Pictures Worth a Thousand Words: How Satellite Imagery is Improving Agriculture in Developing Countries
By Lauren Harper and Andrea Meado
From the first images of the whole earth to photos of Saturn’s rings cascading shadows on the gas giant’s surface, images from space have had a profound impact on people. Space exploration birthed remote sensing technologies and accelerated our understanding of Earth’s systems with the establishment of the National Aeronautics and Space Administration (NASA) in 1958. Shortly after, the NASA Goddard Institute for Space Studies in New York City (NASA GISS) was founded to conduct basic research in support of spaceflight. Later, it became an affiliate of the Earth Institute at Columbia University and a hub for climate research. The work of scientists at NASA GISS and the Earth Institute has improved our understanding of the atmospheric characteristics of our world, the evolution of the solar system, and the structures of stars and planets.
One partnership between NASA GISS and the Earth Institute’s Center for International Earth Science Information Network (CIESIN) utilizes satellite imagery and remote sensing to safeguard Africa’s soil resources. The program is called the Africa Soil Information Service (AfSIS), and it aims to develop standards and methodologies to better manage cropland in Africa. This research helps African communities by supporting sustainable practices that increase agricultural output while reducing the environmental impacts of farming. To promote and successfully implement these sustainable agricultural practices, AfSIS has centered its research priorities on Africa’s croplands.
Between now and 2050, the population of sub-Saharan Africa is expected to double from 1.1 billion to 2.4 billion. As the population grows, so will the demand on agricultural land to produce food. To sustain this expanding population, it is crucial that nations on the continent work to increase their agricultural production. With sub-Saharan Africa having 50 percent of the world’s agricultural land, one might think this is a simple fix. However, only about 1 percent of that land is useful for long-term cultivation. This gap is largely due to nutrient deficiencies in the soil and sub-optimal land management, plus pests and agricultural diseases.
To help improve Africa’s agricultural output, the AfSIS team is working to rapidly map the soil texture, moisture levels, and nutrient levels, all across the continent. AfSIS’s digital maps of Africa’s soils are the first of their kind, combining data from remote sensing—including satellite images—and in situ soil samples. The maps serve show local farmers areas that can help to maximize their food production. This tool also helps to recognize clear-cutting and deforestation practices that contribute to climate change and threaten local biodiversity.
In Africa, 22 percent of land area is forest. Much of this forested area is concentrated in the Congo as well as Guinea, Sierra Leone, Liberia, Côte d’Ivoire, Ghana, and Togo. These forests support a variety of animal and plant species, including the mountain gorilla, bonobo, chimpanzee, and forest elephant. Many people living in or near the forests cut down trees and plants, burn the area to increase soil nutrients, and plant enough crops to feed their families for the year. After a while, the ground is no longer fertile and the process starts again, removing additional acres of forest. The forest clear-cutting, burning, and pollutants associated with subsistence farming threaten animals.
To prevent deforestation from subsistence farming, it is important that scientists and local farmers work together to strategically increase agricultural yields throughout Africa. Satellite imagery, remote sensing, and field surveys are helping to provide information for better land use planning, such as identifying ecologically important areas that shouldn’t be disturbed, and acreage that would be best for boosting crop yields. These strategies prevent deforestation while increasing food security in the region.
Without programs that help to implement sustainable land management, like AfSIS and the UN’s Food and Agriculture Organization (FAO), African nations risk losing both their forests and iconic animal species. Furthermore, the removal of trees and other vegetation will contribute to climate change on a continent that is already vulnerable to sea level rise, drought, and rising temperatures, as well as severe weather.
Bodies of water such as coastlines, lakes, and rivers will be crucial for Africa’s growing population. Africans are already concentrated along the floodplains of major rivers, where fertile soil and year-round water availability create arable land. In the future, these spaces could become more crowded.
On average, West Africa’s population has been growing at an annual rate of 2.75 percent and is becoming increasingly more urban than rural. In 1950, West Africa’s urban population made up 8.3 percent of the overall population. In 2015, city-dwellers made up 44 percent of the total population. Similarly, land use footprints in newly settled or built-up regions have grown by 140 percent between 1975 and 2013. This increase in land development will need to be accompanied by active water resource monitoring to ensure the rivers can provide a sustainable water supply to support growing numbers of people.
Surface water is easy to visualize, but moisture held in soil below the surface may be less apparent. Understanding the hydrologic conditions of soil is important for agriculture; 95 percent of existing farmland in sub-Saharan Africa receives its water through rainfall. AfSIS’s soil maps and satellite data on precipitation help the Hydrological Sciences Lab at NASA’s Goddard Space Flight Center model soil moisture in Africa. The model accounts for soil data profiles, rainfall, temperature, evaporation, runoff, streamflow, and more, to determine how much water is available for plants. The model helps in understanding why previous harvests were unsuccessful and anticipating patterns for upcoming growing seasons, and informs Africa’s Famine Early Warning Systems Network. Sustainable water practices and active monitoring are essential for people living in harsh climates.
National and International Impacts
Video: How AfSIS is addressing agricultural challenges in Africa with digital soils maps, field trials, and land management techniques.
Trees and plants store large amounts of carbon, so mapping changes in vegetation—such as replacing forests with farmland—helps researchers estimate how much CO2 is being stored or released into the atmosphere. Once quantified, this information will better illustrate how deforestation and the degradation of ecosystems affect global temperatures. This, in turn, could help to shape land use policies that can help fight climate change.
Understanding the soil composition in counties with food scarcity may be key to improving quality of life and reducing malnutrition and hunger issues that persist in countries around the world. Projects like AfSIS are paving the way for sustainable agriculture and strategic land use in African nations and possibly the rest of the world. As we move into an era where it is crucial to produce more with less, imagery from space and remote sensing will continue to help us achieve these goals. With these tools and the close-knit partnership that exists between Columbia University’s Earth Institute and NASA’s Goddard Institute for Space Studies, there is no doubt that we will make headway in improving global land management in the future.
AfSIS is funded by the Bill and Melinda Gates Foundation and is supported by close partnerships with the respective national governments. Main contributors to AfSIS achievements are the Earth Institute of Columbia University, the World Agro-Forestry Centre, Rothamsted Research, and ISRIC-World Soil Information.
Lauren Harper is an alumna of the Environmental Science and Policy MPA Program at Columbia’s School of International and Public Affairs.
Andrea Meado is a JETS contracted geoscientist for Jacobs at NASA Johnson Space Center. She works within the Earth Science & Remote Sensing unit of the Astromaterials Research and Exploration Science division.