Judging by questions we all are getting this spring, clearly we are having some growing pains managing cover crops across Tennessee. Indeed the 2^nd most common question I have gotten over the past month is how and when to burndown a cover crop “X“ before a cash crop “Y”.

In general folks have had good luck burning down cereal rye and in most, but not all cases, wheat.  The covers that most have had trouble controlling before planting have been blends ranging from the NRCS blend to homemade ones of say vetch blended with wheat.

What we have learned is that (1) if tillage turnips do not winter kill it is nearly impossible to control them with a herbicide, (2) glyphosate is not an effective option to control most of the canola used for cover and 8 to 10 ozs of dicamba mixed with the glyphosate offers little help for canola and (3) a sequential application of glyphosate applied 7 to 14 days before planting followed by Gramoxone at planting is the most effective control option for blends of cereal and vetch covers.

Despite some of the struggles we have had with cover crop termination this spring there are two pieces of good news.  First the covers have done a great job keeping horseweed in check. Moreover, as thick as many of the covers have become they should help a lot on Palmer amaranth as well.  Second, in the years ahead when we have labels in hand to use dicamba on Xtend crops or Enlist Duo on Enlist crops we will have much more effective options to manage cover crop blends than we do today.  Based on our cover crop research where we integrated cover crops before Xtend soybean as an example we were able to effectively terminate thick cereal rye and vetch blend with one application the day we planted as well as separate treatments where we terminated 7 and even 14 days after soybean planting. Delaying cover crop termination to PRE or 7 or even 14 days after planted in our research greatly increased the Palmer amaranth control the cover crop could provide.