New, nondestructive soil-analysis device measures carbon, more, in situ

Lucian Wielopoloski (right) and Sudeep Mitra are seen in BNL.s new Soil Analysis Facility with the new device that measures carbon and other elements in-situ and nondestructively. Roger Click here for a high resolution photograph.

With funding assistance from DOE's Office of Science and the National Energy Technology Laboratory, Lucian Wielopolski of the Environmental Sciences Department (ES) has developed a device that can measure carbon and other elements in soils non-destructively and in situ.

The device is mounted on a cart and is field-deployable. It was created as part of the Lab's ongoing effort in carbon sequestration in the free-air CO2 enrichment (FACE) facility, and could have national and international implications for both agriculture and the environment.

Sudeep Mitra, also of ES, assisted Wielopolski in his research. Housed on site at the Lab's newly constructed Soil Analysis Facility, Bldg. 487, that opened in December 2004, the instrument employs different methods of neutron activation to determine how much carbon is sequestered in soils. Over the past year, it has been undergoing modifications and field tests on site and at the FACE facility in North Carolina.

Plans call for it to be used jointly by scientists from the U.S. Department of Agriculture and DOE facilities in Alabama and from the University of Tennessee.

"In the past, soil carbon measurement was done by taking samples from small cores or large excavations back to the lab," Wielopolski said. "Now, with this device, we can sample a large volume at the site so that normal lateral fluctuations are smoothed out."

Unlike other soil carbon measurement technologies, which are destructive, Wielopolski's device allows for multi-elemental soil analysis. It can also be used in a scanning mode, allowing scientists to obtain average values of a large area.

The device may be of particular interest to farmers worldwide, who have been switching in increasing numbers from conventional agriculture methods that turn the soil to what is called "no-till" farming. Since carbon generally improves soil fertility, it will allow farmers to determine when soil conditions are ideal.

There is another reason the farmers may want to keep track of how much carbon is present in their soils.

"Photosynthesis sequesters carbon in the root systems of plants and finally in the soil," Wielopolski said. "Switching from till to no-till agriculture increases carbon sequestration and farmers will want to be able to verify the amount of carbon stored.

Since carbon sequestration removes carbon from the atmosphere, thus mitigating the global warming, this will allow the farmers to receive carbon credits."

Pursuant to the Kyoto Treaty on reducing greenhouse gas emissions, "carbon credits" will be available to farmers whose soil contains large amounts of sequestered carbon.

Polluting industries are allowed fixed amounts of carbon dioxide emissions, after which they will have to buy carbon credits, now being actively traded on stock exchanges from Europe to Chicago.

The technology is also the subject of a CRADA with the XIA Company of California. In the future, Wielopolski and Mitra look forward to using tagged neutron beams by applying the associated particle neutron time-of-flight technique that could provide vertical profiles as well as the current total carbon in a volume of soil.

"It would be a quantum technological jump," Mitra said. "I have used this technique to measure carbon in live sheep."