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This article in AJ

  1. Vol. 95 No. 4, p. 1028-1033
    Received: Nov 8, 2002

    * Corresponding author(s): yxz117@psu.edu


Corn–Soybean Rotation Effects on Nitrate Leaching

  1. Y. Zhu * and
  2. R. H. Fox
  1. Dep. of Crop and Soil Sci., 116 A.S.I. Bldg., The Pennsylvania State Univ., University Park, PA 16802


Because agricultural production is a primary nonpoint source of NO 3 in the nation's waters, a better understanding of the effects of cropping systems on NO 3 leaching is required for developing agricultural production practices that reduce NO 3 leaching. A 4-yr experiment was conducted to study the effect of a corn (Zea mays L.)–soybean [Glycine max (L.) Merr.] rotation on NO 3 leaching using passive capillary fiberglass wick lysimeters. The experiment had five N rates on corn (0–200 kg N ha−1 in 50-kg increments). Corn was planted in 1997 and 1999, and soybean was planted in 1998 and 2000. The increase of soil residual NO 3–N concentrations in the surface 25 cm of soil after crop harvest was not significant (p = 0.05) when N fertilizer rates applied to corn increased from 0 to 100 kg ha−1 but was significant when N rate increased from 100 to 200 kg ha−1 in the corn years. The 2-yr average soil residual NO 3–N concentrations and annual flow-weighted NO 3–N concentrations in leachate were significantly higher (p = 0.05) in soybean years than in corn years at 0 and 100 kg N ha−1 applied to corn, but the differences at the 200 kg N ha−1 rate were not significant. The results indicate that at recommended N rates applied to corn in a corn–soybean rotation, NO 3 leaching potential is similar for corn and soybean, but at less than 100 kg N ha−1 rate, a greater NO 3 leaching potential exists under soybean than under corn.

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Copyright © 2003. American Society of AgronomyPublished in Agron. J.95:1028–1033.