Angola Field System

This design is for a plot along the Kikuxi irrigation canal in the Luanda region of Angola. The client requested a plan that would allow the site to be used for the production of a range of organic fruits and vegetables.

The site lies on 75m above sea level The prevailing climate in Luanda is known as a local steppe climate. During the year there is little rainfall. This location is classified as BSh by Köppen and Geiger. The average temperature in Luanda is 24.4 °C | 75.9 °F. In a year, the rainfall is around 405mm but the variability is amongst the highest in the world, with variation of above 40%.

The climate is warm to hot but surprisingly dry, owing to the cool Benguela Current, which prevents moisture from easily condensing into rain. Frequent fog prevents temperatures from falling at night even during the completely dry months from May to October. The short rainy season in March and April depends on a northerly counter current bringing moisture to the area: it has been shown clearly that weakness in the Benguela Current can increase rainfall about sixfold compared with years when that current is strong. Soil is sandy and dry. Naturally, this is a savannah type landscape.

I have suggested that the site be divided into a series of ten fields, which will be managed for the cultivation of crops – with polyculture planting and crop rotation. These fields will be divided by shelter belts of more drought tolerant trees and shrubs, with plenty of species native to the region. Of course, within the delivered plan, I have included suggestions for plant choices.

The primary goals for this site will be to improve existing soil and minimise water use, while maximising the yield of fruits, vegetables and other food crops that can be grown organically.

The role of these field borders or hedgerows is to provide some shade, sources of vegetative matter for maintenance of fertility and soil improvement. Though they will also provide additional yields and be beneficial for native wildlife.

The fields should be created by making rows of organic matter, with layers of carbon rich and nitrogen rich materials. (No till system). (A composting system should be quickly implemented to generate material to build and improve the soil over time.)

Before the annual crops shown in the plans above are planted, I have recommended sowing leguminous cover crops to improve the soil. (Pigeon peas, cow peas, beans etc..) These should be chopped and dropped before main annual production begins in each field.

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