Tips for monitoring emerging crops

WATERVILLE, Ohio — Scouting emerging corn and soybeans provides both a chance to determine that crop’s current needs as well as guidance to correct any mistakes next year.

“Get out and scout. When everyone starts sidedressing and spraying is when my phone starts ringing because that’s when a lot of farmers are back in the field for the first time after planting, aside from maybe some roadside scouting at 50 mph,” Mike Hannewald, Beck’s field agronomist, said in a recent episode of The Dig.

“Take the time, get out there. Maybe when it’s wet and you can’t be out in the field, just walk the field quick, take your shovel along, look underground.”

Here are Hannewald’s recommendations of what to scout for, from emergence to root development and early stress signals.

On Root Digs

Allow enough time for the crop to get out of the ground. Many times I’ll get a call that corn and soybeans have uneven emergence.

We have to have 100 to 130 growing degree units for corn or soybeans to emerge. So, just make sure that you’ve actually had those GDUs.

If we have a cooler spring, it sometimes takes a little bit longer and the corn or soybeans shouldn’t be out of the ground.

Always carry your shovel when you’re scouting because what’s going on below the ground is just as important as what’s going on above the ground.

One of the reasons I really like to carry a big shovel into the field is not only is it easy to dig things up and easy to check your roots, but just how you put the shovel in the ground can tell you a lot.

I like to have the shovel put in the ground and have the row running in front of me and as I push the shovel into the ground and pull back on it watch what happens.

That corn seed slot can tell you a lot about what you might see in your roots later on. If the slot splits perfectly down the line and you start to see some hatchet roots or some roots that have some restricted growth, it might have been a touch wet when you planted.

Pay attention not just when digging it up, but how does that soil react to you shovel. That can tell you a lot, as well.

On Corn Emergence

First, look at the overall appearance of the plants and as we’re looking down the row we want to have consistent spacing, that picket fence stand.

But we also want identical plants because ideally we want those corn plants emerging all at the same time within hours of each other.

I’m much less concerned about variability from one area of the field to another. The corn plant doesn’t care about what’s happening 100 feet away from it. It cares about what’s going on right next to it.

So, inconsistency across the field, no big deal, but inconstancy within a row is a problem. There’s not a lot we can do at that point, but there are things to learn about our planter for next year.

On Early Development

I’m going to start looking at what’s the overall condition of the corn plant and what’s the plant telling us.

As an example, if we have a V4 corn and can see yellow striping on the leaves, this is one of the most common nutrient deficiencies that I see out in the field and it tends to be sulfur deficiency.

It could also be manganese deficiency, the symptoms are the same, but every time we check it with a tissue test, 95% of the time it’s sulfur deficiency.

Something that we’ve seen really good results from in Beck’s Practice Farm Research is applying sulfur with your starter fertilizer to help alleviate that.

You might see some purpling in the corn. That can tend to happen when you have warm, sunny days and cool nights. That plant has kind of a defensive mechanism to slow its growth as we get through that cold period.

On Early Warning Signs

As we get to V4, V5, you might start to see some of those early season diseases show up. Dig the plant up, knock as much soil off as you can and then take your knife and split the stalk lengthwise and cut right down through the crown.

We’re then able to look at a cross section of the crown and the plant. At the plant’s crown, we’re looking for a yellow to cream color or white and that’s a very healthy crown. The corn plant is susceptible to crown rot from V2 to V7.

If we get excessive rainfall in saturated soils for an extended period of time, we might start to see the crown turning brown and start to rot in there. That can potentially be problematic and we’d want to hit it with an early fungicide in that case.

The other thing is if we start to see the mesocotyl start to turn brown, that might be a case of some pythium.

There are some other seedling diseases that might impact. In that case, there’s not a lot we’re going to do about it. Our seed treatments offer pretty good defense against those, but it just becomes a race.

Can the plant grow faster than what disease develops? As long as the plant outgrows the disease, most of the time it will be just fine.

The other thing is a corn plant is going to go through a phase where if it has any stress it’s going to struggle a little bit.

When we get that V2 to V4 time frame, the plant is transitioning from living off the seedling and the seedling roots to living off of the nodal roots. Any kind of stress there might be exaggerated just a little bit.

That’s why I think we’re seeing some sulfur deficiency a little more exaggerated because those nodal roots aren’t fully engaged yet. So, don’t panic if you see a little bit of stress at that point.

On Early Treatments

If your farm soils that are perennially wet and that extended period of saturated soils is common, a product like Xyway fungicide is going to be a great choice. We’ve seen good results in our PFR Proven and that’s going to help protect the health of that plant.

If you don’t put Xyway on or if you’re seeing crown rot after your crop is already up, hitting it with a V5 fungicide like a generic is not a standard practice we recommend, but that’ll help in this situation.

On Soybean Emergence

Evaluate the soybean roots. The way to tell if the nodules are firing and production nitrogen is to split the nodules in half with your fingernail or pocketknife. If you see a rusty, reddish orange color, it’s nodulating.

If the inside is tan like the outside of the nodule, there’s nothing wrong with it — it’s just not fully developed. If it’s starting to turn green or dark brown, that tells you it’s failed.

When we’re looking at soybeans, we have a good stand of VC or V1 soybeans and they just kind of sit there for a while and there’s really slow growth before they get to V3.

I call it the ugly yellow phase. It’s not a technical agronomy term. It’s just what I call it because that what it looks like. The soybeans are kind of a pale green color and they’re just sitting there for like two weeks.

That’s something that’s very common. Don’t panic when you see it, just come back a week later and the soybeans will probably look a lot better.

What’s going on is that’s the time period when soybeans are forming the nodules that are producing the nitrogen.

That’s a really stressful time for the soybean plant because it’s usually deficient of nitrogen at that point, it’s struggling to find what it needs in the soil and it’s putting so much energy toward building and developing nodules for the bacteria to eventually colonize and start producing nitrogen.

On Early Soybean Diseases

Soybeans, just like corn, are going to be susceptible to diseases, especially if they lay in cold, wet soils for a long period of time.

Basically, you look for any discoloration, brown color of the lower stem and the roots. Again, it’s a race.

Can the soybeans grow faster that the disease develops? It’s going to come down to what are the soil conditions that we’re experiencing, the temperature and such.

Our seed treatments give us great protection on soybeans with multiple fungicides, but that seed treatment is full strength for about two weeks and then we get partial strength for about six weeks.

Farmers are pushing to get soybeans planted earlier and earlier which is great because we’ve seen really good results from that, but sometimes we’re asking a lot of our seed treatment to last that long. So, basically you’re looking for any brown discoloration and an actual rot of the stem.