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| in recent years ISU's resident bean guru ( Who jumped ship to join Syngenta last year) has been pushing very early planting and no more than 120K hoping for at least an 85K stand being the most profitable.
Last fall, Iowa Soybean Association's research guru put out a note that said he found more yield from 160K than from lower planting rates and indeed his raw data did show almost a bushel more than at lower planting rates.
A $13 bushel of yield might almost pay for 1/3 sack of $40 seed, but not $60 seed.
Palle Pedersen is talking profit, Tracy Blackmer is talking absolute yield and not much difference over the ranges of tests.
Seed cups work more on volume than a seed count and are not precise in these relatively costly seed times. They are more attuned to the days of planting a bushel to the acre than a count. (140K of 2850 seed to the pound makes a 56 pound bushel).
Best I can tell the penalty for planting the traditional 160K is seed cost and the benefit for cutting back to 120K or less is saved seed cost with little effect on the yield.
As for planting in early May, I must presume the guru has some magic scheme to prevent frost burning off the first planting. Last year in central Iowa, corn suffered from cold on Mother's Day. Beans would have suffered more, I think.
If you search this forum for "soybean population" you should find 40 or 50 discussions over the past couple years.
Gerald J. | |
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Soybean Population ?
