It occurred to me the other day that I often talk about what I feel is a core piece in Precision Ag, the Variable Yield Goal, but I have never actually discussed what all goes into the VYG. As far as I’m concerned, anytime we start talking about adding any degree of accuracy to our prescriptions, it starts with the VYG.
A good Variable Yield Goal starts with a minimum of identifying the obvious out in a field. The division of where our irrigated acres end and our dryland begins is a simple one. A more complex VYG takes into consideration the simple and adds so much more. Historical yield data is a great place to start. Many of you have had a yield monitor for over ten years now, and have little more to show for it than a pile of books. Yield Data needs to have work done on it to be useful. At a bare minimum, we have to clean up the starts, stops, and bad spots to have a more consistent layer. But, we also need to adjust it. While you’re harvesting, you don’t notice that the pivot track is 12 feet off going back and forth, but on the maps it’s obvious. In many cases, we can correct that and put it back where it belongs.
Here is another important thing to realize on yield data. Not all data is useful data. For instance, dryland acres from 2012 probably don’t tell us a whole lot, and including them in a decision may or may not be relevant. Often when working with yield data, a judgement call has to be made that a computer just can’t do on its own. And that’s ok. Look in the junk drawer in your kitchen. Not everything we keep is valuable. And for those of us that don’t have yield data that goes back more than a couple of years, there are some things we can do with imagery to build a map of vegetation. Biomass doesn’t always equate to yield, but it does usually equate to plant health.
So this is your take home for the day. Building a Variable Yield Goal is a concept, not a blueprint. A lot like Legos. You can follow a set of directions once and wind up with something cool that lots of other people have. Or you can look at the pieces you have in front of you come up with a vision of what you want in the end, and start building towards that vision. And like building with Legos, everything that we have at our disposal is valuable, but it’s not always useful. But once we sort through the pieces, we can find what we need to complete our vision.
Once your trusted advisor and ACS Specialist have worked with you on your Vision, and then it’s time to actually build it. The ACS VYG is unique in a way because we realize that history doesn’t always reflect reality. There are always areas in a field that need more adjustments to be correct. But after that’s done we can get down to business. A good Variable Yield Goal will serve you for fertility recs, Seed decisions, and Nitrogen applications. Again, if you ever built anything with Legos, you know if the base or foundation of your creation is unstable, you don’t get the result you want and get to start over. Except in Agriculture, it’s too costly to start over.