Cover Crop Termination When Planting Green
Each year we receive questions on termination timing of cereal covers. This question occurs as farmers consider trade-offs between a positive return on investment from the cover crop, by allowing more biomass growth with the potential for yield loss if termination is delayed too long.
icon search Searchable Transcript
Toggle between list and paragraph view.
[00:00:01.235]This is Amy Timmerman
with this week’s extension update.
[00:00:03.899]A fall-planted cereal rye, wheat,
or triticale cover crop can have both
[00:00:08.556]positive and negative impacts,
for example by tying up nitrogen,
[00:00:13.086]reducing soil moisture prior to planting,
increasing insect pressure,
[00:00:17.086]reducing weed pressure,
reducing soil erosion and allelopathy.
[00:00:22.545]Each year we receive questions on
termination timing of cereal covers.
[00:00:26.545]This question occurs as farmers consider
trade-offs between a positive return on
[00:00:30.455]investment from the cover crop,
by allowing more biomass growth with
[00:00:34.255]the potential for yield loss if
termination is delayed too long.
[00:00:37.620]Information being shared can be confusing,
with one source saying to terminate
[00:00:41.620]pre-plant but other sources
say to plant green into the cover.
[00:00:45.740]What’s the “right” answer?
We don’t know if there is one.
[00:00:49.370]That’s because farmers’
goals and level of risk vary.
[00:00:52.700]In general, there are less risks to
planting green with soybean than corn.
[00:00:56.876]Today I am going to share items to
consider when planting green.
[00:01:01.053]When planting green consider
starting with number 1 -
[00:01:05.053]Apply nitrogen as a starter with
corn when planting green;
[00:01:08.553]nitrogen tie-up is perhaps a bigger
issue than any potential allelopathy.
[00:01:13.536]2. Wait for the corn or soybean
seed to begin germination before
[00:01:17.486]terminating the cover crop
(which may be a few days).
[00:01:21.546]3. Waiting to terminate a few days
after planting also allows the rye
[00:01:25.686]that’s been run over by the
planter to regrow and kill better.
[00:01:30.502]4. If irrigation is available, have
the nitrogen system ready to
[00:01:34.872]go prior to planting in the event you need
to add some moisture into a dry seedbed.
[00:01:40.071]5. Upon planting the field,
scout for insect pressure,
[00:01:44.511]particularly observing if any adult
wheat stem maggot flies are present.
[00:01:50.166]6. For those who wanted
the greatest amount of
[00:01:53.646]biomass for weed
suppression in soybean,
[00:01:56.225]termination of rye
occurred closer to heading.
[00:01:59.457]For those who plan to
roller-crimp rye for weed control,
[00:02:02.240]termination occurs at
boot stage to heading.
[00:02:06.279]6. When terminating a rye cover crop,
if the cover is 12 inches or more
[00:02:10.907]and you’re planning
on a residual herbicide,
[00:02:13.699]consider waiting on the
residual as a second pass
[00:02:16.269]over the rye after it starts dying.
[00:02:19.195]We realize no one wants
an additional pass or expense.
[00:02:23.005]Observation and research
show that less residual gets
[00:02:26.375]down to the soil when cover
crops are 12 inches or taller.
[00:02:29.815]How long one waits for the second pass
for rye to start dying will depend
[00:02:34.135]on the environmental
conditions each year.
[00:02:36.845]The other option if one chooses
to add residual when terminating
[00:02:40.446]is to plan on an irrigation or rainfall
event shortly after application
[00:02:44.446]to help move the residual
herbicide down into the soil.
[00:02:48.677]And finally, Risk Management Agency
Guidelines allow for planting green
[00:02:53.666]and are based on
“best management practices”
[00:02:56.407]for different zones and for
irrigated or non-irrigated ground.
[00:03:00.407]You can read more about this
at USDA’s Cover Crops site.
[00:03:05.367]This is for crops with a contract change
date of June 30, 2019, or later, beginning
[00:03:10.797]with the 2020 crop year and
including successive crop years.
[00:03:15.131]If you have additional questions
about terminating cover crops
[00:03:19.403]prior to planting please reach out
to your local extension educator.
[00:03:22.663]This has been Amy Timmerman
with Nebraska Extension
Log in to post comments