Estimating Crop Residue from Space via Satellite
By Don Comis
April 2, 2009
How much of Americas croplands
are being farmed using conservation tillage? Agricultural Research Service (ARS)
scientists are developing techniques to use satellites to answer that question.
The ARS scientistsresearch agronomist
Daughtry and agricultural meteorologist
Doraiswamyare also studying satellite sensors and geographic
information systems (GIS) technology to identify farm fields that can sustain
more residue removal for ethanol production without harm to the soil. Daughtry
and Doraiswamy work at the
Hydrology and Remote Sensing Laboratory in Beltsville, Md.
Conservation tillage leaves enough crop residue to cover at least one-third
of the soil, while conventional tillage leaves the soil nearly bare.
Currently, methods for estimating tillage intensity based on crop residue
cover are time-consuming. The private
Information Center does its estimates by driving around farmland in each
county and stopping every mile for a look. USDAs
Natural Resources Conservation Service
(NRCS) estimates residue cover by placing a transect line with evenly spaced
beads across crop rows and counting the number of beads hitting residue.
Each spring, the ARS researchers go to Midwestern corn and soybean
fieldsand Marylands Eastern Shoreto check residue levels and
compare their estimates to infrared digital pictures taken by experimental
satellites and to hyperspectral images taken from aircraft. Last year, they
added fall measurements to see how much residue could safely be removed to make
ethanol and maintain adequate residue cover for soil conservation.
Daughtry and his colleagues are working with the
National Aeronautics and Space
Administration to develop an accurate measurement method for use by NRCS.
more about this research in the April 2009 issue of Agricultural
ARS is the principal intramural scientific research agency in
U.S. Department of Agriculture.