|Lamb, John - UNIVERSITY OF MINNESOTA|
|Anderson, James - UNIVERSITY OF MINNESOTA|
|Rehm, George - UNIVERSITY OF MINNESOTA|
Submitted to: Journal of Production Agriculture
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 17, 1997
Publication Date: N/A
Interpretive Summary: Crop yield variability within a farm field leads to an inefficient use of applied agrichemical, increasing the potential for ground water contamination. Year-to-year consistency of yields is needed to use site-specific management for correction of these inefficiencies. A five year study was conducted to determine if patterns of corn grain yields were esimilar over a number of years and if yields from one or more years can be used to predict grain yields for subsequent years. The experimental site at the Northern Cornbelt Sand Plain Management Systems Evaluation Area near Princeton, Minnesota, was 4.4 acres of continuous corn from 1990 through 1995 following alfalfa from 1981 through 1989. Cultural practices were applied uniformly to the site each year. The 4.4 acres were divided into 60 grid cells (50 ft. x 60 ft.) and grain yields were determined within each cell. Differences between highest and lowest grain yields ranged from ma high of 72 bu/acre in 1991 to a low of 44 bu/acre in 1992. Grain yields were not spatially consistent from year to year. Areas with better grain yields were not consistent from year to year, and conversely, poor production areas were not found in similar locations each year. This lack of grain yield stability raises a serious question about the utility of this information for predicting future crop fertilizer needs. This information will be used by farmers, farm consultants, farm managers, and farm planners as they devise crop fertilization programs.
Technical Abstract: Year-to-year consistency of crop yields within a farm field is needed to use site-specific management. A five-year study was conducted from 1991 to 1995 to determine if patterns of corn grain yields were similar over a number of years and if grain yields from one or more years can be used to predict grain yields for subsequent years. The research area was 4.4 acres swith soils mapped as three variants of the Zimmerman fine sand and a Cantlin loamy fine sand. Continuous corn was grown from 1990 through 1995 after a previous history of alfalfa from 1981 through 1989. Cultural practices were applied uniformly each year. The 4.4 acres were divided into 60 grid cells (50 ft. x 60 ft.) and grain yields were determined by hand harvesting an area (two rows 20 ft. long) within each of the 60 grid cells. Differences between highest and lowest continuous corn grain yields in the research area were 72 bu/acre in 1991, 44 bu/acre in 1992, 45/bu acre in 1993, 51 bu/acre in 1994, and 57 bu/acre in 1995. Areas with better grain yields were not consistent from year to year, and conversely, poor production areas were not found in similar locations each year. Only 4 to 42 percent of the grain yield variability for one year was accounted for by a knowledge of the grain yields from a previous year. The lack of grain yield stability on a sandy soil raises serious questions for the potential for utilization of this information. The data indicate that the use of grain yield maps for fertilizer recommendations on a site specific basis will require a much longer term database than the normally recommended five years.