Shaggy, I can only give the example I observe. We have been paying for it for two years and have yet to apply it in a way that is measureable on the yield monitor ------------- measureable in a way that cannot be atributed to something else.
This year we are harvesting our first experiments with variable rate fertilizer through an air seeder by soil maping and by hired application.
The jury is still out, we will see at harvest. How well we keep records of the additional costs, and the fertilizer savings compared to a blanket broadcast application? What savings there was on fertilizer? And how well the harvest results can be connected to the variable application??
A lot depends on the original theory applied. Do you push the good soils and take lumps on the weaker soils or do you try to fix problems? for example....
And finally...... how many years do you have to run the test until your sure your fertilizer history is not affecting your test??
And of course is there enough variation in the field to be worth aditional expense of the testing?
We did get a couple of suprises on a field that showed more fertilizer in locations than others. But knowledge of the fields history would have told us the same, since portions had once been flood irrigated.
But the original idea for us was to use VRT on corn planting of circles and corners, a theory we might get back to, but ofter the variety needs to change as much as the population.
I am not sure how many years and acres it would take to prove VRT benefit over traditional population or volumes, but It will be enough that I would let KSU spend the dollars on research.
Ever notice it is d____ed expensive being the first on your block to have the new ideas??
And in ag, over the years, only 1 in 5 of those new ideas pan out for everyone. There are just too many differentials to consider.
I drove east out of Ulysses yesterday all the way to Dodge City. I bet there is 15 miles in there where the soil type and topography does not change much.
