provides graphical evidence on the

provides graphical evidence on the key identifying assumption of parallel trends. Given the high degree of co-movement between pre-treatment productivity in the two sectors, the fact that corn and sugar beet are grown in the same geographic areas, planted in spring and harvested in fall, the similarities between production practices in the two industries (tractors, plows and seeders are used during planting while combines are used during harvesting), and that corn and sugar beet are not grown in rotation, corn appears to be a valid counterfactual.