Is It Good Under the Hood?

Maintain Peak Soil Performance by Avoiding Fall Tillage

 October 1, 2009

Without proper maintenance, even the most powerful engine can lose the ability to perform at it’s peak. Spark plugs and oil need changing, air filters need replacing, even tires need the proper inflation. The same goes for your soil.

“To make sure your soil is performing at its peak, producers need to make sure they are avoiding management activities that reduce organic matter, damage soil structure and increase the risks of erosion. A good place to start is reducing tillage,” says Barb Stewart, state agronomist for USDA's Natural Resources Conservation Service in Iowa.

A soil’s performance is directly related to a soil’s quality or health. A healthy soil will do a better job at: resisting erosion; cycling crop nutrients; supporting root growth; infiltrating water; and sequestering carbon, she said. 

Tillage and Soil Performance

Many agronomic decisions affect soil organic matter, soil health and soil performance. These include what crops are grown and in what rotation; the use of cover crops; fertility practices; and other erosion control measures. But what probably matters the most is a producer’s tillage practices.

“One of the most crucial of these decisions affecting soil performance is a producer’s residue management or tillage practices,” said Stewart. “So producer’s who till the soil this fall could already be reducing their yield potential for the following year by damaging the soil performance on their farm.”

Reducing tillage minimizes the loss of organic matter and protects the soil surface with plant residue. Tillage can break up soil structure, speed the decomposition and loss of organic matter, increase the threat of erosion, destroy the habitat of helpful organisms and cause compaction. Each of these potential outcomes negatively impact soil quality. 

Soil Structure: A healthy soil structure provides the framework for good water infiltration, reduced runoff and root development.

Organic Matter: The amount of organic matter in the soil is probably the number one indicator if the soil is at it’s peak performance. Tillage aerates the soil, triggering increased biological activity, resulting in rapid decomposition, loss of soil organic matter and release of CO₂ into the atmosphere. Basically, tillage promotes the “burning” of organic matter.

Erosion: The evidence of erosion can be an indicator of poor soil health, but it is also a contributor to poor soil performance. When soils erode, they lose valuable organic matter decreasing soil quality. Tillage operations which leave the soil unprotected from the erosive forces of wind and water are a key contributor to soil loss from erosion.

Habitat: Tillage can destroy the soil structure needed for good habitat for the microorganism’s living in the soil. Most of these organisms live in the top two inches of the soils surface, so even the most shallow tillage operations can have damaging effects. These microorganisms play an important role in nutrient cycling and helping decompose organic matter.

Compaction: Tillage can damage soil structure making it more vulnerable to compaction. This compaction reduces the amount of air, water and space available to roots and soil organisms. When this space is removed, runoff is increased, root development is impacted as well as the fertility of the soil.

So before tilling the soil this fall, think about your soil performance, advises Stewart. “Tillage can have a lasting impact on how well your soil performs for your operation,” she said.

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Contact:
Laura Greiner, State Public Affairs Specialist
Phone: 515-284-4262

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