In a van, down by the river... | I'll worry about making 4 years above trend after we get through the third. I'm not sure what I'm missing here, but this is my trend-line yield plot using USDA data back to 1973. The standard error of the residuals (i.e. the average difference between individual points and the line) is just over 11 bpa. Therefore, banking on anything greater than an 11 bushel deviation from the trend is probably going to be a losing bet about 68% of the time. Furthermore, while I don't see any 4-year stretches of yields far above trend, there are several strings of years where yields were consistently at or above, or not much more than a few bushels below trend.
At about this time last year it was difficult to hear yourself think over the noise created by everyone who said that "high yield years are always followed by much lower yields." The justification was producers skimping on fertilizer/depleted soils, etc. I posted a similar plot last year, with the opinion that until Mother Nature gives me a good reason to change my mind, I'm sticking to MY trendline estimate + or - a few bushels. I feel pretty much the same way this year.
The red dot indicates the yield USDA guessed at their outlook forum.
I'm happy to share the spreadsheet if anyone wants it.
 (Trend Yield.jpg)
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 Trend Yield.jpg (40KB - 54 downloads)
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Corn trend line yields
