In 2050, when the population of Africa is two and a half times larger
than now, the continent will scarcely be able to grow enough food for its own
population. Even if much higher yields are achieved on all current cropland,
further expansion into uncultivated areas is likely and very risky due to
biodiversity loss and increased greenhouse gas emissions. Based on local data
and model calculations, this was the conclusion of a study conducted by a team
of researchers from Wageningen University & Research, several African institutes,
and the University of Nebraska. Their findings were published in the journal PNAS of this week.
Agricultural yields
per hectare in sub-Saharan Africa are currently low. For example, the maize
yield is only 20% of the potential yield with good management. In comparison,
the yield in the Netherlands or USA is 80% of the potential yield. Although
extensive farming now satisfies most of the African population's demand for
grain, in the next few decades the African population will grow by a factor of
2.6 and grain demands even 3.4 times. Therefore in 2050 self-sufficiency on existing farm land is
only feasible if the yield per hectare will rise to 80% of the potential, just
as in the Netherlands or the United States.
Sharp increase in yield required
During the past
decade, the maize yield per hectare was less than 2 tonnes, with a very small
annual increase (approximately 30 kg per hectare). In 2050, the yield must be
approximately 7 tonnes per hectare. As a result, an annual increase in yield
per hectare of 130 kg must be achieved – starting now. “In addition, there are still
possibilities to grow multiple crops per year and to expand the irrigated area,
but these are options with many uncertainties,” emphasises principal
investigator Martin van Ittersum of Wageningen University & Research.
If that fails, then
major expansions of farmland are required, which will be at the cost of natural
habitats and increased greenhouse gas emissions, or enormous grain imports that
must be paid with scarce foreign exchange. In some countries, the required area
is simply not available, and expansion of farmland is not sustainable, explains
one of the researchers, Professor Abdullahi Bala from Nigeria. Van Ittersum:
“You still hear people say that Africa can become a major grain basket of the
world, but it may be very challenging for Africa to remain even self-sufficient
in the future.”
Modernisation of agriculture in Africa
Consequently,
according to the international research team including Kindie Tesfaye from the
International Maize and Wheat Improvement Centre (CIMMYT) in Ethiopia, a rapid
intensification of African farming is required. He sees options that will lead
to improved yields, such as grain varieties that are adapted to local
conditions, and improved fertilisation and control of diseases and pests,
including parasitic plants. Tesfaye also stresses the importance of improved
farming with multiple crops per year and the expansion of sustainable
irrigation. Van Ittersum adds: “As a result, large investments are required in
research and development, in the private and public sectors, to increase
production while limiting environmental impact.”
Although the
researchers restricted their study to biophysical limits and possibilities,
they also call for attention to market access, especially for smallholder
farmers, and to transport, infrastructure, farm loans and insurance. As a
successful example, co-researcher Professor Bala of the Federal University of
Technology, Minna refers to a policy that is linked to the private sector,
which has been used successfully to improve rice yields and cropping intensity
in Nigeria.
The researchers from
Wageningen University & Research, and their colleagues from African research
institutes and the University of Nebraska, collected data from 10 African
countries which accommodate 54% of the total population of sub-Saharan Africa
and which contain 58% of the total cropland on this part of the continent.
They mapped out the
production and demand for five major grains – maize, millet, rice, sorghum and wheat – in Burkina Faso, Ghana, Mali, Niger, Nigeria,
Ethiopia, Kenya, Tanzania, Uganda and Zambia. They consider it unlikely that
the situation is more favourable in other African countries because there the
availability of arable land per capita is slightly lower.
The research was
supported by the Bill & Melinda Gates Foundation as part of the Global
Yield Gap Atlas, a
project that is jointly led by Wageningen University & Research and the
University of Nebraska at Lincoln in the United States.
PNAS Publication
Can sub-Saharan Africa
feed itself? M.K.
van Ittersum, L.G.J. van Bussel, J. Wolf et al. Proceedings of the National
Academy of Sciences of the United States of America (PNAS) Online Early Edition the
week of 12 December 2016.
For more information,
please contact Professor of Plant Production Systems, Martin van Ittersum,
Wageningen University & Research, tel. +31 (0)317 482 382, martin.vanittersum@wur.nl, or science information officer Jac Niessen,
tel. +31 (0)317 485003, email jac.niessen@wur.nl.
Source : Press release Wageningen UR, no. 111, 12 December 2016
Note : All
the rice yield gap analyses considered in this study have been carried out by the
Africa Rice Center (AfricaRice) scientists Dr P A J van Oort and Dr K Saito,
who are co-authors of the paper.
