Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/9/2000
Publication Date: N/A
Technical Abstract: In modern agroecosystems, acidification of soils results mainly from nitrification of excess ammoniacal nitrogen inputs. Leaching of nitrate due to excess N inputs also leaches base cations, primarily Ca and Mg, by virtue of charge balance. In addition to acidification from excess N inputs, soil acidification may be introduced by crops by imbalance in the extraction of cations vs. anions, requiring plants to produce organic anions by deprotonating organic acids. After long periods of acidification, loss of cations by leaching and reduction of CEC by acidification can account for a large fraction of the total exchangeable base cations in the soil. The Wisconsin Cropping System Trial, located at the Arlington Research Station of the University of Wisconsin-Madison, has archived soil samples and performed plant analysis since 1989 for soils managed under common cropping systems of Midwestern United States. This trial represents a prime opportunity for studying the coupling of N and H cycles and to evaluate the acidification potential of these agricultural agroecosystems. Soil acidification and leaching of base cations will be considered as fingerprints of the long term effects of agroecosystems on soil chemical properties.