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Issue No. 22, Article 2/September 24, 2010

Soybean Harvest 2010: Time Is on Our Side, But Will Timing Harvest Remain a Challenge?

With last week's favorable weather, harvest for both corn and soybean started very rapidly. Rains last weekend slowed some people up, and rains this week could do the same. For soybeans, the USDA reported 87% turning yellow, 65% shedding leaves, and 10% harvested as of September 19. That puts the pace ahead of the five-year averages at 14%, 21%, and 5%, respectively. For many of the soybeans that are still not turning yellow, growing conditions have remained favorable to finish making good yields in most locations.

Low soybean seed moisture, and consequently seed splitting, was one of the most challenging problems for many growers last week, even though they had just started harvest. The best time to harvest soybeans is after pods reach their mature color, plants have lost their leaves, and seed moisture falls below 15% the first time. If conditions are aligned perfectly, you harvest between 12% and 14% moisture, and average about 13%. If you harvest under these conditions, plants will have maintained maximum physiological plant integrity, so loss of seeds to dropped pods, seed shattering, broken branches, and other factors is minimized. Also, you don't want to let seeds drop too far below 13% because no one likes to lose bushels (or dollars) by losing excessive water weight from the seed.

Maybe it's too early to tell, but so far it has been challenging to catch the best harvest timing this year. I've heard several complaints about seed moistures running between 8% and 10% last week. I have also heard that stems have been tough to cut. My program has harvested several research trials now, and these complaints have held true for us. We've harvested beans below 10% moisture that were mature in color and leafless, but the stems were "fleshy" or almost "woody" and very tough to cut.

The good news is that early yield reports have been favorable. Yields have commonly averaged between 62 and 75 bushels per acre in our trials harvested thus far. It has been difficult to assess whether this is truly a concern to share or just an artifact related to the earliest-maturing beans. Nonetheless, we're still in the last week of September, so I expect ample opportunity to select favorable times to cut soybeans over the next two weeks, which ought to help.--Vince M. Davis

Vince Davis

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