Ag Weather Forum

Variety in El Nino Yields

By Bryce Anderson , DTN Ag Meteorologist and DTN Analyst
The 2015-16 El Nino compares favorably to 1972/73, 1982/83 and 1997/98 -- with big differences in yields. (USDA graphic by Scott Kemper)

Another national farm convention/show, another set of questions about El Nino/La Nina in the Pacific. That's the way the Commodity Classic weather discussion transpired last week in New Orleans, Louisiana. But, there was an addition to my info rundown this time, thanks to the USDA think tank. USDA meteorologist Harlan Shannon did an El Nino discussion during the Ag Outlook Forum in late February, and one of the charts from that slide set dovetailed well with my main points. (That chart is the illustration for this blog entry.)

The graphic illustrates the various swings of warm (El Nino) and cool (La Nina) Pacific temperatures going back to 1950. Looking at the graphic, it's easy to see how the 2015-16 El Nino compares with other El Ninos in the past 63 years. There are only three other times when the Pacific has gotten as warm as the 2015-16 El Nino. They are: 1972/73, 1982/83, and 1997/98.

What we're looking for, of course, is: "How did crop production do in the second of the two-year period mentioned?" Those years are: 1973, 1983, and 1998. And what we find is that there were both good and not-so-good years represented.

In 1973, corn production totaled 5.67 billion bushels, and soybean production totaled 1.55 billion bushels. Corn yield was 91.3 bushels per acre, down about six bushels an acre from 97 bpa in 1972. Soybean yield was approximately 26 bushels per acre.

In 1983, corn production totaled 4.17 billion bushels, and soybean production came in at 1.64 billion bushels. Corn yield was only 81.1 bushels per acre, 32 bpa down from 113.2 bpa in 1982. Soybean yield was 23 bushels per acre. (NOTE: 1983 yield was definitely down, but production was also skewed by the government instituting the Payment-In-Kind, or PIK, program, which in an attempt to draw down grain surpluses, also brought on a giant reduction in corn planted acreage. But, mid- and late-summer weather was brutally hot and dry after a very wet spring.)

In 1998, by contrast, production was bountiful. Corn production totaled 9.76 billion bushels, and soybean production reached 2.74 billion bushels. Corn yield, at 134.4 bushels per acre, was almost 8 bpa more than 126.7 bpa in 1997. And the soybean yield at 36 bushels per acre was also higher than the previous year. The 1998 soybean crop actually was a record for the time.

Do these numbers from the record book offer any definite insight into how 2016 will play out? Well, no they don't. But a quick review does suggest that two out of the three years following a big El Nino maxing out did have yields that were lower than the previous year. That's why I have made a point of discussing yield prospects for 2016 in the context of trendline quite possibly being the maximum that we will see at harvest.


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Bryce Anderson 3/8/2016 | 1:52 PM CST
There is also a comment out in the ag media universe saying that the Australia Southern Oscillation Index (SOI) in 1983 had begun going to Neutral by this time. That is not correct. The monthly SOI in 1983 looked like this: January -31.4; February -35.7; March -25.7; April -15.5. In those months, the Pacific ENSO was described as "consistently negative". The 3-month Oceanic Nino Index (a temperature parameter) also stayed well above the threshold of -0.5 degrees Celsius for El Nino classification until the May/June/July period when it went to Neutral for the rest of the 1983 year. 1983 and 1988 acted completely different from each other in terms of Pacific conditions.
Bryce Anderson 3/8/2016 | 8:05 AM CST
You may note that the 1987/88 El Nino to La Nina occurrence is not included in this rundown. That's because the '87 El Nino was much weaker relatively speaking than the four other episodes looked at--especially this year's El Nino. By this time in 1988, the Pacific had already gone neutral and was on its way to La Nina.