Wheel-track planting confirmed that only a small area of fine, firmed soil was needed for soil germination. As a result, planter experts were soon asking the next logical question:
"Why do we need to turn over 500-1,000 tons of soil per acre with a moldboard plow when we only need 8% of the ground for a seedbed?"
The question led to the development of the A-C No-Til coulter by Maynard Walberg, an Allis-Chalmers implement engineer. It was a deep-fluted, 17-inch diameter coulter that would slice through crop residue or sod to prepare a 2½-inch seedbed ahead of the planter unit. A heavy rubber torsion-spring provided penetration in tough soils and protected the coulter when dealing with rocks or other obstructions.
To accomdate the coulters, Allis-Chalmers engineers designed planter frames with three toolbars for 20- to 40-inch rows. The first toolbar held the coulters, the second toolbar carried the fertilizer boxes/tanks plus openers, and planter units were attached to the third toolbar.
The company offered three blades for different soils and field conditions, but the most popular was the full 2½-inch fluted coulter.
-Adapted from "Allis-Chalmers Farm Equipment 1914-85" authored by long-time company employee Norm Swinford