AGRONOMIC NEWS ITEMS
From Agronomists of the
Potash & Phosphate Institute
655 Engineering Drive, Suite 110
Norcross, Georgia 30092-2837
Phone (770) 447-0335
Spring 1997, No. 7
But the real story is that we are again seeing the need for, and value of, sound agronomic decision making, with all of the research and education needs associated with it. We are really using new technology to ask some of the same questions that we asked 25 years ago. We now have new tools to measure and document variability, to control variable-rate applications targeted to the variability, and to measure and document the response (yield variability) to the variable-rate applications made on a variable-resource basis. This is one of the most exciting opportunities agronomists have ever had.
Yield maps often don't match soil test maps. That is a tribute to the successful use of soil testing and nutrient management to remove soil nutrient supply as the main yield-limiting factor. This does not mean soil testing and grid sampling and variable-rate nutrient management aren't profitable. The site-specific management tools help us more accurately measure soil nutrient supplies and more accurately apply the nutrients needed for the crop and to build and maintain soil nutrient supplies...so the soil fertility variable can continue to be a less-critical limiting factor...and we can focus on managing other variables.
Yield maps are helping identify problems we didn't even suspect, measure responses to factors we couldn't even identify before, and document the responses to within field variability, whether natural or management-induced. Production and economic significance of drainage problems, pest problems, and compaction, among other factors, can be accurately documented within the field for the first time.
Let's not get too discouraged with the problems. By identifying them we have taken the most critical step to solving them. Site-specific technology is working...often helping us in ways we could not have predicted. We know so much more about our fields already as a result of the small percentage of farmers adopting this technology, and each year we learn more, adding to the knowledge base of individual farmer fields and of crop and soil management in general.
So don't stop questioning the technology...and don't stop expecting more than it can deliver...but don't overlook what we have learned and the tremendous potential that knowledge represents for improving crop profits. Few, if any, yield monitors are being taken off combines...nor have many people backed away from site-specific management. It is in our future and we should welcome the opportunities it will bring.