2019 Corn Companion Crop

Well, I feel a bit like a mad scientist at it again but here's the plan: I'm going to plant my corn on wide rows (44") then immediately drill a companion crop underneath to aid in weed suppression, nitrogen fixation, soil health, and grazing forage. This project is the result of several unsuccessful attempts in previous years, literary research, and a little advice from the master, Gabe Brown.

Our basic plan is to plant the corn then immediately drill the companion seed. Once everything is emerged we can lay down our herbicide and be done until harvest. After corn harvest we plan to bring in cattle to make use of the green cover crops mixed with the dry corn stalks over the winter. Then, come spring, we will remove the cows as soon as winter recedes to allow the winter wheat to recover and make the 2020 cash crop. If needed we can then spray herbicide on the wheat to terminate the companion crop.

The total seed blend for 100 acres was:
-9000 lbs winter wheat
-110 lbs phacelia
-55 lbs plantain
-100 lbs arrowleaf clover
-200 lbs crimson clover
-400 lbs common vetch
-400 lbs hairy vetch
-200 lbs alfalfa
-35,000 seeds/A corn (cash crop)

Our selection of plants was based on:
-grazing potential in the fall with the dry corn stalks
-short plants that would not compete with corn or impede harvest
-8 total species to promote synergy
-numerous legumes for nitrogen fixation
-flowering species for pollinators
-diversity for beneficial insects
-herbicide compatibility

For weed control the plan is to spray with Basagran to kill emerged weeds and Prowl H2O for pre-emergence control. This mixture will have to be applied after companion crop emergence so the prowl won't stop the companion plants from germinating.

A quick look at how I got everything seeded on this field. The photo is looking right down a planted corn row and you can see I decided to drill the cover crop perpendicular to the corn. My reasoning was mainly I didn't want a drill line to directly follow a corn row if seeded the same way and create excess competition. This also gives me another direction for the rows which should help retain my sprinkler water on the hillsides. Finally, going crossways with the drill is a much longer row so I didn't have to turn around so much.

So my concoction is sprouting. Thus far I am very pleased with the way things seem to be progressing.



This photo just happens to be on the edge of the field where the corn was seeded 8 days before the companion crop. The sprinkler is on its way for the first time to help germinate some of the dry cover seeds.

One of the fields with this mixture is gravity-irrigated. We pulled some shallow corrugates when we planted but after the drill went through we clearly needed better corrugates to properly irrigate the field. Also, pulling the corrugates after the drill had passed gave us the chance to toss the seed out of the corrugates to make a clean channel for the water to run the 1/4 mile.

We have the strangest looking corn field in the county, I think. It's very hard on my brain to see this every day and not go out with herbicide.

The corn is at V3 this week and progressing rapidly. In terms of competition we got our first round of tissue sample results back and all nutrients looks good so far. The phacelia (fern-looking plant in lower photo) and winter wheat is doing the most to create canopy so far but all species are growing. Nodulation on the vetch is very encouraging so far.

Well, the balance has shifted in the field a bit. The phacelia has done quite well in competing with the corn. Most of the other species have reached a plateau in growth and aren't a major concern at this point. Our weekly tissue sampling has also started showing nitrogen deficiencies in the corn, which you can see a bit in the photo with the bright green color.

After some discussion with a long-time cover cropper, I decided to use a little chemical to try and stunt the cover crop (mainly phacelia) to let the corn get growing again.



This is what the crop looked like out the sprayer window. The corn is clearly struggling and mighty scrawny for June 26. My chemical mix is Bentazon (Basagran) and crop oil.

The corn is slowly growing but the phacelia is keeping pace at this point. So far we have run some phosphorus, potassium, 30 units nitrogen, and some molybdenum through the water trying to get this corn to wake up. The sprinkler in the picture is applying another 60 units nitrogen since the tissue tests and visual signs show terrible levels.

Our attempt to stunt the phacelia was essentially a waste of time. A few plants showed a few brown leaves for a couple days but it quickly recovered.

That last big shot of nitrogen, along with some warm weather, seems to have the corn growing, finally. The color has improved and our tissue samples are finally looking better (far from optimum). I just hope it's not too late to make a crop this year.



The phacelia appears to have reached the end of it's run; it's flowers are drying up and it's starting to enter senescence.

As I was walking along the edge of this corn field today I noticed a few places where the crop was doing far better than other places. This one place in particular the sprinkler pauses for a little extra time and it certainly has made a positive impact on the corn (see left side of photo). The trouble is I don't know if it's the extra water or the nutrients in the water that have made this stark contrast.



There is one other spot in the field that has a similar line through it but it's not a location where the sprinkler pauses. My best guess as to the reason is a sea salt product we tried to apply but had extremely spotty distribution on due to some handling challenges. I will certainly be follow up on this idea in the future.

Despite the seemingly endless supply of downsides to this project, I would like to point out the actual weed population is very low. There are a few weeds here and there but no more than I would expect in a conventional field. Considering the only herbicide was glyphosate pre-emergence this is quite remarkable. There are a couple small pockets of kochia (less than 1 acre in 80) that are pretty bad but they didn't die with that glyphosate application so have been able to compete from the start.

A few final thoughts and photos for the summer on the progress. The winter wheat died during the peak of summer; not sure if because of shade or heat. Since the phacelia has long since matured seed it is slowly vanishing into the background leaving the vetches as the predominant cover. The clovers, alfalfa, and plantain are present but in relatively low volume.



Our corn crop has recovered somewhat from its dismal appearance in July. Even though it has gained some height over the cover it still has somewhat spindly stalks, small ears, small roots, and leaf necrosis.



Not only are ears small but they are a couple weeks behind on maturity for this date. Most ears I pull are of similar size which indicate about a 150 bu/A final yield. Not great numbers considering 225 is more typical here but at least it's something.



A look a what lies under the vegetative mat -- not quite as awesome as I'd hoped to see. The soil is surprising short of decaying bio matter on the surface. As you can see around the edges, there is plenty of dead material to come but it's not making contact yet. This probably explains the general lack of earthworm activity: not many holes or castings.

Although, now that I think about it I dug up a small hole near the corn row a couple weeks back and had 10 earthworms  in that shovel-load. The worms all seemed to be the same size (~1.5 inches) and focused around a root system (dead wheat if memory serves).

Well, harvest time has come and gone. The crop maturity delays this summer made the harvest much later (late November into December) than I anticipated but thankfully the weather cooperated. As expected, harvest was quite easy since the ears of corn stood above the canopy about 2'. I just set the combine header to skim over the top of the canopy and it easily got the corn.

Now the detail everyone asks about: yield. The corn did not yield well on the average, about 50% of an average crop out here. That being said, there were spots in the field where the corn did well all summer that yielded much closer to average. These spots make me think the companion crop concept has potential, we just need to work out the details.

With the corn out of the way, it was time to start phase 2: grazing. A cattleman was able to bring in 150 bred heifers for this project. After the perimeter was fenced with 2 strands of electric wire, the divisions are made with single strand electric. The cows are put in a paddock just under 3 acres in size for 2 days. then moved to the next paddock.



A few minutes after the cows are moved, they get spread out over the entire paddock and begin eating. From a distance the stocking density doesn't appear crazy compared to some "mob grazing" photos I've seen.



This is what the feed looks like before the cows get there.



And here is what the ground looks like when the cows have taken their fill. You may notice the corn husks, leaves, cobs, and smaller stalk parts are gone along with the cover material.



Thinking ahead to spring planting, I am very happy with the conditions the cows are leaving. They have eliminated the most troublesome residue for creating a seedbed (husks and cobs) so I think a light tillage trip to size the remaining stalks should leave the field ready for planting. Since the weather has been fairly dry and the cows get moved to new ground regularly compaction should be very minimal. This should be further mitigated once the worms come up in the spring to feast on the cow pies and surface residue.