Iowa Farmer Today
09-15-07
Iowa needs Soil Science Institute
By Kendall Lamkey
Besides its people, Iowa’s most valuable natural resources are an abundance of
sunlight, rainfall, and soil. These lst three make Iowa one of the top agricultural
states in the country and one of the most-productive agricultural regions in the
world.
We have little control over sunlight and rainfall, although evidence is mounting
human activities — such as releasing carbon dioxide and other green house
gasses into the atmosphere — are affecting the amount and quality of solar
radiation Earth receives and the frequency, duration and quantity of rainfall.
Soils, on the other hand, are largely under the control of humans. There is no
argument Iowa has an abundance of the highest-quality soil of any place in the
world. This makes soil not only Iowa’s No. 1 natural resource, but also its No. 1
economic resource. Land-use patterns are clearly a direct function of soil quality.
If Iowa had lower quality soils, we would certainly have a much different
agricultural and economic outlook in the state.
SOILS PRODUCE plants to feed humans and animals. Soils are critical for our
hydrologic cycles and water quality. Soils hold rainwater, decrease flooding and
store water for use by plants. Sunlight is converted to heat at the soil surface, so
soil serves as a regulator of climate. Soils that are rich in organic matter and
certain clay minerals (like those of Iowa) serve as the earth’s filters and remove
many of the pollutants that we introduce into the environment.
So the question arises: If soil is so important to the well-being of the Iowa, why
do we treat soil “like dirt”? The most recent average erosion estimate for Iowa is
5 tons per acre. That means every year, on average, 10,000 pounds of soil per
acre move from one location to another. So, for an average corn crop of 200
bushels per acre, about a pound of soil moves for each lb. of corn produced. For
an average soybean crop of 50 bu./acre, this means about 2 lbs. of soil moves
for each lb. of soybeans produced. Some of these 10,000 lbs. of moving soil
stays in the field. Some moves to streams and rivers, and some eventually ends
up in the Gulf of Mexico. When soil moves — even if it moves from one place in
the field to another — it becomes dirt because it is in a less-useful place. But, soil
erosion is regulated by soil management, and high soil erosion rates in Iowa tell
us we can and must do a better job of managing our soils.
Soils are the largest terrestrial reserve of carbon on the planet. As such, soils
and oil share many common features. Both are rich in carbon. The carbon in soil
and oil was created by the same process — plants fixing atmospheric carbon
dioxide through photosynthesis. Under the most-common soil management
systems, carbon is released to the atmosphere when soils are used to produce
crops just as it is released when oil is used to create energy. The degradation of
soil and the depletion of oil is largely an irreversible process. High-quality soils
and oil have been vital to the existence of modern civilization. Both have been
taken for granted by society and it has been implicitly assumed both will last
forever.
Iowa soils are geologically young, having only been recently disturbed by human
activities. Today, many of Iowa’s soils remain incredibly productive, thanks
largely to the organic matter they contain. This organic matter was created and
stored over several millennia by tall grass prairies that once covered most of
Iowa. Although the organic matter in Iowa soils is no more than 50 percent of
what it was when the soils were first tilled, an average acre of Iowa soil will still
mineralize 150 lbs. of nitrogen through the decomposition of organic matter. Corn
production requires about 275 lbs. of N per acre. Only about half of that N comes
from fertilizer or manure; the rest comes from nitrogen mineralized in the soil.
Soil organic matter provides an unseen nutrient source for Iowa farmers and
allows them to use the crop-production practices they currently employ.
At Iowa State University in the Department of Agronomy, we believe there is
nothing more important to Iowa and its future than our soil. For a bio-economy
based on the production of bio-energy crops to be successful, three things are
needed — sunlight, rainfall and high-quality soil. If any are not present, the
production of food and the production of energy from plant-based feedstocks will
become much more expensive and difficult.
BECAUSE SOILS are so important to Iowa’s future, we believe Iowa should lead
the way in the United States not only in the bio-economy, but also in the science
that will keep our soils from becoming just dirt.
That’s why we’ve begun discussing the establishment of a Soil Science Institute
at Iowa State University to provide the information and science needed to
manage and maintain Iowa’s most valuable resource. Our agronomy faculty
already includes some of the most accomplished soil scientists in the world.
Even though soil is the hidden basis of our entire civilization, because it is
underfoot, we take it for granted. A Soil Science Institute would work to make
sure that doesn’t happen.
In short, the degradation of soils can be directly linked to long-term human health
because of the role soils play in plant production, water quality, climate,
ecosystem health and pollutant fate.
That’s why we need new approaches to preserve and maintain our No. 1 natural
resource. We must invest in Iowa’s future by investing in research for Iowa’s
soils.
Kendall Lamkey has lived and worked in Iowa since 1982 as a corn breeder
with the USDA-ARS and Iowa State University. Since 2006, he has been
chairman of the Department of Agronomy.