If you trade the grains or soybeans, Friday is a big day for you, even if you seldom look at fundamentals. The U.S. Department of Agriculture will release a series of reports Friday morning that generally simply tweak estimates that are already widely known. However, in this sensitive year with prices at record levels, even small changes in those reports could be very significant for the ongoing direction of prices. In fact, the surprise might be if the reports don’t have any surprises.

The first report is the final summary of 2007 production. Often, that just amounts to minor changes from the November crop report. This time traders expect it to show some reductions in yield and production for both corn and soybeans.

The second report provides the Stocks in All Positions figures, which is a clue to the rate of usage during the first quarter of the crop season for corn and soybeans. The first quarter is usually the biggest consumption period for corn and soybeans so it acts as kind of a gauge for the whole year.

The third report combines those two reports in the latest Supply/Demand estimates for the year. (The report really should be called Supply/Usage or Supply/Disappearance – demand and usage are two different things.) The crops appear to have some big usage numbers so far, and this report will put some numbers on how things are going. One number traders will be watching will be any significant changes in the end-of-season stocks or carryover estimates for this season. Those estimates should be getting smaller, if reports on exports, ethanol and other usage are correct.

Perhaps the biggest report of all on Friday will be the number of acres seeded to winter wheat. Prices have gone up – and down – rather dramatically since U.S. farmers began sowing wheat in September. How many acres were attracted to wheat by historically high prices? The average trade guess is a little under 49 million acres. If farmers fell somewhat short of that, it could send wheat prices to the $10 level again and could increase the area devoted spring wheat in the competition for acres with corn and soybeans. If farmers sowed more than 50 million acres, it could mean the highs are in. Historically, farmers haven’t often had a chance to sell wheat for above $5 a bushel, and with prices nearly double that, a lot of traders are thinking wheat has to be a short candidate at some point.

In addition to U.S. crops, other reports Friday will cover the world situation including the soybean area in South America and the outlook for Australia, China and elsewhere.

Friday’s reports shape up as a key marker on the path of 2008 grain and soybean prices, and the action could be volatile when the regular trading session opens at 9:30 a.m. two hours after the reports are released.