Sustainably increasing production in mixed crop-livestock systems is essential to ensure food security, write M. Herrero and colleagues in Science.
Mixed crop-livestock systems are home to two-thirds of the global population and produce almost half the world's cereals and most of the staple crops, meat and milk consumed by poor people.
But to cope with the population growth, environmental change and rising demand for animal products predicted for the next 20 years, these systems will need to raise both productivity and resource use efficiency.
In some areas, this will mean finding ways to produce more food on less land, say the authors. One solution could be to change the type of livestock reared. In South Asia, mixed systems are already changing from rearing ruminants to poultry, which has enabled a much faster growth in production.
Elsewhere, increasing productivity could be achieved through appropriate farming practices. The authors suggest that the yields of dryland crops such as sorghum or millet could be tripled with proper land preparation, planting and use of fertilisers or pesticides.
Crops genetically modified to withstand pests, diseases and extreme weather could also boost productivity in mixed systems, they say. 'Dual-purpose' crops bred to give both high yields and high-quality residues that can be used as animal feed are another option.
Whatever the solution, developing country governments will need to improve infrastructure and services — including roads, markets and health facilities — to support more extensive mixed systems. Donors must also support such systems, as well as invest in livestock research and development that has been previously neglected.