Nairobi (Kenya), 28
August 2009 - The World Agroforestry Congress
held at the UN's Africa headquarters in
Nairobi (Kenya) has offered some tree-planting
solutions which could help the African continent
deal with climate change and also provide
a long-term solution to the continent's
food scarcity problems.
Dennis Garrity, the
Director General of the World Agroforestry
Centre, highlighted some of the centre's
most recent research, which is designed
to increase maize production in Africa by
up to four times by planting trees that
act as organic fertilizers.
"We have evidence
of how maize yields have doubled and tripled
for smallholders, without an overall increase
in labour or the need to apply nitrogen
fertilizers," said Garrity.
Garrity told the Congress
the secret to higher maize yields lay in
a tree called Faidherbia.
This tree has a special
nitrogen-fixing property and an unusual
habit known as "reverse leaf phenology".
Unlike other trees,
Faidherbia sheds its leaves and goes dormant
during the early rainy season.
Its leaves grow again
only in the dry season. This means that
it is extremely compatible with food crops
because it does not compete with them for
water, nutrients or light.
According to the Agroforestry
Centre, farmers in Malawi testify the tree
is like a "fertilizer factory in the
field", as it takes nitrogen from the
air, fixes it in the leaves and subsequently
incorporates it into the soil.
The Agroforestry Centre's
research showed that in Malawi maize yields
increased by 280 per cent in the zone under
the tree canopy compared with the zone outside
the tree canopy. In Zambia, unfertilized
maize yields in the vicinity of Faidherbia
trees averaged 4.1 tonnes per hectare, compared
to 1.3 tonnes nearby but beyond the tree
canopy.
The latest research
was welcomed by Kenyan officials, environmentalists
and agronomists at a time when Kenya is
asking for emergency food aid in order to
prevent widespread famine.
Maize is the staple
food for many African countries, but when
grown as a mono-crop over many years it
drains the soil of vital nutrients.
On average, maize yields
on the 27 million hectares on which it is
grown in Africa are one tenth the equivalent
of American yields. One of the reasons is
limited use of fertilizers, but the Faidherbia
tree - pending some further research on
its impact on the water table - may now
provide a natural and widespread fertilizer
fix.
Plant Trees or El Nino
and Climate Change will Claim Lives
The congress also emphasized
how tree-planting can provide farmers with
everything from nuts and fruits to windbreaks,
erosion control, and fuel for heating, timber
for housing and fertilizer to improve much
needed food security.
Founder of the Greenbelt
Movement and Nobel Prize laureate Wangari
Maathai emphasised the urgency of planting
trees to help Africa adapt to the more extreme
weather conditions brought on by climate
change. Maathai said that climate change,
like a disease, can easily kill a body already
weakened by decades of environmental mismanagement.
Maathai made her plea
to an audience of African journalists in
the context of a fast approaching El Nino:
"We need
to prepare for El Nino. We need to plant
trees and have vegetation covering the soil.
We need to dig trenches and cut off drains
that to allow water to go into the ground.
It cannot wash away to the rivers, which
will then wash away all the top soil. Let's
not wait for the governments, let us do
it ourselves."
