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ARS Home » Pacific West Area » Pendleton, Oregon » Columbia Plateau Conservation Research Center » Research » Publications at this Location » Publication #68748


item Douglas Jr, Clyde
item KING, K. - BMCC

Submitted to: Pendleton Station Field Day
Publication Type: Experiment Station
Publication Acceptance Date: 3/18/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: A five-year study, in northeastern Oregon, determined the effect of a winter wheat-spring pea crop rotation on the amount of nitrogen lost as soil and water were lost from a series of field plots. Nitrogen in the water was less than 2% of the amount of nitrogen added as fertilizer to either winter wheat or spring peas. Total nitrogen loss was closely associated with the amount of soil lost. Nitrogen lost from plots where no nitrogen fertilizer was added, was 66% of the nitrogen lost from the fertilized winter wheat plots. We conclude that the inherent nitrogen supplying capacity of these soils, not fertilizer nitrogen, is the largest contributor to nitrogen in water and soil lost from a wheat- pea rotation. It is important to control soil erosion in order to reduce the amount of nitrogen entering streams and lakes in northeastern Oregon and Washington.

Technical Abstract: Fertilizers have been suggested as a major source of nitrogen and phosphorus in lakes and streams. Soil management practices can critically affect the amount of nutrients in sediment and surface runoff. However, there is relatively little information available on nutrients in surface runoff and sediment in eastern Oregon and Washington. There is also little information on effects of different crops and crop rotations on nutrients in runoff and sediment. Surface runoff, erosion, and nutrients in runoff and eroded sediment were evaluated in a five-year study in Northeastern Oregon. The objectives of the study were to evaluate the effects of a wheat-pea rotation on nitrogen in surface runoff and eroded sediment. Soluble nitrogen losses were < 2% of applied fertilizer nitrogen for both winter wheat and spring pea treatments. Sediment nitrogen was the primary source of nitrogen loss.