I would like to invite readers to consider a question that is at the very heart of the shift toward precision agriculture practices: What causes field variability in the first place?
First, let’s look at the obvious factors such as elevation, slope, soil type and water availability. There’s not much you can do to change these conditions, many of which stem from years and years of soil formation and climate conditions. The goal is to map them and then adapt your strategy to work with these variabilities.
A lot of times we look to place blame on field variability and conclude that it is out of our control. But here is something that is in our control: Did you ever think about the fact that when we apply a flat uniform rate of fertilizer across a field and get varied yield results, that we as farmers are the ones causing field nutrient variability? The longer we do this, the more variability will exist.
When you think about it, our history of flat-rate farming has played a part in exacerbating the natural farmland variability that exists.
Let me explain: First, I’m not blaming farmers for causing variability. It’s a reality and we work with it.
However, I do believe that regardless of how long it takes for full adoption of Variable Rate (VR), flat-rate will become a thing of the past —and when it does, farming will start to look a lot more like it did in our grandparents’day.
It’s all a matter of scale. Consider that when a Western Canadian farmer today thinks about average field size, he’s probably thinking in the range of about 200 acres. A generation ago that number was about 100 acres and two generations ago, when my grandfather was a young farmer, the average field was about 40 acres.
Those 40-acre fields are now about the size of one agronomic zone in today’s field. What’s changed is the scale —we think there is now so much variability in one field, but that’s actually because one field today is equivalent to about five a few generations ago. If we treat the five different zones in one field differently, it’s the same as a farmer back then treating each field according to its unique characteristics.
So, my point is not that field variability is on the rise, but that it only seems that way because average field/farm size is on the rise. Our grandparents, who used flat-rate application, were actually doing the same thing we are. They were treating every zone individually, except for them a zone was the size of one field.
This is why I think the movement to variable rate management is inevitable. If we apply flat-rate to a 200-acre field, it’s not the same as our grandfather using flat rate on 40 acres. And by doing this for the past 30 years, we have been perpetuating —and exacerbating —field variability because each time you flat-rate a 200 acre field, you further engrain those variabilities. Crop uptake is different in each zone, so you’re just cementing in those variabilities by overloading or under-loading a zone when you use blanket treatments across an entire field.
Again, this isn’t about pointing fingers. It’s about realizing that precision farming is a natural and progressive evolution that truly brings agriculture in harmony with the over-arching value of sustainability and finding balance in environment
Comments? I’d love to hear your thoughts.
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