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Seymour, IL | fair enough questions 555... I do not know all the answers
not sure ecmo read the article.... the question I was trying to address was "how could they have ever estimated 181'?
if you look at the data, easy to see how the estimate was made (so it appears to me). Picking short durations and averaging is not trend.
In regard to timeframe, part of it is based in the differences between trend analysis, averages, etc. Trends in commodities, weather, etc. are typically 30 year windows (and farmdoc does break those down further into 20 years groups)
you make a good point about the advances in production.... however what is to say they cannot continue? I keep hearing about 100 bu/a soybeans that are on whole fields and not in yield contests.
I think in general we tend to remember the recent past the most and give it more weight.... whereas in trend analysis, they are just additional data points. it takes more than a couple of years to bend the arc of the trend. however if a plateau has been reached, it will become apparent in the data.
I thought it was interesting the farmdoc team was able to identify stretches of above and below trend....
above trend from 2003 to 2009,
below trend from 2010 to 2013,
above trend from 2014 to 2018, and
below or at the trend from 2019 to 2022.
"However, the existence of those periods does not suggest that the longer-term trend increases have changed much. To investigate, we fit models of shorter duration. For each year from 1950 to 2023, we used the previous twenty years to fit a linear model and forecast the subsequent trend yield. For example, the 2023 trend yield for these “20-year Models in Figure 1 is found by fitting data from 2003 to 2022 and then forecasting the yield for 2023. The slopes for each of the models also are reported in Table 1. For example, the 2023 model, based on data from 2003 to 2022, results in a 1.7 bushel per acre per year trend."
I have no idea of what the future will hold. Technology, time, and weather all change and have an influence on the results. 189 sounds way out there, but is it? Consider this:
"The 2022 state yield for Illinois was 215 bushels per acre, an all-time high, exceeding the previous high of 210 bushels per acre set in 2018 (see Figure 1). The 2022 trend yield — a projected yield based on a linear trend fit through the most recent 20 years from 2002 to 2021 — was 200 bushels per acre. The 2022 actual yield was 15 bushels above trend (see Figure 1), indicating that corn yields in Illinois exceeded expectations. Overall, 2022 was a good production year, although several recent years were above trend by more than 15 bushels including 2014 (33 bushels per acre above tend), 2016 (20 bushels), 2017 (19 bushels), and 2018 (23 bushels)."
https://farmdocdaily.illinois.edu/2022/12/corn-and-soybean-yields-in...
cheers
bryon
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Fast planting pace
