No. 24 Article 8/November 11, 2005

Looking for Volunteers for On-Farm N Rate Trials

While we have more N rate response data from Illinois trials than any other state has, we need data from more and better-distributed trials to better support the recommendations. We are thus asking producers in all parts of the state to carry out N rate trials using field-scale plots and equipment. Our goal for 2006 is to have at least 100 on-farm N rate trials in Illinois.

We have applied for funding for this work, but we will not know until early spring if it is available. We would use funding to provide a stipend to each producer to cover the loss of yield due to N deficiency in the low-rate strips, and also to partly compensate the effort. For now, we are asking for volunteers to run such trials with the understanding that funds may not become available. If we are unable to get funding, those who lay out trials this fall and do not want to continue can delete the trials by applying N next spring.

Doing such a trial is not complicated if the equipment is available to place rates precisely and to record yield data. Here's a rundown:

From our experience with the WATER plots, we estimate that with average-sized strips, the loss of yield from lowered N rates will be less than 100 bushels for the whole trial. Some of this might be compensated for by yield gains at the higher N rates (the average N rate is only 100 lb/acre, which means a little less N expense as well). Trials where corn follows corn will often lose more yield than this, and if we get funding the stipend will be larger to cover that difference. Strips typically need to be at least 12 rows wide (maybe 8 rows in rare cases), but making plots only 500 ft long will mean less yield loss than with longer plots. It is possible to apply rates only half of the way down 1/4-mile rows, then use the normal N rate for the rest of the length, marking the rate change either with GPS or flags.

If you are willing to conduct a trial, feel free to lay it out and apply N rates as indicated above. Please contact me if you are doing a trial and I will send a short form that we'll need to put each trial on our list. Either a yield monitor or a weigh wagon will be acceptable for taking yields next fall.

If you might have interest in doing a trial but would like to talk about it first, please email me at or call 217-333-4424. We will be working with several seed and fertilizer companies on this project, so we may put you in contact with one of them. We probably can't handle a dozen such trials clustered within a county or two, especially if that means not having trials in some areas of the state. So while we might not be able to support all trials with dollars, we will certainly welcome all data. Within reason, the more data we get the better, and every corn producer in Illinois will benefit directly from this effort.--Emerson Nafziger

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