# Cover crops and residual herbicides



## mlappin (Jun 25, 2009)

So have noticed something this summer while spraying beans, with the wet spring we had we fixed a lot of tile and added more in some spots while waiting for things to dry out. Where we added it got disced level afterwards, fixed spots just got graded off level, either way had bare dirt.

When spraying burndown for beans we use Resist (generic Canopy) and 2-4d, when spraying RU now for cleanup have noticed the spots that were bare when spraying burndown are as clean as a whistle while where we had cover crop its like we never sprayed a residual. Can the cover crop tie the residual up so it never makes it to the ground? This is really apparent in the last few fields we sprayed burndown on that had a two foot tall cover crop. If so what is the workaround? The clean spots are also void of any mares tail as well.


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## endrow (Dec 15, 2011)

, I am not going to have the answer you're looking for, but I could guess maybe the rate of canopy you used was sufficient for Bare ground but possibly a higher rate was needed for the cover crop. I do not have a lot of experience with canopy but I know with most other residual herbicides they have an organic matter chart somewhere on the label. Quite often then it tells you to increase the amount of product for higher organic matter.


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## mlappin (Jun 25, 2009)

Issue is too much then the cover crops we fly on in September may suffer.

We base the rates on soil tests far as organic matter, not sure how to even guesstimate the OG with live cover crop.


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## haybaler101 (Nov 30, 2008)

Just the opposite here Marty. Where I had a good stand of cereal rye, beans are perfectly clean. On fields that I didn't get a stand of rye, water hemp and marestail have been a serious issue even with residuals. In fact, I have two passes of Liberty on those beans now.


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## mlappin (Jun 25, 2009)

Weird, cereal rye on a few of these fields was thick enough we almost gave it a shot of nitrogen and left it for seed.


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