In sub Saharan Africa, days are long, sunny and warm. In this environment crops should grow well. However, a large portion of the soil in areas of the Sahara desert is depleted. It simply lacks the organic matter and nutrients needed to support crops. At this point, chemical fertilizers alone cannot do the job of repairing badly depleted soil for growing maize.
The Push
Is produced by intercropping plants that are low growing and exude chemicals that repel the stem borer. It also curbs weeds, helps maintain soil stability and improves fertility in the soils by adding organic matter thus reducing the need for fertilizers. The plant best discovered for this application so far is desmodium. It helps maintain soil stability and is also a highly nutritious animal feed.
The Pull
Method for natural pest management relies on border cropping of companion crops around the maize. It is used to attract and trap stem borer moths. Wild and domestic grasses offer crop protections as the insects are more attracted to an appetizing meal and are drawn by the chemicals emitted by the grasses. Napier Grass is particularly suited for this as once they are attacked by the borer larva it secrets a sticky material which actually traps the pest and limits its damage. Afterward the Napier grass is used as livestock feed.
The more than one million African farmers who have used this strategy for controlling insects as well as providing livestock feed have rebuilt soil while greatly improving their crop yield.
Source:
Scientific American (2016 May) Rebuilding Africa’s Soil, 1 Farm at a Time
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