A Burning Issue in Winter Wheat Production
Perry March 12, 2009
Some Pacific Northwest winter wheat producers burn fields to remove
straw left after harvest before reseeding. Agricultural Research Service (ARS)
scientists and cooperators have shown that with careful management, this
practice does not result in any more soil erosion than other postharvest
Continuous winter wheat cropping systems are used in some parts of the
Pacific Northwest where high amounts of rainfall result in excessive residues
that must be managed after grain harvest. Conventionally managed (CM) winter
wheat crops typically require multiple tillage operations before this residue
is adequately incorporated into the soil. Although CM techniques reduce
residues and control weeds and diseases, repeated tillage also promotes higher
levels of soil erosion.
The practice of burning fields and then conducting no-till or
two-operation seeding--called burn/low-till, or BLT--provides an alternative to
CM. After the postharvest residue is burned, only one or two tillage
operations, including seeding, are needed in the next round of crop production.
Burning the fields leaves the soil surface bare before new wheat seedlings
begin to emerge, but undisturbed plant crowns that remain after burning help
hold soil in place.
McCool and soil scientist
Kennedy work at the
Land Management and Water Conservation Research Unit in Pullman, Wash. They
teamed with U.S. Forest Service scientist
Pam Fletcher and Washington State University
soil scientist Chris Pannkuk to conduct a three-year study that compared soil
erosion rates and other factors affecting soil quality between BLT fields and
The team found that BLT did not adversely affect soil loss or soil
quality in fields used for continuous winter wheat production. Soil loss from
BLT fields was as closely related to the number of tillage operations as to the
amount of straw residue remaining on the soil surface. As in CM production,
higher tillage rates in BLT fields generally resulted in increased soil loss.
This information can help producers evaluate the pros and cons of
converting to BLT practices--which are subject to burning regulations that vary
from state to state--for winter wheat production.
ARS is the principal intramural scientific research agency of the
U.S. Department of Agriculture.