By Esther Ngumbi
Soil is everything. It is the foundation of life and it is the base upon which we grow our crops. We must protect it. As José Graziano da Silva, director general of the Food and Agriculture Organization of the United Nations, discussed recently, healthy soils are critical to global food production.
There are many ways to improve land and soil health, but most researchers agree that soil health improves through efforts that diversify crop rotations, disturb the soils as little as possible (no-till and reduced tillage), and keep the soils covered with cover crops (crops grown for the enrichment of the soil). These practices are the basic principles that underpin conservation agriculture.
Apart from improving soil health, these practices also eliminate soil erosion to a large extent, and increase water infiltration and retention by the soils, thus reducing the amount of water needed for irrigation. These can be advantageous to African farmers in particular, who mainly still rely on rainwater. Furthermore, these practices help conserve biodiversity because organisms like bacteria, fungi, and earthworms that live in the soil are allowed to flourish.
Unfortunately, many farmers, including African smallholder farmers, have not adopted these best practices. Hence, unhealthy and degraded soils and low productivity help drive Africa’s never-ending hunger and food insecurity cycles.
But Africa is not alone. Unhealthy soils and the resulting effects such as soil erosion are global problems. According to a U.N. FAO report, more than half of the world’s agricultural soils are moderately or highly degraded.
Though this problem has reached crisis levels around the world, there is still no widespread adoption of simple, low-cost, soil health-improving practices that can help rebuild the vitality of degraded agricultural soils. For example, one study by the U.S. Department of Agriculture reported that cover crops—one such restorative method—were used on less than 2 percent of total cropland, covering 6.8 million acres.
It is easy to understand why farmers, including African farmers, have yet to adopt many of these practices. They often lack awareness and incentives. Farmers must be educated about these practices and be shown hard evidence that they work and can offer other benefits, including reduced labor and reduced costs of inputs. Farmers also need to be convinced that adopting these practices would translate into increased productivity and financial gains.
Indeed, a study that examined how farmers in the U.S. decide whether and how much to adopt environmentally beneficial practices like cover cropping revealed they were reluctant because of the perception that these methods often result in lower profitability and higher labor requirements.
This problem can be counteracted by setting up more demonstration farms across the world to prove to farmers that these concepts and practices do indeed work. For example, No-till on the Plains is an African farm that practices all these soil health-building initiatives. Located in Ghana, this center brings in local farmers to showcase best practices. Africa needs more of these demonstration centers.
In the U.S., there are quite a few examples of demonstration farms. University of California, Davis has a long-term experiment (a 100-year study) that measures and demonstrates to the public and farmers alike the impact of these practices. Rulon Enterprises, a family farm, uses cover cropping and other soil health-building practices and regularly invites the public and other farmers to see these practices in action, sharing with them the ways the farm has benefited as a result of adopting these practices.
In addition to demonstration farms, we need more science-based evidence of the impacts of these practices. A global synthesis of 610 peer-reviewed scientific studies from 63 countries that compared no-till farming with conventional tillage showed that no-till combined with other soil health-improving techniques, such as crop rotation and residue retention, significantly increased rain-fed crop productivity in dry climates. Since many African farmers still practice rain-fed agriculture, these practices would most likely be beneficial to them and other farmers in dry climates. More short- and long-term studies that quantify the benefits, such as increased crop yields, of implementing practices like cover cropping and crop rotations should be commissioned and their results widely shared. When farmers see data evidence, they will be more willing to adopt these practices. Additionally, further study can be done comparing the impacts of different practices, crop combinations, and environments on yield outcomes and soil health improvement.
Most importantly, we need scientists around the world to continue to convene meetings to discuss recent studies and discoveries on soil health research. For example, Colorado State University hosted the Ecology of Soil Health Summit and the Soil Ecology Society meeting, bringing together over 200 scientists who work on different aspects of soil health, in June 2017. It is at these venues that the most pressing needs for advancing soil health research are discussed and new research priorities are identified. At the meeting in Colorado, for instance, attendees determined that further study was needed on the impacts of soil health building practices on yields and the diversity of organisms, including beneficial microbes, living in the soil. The scientists also recommended that standard research protocols be established and communicated with farmers, and that existing studies be compiled in a way that is accessible for farmers and other stakeholders. These suggestions are more than just procedural; making it easy for farmers to find information about ways to build soil health would also help accelerate the adoption of these practices.
Finally, global adoption of soil health-building practices also requires funding and the broad participation of various stakeholders. Thankfully, there are numerous examples of both private foundations and government organizations that are already investing in research and other initiatives related to improving soil health. The Howard G. Buffet Foundation, General Mills, Foundation for Food and Agriculture Research, The Samuel Roberts Noble Foundation, The Nature Conservancy, and USDA Natural Resources Conservation Service are just a few of the organizations that have committed funds. We need such support to continue. Specifically, there is need to fund more soil health improvement initiatives in the African continent—many of the projects these foundations support are being implemented in the U.S.
Improving the health of soil by adopting these low-cost practices globally is a smart investment for farmers. These practices bring many returns, including increased crop productivity and soils that are more resilient in the face of an ever-changing climate.
Esther Ngumbi is a post-doctoral researcher at the Department of Entomology and Plant Pathology at Auburn University in Alabama. She serves as a 2017 Clinton Global University (CGI U) Mentor for Agriculture and is a 2015 Food Security New Voices Fellow at the Aspen Institute.
[Photo courtesy of Iapping]