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Study looks at how tillage impacts soil

Soil scientists with USDA’s Natural Resources Conservation Service are currently working on a project that will help farmers understand how tillage methods impact soil quality.

The Dynamic Soils Properties study, based out of Lincoln, is the first of its kind for NRCS, says Dave Kohake, NRCS soil scientist.

At a glance

• Nebraska’s NRCS looks at the impact of tillage on the soil.

• Five sites in southeast Nebraska were evaluated in the study.

• Researchers want to identify soil’s organic carbon content.


“In the past, studies have dealt more with the soil’s intrinsic properties,” he says. “This project will focus more on the dynamic soil properties affected by management.”

The study focuses on two tillage methods — conventional tillage and no-till. For this study’s purposes, a field is considered to have been conventionally tilled any time the soil has been disturbed with full-width tillage implements, such as disks, chisel plows or field cultivators. A field is considered to have been no-tilled if it has not had tillage to the soil’s surface within the past 15 years. A couple of organically farmed sites will also be evaluated as part of the study.

The Dynamic Soil Properties study team also includes Casey Latta, Cindy Stiles, Deb Harms and Bruce Evans. They identified five sites for each tillage method across southeast Nebraska with similar soil types. The team has been traveling around to these selected sites throughout the fall to collect soil samples.

Once at the site, the soil scientists prepare the test location by setting up a grid and, within the grid, five sampling pits are dug, each 16 inches deep. That’s the depth where the impact of different farming techniques can be detected.

The soil scientists then begin identifying the different layers of soil. A sample of each layer is taken to the USDA’s National Soil Survey Center’s laboratory, located in Lincoln, for analysis. The lab will check each site’s soil samples for several properties, including bulk density and organic carbon content. Organic carbon, according to Kohake, is directly related to soil health.

“The amount of organic carbon content found within soil is the best indicator we have for soil quality. The higher the carbon content, the higher the soil quality or health.”

This study will compare the lab results to show how conventional tillage, no-till and organic farming methods affect soil properties. The results from this fall’s study should be available by next planting season.

For more information about soil quality, visit your local NRCS office or the Web Soil Survey at websoilsurvey.nrcs.usda.gov/app .

Source: Nebraska office of the Natural Resources Conservation Service.

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SOIL PROPERTIES: Casey Latta, NRCS soil scientist, identifies soil properties at one of the study sites in Lancaster County.

This article published in the February, 2010 edition of NEBRASKA FARMER.

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