The future of agriculture in sub-Saharan Africa and South Asia depends on the management of crucial natural resources, primarily soil and water. Soil quality has been identified as the number one challenge to agricultural productivity in these regions, and the prospect of water scarcity is a commonly raised issue of concern for the future, especially given climate change projections. Sub-Saharan Africa currently has little installed irrigation, and South Asia faces inefficient water use and water degradation.
Tier I Technologies
Soil management techniques
Both soil and water management are integrative technologies—they require multiple methods for each particular site. Promising soil management techniques include controlled grazing; mulching with organic matter; applying manure and biosolids; use of cover crops in the rotation cycle; agroforestry; contour farming; hedgerows; terracing; plastic mulch for erosion control; no-till or conservation tillage; retention of crop residue; appropriate use of water and irrigation; and integrated nutrient management, including the judicious use of chemical fertilizers.
Integrated water management
Arrays of efficient, on-farm water capture, storage, pumping, field application and drainage technologies could help address water challenges in both regions. Water management technologies include tube wells, on-site storage tanks, and effective irrigation methods. Subsurface drip irrigation, in which buried tubing delivers water directly to plants’ root zones, is the most efficient form of irrigation technology, but it is currently expensive.
Climate and weather prediction
Increased climate and weather prediction capabilities would be a transformative development for farmers in sub-Saharan Africa and South Asia. If farmers could more accurately predict drought or the onset of the tropical rainy season, they would be better equipped to make pivotal timing and management decisions. Weather models, databases, and monitoring devices are taken for granted in many parts of the world, but these tools still need to be built for sub-Saharan Africa and South Asia. In developing these capabilities, specific attention is needed to ensure that farmers can easily receive and use the information that is generated.
Tier II Technologies
The emerging field of nanotechnology shows promise for developing innovative agricultural technologies, such as nanotechnology-based soil amendments that enable better control over the conditions for or timing of fertilizer release. These materials may also help remediate toxic substances in soil that can inhibit the growth of plants and beneficial soil bacteria.
Manipulation of the rhizosphere
Current research suggests that it is possible to manipulate plants’ rhizosphere (where a plant’s roots interact with the surrounding soil) by optimizing their root structures for better water and nutrient uptake and increased yields. In addition, it may be feasible to take advantage of the chemical signals emitted by plant roots to manipulate soil microorganisms in ways that reduce the need for off-farm nutrient inputs. To develop such strategies into applications, however, a better basic understanding of microbial ecology in major crop systems of sub-Saharan Africa and South Asia is needed.
Remote sensing of plant physiology
Remote sensing technologies could potentially allow farmers to monitor the biological status of their plants and make management decisions based on that information. Increasingly sophisticated optical imaging equipment (both hand-held and satellite-based) can detect subtle differences in plant physiology, such as the presence of disease or the rate at which the plant is using nutrients. Farmers could receive remotely collected information via cell phones or the Internet and take appropriate action, such as irrigate or fertilize their crops. Although today it seems an unlikely tool for poor farmers, remote sensing has the potential to become a practical and valuable decision-making tool.