10
The Graham-Hoeme plow and the Noble Blade Cultivator brought an end to the
emphasis on deep tillage and dust mulch that was earlier believed essential for dry-
land farming. These two implements were the forerunners of tillage implements
used worldwide in dryland farming areas. In 2000, the Graham-Hoeme plow was
dedicated as a National Historic Agricultural Engineering Landmark by the
American Society of Agricultural and Biological Engineers and chisel plows and
historic plaques are exhibited at Hooker, Oklahoma and at the USDA Conservation
and Production Research Laboratory, Bushland, Texas.
4 Changing Tillage to Control Wind Erosion and Water
Saving
Although Mr. Noble recognized that keeping residue on the surface would have a
positive effect on soil water, particularly by trapping more snow, his primary focus
was on controlling wind erosion. There is every indication that Mr. Hoeme focused
entirely on controlling wind erosion. However, it became evident that the change
from deep plowing and dust mulching to stubble mulching by using sweep and
chisel plows resulted in more stored soil water in the soil profile during the fallow
periods and increased yields of subsequent crops. Countless studies worldwide have
shown that soil becomes air-dry to whatever depth the soil is plowed resulting in
large losses of water. Therefore, farmers moved away from using dust mulch that
had been widely promoted. Theoretically, dust mulch reduces water loss because
plowing the soil to create the mulch forms large pores. Water cannot move from
small pores into large pores by capillary action so the mulch prevents upward move-
ment of water from the wetter soil below the mulch. However, by the time a soil can
be tilled to create dust mulch, it has already dried to the point that capillary water
movement has essentially stopped. Crop residues on the soil surface have other
Fig. 3 A Graham-Hoeme
plow developed in 1933
and marketed as the “Plow
to Save the Plains”
B.A. Stewart and S. Thapa