Divisive field-scale associations between corn yields, management, and soil information

For corn crops on soils with fine texture in eastern Canada, research has b een ongoing on the relationships between corn grain yields and management p ractice, soil strength/compaction, and soil nutrient status. However, these variables can operate in a complex manner that may not be detectable via u ni-structural models. This study used regression-tree analysis, in an explo ratory context, to model corn grain yields over a relatively flat clay to s ilty loam field on the basis of several soil physical, soil nitrate, and ma nagement variables. It was found that corn grain yields were first subdivid ed by length of time under corn production (Ist and 3rd year corn groups). These yield groups were further subdivided by cone penetration resistance, elevation, soil nitrate, and soil texture information. Generally, higher co rn grain yields were associated with Ist year corn, lower relative soil str ength/compaction, and higher post-growing season soil nitrate levels. The m odeled results helped to identify equifinality, context dependent relations hips, and spatial continuity in inferred formative mechanisms; issues impor tant in many field and/or landscape studies of spatial processes. (C) 2001 Elsevier Science B.V. All rights reserved.