Friday, February 12, 2016

Looking ahead to 2016: The Weather

At nearly every farmer production meeting this winter, speakers have been addressing the unprecedented El Niño event occurring in the Pacific Ocean. Data for El Niño and La Niña events have been collected by the National Oceanic and Atmospheric Administration since 1950 and can be found at This El Niño is as strong as other previous events that occurred during 1997-1998, 1982-1983, and 1972-1973 (Figure 1). I heard one climate extension specialist describe this event as the "Godzilla" of El Niño cycles. He further went on to describe the North Pacific Ocean "Blob" where the warmest observed sea surface temperatures are occurring since record keeping began in 1950. Certainly the data is extraordinary.

Figure 1. Cycle of El Niño events as measured by the Oceanic Niño Index (ONI). Data derived from

I was curious about how El Niño and La Niña events affect Wisconsin corn yield. In Figure 2, I superimposed Wisconsin corn yield data on to the cycle of El Niño events in Figure 1 and added a trendline to the yield data. Since 1950, we have had 6 years when yields were significantly lower than the trendline (1974, 1976, 1988, 1992, 1993, and 2013). Three years, 1974, 1976 and 1988 were "drought" years that were associated with strong La Niña events. However, there are numerous La Niña events where there was no effect on yield and often yields were above the trendline. For the remaining low yielding years, "cool and wet" conditions best described 1992 and 1993, while a "drought" best described 2012; there were no significant El Niño/La Niña events associated with these years.

Figure 2. Cycle of El Niño events as measured by the Oceanic Niño Index (ONI) versus Wisconsin corn yield. Red circles are lower yielding years not related to El Niño/La Niña events. Blue circles are lower yielding years related to strong La Niña events.  Data derived from and USDA-NASS.

I then went one step further and plotted U.S. corn grain yields on to the cycle of El Niño events (Figure 3). The red and blue dots in Figure 3 are the years when Wisconsin had significantly lower yield from the Wisconsin trendline as shown in Figure 2. Only two years, 1974 and 1988 were associated with La Niña events. While Wisconsin had poor grain yields in 1976 and 1992, the rest of the country had trendline and record yields. No strong El Niño/La Niña events were associated with lower U.S. corn yields during 1993 and 2012.

Figure 3. Cycle of El Niño events as measured by the Oceanic Niño Index (ONI) versus U.S. corn yield. Red and blue circles are lower yielding years in Wisconsin.  Data derived from and USDA-NASS.

I do not see much association of Wisconsin and U.S. corn yields with El Niño/La Niña events (Figures 2 and 3). Some years line up, but many do not. It seems like equal odds for above and below trendline yields. The weather outlook on January 31 is forecasting a drier and warmer summer than normal (source:

So from a crop management perspective, how should we plan for 2016? Most agronomic recommendations are based upon multi-location averages. Agronomists collect data and input responses over numerous sites and environments and develop recommendations accordingly. These recommendations are good places to begin as you implement practices in your farm management. Even though the El Niño/La Niña events are unprecedented, I would not change my management style much. Plan for an average year and if the weather is good we can take advantage of it.