
Crops and
Conservation Tillage Glean Carbon for the LandBy Don Comis March 9, 2001Parking the plow can build new topsoil
and keep atmospheric carbon dioxide levels down,
Agricultural Research Service scientist
Don Reicosky reported today at the 27th annual Mid-Atlantic No-Till Conference
in Delaware. Reicosky, a soil scientist in Morris, Minn., has found that tillage releases
carbon into the atmosphere in sudden rushes or burps of CO2 as soil
is opened up. CO2 is one of the greenhouse gases that may be causing global
warming. Reicosky described how he measures CO2 losses by placing a large portable
chamber on the soil shortly after plowing. He has found that when wheat fields
were plowed, as much carbon escapes in the form of CO2 as was added the
previous season by leaving unharvested wheat straw on the field. Since the 1970s, farmers have increasingly been leaving a third or more of
their fields surfaces covered with unharvested crop stalks and
leaves--after planting--to protect soil from erosion, in a practice known as
conservation tillage. Conservation tillage includes a range of tillages, with
no-till being the one that disturbs soil the least. Farmers are also planting
cover crops for more residue, especially after crops with low amounts of
residue. Reicosky talked about defining the various tillage options by the amount of
CO2 each releases. He discussed how keeping carbon in the soil leads to many
economic and environmental benefits, such as better yields with less chemicals,
keeping waterways clean by preventing erosion and speeding the breakdown of
chemicals. Reicosky shared center stage with Carlos Crovetto Lemarca, an
internationally recognized no-till farmer-author from Chile. Reicosky has spent
several days on Lemarcas two farms in Chile, where Lemarcas
soil-building techniques have added an inch of new topsoil in less than a
quarter century--twenty times faster than Natures process of building
soil by weathering rocks. ARS is the U.S. Department of
Agricultures chief scientific research agency. Scientific contact: Don Reicosky, ARS
North Central Soil Conservation Research
Laboratory, Morris, Minn., phone (320) 589-3411, fax (320) 589-3787,
[email protected].
U.S. Department of Agriculture |