A study of machinery for growing and harvesting corn has been carried on at Ames, Iowa, since 1931 by the Agricultural Engineering Section, Iowa Agricultural Experiment Station, cooperating with the Bureau of Agricultural Chemistry and Engineering, U. S. Department of Agriculture. Experiments were conducted on the Agricultural Engineering Research Farm at Ames. This farm comprises soils in the Webster and Clarion Series, and the topography is comparatively level. Maximum slopes are about 5 percent. The purpose of this bulletin is to report the results of these experiments insofar as they relate to the methods and machinery best adapted for controlling weeds in surface-planted corn.

Recent improvements in machinery enable the corn grower to produce his crop with less labor than was formerly required and to improve the control of weeds in cornfields. Machinery, labor and power for producing corn have been discussed in a previous publication.

Improving weed control is the principal objective under consideration in the present bulletin.