Understanding corn stress and happiness on a new level

Brian Hornbuckle/ISU Agronomy: In the last 10 years or so, we've realized that this water in the plants in the crops could also be useful in telling us about what's going on with the plants. And so we've done some work and relating this satellite signal to the water and plants. And we had found out that, yes, we can see basically plants growing that as they grow and develop, they accumulate more water. And it turns out the satellite, the NASA satellite that we're using, makes measurements in the morning, and then again in the evening, at 6am. And at 6pm. The reason why we were interested in looking at water in the morning versus one that evening is for the following reason. We think that when plants are happy, in other words, plants are they have enough water to do the thing that they're made to do, which is to turn sunlight into the stuff that we harvest the food feed fiber fuel, that we harvest from crops, when they're happy, they do photosynthesis, which is this chemical process and leaves that turn sunlight and water into and carbon dioxide into these carbohydrates that we harvest in oxygen. To do that, they have to open little tiny holes in their leaves that we call stemmata. They have to open them up because to do photosynthesis, they need that carbon dioxide to come in to the leaves. Okay. Turns out though, when they open their stomata to pink in the carbon dioxide, water vapor leaks out. So, for plants to do photosynthesis and do what we want them to do, they have an A have to have enough water so they can afford to lose some water, when they're bringing in this carbon dioxide, spend a little to make a little band a little to make a little happy plants, we should see a difference. More water in the morning, less water in the evening. Stress plants, we should see the same. That's our hypothesis.

Paul Yeager: You know, the old eyeball test of looking at a field when you're driving by at four o'clock in the afternoon when it's really warm. That leaf really kind of curls under. And it always protects the moisture. And that's when we always think the crop is stress. But if this is way more than than than eyeballs here on these plants,

Brian Hornbuckle/ISU Agronomy: This is more microwave eyeballs looking at the plant now in a way that we can put a number to it. And so our hope is that we can look at number one, we want to we want to see if we can see this difference between morning and evening. And then our hope is that we could put a number on that and say, how stressed was that plant that day? And that could help us understand what are we going to get? In the fall when we harvest trees. If we had more stress,

Paul Yeager: You might understand. We had more you might understand that. That is that real stress in June or that week in July or that week in August is maybe why we lost 5% of our bushels per acre.

Brian Hornbuckle/ISU Agronomy: Because the plant couldn't open its tomato during that time because it didn't have enough water to do that. That's that's what that's what we hope to see. Now we're in the very early stages of looking at this. And we've only done this at three different points in Iowa so far. And we've looked at drought years versus non drought years. And we see a signal that is consistent with what we think we should see. But there's a lot more work here to be done to really make sure that we're understanding what the data says. But the exciting thing, I guess, Doc, go ahead.

Paul Yeager: Doctor, I'll ask you this. As we get towards the end of our discussion, if I'm a producer of a field, what am I hoping that your data allows me to change or alter my farming practices to better to be a more proficient producer of grain,

Brian Hornbuckle/ISU Agronomy: Right? So here in Iowa, we operate primarily rain fed systems, right? We're not doing any irrigation. So for the vast majority of farmers here in Iowa, we're now making decisions about should I irrigate or not? If I were in a situation like in western Nebraska, where your irrigation was a thing then this information would help you decide do I need to turn the irrigation on or not? Here in Iowa, potentially what we could use this information for, is to make marketing decisions. We can say, all right, I know there's been this number of water stress days. And I can use that information to say, Alright, I'm going to take this much of a yield hit when I harvest this fall, and that might help me decide whether or not I'm going to sell the grain that I've got stored right now or later, how might prices be like later on when I'm harvesting, I can look at what's happening in other areas in terms of the amount of water stress that's happened over the growing season. So this information will help you make some marketing decisions, not management decisions because we don't irrigate but some marketing decisions about what to do with your crop and the crop that you've got stored in terms of prices and things like that.

The full interview with Dr. Hornbuckle will be released Tuesday as part of the MtoM Podcast. 

contact: Paul.Yeager@iowapbs.org