Farmers in the northern Corn Belt, mark your calendars for the last Thursday in February, the third Thursday in May and the first Thursday in July.

Over the past 18 years, these have been profitable times to market corn and soybeans.

By using futures and options to sell on those days, a typical northern Iowa grower with 1,000 acres could have increased his average annual net return by $18,000 or more during that period.

Using data analyzed by a computer simulating an average northern Iowa 1,000-acre farm, Bob Wisner, Iowa State University extension grain marketing economist, has developed strategies that clearly illustrate historically profitable times to sell.

By using his marketing-by-the-calendar strategy, coupled with Crop Revenue Coverage (CRC) crop insurance, growers can solidify their marketing programs, says Wisner.

With the still-new farm program, producers can't wait for the best harvesttime price and deficiency payment checks to make up for a bad price year, reminds Wisner. Like it or not, they must learn marketing techniques, then use them to develop selling strategies.

Mayday! That's not a distress call, although farmers could drown in their tears if they by-pass Wisner's third-Thursday-in-May pricing time.

"We asked our computer to find a profit-maximizing combination of marketing strategies," he says. "For corn, the optimum strategy was to cover 80% of the farm's 16-year average yield by buying at-the-money December put options on that day, then adding another 10% with hedge sales of December futures the first Thursday of July.

"For soybeans, the numbers recommended that 90% of the long-term average production be priced at planting time using 'synthetic puts,' in which November bean futuresare sold, and at-the-money November calls are bought."

Wisner's May recommendations are based on December corn futures contract price patterns. The contract's highest prices fall between early May and mid-July about 75% of the time. November soybean futures normally peak about the same period.

Buying December corn puts in May establishes a floor price. If prices rally due to drought or other bad growing conditions, the corn is still open to upside price potential.

In the soybean synthetic put, selling November futures locks in a price. Buying call options will also enable the producer to take advantage of a summer price rally, if it should occur.

In most years, if crop problems are going to push prices higher, indications of trouble begin to show up by early July. Wisner's analysis showed some additional advantage from selling futures on another 10% of growers' corn and the remaining beans projected for harvest the first Thursday of that month (Wednesday if the fourth falls on Thursday). The remainder of the crops were sold at harvest in Wisner's simulated farm.

These pricing dates aren't the guaranteed high-price dates of the year, and there's nothing magic about the exact day.

"But history says the odds are in your favor to price at these times," says Wisner.

However, in years when the previous crops were below total domestic usage and exports, earlier pricing on December corn or November bean futures typically adds to profits.

When short crops occur, prices often increase at or just after harvest. That often creates an increase in production the following year. So earlier hedged forward sales of new-crop corn and beans have a long history of being advantageous.

"For both corn and soybeans, returns have been substantially increased by shifting the pricing to hedge sales of harvest-delivery futures on the fourth Thursday of February in years following a short crop," he says.

He points out a phenomenal near 90% track record for this strategy.

"Almost every year following a short crop, late-February pricing has generated much higher returns than harvest sales," he says. "One exception was the 1975 crop, when highly unusual world developments pushed fall prices above February levels. Other exceptions were the start of World Wars I and II. Management analysis indicates buying out-of-the-money calls can help deal with that type of market situation."

Wisner's research revealed that, from 1979 to the mid-'90s, harvesttime cash corn sales on his O'Brien County simulated farm produced a $76,144 return over variable costs. The optimum pricing strategies brought $85,964, a $9,800 better return. For 1996, cash sales produced a return of $105,190. But by applying the marketing-by-the-calendar strategies, the same crop would have yielded a return of $133,540.

For soybeans, the overall cash sales from 1979 to 1994 averaged $70,504, compared to optimum pricing returns of $79,416 - $8,912 more.

"Together, the corn and beans produced better than an $18,700 return over harvest cash sales."

In normal marketing-by-the-calendar years, the same strategies used in southern Iowa would have worked 63% of the time for corn and 75% of the time for soybeans, due to more years of lower yields.

"Average returns over all years in southern Iowa were greater than those from strictly cash marketings. And the marketing strategies should also work well in other Corn Belt regions."

Wisner adds that this pattern could change if enough farmers change their marketing practices.

CRC offers growers yet another mechanism that can help build confidence for marketing. Growers can take CRC for 65% or 75% of their average yield at a cost of $8-20 per acre, depending on their location. They can set a minimum CRC corn revenue per acre, based on 95% of the December futures price or a soybean price based on 95% of November futures.

It can be done in February or November for corn, or February or October for beans. February prices set the minimum revenue, with the guarantee moving up to fall prices if the market strengthens.

In figuring a northern Iowa corn farm in which yields average 144 bu and December futures are $3.10 in February, a 75% CRC would ensure $318 per acre, ($3.10 x 0.95 x 144 x 0.75). If a bad crop year yields 80 bu, and futures rise to $4 in November, the insured coverage jumps to $410 per acre, ($4 x 0.95 x 144 x 0.75).

If the actual crop value is $304 (80 x $4 x 0.95), the insured benefit is $106, plus any additional price increases made with marketing moves.

"Those concerned about production risk should consider incorporating crop insurance with optimum pricing," Wisner concludes. "It can also help boost their confidence level for preharvest pricing."