It's almost time to till under the red clover we planted last fall with winter rye to plant brassicas as part of our ongoing crop rotations. Farmers across the country have been taking advantage of the benefits of adding red clovers to cereal grain crops like wheat and triticale harvested for grain, for some time now. They often fly red clover seed into standing soybeans or frost seed it into winter cereals but for whitetails we can add it at planting time in late August.
Now...by early July the red clover is nearly knee high and keeping our deer happy!
So what now? How best to take advantage of the tons of biomass and 100+ pounds of nitrogen that red clover can add to our soils? There are options for everyone regardless of equipment or lack of it with some providing slightly more benefits then others.
Farming crop systems are slightly different then ours of course because crops are harvested, combined, baled or grazed so agricultural links on this subject have great information, all of which however is not applicable to food plot/whitetail management situations.
The quote below holds some valuable information and comes from this ISU publication:
Cereal Grains and red Clover
There are many options for managing red clover as a
green manure crop, including tillage and chemical control
in both fall and spring.
Plowing red clover provides about
two times more nitrogen to a subsequent corn crop as
chemical control.
Zone tillage of clay loam soil following
red clover has produced corn yields similar to conventional
tillage. The high nitrogen content of red clover residue
accelerates the decomposition of cereal crop residue.
There are several advantages associated with autumn
chemical kill of red clover before planting no-tillage corn,
including earlier planting dates, warmer soil conditions,
reduced risk of dry seedbed conditions, and reduced
likelihood of clover competition with early corn growth.
Red clover residues decompose rapidly after spring kill
with half of the nitrogen released within 4 weeks after
burial and very little nitrogen released after 10 weeks.
When red clover is killed before planting, nitrogen is
released from residue in synchrony with the nitrogen
uptake pattern of corn.
Delaying kill of red clover from
fall until spring does not increase nitrogen availability.
Killing red clover in the fall or early spring can be effective
for limiting soil water loss without sacrificing benefits to a
subsequent crop.
Two key elements to consider here are that tiling the red clover under will in the end provide more nitrogen for your brassicas then chemically killing it and no-tilling into it. Looking at the time frame in which nitrogen is released from the rapidly decomposing clover we see that it is perfect for short season brassicas! If we plant 60-90 season brassicas the 10 week time frame is ideal to help provide at least a portion of the nitrogen our brassicas will require.
By this time the rye will be starting to mature and dry down (turn brown) if it was left standing and regardless if mowed or plowed under the decomposing root systems will also release scavenged nutrients for the following crop.
Rye and red clover
Lacking a plot many small plotters will find that they will need to mow the clover and rye to chop/shred it to a manageable height and then you have the option of no-tilling brassica seed into the stand and killing the clover with 2 quarts of glyphosate or discing/tilling it under to conventionally plant your brassica seed.
It is not necessary to completely turn under all of the clover/rye to have a successful brassica planting, doing so however does increase the available N as we see in the above quote. The ability of the soil to hold nitrogen is of course another factor in all of this so increasing the organic matter is extremely important and work towards that end every time we incorporate crops like clover and rye back into the soil.
Higher OM content also increases the ability of the soil to hold water and nutrients , versus very sandy soils for instance that allow rapid leaching of both water and nutrients. That being said, each of us has different soils so the need for additional nitrogen will vary widely...those with deep, rich black loam soils will probably get by with less then those with coarse sandy soils for instance.
Those of you who can see the value in planting multiple crops within each field and then rotating those crops yearly will want to experiment with additional nitrogen applications. I prefer to till in urea at planting rather then take a chance on catching a rain to incorporate it later so you may try marking off areas and applying urea at different rates to check the brassica response. What you learn may yield answers for future plantings on that soil type. If the ares you apply lower rares appear to suffer compared to the higher rates you can always broadcast additional urea on later (just time it within 24 hours of a good rain!)
If you are following white or red clover with brassicas this year...try varying rates of added nitrogen and then share the results so that others can learn as well.... :way: