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| Misnamed, should be Iowa GYPSUM Trials, 2009, despite ponds.
Its not that big a deal to adjust N application rates to compensate for AMS as the sulfur source and that would have eliminated one confounder, that of need for or the existence of excess calcium.
There is way too little detail to allow trust in the report, which denigrates the paper its printed on. There is neither good nor consistent measurement of yield, there is no way to judge the control of the application, no indication of fineness of grind or application machine. A truly fine grind won't spread uniformly with a spinner, nor will there be an abrupt edge to the spread. Judging by the coop involved this trial (and I use that term with reservation) was conducted in the swamps and ponds of southern Story County and Northern Polk county in a very unusual weather year where many a field was drowned out by persistent and recurring ponds. And its only one year. There were no pre application soil or tissue tests to show a NEED for S or Ca. Then because the yield monitor results were so varied (in my field the yield monitor varied from near zero in the ponds to about 240, sometimes in less than 200 feet distance) they were adjusted and averaged with a statistics program. And there is no comparison of yield monitor to weigh wagon to hint at yield monitor calibration.
Replications were tolerably adequate.
The researchers should be ashamed of this document and should withdraw it, even if the sponsor wishes otherwise.
Gerald J. | |
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Iowa Sulfur Trials, 2009
