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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Adaptive Cropping Systems Laboratory » Research » Publications at this Location » Publication #334081
Title: Nitrate leaching from winter cereal cover crops using undisturbed soil-column lysimeters

Author
item Meisinger, John
item RICIGLIANO, KRISTIN - University Of Maryland

Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/30/2017
Publication Date: 4/27/2017
Citation: Meisinger, J.J., Ricigliano, K.A. 2017. Nitrate leaching from winter cereal cover crops using undisturbed soil-column lysimeters. Journal of Environmental Quality. doi: 10.2134/jeq2016.09.0372.

Interpretive Summary: Cover crops are important management practices for reducing nitrogen leaching in the Chesapeake Bay watershed. Annual grasses such as barley, rye, or wheat are common cover crops, but studies are needed to directly compare field nitrate-N leaching losses from these species. A three-year lysimeter study was conducted in Beltsville, Maryland to compare nitrate leaching losses from cover crop treatments of barley, rye, wheat, or a no-cover control. The tension-drained undisturbed soil-column lysimeters were set-up to exclude runoff and to directly measure nitrate leaching and drainage volumes. The end-of-season cover-crop total nitrogen uptake and carbon content was also collected. The pattern of nitrate leaching over time and the whole-season nitrate-nitrogen concentration showed a consistent and large significant difference between the cover-crop vs. the no-cover treatment, but only small and periodic differences between the barley, rye, and wheat covers. Nitrate-N leaching was more affected by precipitation than by type of cover crop, with below-average precipitation producing low nitrate leaching with cover crop leaching reductions averaging 92%, while above-average precipitation years produced high nitrate-N leaching and cover crop reductions of 41-45%. These results are important to scientists, nutrient managers, and policy makers because they provide real-world data on the ability of grass cover crops to reduce nitrate-N leaching and thereby improve water quality in the Chesapeake Bay environment.

Technical Abstract: Cover crops are important management practices for reducing nitrogen (N) leaching in the Chesapeake Bay watershed, which is under Total Maximum Daily Load restraints. Cool-season annual grasses such as barley, rye, or wheat are common cover crops, but studies are needed to directly compare field nitrate-N (NO3-N) leaching losses from these species. A three-year lysimeter study was conducted in Beltsville, Maryland that compared NO3-N leaching losses from cover crop treatments of barley, rye, wheat, or a no-cover control using duplicates for each treatment. The eight tension-drained undisturbed soil-column lysimeters were configured to exclude runoff and to directly measure NO3-N leaching and drainage volumes. End-of-season cover-crop total N uptake and carbon content was also collected. The temporal pattern of NO3-N leaching and flow-weighted NO3-N concentration showed a consistent and highly significant (P < 0.01) difference between the cover-crop vs. the no-cover treatment, but only small and periodically significant (P < 0.05) differences between the barley, rye, and wheat covers. Nitrate-N leaching was more affected by precipitation than by cover crop species, with below-average precipitation producing low NO3-N leaching with cover crop reductions averaging 92%, while above-average precipitation years produced high NO3-N leaching and cover crop reductions of 41-45%. These results are important to scientists, nutrient managers, and policy makers because they provide real-world data on the ability of cool-season grasses to reduce NO3-N leaching and thereby improve water quality in the Chesapeake Bay environment.