Research Areas

Global Climate Changes-Soil Carbon Dynamics 2002-2004

Researcher: Helvecio de Polli

PROJECT TITLE: Movement of Carbon in Soil as Affected by Soil Management and Improvement of Cooperative Research Work Between ARS and EMBRAPA Related to Global Climate Change.


The research is under way primarily at the USDA/ARS/BARC West, Environmental Quality Laboratory and South Farm, Beltsville, MD. Analysis concerning 137Cs tracer studies are been developed at the Hydrology and Remote Sensing Laboratory (BARC West)- Jerry Ritchie, and analysis of mid-infrared (MIR) and near-infrared (NIR) diffuse reflectance spectroscopy for soil carbon measurement are been conducted at the Animal Manure and By-Products Laboratory (BARC East)-James Reeves.


Cesium-137 originated from nuclear testing on the 60’s and globally spread out can be used as a tracer to study movement of soil due to agricultural practices leading to erosion and carbon loss.  Assumption is made that the decline in 137Cs activity for a potentially eroded soil in relation to a soil from an uneroded site is proportional to soil loss. We selected two points for sampling in Brazil in collaboration with (1) Embrapa Temperate Climate/Federal University of Santa Maria, Clenio Pillon, and (2) 

Universidade Estadual do Norte Fluminense-(UENF), Emanuela F. da Gama-Rodrigues. First results demonstrated the feasibility of the methodology for South of Brazil but in the lower latitude-region we still evaluating the case.


MIR and NIR spectroscopy studies on soil organic matter will quantify and characterize patterns of C on Brazilian soils creating a spectrum library. This work is a partnership with Embrapa Solos, Beata Madari and Pedro Machado. It was approved as a project at Embrapa involving also Embrapa Agricultural Instrumentation Center. The first results from two sites in Brazil (Santo Antonio-Goias, and Londrina-Parana, were presented and discussed during our visit (Gregory McCarty and Helvecio De-Polli) at Embrapa Soils Center on July 28, 2003.


The main study area in the USA is a field site at South Farm at the USDA/ARS/BARC were a ten-years old tillage experiment on no-till plow-till is been conducted and soil microbial biomass, CO2 emission, N2O emission, CH4 emission/oxidation is under monitoring year around following the protocol of GraceNet/ARS. Interaction was done with Pat J. Unkefer (Los Alamos National Laboratory, US DOE) to perform cellulase gene probes analysis on the soil from the experimental parcel.