Fig. 19. (a) A modern 375-horsepower Caterpillar 85E crawler tractor pulls a 3800-L tank filled with aqua NH₃–N, and a Haybuster undercutter during primary spring tillage plus N fertilizer injection near Lind, WA. The 11 m wide implement is operated at 10 km h^–1 and covers about 75 ha d^–1. The tank needs to be refilled with aqua NH₃–N every hour. (b) The wide, narrow pitch, and overlapping V-blades on the undercutter implement slice below the surface with little soil lifting or disturbance of surface residue, but completely sever soil capillary continuity to halt upward movement of liquid water to maintain seed-zone moisture in summer fallow. Note the standing stubble that is much more effective than flattened stubble for wind erosion control. This represents the best technology currently available for profitable and environmentally sound winter wheat–summer fallow farming in the low-precipitation zone of the Pacific Northwest. Photos by W.F. Schillinger.