Many farmers are focused on rebuilding our soil—here's why you should be too. Part two of a two-part dispatch on the sorry state of our nation's soil and what we can do to fix it. Read part one here: "Too Sick to Function."
It's easy to overlook soil's ill
health because overall it still does what we want it to do: produce bumper
crops. But as organic matter levels drop, those yields are increasingly reliant
on fertilizers like nitrogen, and, as the Minnesota
Pollution Control Agency reported in June, so much of this nutrient is
escaping the land that 27 percent of lakes and rivers in the southern half of
the state are too polluted to be used for drinking water. Removing nitrates
from drinking water is costing the Des
Moines Water Works $7,000 a day. It's a vicious cycle: more chemicals
result in less of the kind of biological activity needed to maintain natural
fertility, which means even more chemicals are needed to prop up yields, which
sends more chemicals into our water.
But since soil organic matter
levels are tied to biological processes, we can have a relatively quick impact
on those processes. Creating a one-inch layer of soil can take centuries, if
not more. But I've been on farms where organic matter has been increased in a
matter of a few years through the use of crop plantings and rotational grazing
systems that diversify the landscape -- above and below the surface -- while
shielding soil from the elements beyond the standard corn-growing season. A USDA
survey released in July found that planting soil-friendly cover crops not
only protected the soil but actually boosted corn yields significantly in parts
of the Midwest most heavily hit by drought in 2012. Soil scientists are monitoring
this revitalized soil and finding it can not only cook up its own fertility and
make use of moisture better, but develop a kind of shielding system that keeps
it from being blown apart by heavy rains.
The other good news is that today's
science is providing fascinating glimpses at an ecosystem that most of us
probably consider dull as, well, dirt, but which is in fact the most diverse on
the planet. An awareness of what we are losing and a realization that
traditional conservation isn't enough has prompted natural resource agencies to
rethink erosion control strategies. One USDA Natural Resources Conservation
is that if all of our nation's cropland was managed using traditional
conservation measures, erosion would drop by 0.85 billion tons annually.
Increasing organic matter on our cropland would drop erosion by 1.29 billion
tons per year.
Creating healthier humus will
require farm policy reforms, as well as market-based incentives and land grant
university research/outreach initiatives that help farmers adopt innovative,
financially-viable production systems. All this requires support from the
non-farm public, a tall order for a society that's quite comfortable treating
soil like dirt. But this isn't just about maintaining crop yields, or even
cleaner water. Soil provides at least $1.5
trillion in services worldwide annually, including stockpiling more carbon than the Earth's
atmosphere and all the plants on the planet. That makes it a key player in
controlling greenhouse gases, among other things.
As the father of soil conservation, Hugh Hammond Bennett, wrote in 1928:
"Farmers have only temporary control over their land … The public's
interest, however, goes on and on, endlessly, if nations are to endure."
Brian DeVore works for the Land Stewardship Project, a nonprofit organization fostering sustainable agriculture since 1982. DeVore writes for and edits the group's publication, The Land Stewardship Letter.
Image: "Healthy Soil" by USDA NRCS South Dakota, licensed under Creative Commons.