Nitrogen fixation helps double yield

A large-scale research and development project
has shown that giving farmers resources and
advice on nitrogen fixation through legume plants
can double yields and boost incomes in Africa.
But not all farmers are benefiting from this
practice due to a lack of access to inputs, such as
fertilisers says Ken Giller, the leader of the
N2Africa project, as a second phase to widen
access to the initiative is announced with US$25.3
million funding from the Bill & Melinda Gates
Foundation for the next five years.
Researchers and representatives of NGOs and
companies gathered in Nairobi, Kenya, yesterday
to discuss the results of N2Africa's first phase.
This was carried out by a partnership comprising
Wageningen University in the Netherlands, the
International Centre for Tropical Agriculture, the
International Institute of Tropical Agriculture and
several NGOs, universities and research centres,
mostly based in Africa.
Through the project, around 252,000
smallholders in eight African countries were given
legumes, such as soybeans, groundnuts or
beans.
Such plants host soil bacteria called rhizobia in
their roots that fix atmospheric nitrogen, which is
important for plant growth, into the soil. These
nitrogen-fixing bacteria can be added to the soil
by applying an inoculant, a mixture of peat and
rhizobia bacteria.
As well as receiving new legume varieties
farmers were advised to use improved
inoculants, special fertilisers with more phosphate
and were given advice on crop rotation and
intercropping.
"We have measurements and observations on
thousands of farmers' fields across Africa," says
Giller, who is a plant scientist at Wageningen
University.
Results from an early impact study presented at
today's meeting in Nairobi show that crop yields
could double using the new legumes, inoculant
and fertiliser.
But average yields increased only between 78
and 272 kilograms per hectare for different crops,
whereas scientists hoped for a target increase of
954 kilograms per hectare.
The average increase in household income was
US$335 a year instead of the hoped-for US$465
goal.