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By Staff | Mar 29, 2013

The USDA is using a 163.6 bushel corn yield in its working model for corn production this year. That would be a full recovery to a trendline yield from the drought.

ISU Extension Climatologist Elwynn Taylor sad that USDA has been putting out these early forecasts since the 1960s and they have been right four times in that period.

You never say never, but a full recovery from the 2012 drought in 2013 would be an anomaly rather than the odds-on favorite outcome.

Neither is it likely that the still unrelenting drought will be bad enough again to produce another 123 bushels-per-acre crop disaster like last year.

2013 corn yield results are likely to average somewhere between trendline and the drought extreme. Taylor has data that shows that it has taken two years to fully recover from a drought extreme back to a trendline yield. His work would be at clear odds with the USDA forecast model.

The epicenter of drought moved across the corn belt and after focusing its damage on the Eastern corn belt last year, it is now centered over Western Iowa, Southern Minnesota, Nebraska and South Dakota.

The existence of either El Nino or La Nina conditions in the Pacific impact the corn belt growing season. If there are El Nino conditions we have never not grown a trendline yield.

Droughts and weather extremes have been associated with La Nina patterns. The condition is tracked by the Southern Oscillation Index which is currently -1.3, which is neutral, requiring -8/+8 on the 90-day average to signal one of the two climate factors are in force for the crop season.

NOAA has now forecast that El Nino or La Nina is unlikely in the Northern Hemisphere this summer. That lowers the means to know with any certainty what kind of weather that we will get. Normal or average will not be enough with depleted soil moisture reserves.

The current drought is not as severe as in the 1930s, more resembling the 1950s drought period. Weather records show that the state of Iowa received 22.7 inches of rain in 1955 and 24.15 inches the next year in 1956.

The corn crop performed better here locally in Northwest Iowa in 1955 than in 1956. The reason is that both years’ rainfall totals are short of what was needed to grow a good corn crop, but they had good subsoil reserves going into 1955 that carried the crop through that year.

While 1956 saw slightly more rain, it started with depleted soil moisture reserves – just like 2012-2013 conditions. The absence of an El Nino weakens the USDA case for a trendline yield.

Taylor is now using 147 bpa as his working number and will revise it shortly after spring weather patterns form in mid-April. 2013 will likely be the fourth consecutive year for below-trendline. In my opinion, new crop prices already reflect a yield higher than Taylor’s.

Taylor is again pointing out that there is an 85 percent correlation between the weather in Arkansas during the month of March and what the corn belt gets during planting. Arkansas has been dry this month and Taylor said that the weather pattern driving that appears to be strengthening.

If so, the odds are against planting delays due to wet soils. It will take a lot of rain where we live to bring soil moisture reserves to the point of creating mud. Taylor forecast that recent wetter conditions will end when low pressure chases the high from the Gulf of Alaska.

I reported personal farm record corn and soybean yields in 2012, located in Clay County. That was due to 9 inches of rain in May filling subsoil reserves to start June with no day above 100 degrees during the summer.

Taylor said that it was assumed that corn roots would go 6 feet deep tapping two inches of water per foot.

Research, however, found that too much surprise, roots eight to nine feet deep with one dig discovering corn roots 9′ 4″ tapping into more soil reserves than thought possible to sustain crops.

Soil type determined drought staying power. Those reserves that saved some crops in 2012 have not been restored so there is nothing down there for the 2013 crop to go after. Taylor said that we are entering an 18-year period of volatile yields.

We have just come through an 18-year period of stable yields and the cycle going back 800 years in tree ring studies and 150 years of corn yield data suggests we will see up and down yields for almost two decades resembling the early 1980s.

There will be years that we hit trendline or better and years that we don’t, with more years falling short of trend-line than seen the past 18 year cycle.

Taylor summarized his outlook: Increase in harsh winters, less than full recharge, El Nino not probable, crop this year better than last, but not up to trend.

David Kruse is president of CommStock Investments Inc., author and producer of The CommStock Report, an ag commentary and market analysis available daily by radio and by subscription on DTN/FarmDayta and the Internet.

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