Based on Corn Belt weather, how drought tolerant is your corn?

Have you been overworked emptying your rain gauge?  If it is like many around the Corn Belt, there is no need to investing in a self-emptying rain gauge.  It would not have been tripped even the first time this year.  So the departure of La Nina, which brought us dry conditions in 2010 and 2011, has left us with similarly dry conditions in 2012.  While much of the Corn Belt begins to accumulate yellow, tan and brown colors on the Drought Monitor, one begins to ask about the capability of current corn hybrids to tolerate drought.  They are getting plenty of experience, whether a drought tolerance gene has been bred into them or not.
The dry years have provided an opportunity for researchers to analyze corn yields to determine if they are any more tolerant of drought than they used to be.  And the results are intriguing. Ag economists Scott Irwin and Darrel Good at the University of Illinois compared the Texas corn yield in 2011 and the Argentine corn yield from this past growing season. 
In Texas, corn is typically irrigated, which over time has kept yields within 10 bushels of the trend yield.  However, the summer of 2011 was so overwhelming to crops, even the irrigated corn yield fell by 33% below the trend line.  The researchers say, “The drop was due to the extreme drought conditions in Texas last year, which were so severe that many irrigations systems simply did not have the capacity to keep up with the water demand of the corn plants. This is a dramatic demonstration that modern corn hybrids are still susceptible to very hot and dry conditions.” 
When Argentine corn production is examined, there is no irrigation so the 2010 and 2011 provide comparison to the recently-harvested crop.  The researchers report the Argentine summer of 2012 produced corn that was 24% below the trend line yield.  They said, “One can argue that this drop is even more relevant to the debate regarding drought tolerance since Argentine corn production practices are comparable to those in the U.S. and the hot and dry weather conditions in 2011-12 that occurred in Argentina were not as historically extreme as those that occurred in Texas last year.”
While the economists say corn is still subject to drought, they needed to normalize the yield with the weather, and compared the yield in the various crop reporting districts in Illinois with any variation in summer heat or moisture.  If the temperature or moisture were dryer or warmer than normal, they looked at yield results within the past decade, when hybrids may have begun to show any degree of drought tolerance.  They found a 4.4 bu. improvement in yields in dryer and warmer years, which represented 3% of the trend yield.
The economists say, “The take home message from this analysis is two-fold: 1) U.S. corn yields are likely somewhat less susceptible to drought conditions than in the past; and 2) a Corn Belt-wide drought would still lead to sizable yield reductions relative to trend.”
With a dry summer shaping up for the Corn Belt, your corn crop yield will be better than it would have several years ago.  While drought still has a negative impact on yield, typical yields in dry and warmer yields in the past decade are 3% better than would have been expected based on trend yields prior to the past decade.
Source: FarmGate blog


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