I spent my day off riding in the combine noting what is going on in the fields. One of those combines I got to witness a grower attempting to harvest downed corn. Not just time consuming but a real depressing activity. Every time we hit the area down the yield monitor dropped 40 bu/acre and if we reversed direction it was even more dramatic. The best method was to push into the corn the opposite direction the corn was down. The soybeans are dry and the decision is to stay on corn or switch to soybeans. Here are some numbers that might surprise you.
It only takes 2 kernels of corn per foot to equal a bushel per acre loss. Four beans per foot to equal a bushel per acre and just 14 per foot with Barley to equal 1 bushel per acre loss.
With soybeans three Midwest universities found that once soybeans were fit in late September with a moisture content of 13% in a matter of 10 days of wet weather in early October losses as high as 20% were recorded by researchers. Further 85% of those losses occurred before the beans entered the combine!
Iowa State found that cutting height differences from 6 inches down to 3.5 inches accounted for an addition 3 bushels of beans in the bin.
A USDA study in four Midwest states found total losses from delayed harvest for corn tripled from 5% to 18% from October to December harvest.
When harvest is in full swing time is essential. There is an abundance of research to support slowing down and being sure that the crop is not lost simply due to manageable factors. With soybeans once the plants have ninety five percent of the pods a mature brown color (R8) they are only 5 to 10 days away from moistures below 15% and are the least likely to escape the combine due to shatter loss. If you are one of the many growers that wait until after high moisture corn is combined to start soybeans you might well be sacrificing a significant portion of your soybean yield. In a field last year I supervised a soybean contest harvest that was 75 bushels per acre in late September. My variety test plots were directly across from the contest harvest and we cut those soybeans in late October and got 51 bushels per acre average for all entries. One of those entries was the same variety as the contest yield. Lodging and shatter losses accounted for nearly a 25 bu/acre loss in yield from delayed harvest.
Supervising numerous 5 acre corn club harvests over the last 12 years I have seen a drastic improvement in harvest losses. The Bt corn entries that result in almost no down or broken plants have eliminated those harvest loss potentials. I have noticed, however, that since the corn stands better some growers have increased combine speeds and with those increased speeds more ears get knocked off before entry into the combine and more kernels can be found in the fodder behind combines. Read the manual on the combine and achieve the proper capacity for the combine and try not to push the limits. By understanding the key losses in corn and soybeans growers may ensure more grain gets into the bin and maximize income. Check out my blog (http://cmegicmlebanon.blogspot.com )that contains some pictures and video of one of the harvests.