Continuing Education
Early January is when we find time to take a deep dive into our yield data from the previous fall. There is a sense of excitement about this exercise as we have come to learn there will usually be a few surprises.
Yield rank comparisons are done for planting date, variety, rotation, county, landowner, and fertility program.
It was no surprise when results showed yields peaked with maturities of 106 day. We had observed this during harvest. Later varieties did not reach maturity due to delayed planting last spring and a cooler summer.
Seeing no yield difference between continuous corn vs corn grown on bean ground was unexpected as bean ground almost always out yields continuous corn. Our explanation for this is most of our corn-on-corn fields are well tiled (40' or less), fertilized with manure, and have a history of high yields. We appreciate every farm we operate, but they are not all rock stars. Invariably, lower yielding farms are delegated to a corn bean rotation.
Drainage proved its value dramatically. We acquired a new farm across the fence from a farm we've had for twenty years. Yield maps this fall showed an immediate 45 bushel drop in yields when crossing the old boundary. Fertility was comparable. Tile was the difference.
One peculiarity revealed by the data goes against conventional wisdom and is still a point of disagreement among my partners. Every year we rank our top ten yielding farms for P, K, and pH levels. It is generally believed you need high test levels of P and K with a slightly acid pH of 6.8 to grow high yields. Our highest yielding farm this year had test levels in the medium range and the lowest test levels of the top ten yielders. This has occurred several times since we started doing this analysis.
My explanation is that medium test levels are sufficient for our current yield potential. Other factors are more limiting. I will admit a little skepticism towards the traditional commercial fertilizer yield recipe of N, P, K, and pH being the end all, be all. While the concentration and availability of these essential elements is not that high in hog manure, no soil amendment has shown us a yield response as great. There is still much to learn in this area.
The most informative spreadsheet is the field profitability ranking. Every single farm is ranked with adjustments made for crop, yield, rotation, rental rate, fertility program, and location. Distance from McIntire increases operating costs. Most years there will be a farm or two "underwater" (predictably these farms are further from headquarters 🤔) due to exceptionally poor yield while the winner is a sleeper close to McIntire that raised the crop of its life despite a mediocre history.
As much importance as we place on the choices we make, weather is the primary determinant. And though we have yet to have a perfect growing season, there is no place else we would rather do what we do.
McIntire is close enough to perfect for us.
Jim