Developed by Kenya’s International Center of Insect Physiology and Ecology (ICIPE), the ‘Push-Pull’ strategy may sound like something from Dr. Dolittle, but it is actually an effective technique for increasing crop productivity without relying on expensive and damaging fertilizers and pesticides.
The UN Food and Agriculture Organization reports that a quarter of the under-nourished global population lives in sub-Saharan Africa. Many of these people are small-scale farmers, so most methods to increase their productivity would lead to massive gains in the fight against global hunger.
The ‘Push-Pull’ strategy is a technique that utilizes intercropping to increase yields by improving soil quality and protecting against pests. The concept is simple. Two of the primary threats to crops in sub-Saharan Africa are stemborers and striga weeds. Stemborers are a type of moth that lay their eggs inside the stems of crop plants. This pest has been known to destroy up to 80% of small farmers’ crop yields. The other main concern for farmers in the region is the striga weed. This weed is parasitic and stunts crop growth, which can mean a loss of 30-100% of yields.
The combination of these two threats alone can lead to $7 billion annually in damages from lost crops. Rather, though, than turn to expensive pesticides and herbicides to neutralize these threats, ‘Push-Pull’ focuses on more sustainable methods. In order to reduce damage from stemborers, repellant plants are interspersed within the primary crop. One such example is the plant desmodium, the presence of which discourages stemborers from the crop. Additionally, a plant that attracts the pests, such as Napier grass, is planted in a border around the field. Thus, the stemborers are simultaneously repelled from the actual crop while being attracted to the border. Along with serving to deter stemborers, desmodium also has the added benefit of producing a substance that interferes with the germination of striga seeds, effectively eliminating this weed from crop fields.
Benefits of the ‘Push-Pull’ technique go beyond those of just natural pesticide and herbicide. Desmodium, being a cover crop, can be plowed back into the soil after harvest, raising the nutrient content of the soil. Meanwhile, Napier grass can serve as a feed crop for livestock as well as assisting in erosion control via its root system.
To date, more than 50,000 East African farmers have implemented the ‘Push-Pull’ system. Remarkably, this change has resulted in triple-the-average maize yields of previous practices. ICIPE plans to expand the practice throughout sub-Saharan Africa, educating and training farmers to take advantage of this revolutionary technique.
– David Wilson