U.S. Geological Survey Toxic Substances Hydrology Program--Proceedings
of the Technical Meeting, Colorado Springs, Colorado, September 20-24, 1993,
Water-Resources Investigations Report 94-4015
  
Nitrogen Uptake and Soil Water Variability Across a Sand Plain
Landscape
by
J.A. Lamb (Associate Professor, Soil Science Department, University
of Minnesota, St. Paul, MN), M.D. Tomer (Research Fellow, Soil Science Department,
University of Minnesota, St. Paul, MN), J.L. Anderson (Professor and Director
of Center for Agricultural Impacts on Ground Water Quality, Soil Science
Department, University of Minnesota, St. Paul, MN), and R.H. Dowdy (Research
Leader and Soil Scientist with U.S. Department of Agriculture-Agricultural
Research Service, St. Paul, MN)
Abstract
Research at the Northern Cornbelt Sand Plains Management Systems Evaluation
Area at Princeton, Minnesota, was conducted to characterize the variability
of whole-plant nitrogen uptake and soil-water content under a continuous
corn-cropping system. The soil was a Zimmerman fine sand (mixed, frigid,
Alfic Udipsamment). Nitrogen fertilizer was applied uniformly in 1991 and
1992. In 1991 and 1992, corn whole-plant samples were collected in 15-meter
intervals along a 244-meter-long transect to determine nitrogen uptake.
In 1992, plastic neutron-moisture-meter access tubes were placed to a depth
of 2 meters every 20 meters along the same transect. Nitrogen uptake ranged
from 115 to 157 kilograms nitrogen per hectare in 1991 and 92 to 132 kilograms
nitrogen per hectare in 1992. Mean uptake of nitrogen was 24 kilograms per
hectare greater in 1991 than it was in 1992. Soil-water content ranged from
10 to 15 centimeters for the upper 1.7-meter depth interval on July 23,
1992. The area where nitrogen uptake in 1992 was least is a sideslope area
where the surface soil was driest. Leaching may have occurred during recharge
events during the growing season at this and positions in the terrain.
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