The Georgia Farm Monitor published a YouTube video news story this week about corn planting in North Georgia, which is finishing up now. The link to the YouTube video is here.
The story featured an award-winning farmer in Dawson County north of Atlanta, who won an award in 1973 for the first farmer in Georgia to get 200 bushels per acre on his non-irrigated, no till farm there. His fields are bottomland almost perfect for growing corn, and he takes care of them carefully. The weather has cooperated with their farming over the years, allowing them to receive several more awards for their yields.
What can this farmer and others across the Southeast expect for corn yields this year? AgroClimate provides some guidance about yields in their County Yield Statistics tool. You can find it at http://agroclimate.org/tools/County-Yield-Statistics/. It breaks down yield statistics by El Nino phase; the results for Dawson County are shown below. The statistics show that in all years the yield is about 65 bushels per acre, in neutral years the yield is about 72 bushels per acre and in El Nino and La Nina years corn yields are down to about 58 bushels per acre for the county as a whole based on NASS statistics.
Another way of looking at it is using the AgroClimate regional yield maps at http://agroclimate.org/tools/Regional-Yield-Maps/. In this set of maps they use detrended yield data to eliminate the rise in yields over time due to improved seeds and management techniques. If you hover over your county of interest, a small graph showing the differences in yields by El Nino phase is shown below. Looking at the residuals of crop yield after the trend is removed, it is clear that El Nino has pronounced decrease in yield compared to La Nina or neutral years. Yields are down about ten percent from what is expected in El Nino years. Since these are just statistical relationships, the cause of the decrease cannot be clearly pinpointed but may be due to the wet conditions present in an El Nino year or some other factor.