Follow the Field 2020 Update #5

June 12, 2020 Update:

Soybeans (51 days)

This field continues to green up as the soybeans get larger.

Check out all of that field cover between the rows! This is a combination of last year’s corn residue (stalks and leaves) as well as what’s left of the winter’s cereal rye cover crop. The cover does a great job at keeping weeds from germinating and helps retain some moisture in the soil for the soybean crop (as opposed to leaving bare soil exposed to the sun, allowing evaporation).

Since we’ve talked about soybean growth stages the last couple of weeks, I thought I’d show you a close-up on trifoliate leaves. To recap, soybeans put out leaves in groups of three, called trifoliates. We measure soybean vegetative growth based on how many sets of trifoliates a plant has. A field is generally evaluated based on the growth stage of the majority of the crop rather than the status of the earliest or latest plants (there’s always a little bit of variance based on seed germination, even though all of the seeds were planted on the same day). The photo above is an emerging trifoliate. The photo below is what the trifoliate looks like when the leaves unfurl.

You can see all of the leaves on this soybean plant in the photo below, and kind of make out the three sets of trifoliate leaves, a set of two leaves (the first true leaves on the plant) and the cotyledon, or the leaves that emerged from the seed when the soybean germinated. You can also just make out an emerging set of trifoliate leaves (lighter green and appear to be “sitting” on another leaf right on the center stem). This will be the fourth set of trifoliate leaves. I would evaluate this field to be solidly in the V3 growth stage, with the majority of plants having three sets of unfolded trifoliates. This field is also very close to entering the V4 growth stage, just as soon as the majority of plants open their fourth trifoliates. Some plants already have that fourth trifoliate open, but we evaluate the field based on the majority rather than the early or late bloomers.

Nothing much happening in this field other than a whole lot of growing. We missed most of the last two big forecasted rains in our area, so we’ll be wanting some additional precipitation before too long.

 

 

Corn (30 days)

I can’t believe that it’s been almost an entire month since we planted this corn. June has just flown by. And the corn doubled in size just this week!

This was a big week for the corn. They received their sidedress nitrogen fertilizer application and a post-emergence herbicide application, which will take care of any weeds that have germinated since we last sprayed the field before planting. This will eliminate weed competition to ensure that the corn is receiving all of the nutrients we just added with sidedressing.

Can you make out the straight lines of disturbed soil right between the rows of corn in this photo? It’s kind of difficult to see, but they’re slightly darker than the soil around them. You might even see a little bit of a “slot” in the soil. This is where the nitrogen fertilizer was applied directly into the soil. Corn needs nitrogen to grow – all plants do, in fact. If you’ve ever looked at the nutrient make-up of your household or outdoor plant fertilizer, you might notice #-#-#. The first number is the amount of nitrogen. The second is the amount of phosphorus. The third is the amount of potassium. These are what we refer to as essential nutrients. Corn needs this and so do soybeans. You probably already know this, but soybeans are a legume, which means they can fix their own nitrogen from the soil. We don’t apply nitrogen to soybean fields because they plants are already capable of obtaining it themselves. But we do have to apply nitrogen to corn fields. Our farm typically does this in a split application, either in the fall or just before planting and then again after the corn is about a foot tall. This second application is what I refer to when I say “sidedress.”

This is the sidedress applicator we used. Or one of them (the first one broke about halfway through). We borrow this from the company that supplies all of our fertilizers and pesticides. In the tank is a liquid that we call “28%.” It’s made up of 28% nitrogen and 72% water and is applied directly to the soil, near the corn root zone. If you look between the rows, you can see the openers that cut into the soil. If you look at the top of the photo, you can see the lines in the field where the nitrogen was applied in that little furrow.

The applicator is pulled by our tractor. As you can see, the space between the rows of corn is just wide enough to accommodate the tires of the tractor. We removed the duals, or second set, of tires from the back so that the tractor is just sitting on four tires (one on each side in the front and one on each side in the back) rather than six (where there would be two on each side in the back – “duals”) so that we wouldn’t run over any corn. For reference, our corn is planted in 30-inch rows. According to Dad, there’s about six inches of clearance on either side of the tire, although it really doesn’t look like that from inside the tractor. It’s important to run over as little corn as possible since breaking the stalk will kill the plant – it won’t grow back at all – and that means lost yield down the road.

And now we wait for the corn roots to intercept the fertilizer as it makes its way down the soil profile. It should give the corn a boost in growth and help it turn a deeper green color (the sun in these photos make it look lighter than it really is in person).