- A traditional rotational practice in some areas of Africa involved clearing bush, growing crops for a number of years, then allowing the bush to grow back again, to replenish the soil.
- This photo shows a maize-cowpea subsistence intercrop. The cowpeas fix nitrogen in the soil and supress weeds, while the maize forms a barrier between the rows of cowpeas, helping to reduce the spread of any disease or insect pest that attacks the cowpea crop.
- This intercrop practice provides plant protection functions while also spreading the labour requirement more evenly over the year and reducing risk: if one crop is damaged by pests, the farm family is still likely to have the other crop for subsistence.
- The result was the adoption of new, high yielding varieties and a switch to monocultures, as shown in this photo of a cowpea crop.
- Since there is a higher risk of revenue loss due to pest attack on a higher yielding, monoculture cowpea crop, farmers often resorted to protecting their investment by applying pesticide as an insurance measure.
