The Geography of Exceptional Soybean Yields

Originally published in FarmDoc Daily

From 2013 to 2018, U.S. soybean yields have been above trend in all years, with an average yield-above-trend of 3.7 bushels per acre. States have had different experiences with above trend yields. Six states had an average yield-above-trend of over 5.0 bushels per acre. Four states had average yield-above-trends of less than 2.0 bushels per acre. The geographical patterns of state yields are described in this article.

Above Trend Yields for the United States
In the December Crop Production Report, the National Agricultural Statistical Service (NASS) reported the average U.S. soybean yield for 2018 as 52.1 bushels per acre. This 2018 yield is the highest, being just a bit higher than the 2016 yield of 52.0 bushels per acre.

Figure 1 shows U.S. soybean yields reported by NASS from 1980 to 2018. Also shown are trend yields. In this article, a trend yield is based on a linear regression using the 40 years of data previous to trend yield. The 1994 trend yield is based on the forty U.S. yields from 1954 to 1993. The 1995 yield is based on data from 1955 to 1994, the 1996 yield used data from 1956 to 1995, and so on. This procedure causes each trend year to be based on the same amount of data. Note further that trend yields are not declining in recent years. If anything, those trend yields are increasing.

Read full article here: https://farmdocdaily.illinois.edu/2018/12/geography-exceptional-soybean-yields.html