|Heintzman, Angille - UNIVERSITY OF MINNESOTA|
|Johnson, Marilyn - UNIVERSITY OF MINNESOTA|
Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: August 1, 1997
Publication Date: N/A
Technical Abstract: Evolving cropping practices and increasing environmental concerns about agriculture heighten the need for accurate crop simulation models. The focus of this study was to refine the predictive capability of CERES-Maize given detailed soil data. Two seasons of field experiments were carried out at three locations, representing a range of soil textures, in Minnesota aand western Wisconsin. First-year treatments consisted of (1) broadcast-applied urea or ammonium nitrate (220 kg N ha-1) and (2) dairy or swine manure slurry (56 m3 ha-1) incorporated at different times after application to examine N losses. In the second year, treatments included broadcast-applied urea (220 kg N ha-1) and two manure slurry rates (56 and 112 m3 ha-1). CERES-Maize predicted check plot yields accurately, however the model overestimated the contribution of N fertilizer by 25%. Whereas measured yields ranged from 7.15 to 7.28 Mg ha-1 in the manure plots and 5.55 Mg ha-1 in the check plots, CERES-Maize did not predict a yield increase with manure addition. Changes to the fertilizer and manure/residue subroutines will be discussed.