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ARS Home » Research » Publications at this Location » Publication #71703
Title: SIX YEAR YIELD VARIABILITY WITHIN A CENTRAL IOWA FIELD

Author
item Colvin, Thomas
item Jaynes, Dan
item Karlen, Douglas
item Laird, David
item AMBUEL, JACK - AG. LEADER TECHNOLOGY

Submitted to: International Conference on Precision Agriculture Abstracts & Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 6/26/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Technologies to support precision farming (PF) began to emerge in 1989 when the global positioning system became available to a limited extent and was tested as a means for locating farm equipment within fields. Substantial PF technology is available, with costs rapidly decreasing, while capabilities are increasing. One major class of information that is missing is a method for determining how much material to apply or what action to take as a result of a condition at a position within a field. Yield variability, within fields, and its cause will need to be understood to provide that information. This study was designed to determine variability within one field. Crop yields showed a coefficient of variation ranging from near 12% in 1989 and 1992 to over 30% in 1990 and 1993. Relative rankings of yields between specific locations were not stable even after 6 years when rankings were recalculated after each new year. Many PF scenarios are based on the assumption of a stable yield pattern within a field. Only a few points in this field have exhibited a stable yield pattern during the study period. Perhaps stable patterns will eventually emerge, but the time frame for this to occur may be quite long. Overall, this study suggests that implementation of PF practices within the Clarion-Nicollet-Webster soil association area will reveal both difficulties and opportunities.