Aug 19, 2010
U. S. Corn Yields May Decline From August Crop Estimate
Author: Michael Cordonnier/Soybean & Corn Advisor, Inc.
It was no surprise that last week's August Crop Report indicated large production estimates for both corn and soybeans. Everything was in place to produce large estimates, but the estimates last week just might end up being the largest of the growing season for the following reasons:
- The report talked a lot about the record early planting pace for the corn. This is already factored into the yield estimate and the planted date can't change. In subsequent reports, the planting date becomes less and less important.
- The report indicated the second highest ear count on record. The crop is so advanced that there can't be any more ears added in subsequent reports. In fact, the high temperatures may result in some of the weaker ears being aborted by the plant.
- The report mentioned the high crop ratings as a factor in the yield estimate. In the states where the corn crop is doing very good, the ratings are at historic high levels and for all practical purposes; the ratings can't improve from their current levels. In the hotter and dryer states, the corn ratings very likely will decline, which could weigh on subsequent yield estimates.
- The final ear weights are yet to be determined for the corn crop. There is an inverse relationship between the August temperature and the eventual kernel weights. The higher the August temperature, the lower the kernel weights. With the temperatures that have occurred thus far during August, I am expecting that the ear weights will be lighter than normal in the eastern and southern Corn Belt. On the other side of the equation, the ear weights should be at least equal to normal in the western and northern Corn Belt.
- The corn is advancing in its maturity at a very rapid pace, too fast in fact for the plant to fill the kernel properly. In the fields where the crop has matured prematurely, the kernel and ear weights could end up being lighter than normal.
- In many fields it appears that the corn crop has run out of nitrogen due to leaching or denitrification earlier in the summer. That is the probably the cause for the firing of the corn plant that is evident in many areas across the Corn Belt.
- The report indicated that the corn harvested acreage is unchanged from the June Planting Report, which cannot be the case at all. Some of the corn was drowned out after the survey was conducted, so therefore, the eventual corn harvested acreage will be lower than what was reported in the August Report. The USDA did not adjust the harvested acreage because they did not have the data necessary to make the adjustment. The data should be available for either the September or October Crop Report.