Tile drainage increases average soybean yields as much as 8

[...]a study of 20 years of data from both experimental trail and producer fields in the North Central United States shows a 4-8% yield advantage for artificial subsurface drainage. More results While there was a 4.1 bushel per ace advantage for artificial drainage in the experimental fields, there was still variation in the magnitude of the yield difference, ranging from negative 1.7 to 11.5 bushels per acre across site-years. While the average producer yield was 2.1 bushels per acre higher for subsurface artificial drainage versus naturally drained fields, there was variation in the magnitude of the artificially drained and naturally drained yield difference, ranging from negative 1.7 to 5.9 bushels per acre.