- COLUMBUS, Ohio (Newswise)
- Restoring soil carbon levels should be a top priority among the global
community, according to a viewpoint article in this week's issue of the
journal Science.
-
- The amount of carbon that can be restored in the world's
degraded agricultural soils will directly influence global food security
and climate change within our lifetime, said Rattan Lal, author of the
article and director of the carbon management and sequestration center
at Ohio State University.
-
- Scientists estimate that, since the mechanization of
agriculture began a few hundred years ago, some 78 billion metric tons
- more than 171 trillion pounds - of carbon once trapped in the soil have
been lost to the atmosphere in the form of carbon dioxide (CO2).
-
- "Converting natural ecosystems to fields for crop
production and pastures depletes a soil's carbon content by as much as
75 percent," Lal said. "And the amount of carbon we emit into
the atmosphere each year from industrial activity is on the rise."
-
- With too little carbon in the soil, crop production is
inefficient. Right now, the world's agricultural soils are alarmingly depleted
of carbon, particularly in sub-Saharan Africa, south and central Asia and
the Caribbean and Andean regions, Lal said.
-
- He calls for adopting "recommended management practices"
for increasing and keeping carbon in farmed soils. These practices include
no-till farming - leaving residue from the previous year's crops on the
field; agroforestry - planting trees or shrubs on or around cropland to
enhance the quality of the soil; planting cover crops, which protect the
soil from erosion during normal growing seasons; and using nutrients such
as manure, compost or biosolids to fertilize crops.
-
- Evidence shows that following such practices greatly
increases and sustains crop yields.
-
- Lal cited an 18-year experiment in Kenya: Farm fields
managed by regular farming practices - tilling the land, using no fertilizer,
leaving fields bare in the non-growing season - produced about 1 ton of
maize and beans per hectare (a hectare is about the size of two football
fields). But fields treated with manure, planted with cover crops and covered
with mulch yielded six times that amount.
-
- "This is the type of quantum jump in crop yield
needed at the continental scale to ensure food security in Sub-Saharan
Africa," said Lal, who is also a professor of natural resources. "Soil
needs enough carbon in order to hold water and nutrients and to grow crops
efficiently.
-
- "But completely removing crop residue for animal
fodder and fuel is the norm in many African and Asian countries,"
he continued. "This drastically reduces soil carbon levels, and we
cannot achieve global food security without returning crop residues and
putting carbon back in soil. Both are necessary for improving soil quality."
-
- According to the report, soil carbon sequestration can
offset global fossil-fuel emissions by 5 to 15 percent each year.
-
- "The potential of carbon sequestration in world
soils - about 1 billion tons per year, is equal to the renewable energy
produced globally during 2001," Lal said. "Carbon sequestration
is an important strategy to mitigate climate change, which can neither
be ignored nor over-emphasized.
-
- "Keeping carbon locked in soil reduces how much
carbon dioxide enters the atmosphere, and it also improves and sustains
soil productivity."
-
- But soil has a finite capacity for holding carbon. And
if the practices Lal outlines in his report are put to widespread use,
the world's soils could reach their carbon-carrying limits in about 50
years.
-
- That will hopefully buy researchers enough time to find
alternatives to fossil fuels, which should reduce the amount of carbon
released into the atmosphere as CO2.
-
- He noted that the United States and some European Union
countries already have CO2 emission-reduction policies in place. For example,
the U.S. government has mandated an 18 percent decrease in CO2 and other
greenhouse gas emissions by 2012.
-
- But until we find replacements for fossil fuels, it may
be difficult at best to meet those goals. In the meantime, some industrialized
countries can take advantage of carbon trading markets - utility companies
and other industries that rely on fossil fuels can essentially buy carbon
credits from farmers who have sequestered carbon in their soils. This ensures
that CO2 in the atmosphere is kept at a minimum while farmers are encouraged
to use methods that increase carbon in their soils. It can also be an important
source of income for struggling farmers.
-
- "Carbon trading isn't a long-term solution, but
it's one option that's being used to buy us enough time to hopefully find
alternatives to fossil fuels," Lal said. "And in the short run
if it helps to restore some of the degraded soil ecosystems in developing
countries, why not use it? It gives resource-poor farmers income, increases
productivity, restores degraded ecosystems and improves water quality.
It is truly a win-win option.
-
- "Soil carbon sequestration is a natural, cost-effective
and environment-friendly process," he continued. "Once sequestered,
carbon remains in the soil as long as restorative land use, no-till farming
and other recommended management practices are followed."
-
- <http://www.newswise.com/about/policy/#copyright>©
2004 Newswise.
- All Rights Reserved.
-
- http://www.newswise.com/articles/view/505448/
-
- Comment
- From Neal
- 6-10-4
-
- Jeff - this is very impotant news of a positive nature
supportive of organic farming soil management practices and the relationship
that has to climate stabilization. It is also a clear example of how we
can grow plenty of food without GMO. In fact, GMO and other "green
revolution" agro chemical schemes are excuses not to practice good
soil management.
-
- The food we eat now, even organic certified (not USDA
but CA certified) is woefully inadequate in the mineral department. In
our farm's subsistence vegetable garden, we introduce large quantities
of red crushed lava rock or other rock powders available. The 3/8 minus
crushed red lava rock decomposes rapidly, turning the soil a nice reddish
color. The growth rates of the plants are phenomenal and fruit & vegetable
production increase dramatically over mineral-depleted soils. You can
also taste the difference. In fact, what tastes 'good' to us in a prime
vegetable or fruit is the minerals. The water blobs with cellulose we get
from the super market variety junk is "tasteless," for a reason.
|