French term (edited): panneau r�cup�rateur

http://www.aces.edu/pubs/docs/A/ANR-1136/
Some drop spreaders have a calibration pan or tray that attaches beneath the opening at the bottom of the spreader. In this case, the operator simply connects the pan or tray to the spreader, fills the spreader with the actual granular product, and makes a pass over a given distance with the spreader open. The collected product in the pan or tray is then weighed. If there is no calibration pan or tray, the operator must weigh the product initially put into the spreader and then spread the granular product over a clean surface such as plastic or a concrete floor. The product is then collected and weighed, and that weight is subtracted from the initial weight to determine the amount that was applied over a given area. Use one of the following equations to calculate the rate of application, and compare that to the targeted rate.

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Note added at 55 mins (2005-05-18 19:21:27 GMT)
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That should of course read calibration tray