In a way this should have been
obvious. There is simply too much
sunlight for many crops in the tropics and this with heavy rains leads directly
to soil deteriation. What nature cannot
do well is to establish a planned distribution of trees able to support a
healthy nutrient base for cropping annuals.
Yet we can.
Thus we see the onset of small
holder agroforestry were the operator uses a lot of trees to provide partial shade,
absorb surplus water for respiration, provide fertilizer by lifting deeply
located nutrients and shedding leaves and also possibly give a cash crop. These are early days, so the cash crop part
is still sorting itself out, but that today is almost the easiest problem to
solve.
The method is not so promising in
temperate climes, but again it is all about spacing and shade friendly crops. If trees are well spaced then the effective
shade will be quite low and may even be beneficial to a lot of crops.
I recall how well some grasses
performed in shaded areas of the barn.
The quick take home from that is that all permanent pasture land needs
carefully spaced shade trees to increase productivity. Non dwarf apples would be a fine start.
Yet oak and the like will provide
fine timber in due time.
The other quick take home is that
the woodlot is badly mismanaged and wasted land on most farms. Cleaning them out – fire is wonderful - and developing a working seed bed is a good
start on a good pasture.
The fact is that we are spoiled
by heavy machinery that wants a thousand acre field. Real productivity needs human inputs and
skilled management with working trees.
Somehow a fifty acre field producing a dense crop of natural grasses,
densified because of occasional shade that supports at least one hay crop and
supports a herd after that while producing hundreds of tons of apples at the
end of the season is surely an improvement over a sundried pasture in
midsummer.
Today we have the hardware to
make all this practical. This would
include wood chippers, chainsaws and a disc plow.
Putting Trees On Farms Fundamental To Future Agricultural Development
by Staff Writers
Trees growing on farms will be essential to future development. As the number of trees in forests is declining every year, the number of trees on farms is increasing. Marking the launch of the International Year ofForest by the United Nations Forum on Forests (UNFF9) in New York on 29 January, Dennis Garrity, the Director General of the World Agroforestry Centre, highlighted the importance of mixing trees with agriculture, the practice known as agroforestry.
"Over a billion hectares of agricultural land, almost half of the
world's farmland, have more than 10 percent of their area occupied by
trees," said Garrity, "and 160 million hectares have more than 50
percent tree cover."
Growing trees on farms can provide farmers with
food, income, fodder and medicines, as well as enriching the soil and
conserving water. As natural vegetation and forests are cleared for agriculture
and other types of development, the benefits that trees provide are best
sustained by integrating them into agriculturally productive landscapes.
Speaking at the High Level Dialogue of UNFF9 on 3 February 2011,
Garrity said, "Agroforestry is a crucial bridge betweenforestry and
agriculture. Essentially, agroforestry is about the role of working trees in
agricultural landscapes, particularly on, but not limited to, small-scale
farms."
Over the next two decades, the world's population is expected to grow
on average by more than 100 million people a year. More than 95 percent of that
increase will occur in the developing countries, where pressure on land and
water is already intense.
A key challenge facing the international community is, therefore, to
ensure food security for present and future generations, while protecting the
natural resource base on which we all depend. Trees on farms will be an
important element in meeting those challenges. In some regions, such as
Southeast Asia and in Central America , tree
cover on agricultural lands now exceeds 30%.
"The transformation of agriculture into
agroforestry is well under way across the globe," said Garrity. "And
there are drivers, including climate change, that ensure that this
transformation will accelerate in the coming years, since agricultural systems
incorporating trees increase overall productivity and incomes in the face of
more frequent droughts, and agroforestry systems provide much greater carbon offset opportunities
than any other climate mitigation practice in agriculture."
In many countries, it is now quite clear that the future of forestry is
on farms. In countries such as India ,
Kenya
Practiced by farmers for millennia, agroforestry focuses on the wide
range of working trees grown on farms and in rural landscapes. Among these are
fertilizer trees for land regeneration, soil health and food security; fruit
trees for nutrition; fodder trees that improve smallholder livestock production;
timber and fuelwood trees for shelter and energy; medicinal trees to combat
disease; and trees that produce gums, resins or latex products.
Reinventing agriculture
Evergreen Agriculture is a form of agroforestry that integrates trees with annual crops. "We see Evergreen Agriculture as nothing less than the radical, but entirely practical, pathway to a reinvention of agriculture," said Garrity. "It is a vision of a future in which much of our food crops will be grown under a full canopy of trees."
Combining fertilizer trees with conservation farming techniques is
doubling and tripling cereal crop yields in many parts of the African
continent. The nitrogen-fixing tree Faidherbia or Acacia albida, is increasing
unfertilized maize yields in Malawi ,
Zambia , Tanzania , Ethiopia
They are now being grown on millions of hectares of crop land
throughout Niger
This development is not happening only in Africa .
The South Asia Network of Evergreen
Agriculture has been launched to advance an evergreen revolution throughout the
subcontinent.
Feeding the hungry
Planting trees that provide natural fertilizers on farms with poor soils helps farmers restore fertility and increase yields. Gliricidia bushes fix nitrogen in their roots and act as natural green fertilizer factories, tripling yields of maize on farms in
The prunings are fed to the animals. The bushes also reduce the risk of
crop failure during droughts and prevent waterlogging when it rains too much.
The nitrogen-fixing tree Faidherbia increased unfertilized maize yield four
times in Zambia Niger
Relieving poverty
Domesticating wild fruit trees in the
Trees grown on homestead farms, in woodlots and on communal lands are
an important source of wood and other products. In humid-zone West African
countries, Burundi , Rwanda and Uganda
In many cash-crop systems, trees are grown for shade and eventually
provide wood - an example is Grevillea robusta in tea plantations in Kenya Sudan , Acacia senegal
Accumulating carbon
Investments in agroforestry over the next 50 years could remove 50 billion tonnes of additional carbon dioxide from the atmosphere. Most of the deforestation in Africa, and in parts of
Agroforestry activities curb emissions of greenhouse gases by slowing
the conversion of forest to farm land and holding carbon in the trees on the
farms. Developing smallholder agroforestry on land that is not classified as
forest could capture 30-40 percent of the emissions related to land-use change.
Encouraging farmers to plant trees has the potential to increase farmers'
income, sequester more carbon and benefit biodiversity.
"The International Year of Forests is a momentous opportunity to
more fully recognize the tremendous importance of agroforestry and evergreen
agriculture in building a better world," noted Garrity.
"Agroforestry is one of mankind's best hopes to create a climate
smart agriculture, increase food security, alleviate rural poverty, and achieve
truly sustainable development. And, thereby, better ensure that our world's
forests can indeed be conserved far into the future."
The World Agroforestry Centre, based in Nairobi , Kenya
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