Grassroots September 2016, Vol. 16, No. 3 | Page 31
News
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Soil erosion may threaten global food security
Joe Turner
SciDev.Net
http://www.scidev.net/global/farming/news/soil-erosion-threatens-global-food-security.html
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G
lobal soil erosion has reached levels that
will endanger humanity’s ability to feed
itself if nothing is done to lower it, a study warns.
Tim Benton, University of Leeds The review,
published in Science last week (7 May), says soils
are being lost faster than they are being naturally
produced in many parts of the world. In addition,
there is increased pressure on farmland from nonfood uses, such as crops being grown for biofuels,
and there may be future shortages of rock phosphate,
which is used to make fertiliser, it says.
“The increases in food production in the
developed regions of the world are plateauing,” says
Ronald Amundson, a soil scientist at the University
of California, Berkeley, in the United States, and one
author of the study. “There are opportunities to
increase food production in underdeveloped nations,
but this will require expenditures for fertilisers to
bring their yields up to what the regions can
potentially produce.”
The phosphorus needed to create fertiliser is
mined. This raw material has risen in price recently,
according to the paper, prompting worries about the
availability of inorganic fertilisers for farmers in
developing countries.
The paper’s authors say that, instead of relying
solely on fertiliser to increase yields from
conventional farming, more efficient food
distribution and nutrient recycling are needed to end
hunger — one of the UN’s proposed Sustainable
Development Goals (SDGs).
Soil erosion is caused by the overuse of land,
deforestation, desertification and water runoff— all
of which are, to some extent, caused by farming. The
Science paper comes as many scientists worry that
Grassroots
soil protection targets in the draft SDGs may be
removed from the final list of goals.
Since January, which marked the start of the
International Year of Soils, scientists have been
calling for greater political focus on soil
management.
Tim Benton, a population ecologist at the
University of Leeds in the United Kingdom, says
better soil management could go a long way towards
producing enough food in the future.
“I don’t think we worry enough about
conserving soil resources for the long term,” he says.
In traditional farming systems, food production
can be increased by using various techniques to
reduce soil erosion, says Rattan Lal, a soil scientist
at the Ohio State University in the United States. For
example, he says farmers can preserve their soils
using agroforestry and by covering it with crop
residues.
But it is a major decision to switch to such
methods, he says, as these are more labour intensive
and can be less economically efficient, considering
many farmers use agriculture to meet household
needs for feed, fodder and building materials.
According to Lal, around 500 million farmers
worldwide depend on farms of less than two
hectares. If soil management were included in the
global agenda to address climate change and food
shortages, much could be done to help the two
billion ‘hidden hungry’, who are not eating enough
nutrients in their food, he says.
September 2016
Vol. 16 No. 3