Dirt is dirt, right?
Not exactly, if you ask an agronomist, farmer or everyday gardener. Dirt, or more appropriately, soil, is considered a non-renewable resource because it forms over hundreds of thousands of years. Indeed, soil is quite possibly one of the most misunderstood — and at times, most abused — part of Earth’s biosphere.
Nearly 60 percent of Indiana’s land is devoted to agriculture. Of Indiana’s 23 million total acres of land, 14.8 million acres are devoted to farmland. The state’s agricultural economy is dependent on health of the soil.
Soil is an intricate ecosystem. Scientists say that up to 50 earthworms can thrive within a square foot of healthy soil. A teaspoon of soil is home to a billion bacteria, several yards of fungal hyphae, thousands of protozoa and dozens of nematodes, all of which have a relationship with the root systems of plants, including plants we eat and plants we feed to animals we eat.
Healthy soil supports stable ecosystems, like Indiana’s original perennial prairies and forests. As soon as Hoosier settlers began clearing forests and prairies for farming and urbanization, soil conditions changed, often for the worse. A major consequence of repeated tilling of land for crop production was erosion — wind and water carry unprotected soil away.
Gary C. Steinhardt, professor of agronomy and extension specialist with Purdue University, said Indiana has erosion issues that need to be addressed.
Though statistics from the Natural Resources Conservation Service show erosion rates have declined significantly between 1982 and 2007, nearly 30 percent of all farmland nationally, including Indiana, still suffers from soil losses that would prevent current levels of agricultural production to continue.
Steinhardt says that cover crops show promise. Cover crops, sometimes referred to as green manure, are crops with no cash value that are planted in place of cash crops to increase soil fertility, decrease erosion, enhance tilth, reduce weeds, slow pests and disease, and increase the soil’s water-holding capacity.
Steinhardt says, “They not only prevent erosion, they’ll also build organic matter. By not plowing, we’re preventing a lot of erosion.”
If we think we’ve treated farmland badly in Indiana, consider what’s been done to urban land. Steinhardt said he is disturbed by the loss of land to development and views responsible development as a way to preserve soil quality. “[Prime farmland] is valuable, it doesn’t get its just due. If we looked at our cities seriously, we’d be trying to figure out how we can make living downtown more attractive. You fritter away land, natural resources and ecosystems.”
Industrialization and urbanization
According to Chris Harrell, principal and founder of Lazarus Group LLC and the City’s former brownfields expert, Indianapolis and other cities have squandered a lot of land. Very little native soil remains in urban areas due to industrialization.
“Through the process of industrialization and urbanization, soil has been moved around and degraded through blending with construction debris and wastes, thus degrading the soil for growing,” Harrell says.
Harrell said that poor urban soil quality is product of an industrialized past. He lists contaminants common to urban areas, including heavy metals, such as arsenic, barium, cadmium, chromium, lead, mercury, selenium and silver; solvents, petroleum products and polychlorinated biphenyls (PCBs). People can be exposed to these contaminants through inhalation, absorption through skin or ingestion.
What can you do to protect soil?
If you must use chemicals, dispose of them properly. Visit a ToxDrop site.
If you plan to grow a garden for food, test your soil and learn to build richer soil.
See the soil resource section.
See also IUPUI’s Garden Safe Garden Well here.
Discover how your land was historically used to make sure it’s not a former dry-cleaners or gas station site.
Read the Urban Garden Fact Sheet.
Indianapolis City Brownfield Inventory.
Consider whether or not to apply a lawn chemical. Learn all you can about a chemical before using it. Always follow label directions. At what expense are you trying to maintain the perfect, weed-free lawn?
Get involved in land-use planning and zoning. Support smart urban growth that protects undeveloped land. Learn about LEED for Urban Development.
Got weeds? They might be trying to tell you something about your soil, if you haven’t already blasted them with weed killer! Weeds move quickly into disturbed areas to protect soil and restore nutrients.
Use natural alternatives to get rid of pests in the garden.
With reporting help from Jordan Martich and Josh Watson. See our glossary for a list of soil contaminants.
All five pieces of the Squandered Indiana series can be accessed here.