On March 31, the USDA will release two important reports, the Prospective Plantings and March 1 Grain Stocks reports.

A lot of discussion has focused on the Prospective Plantings report and the importance of farmers' intentions for total planted acreage and the acreage of individual crops. There has been less discussion of the estimate of March 1 grain stocks, said University of Illinois agricultural economist Darrel Good.

"Expectations for very small inventories of corn and soybeans at the end of the current marketing year put additional importance on the mid-year stocks estimate. The estimates will provide an opportunity to evaluate the pace of consumption that can be supported during the last half of the 2010-11 marketing year," he said.

Forming expectations about the level of March 1 inventories is limited by incomplete data on the consumption categories that are reported on a weekly or monthly basis and the lack of any ongoing estimates of feed and residual use of corn. The following calculations provide some context for forming expectations about the likely level of March 1 soybean and corn stocks and for evaluating the actual estimates when they are released.

For the December through February quarter of the current marketing year, the Census Bureau has reported estimates of the domestic soybean crush for December and January. Crush in those two months was 11.2 percent less than in the same period last year.