(Funding: NNYADP) In a 2019 study of nine conventionally tilled dairy farm corn fields in northern NY, compaction at the surface and at depth was revealed in all fields, with considerable within-field variation. We are examining soil compaction distribution further, by looking at the relationship between historical yield and soil compaction on 4 fields on 2 commercial dairy farms. Collaborators include: Quirine Ketterings, Cornell University; Kitty O'Neil and Mike Hunter.