Wheat, rice, maize – these staple grain crops make up more than 60% of the world population’s caloric intake, yet must be tilled, replanted and regrown every year. Aside from the amount of labor and risk involved in this cycle, it also contributes to soil degradation, erosion and the need for nutrient inputs in order to maintain levels of production necessary to feed a growing population. At the World Wildlife Fund’s April Fuller Seminar, Dr. Jerry Glover, Science and Technology Policy Fellow working with the US Agency for International Development’s Bureau for Food Security, offered an alternative production system based around perennial crops, or those grown over the course of several years. Dr. Glover mentioned other possible solutions to present cropping system dilemmas, including conservation agriculture and organic methods, but he argues that these are “software solutions” and what is needed now is new “hardware,” a novel operating system for agriculture.
In the United States, 85% of native plant species are perennials. And because the plants are not uprooted annually, they form much deeper and more intricate root structures than their annual counterparts. Dr. Glover called this system an “elegant safety net.” Not only does a broad root network facilitate a plant’s uptake of nutrients and water even in times of scarcity, but it also provides a primary source of energy for soil microbes and maintains soil structure, increasing water infiltration, and decreasing erosion, runoff and evaporation. Particularly in times of drought, these characteristics can be essential for crop survival and success. Moreover, as the plant does not have to re-create roots every year, it can build off the previous years’ growth, reaching depths of 2-3 meters.
What relevance does this have for food security? While annual crops account for 68% of agricultural land cover, there is great potential for perennial varieties of staple grains to enhance food security and support a healthier environment. Dr. Glover illustrated this point with an example from Malawi, where two-year perennial pigeon peas are grown in conjunction with a maize and groundnut rotation. Not only did the peas provide the farmers with two extra harvests, but they increased nitrogen fixation, carbon sequestration and phosphorous mobilization. Maize yields were the same as previous years’, yet required only half the fertilizer. Research on plant breeding and genetics of perennial food crops continues, but it must expand considerably to address future grain production needs.