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Tillage: A Grower's Drought Assistant
May 20, 2003
Conservation tillage continues to be
good for the environment--and can boost farmers' profits by helping them use
water more efficiently, according to studies by
Agricultural Research Service scientists
In test plots of cotton and peanuts at Tifton, Ga., conservation tillage
limited rainfall runoff to less than 10 percent. In some cases, conservation
tillage increased water infiltration into soil by up to 50 percent, compared to
conventional tillage. Conventional plots also released five times more soil and
rainfall runoff than conservation tillage plots, making a strong case for
conservation tillage. Water that washes away from fields can carry soil
sediment, nutrients and pesticides to streams and lakes.
The research, led by soil scientist Clint Truman and hydraulic engineer
David Bosch at the ARS Southeast
Watershed Research Laboratory in Tifton, indicates that a type of
conservation tillage called strip-till not only reduces runoff, but increases
water infiltration and appears to improve soil quality.
In strip-till fields, narrow rows, four to six inches wide, are made for
planting seed into the previous year's plant- and cover-crop residue. Plant
residues reduce water evaporation from the field and intercept raindrops from
impacting directly on the soil surface, decreasing soil movement and cutting
down on rain washing away pesticides and nutrients from a field. With
conventional tillage systems, old plant residues are often removed or
incorporated into the soil.
Southeastern soils have been intensively cropped, tend to be drought-prone,
and are susceptible to erosion. While rainfall registers about 50 inches per
year, growers often have to irrigate to keep crops alive during extended
drought periods. Producers in this region face a major problem: maintaining
crop yields and water use efficiency while addressing soil and water quality
concerns associated with sediment, fertilizer and pesticide losses to off-site
More information about this story can be found in the
May issue of
Agricultural Research magazine.
ARS is the U.S. Department of
Agriculture's chief scientific research agency.