We expect late planting and subsequent dryness in some areas to be a limiting factor for corn yields. Maturity is about 2-3 weeks behind; in some cases more than a month late. We found few fields where grain development was past the blister stage, so August weather will play a more significant role this year. The areas with the best yield potential include northwest Illinois, east central Iowa, southwestern Minnesota, western Iowa and northeastern Nebraska.
East of the Mississippi, we found favorable yield prospects for most of east central Illinois, western Indiana and most of northwestern Ohio. The problem areas stem mostly from a higher proportion of very late planting. These areas include northeast and north central Iowa and western Illinois. Dryness during July has also had a negative impact on the crop in portions of central Illinois, where we actually found corn firing and below average ear size - at least in the earlier corn. Recent cool temperatures and timely rain will benefit the later corn.
Everywhere along our route we found higher ear counts than we have ever seen before. The average ear count for the trip was 30,500 per acre, up 3,000 from last year and well above our previous high (from 2011) at 30,200 per acre. Our ear-count data has proven strongly correlated with USDA’s, so we expect USDA to find higher populations as well as they survey for the Aug. 12th Crop Report. Rising ear counts are the main driver behind increasing yields over time. The high ear count will clearly have a positive influence on the 2013 yield estimate, assuming USDA finds the same.
The other yield factor is ear size, or grain weight per ear. Since the crop is late, ear development is behind normal, so judging grain weight is difficult. One variable used to determine ear size are the kernel rows, typically running from 12 to 20 rows per ear. Row counts this year averaged 15.9 rows per ear, which is near the long-term average. Last season our kernel row count average was low, at 14.9 rows per ear. (The high was 16.6 in 2010.) How well the ear fills will depend on weather the next 30-60 days. In the end, given the lateness of the crop, we would expect no better than average grain weight this year.
Doane’s national corn yield estimate is 161.2 bushels per acre. This is a few bushels below 2009’s record yield at 164.7 bushels, but with much higher acreage, production reaches a record 14.269 billion bushels, up 32% from a year ago. This is also 319 million bushels above USDA’s July production at 13.950 billion bushels, which tilts our thinking towards a bearish report.