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VERTICAL DISTRIBUTION OF
PHOSPHORUS IN WISCONSIN CROPPING
SYSTEMS
Juli Meyer [1] and Phil Barak [2]
In recent years, eutrophication of surface waters has brought agricultural
phosphorus to the forefront of environmental concerns. However, current
testing procedures largely use the same methodologies to determine both
crop requirement needs and environmental hazard levels, with little or
no consideration of vertical distribution of available phosphorus. Therefore,
we are examining the plots from various cropping system of WICST to determine
the amount of phosphorus with regard to depth and management practice,
as well as the phosphorus buffer capacity of the soil. At the Arlington
Agricultural Research Station, 1-m soil cores were taken in the fall
of 2002 and the spring of 2003 from five cropping systems, including
continuous corn (CS1), no-till corn/soybean (CS2), corn/soybean/wheat-red
clover (CS3), corn/alfalfa/alfalfa/alfalfa (CS4), and pasture (CS6).
These cores were sectioned to a resolution of 1-cm and labile P, solution
P (including heavy liquid displaced soil solution), and P sorption curves
are being determined. Striking stratification of soil phosphorus has
been noted within the plow layer of most of these rotations. Further
data analysis is forthcoming.
Link to poster:
http://www.soils.wisc.edu/~barak/poster_gallery/ASA_2003/index.html
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