Corn yields tripled in the U.S. between the 1930s and 1980s. Many new technologies and practices contributed to this increase in corn yields: hybrids, fertilizers, herbicides, insecticides, increased plant populations, early planting. A researcher at the University of Minnesota studied all of these factors to determine their contribution to the increase and determined that herbicides contributed about ¼ of the increase due to better weed control.

“Corn (Zea mays L.) yields in Minnesota have increased from the 2,010 kg/ha yield level of the pre-1930’s to the current 6,290 kg/ha average. This increased yield can be attributed to a series of technological, cultural, and management practices adopted by farmers. My objective is to attempt an analysis of the magnitude of the changes and the relative contributions to grain yield each practice has made over the 50-year time period.

Improved weed control by the use of herbicides on 93% of the hectarage has increased yields 23%.”

Author: Cardwell, V. B.
Affiliation: University of Minnesota, St. Paul.
Title: Fifty years of Minnesota corn production: sources of yield increase.
Source: Agronomy Journal. 1982. 74[November-December]:984-990.