Almost all of the Middle East, more than a third of Africa, and half of India are considered “dryland”. This means that, in these regions, on average, the amount of water evaporated from the Earth’s surface and transpired by plants exceeds rainfall.

Drylands support one-third of the global population, up to 44% of all the world’s cultivated systems, and about 50% of the world’s livestock. Hunger, malnutrition and poverty are high in these areas.

Droughts, poor soils and the high risks associated with investments in productivity-enhancing inputs have kept crop yields low. There is a spectrum of potential for food production within drylands: from areas where cropping is not possible and livestock grazing can serve as a way to “harvest” highly dispersed and erratic rainfall to areas where crop and livestock production can potentially develop synergistically.

Threats to dryland food production

The most prominent constraints for food production in dryland ecosystems are water scarcity and land degradation. Increasing pressure on land and water resources, caused by population growth and migration, is intensifying these constraints and threatening the viability of agroecosystems.

Dry areas are relatively vulnerable to soil erosion, salinization and land degradation, in general. Desertification, defined as resource degradation (land, water, vegetation, biodiversity), is a major environmental problem in dryland areas. The expansion of cropland, inappropriate grazing practices and barriers to the mobility of pastoralists can all contribute to desertification.

According to the desertification paradigm, which is based on the assumption that natural systems are in a state of equilibrium that can be irreversibly disrupted, desertification leads to a downward spiral of loss in productivity and increasing poverty. However, there is increasing evidence of the recovery of areas that were previously thought to be irreversibly degraded (e.g., the greening of the Sahel).

The way forward

Despite the fragility of drylands, there are opportunities to sustainably increase the productivity of agroecosystems in these areas:

• New technologies, new cultivars and land and water management practices, such as efficient collection of runoff and soil-based storage of moisture, can be combined to greatly increase water productivity in cropped areas and restore degraded range- lands. Cultivation of local plants, desert-adapted plants, silvopastures and perennial grasses have the potential to capture benefits from infrequent and erratic rainfall and control erosion in areas too dry to support traditional field crops.
• Securing the mobility of herds for accessing natural resources, trade routes and markets through appropriate policies that take into account transboundary herd movements, e.g., by the creation of corridors and the establishment of water points and resting areas along routes. This enables livestock keepers to get more benefits from smaller herds and prevents overgrazing and degradation caused when animals are confined to smaller areas.
• At farm and larger landscape level, the integration of crop, tree and livestock production can lead to resource recovery in the form of manure for soil fertility and crop residues and tree fodder for feed. For instance, in savannah woodlands, farmer- managed natural regeneration helps increase tree cover.

The link between healthy ecosystems and food security

A new report from the United Nations Environment Programme (UNEP) and the International Water Management Institute (IWMI), in partnership with 19 other organizations, recognises healthy ecosystems as the basis for sustainable water resources and stable food security. Healthy ecosystems can help produce more food per unit of agricultural land, improve resilience to climate change and provide economic benefits for poor communities, according to the report.

Download the UNEP-IWMI report, An Ecosystems Approach to Water and Food Security, as well as the background document Ecosystems for Water and Food Security, from www.iwmi.org/ecosystems and www.unep.org

Picture courtesy Peter Casier/CCAFS