Follow the Field 2020 Update #9

Yep…still need some rain.

July 10, 2020 update:

Soybeans (79 days)

Slow and steady wins the race with soybeans. Last week, I talked about how just because they weren’t growing taller didn’t mean they weren’t progressing (as in, branching out and filling the gaps between plants and rows). These beans definitely felt taller as I was walking through the field and they’ve become much bushier, too.

See how the space between rows is almost covered? That’s important to maximize sunlight capture and to shade out any weed seeds that are hanging out on the ground just waiting to germinate.

Many of the flowers that bloomed starting a couple of weeks ago have been pollinated and have started to drop off. I *think* this is the beginnings of what will eventually be a soybean pod (that’s the next step in the reproductive process, anyway).

There’s not a whole lot more to report on the soybeans other than that they look really good given our current weather conditions. It’s been hot for the last week or so and really dry for the last several weeks. There’s been a little bit of insect feeding on the leaves, but nothing to worry about yet.

You can kind of see the haze from the rain clouds that were west of us as I snapped this photo yesterday evening. We did end up catching the storm that came through central and northern Illinois last night, but the farm got very little rain – maybe a couple of tenths. It’s crazy how isolated rain has been the last several days. This week, my house about 20 minutes away caught a downpour that lasted more than an hour and resulted in more than 2 inches of rain. I guess when you wish for rain, you have to include the address where you want it. 🙂

 

Corn (58 days)

Yeah, so the corn grew a bit over the last week. It was about chest-high at this time last week and is now taller than me (I’m 5’10”). That’s a 4-foot measuring stick out there.

Like the soybeans, the corn looks surprisingly good for how little rain we’ve gotten. I talked a little bit last week about how corn will “pineapple” and roll the leaves to conserve water, but the fields don’t seem to be exhibiting much heat stress quite yet, which is good!

Corn actually really likes this warm weather. Corn growth is measured using Growing Degree Days (GDDs) and corn hybrids (varieties) are classified by how many GDDs they need to reach maturity.

To explain this simply, we use a formula to determine the number of GDDs in a given day to help measure the potential for plant development. There are a few rules about the highest maximum temperature (86°F) and the lowest minimum temperature (50°F) to use based on what conditions corn will grow in. That formula is as follows:

• Daily Average Temperature (°F) = (Daily Maximum Temperature °F + Daily Minimum Temperature °F) / 2
• Daily Corn GDD (°F) = Daily Average Temperature °F – 50 °F

So if we wanted to figure out today’s accumulated GDDs, we would use the observed maximum temperature (or high) of 88°F and the observed (well, predicted in this case) minimum temperature (or low) of 64°F. And remember, the highest maximum temperature is 86, so we’ll use that instead of 88.

• Daily Average Temperature = (86°F + 64°F) / 2 = 150 / 2 = 75°F
• Daily Corn GDD = 75°F – 50°F = 25 GDDs

If you’re around central Illinois, you know we’ve had some very warm nights the last few nights with lows as warm as the lower 70s. So the corn has likely accumulated more than the average number of GDDs this week, which is good. (Still could use some rain!)

Seriously, look at that growth. Hard to see in the photo, but this plant has five leaves in development. As soon as one begins to unfurl, another begins to peak out. Some of the corn around here that was planted earlier than this corn tasseled this week, so I expect that this field will tassel in the next 10 days or so – maybe even by next week’s update.

Fingers crossed we get some chances at rain over the next week (and that it actually pans out)!