MSU Extension MI Ag Ideas to Grow With

 - Our next presenter we've got, Let's see, actually you know what? I wasn't even sure, oh yeah, great. You're on. All right, so from Purdue university probably in your outline for those of you who are looking at, you know, what the day is gonna be, we had Dr. Bill Johnson and Marcello Zimer and Marcello is gonna be here sharing with us some interesting technology specifically dealing with weeding, 'cause I know a couple of you had some questions about robotic weeding and things like that. So that is exactly what we're gonna hear about, so Marcello you can go ahead and share your screen and take it away. - All right, Thank you. Again my name is Marcella Zimer and I work as a weed science program specialist at Purdue university with Dr Bill Johnson. I'll be presenting today on the weed zapper technology and Bill is in the call as well so if you have any questions for either of us at the end, we'll be happy to take those. So again, we were sharing some of the knowledge that we acquired working with the weed Zapper in the past the growing season. This again is a collaboration with the University of Missouri, they're the ones leading this research. So my object for today's presentation is basically to explain briefly how the system works in case you're not familiar with it, discuss some of the applications of this system and some of the limitations of the system as well, and also presents some preliminary results from this multi-state study that we even conducted that's been led by the university of Missouri with Dr. Kevin Bradley. And just to make everyone happy today, I had both a Rand and the green tractor so nobody is gonna say that I have the wrong tractor here today. So first thing is how the system works, basically it's a fairly simple concept. We have a back mounted electric generator here on the back of the tractor that is attached to the PTO shaft to a belt driven system. So the generator is not directly attached to the PTO because that could cause some problems with the de generator itself. So there's a belt driven system that was gonna help to keep that system safe. Once the electricity is generated by the generator, its then transform from low voltage to a high voltage again there's a transformer here and the back as well. And when this unit's running there's a light right here at the top, they'll help you tell that... They'll let you know that the system is producing electricity at that point in time. Once the electricity is transformed to high voltage, its then run to the front of the tractor to a line to a front mounted room system which is basically a copper bar. And that copper bar once it has charge with electricity, its gonna come into direct contact with the weeds above the crop canopy as well. So again this is a technology that aims to control weeds above the crop canopy, you're not going to be able to control weeds below the crop canopy with this particular setup. The boom length can be anywhere from 10 to 40 feet in length and the longer it is, the harder it is to operate. So if you're trying to use a 40 feet boom, you're gonna have some issues especially if you have a fuel that has a challenge with topography, you might have to run it at the slower speed to make sure that you keep contact with the weeds but you're also not bouncing around all over the place not making contact with the crop either to prevent the crop injury. The company that develops this weeds zapper is also working on a design that can work within the rows, but I don't think they have that available at this point in time yet. So one thing to keep in mind as well is that the coulters, I don't know if you guys can see it here in the picture but the coulters will serve as the ground for the unit. And they also gonna have motion sensors for safety So as long as those coulters are running or they're moving the unit is transmitting electricity to the bar. As soon as those cultures stop moving, the electricity is gonna stop running to that bar as just an additional safety measure of this system as well. But that's not the only safety measure there's a bunch of controls that goes in within the cabin of the tractor here, and a lot of safety precautions that you have to check before you can turn on this unit. Now again how it works once the bar makes contact with the weeds, the electrical current is then transmitted to the plants stems down to the root system, down to about four to five inches deep into the soil. So we can get the roots of the plants as well and once the electricity is transmitted to the plant its gonna boil the water inside the plant cells and bursting the cell wall. So that's how it actually kills the plant is by forcing the water to boil, and that increases pressure within the cells and causes them to burst. And the plan response then will occur fairly quickly within minutes of application, this is one of those systems that provides a lot of instant gratification. If you like to see the results right away, that system will make it happen again within a few minutes after application, those plans are already starting to wilt. As you can see in this photos here, this is within a few hours after the application of the weed zapper. Now, let me try to show you guys a quick video here just to show how the system operates in the field. And this is footage that we had from a field, from one of our research trials here Lafayette Indiana in 2021. Basically we're looking into the weed zapper for control as a rescue treatment in giant ragweed. And let me just stop here for a second, as you can see here the culture wheels will make direct contact with the soil, and that will serve as the ground for the system as we have the copper bar here making contact with the weeds and providing that there's charge that goes through the plant and causing plants to die. Now here from a different perspective here, as you can see we have this middle line right here that brings the electricity or the electric current to the copper bar or boom system. It is important that we adjust the height appropriately, so we wanna be above the crop canopy but also making good contact with those weeds. If we don't have good contact with the weeds this system is not gonna work well. So again it requires a high differential between the Weeds themselves and the crop canopy. Also when operating the system the speed is very important, if you're running it too fast or when you take off that bar's gonna bounce around quite a bit. So it's important to operate this at a certain speed to make sure you're making contact with the weeds but that bar is also fairly stable. Now let me go back a little here, Now, again the effectiveness of the efficacy of the system is highly dependent on the moisture content of those weeds, so if you have weeds that are close to maturity they're gonna have lower water content the system is not gonna work as effectively, you need to have plans to have plenty of moisture so if you under a dry condition, in fact efficacy of the system can be reduced. Also for weeds like grasses and belle leaf, they naturally have a lower moisture content and generally those species are more problematic for control with the weeds zapper. As one disclaimer here, no graduate student was injured during the recording of this videos, we actually use a GoPro camera attached to the weed zapper to record this footage. All right, let me go back to the slides now. All right. So some of the applications of this system, one of the applications that we've heard about is using it for burndown and cover crop termination. I put a star by this because I believe that that can be complicated, especially in a burndown application you have lots of biomass. You may have to run that unit fairly slow to actually have decent control of those weeds. And the same goes for cover crop termination as well if you have lots of biomass, which is that's what you want with cover crops it can be challenging to get good activity with weed electrocution, but it can be used as an additional strategy. Again, if you did a burndown application or any other strategy of a herbicide and you have some scapes, maybe you could use the weed zapper as well to take care of some of the scapes before planting your crop. One of the applications that I think that the weeds zapper can work very well is for pasture weed control. Again, after the animals have grazed through a pasture field, there's a pretty good gradient between the weeds that aren't desirable and the crop itself. So it be fairly easy to run the weeds zapper to a pasture field after the animals have grazed. The only problem we could run into with using the weeds zapper and pastures is that if those plants are already close to maturity, they're gonna have a lower water content and maybe the effectiveness or the efficacy of the system will be compromised. So we'll have to make sure that those weeds are in a vegetative stage so they have plenty of moisture and that optimize efficacy of the weed zapper. There's a system that can also work fairly well for organic and conventional row crops, especially crops that have a short stature like soybeans for example, late in the season. That's when we have those late season weeds that grow above the crop canopy and using the weed zapper there can be very effective in controlling those weeds and preventing them from producing seeds. For crops like corn for example, corn is a crop that can grow very tall fairly quickly, and that would be challenging to control weeds above a corn crop because they just so tall so quickly. Now some of the weed species that can be controlled in this system include several broad leaf species that problematic because of herbicide resistance, including giant ragweed, the pigweed species like waterhemp, Palmer and redroot pigweed, marestail, thistles, and even a couple grasses, including johnson grass and foxtail. However the efficacy in grasses can be not as great sometimes, especially because most of the grassy weeds they're gonna have most of their biomass below the crop canopy. So it can be a challenge to actually make good contact with that vegetation to get a hundred percent control of those weeds. So grasses can be a little challenging when it comes to using the weed zapper. Now some of the limitations again of this technology one of the main ones is that the weeds need to be above the crop canopy, you cannot control weeds within the row. And like I said this company, the company that designs the weed zapper supposedly is working on a enter row unit that you can control weeds within in the road. There are other companies out there that already have some systems like that as well, but that's not the focus of the conversation today. But again if you are waiting for weeds to be above the crop canopy, at that point in time you already compromised your crop yield, you're not gonna recover the yield that was already lost due to competition. So that can be problem or a limitation of the system. Another limitation is that again the efficacy is highly dependent on plant moisture content. So if the crops is, if the weeds are close to maturity, they're gonna have a lower water content. Also, if you're going into a drought or a dry spell, those plants are also gonna have lower moisture content, and you're gonna have more of a hard time controlling the weeds using the zapper. One bullet point here are some of the conversations we had with the researchers in Missouri. They indicated that the system can also initiate some fires, if you have a significant amount of dry plant residue in the field, especially if you had a cover crop that you terminated or before planting, and then you are using the weed zapper as a post emergence treatment. If you have a lot of dry biomass in the ground and maybe you are going into a dry spell, that can cause the potentially problems with some of that biomass catching on fire. So that's something to keep in mind. And also we have reduced efficacy on grassy weeds, Some of the recommendations if you're trying to control grasses is to use a slower speed or maybe use multiple passes. This system also have different settings according to the weeds that you're trying to control. So there's a setting for grasses, a setting for broad leaf weeds, and they have a setting for low weed infestations. So if you have a field with a very low weed pressure you can reduce the power on the unit as well, because you don't want those plans to explode as they are contacted with the weeds zapper, You want the current to go all the way to the root system before those plants actually explode. So if you have too high of a charge, the plant that above ground biomass may explode but those roots are still alive underneath the soil surface. And another limitation again is the speed of operation. Again, these systems are not autonomous When it comes to the height of the boom, that's something that the operator needs to take care of. So if you're trying to run the system faster at a high speed you're gonna have the boom moving around quite a bit and that can be a challenge for keeping appropriate contact between the weeds and the crops. Now, I wanna share some of the research results from this multi-state study that we conducted in partnership with the University of Missouri, with especially led by Dr. Kevin Bradley, and one of his graduate students, Jacob Bond. So the objectives of this study were first to determine the efficacy of weed electrocution on different weed species and also evaluate the effect of different tractor speeds across North Central region. The other objective was to compare the efficacy of weed control weed rescue treatments with other alternative rescue treatments that are available in the market. So for data collection, we collect the visual ratings for weed control at seven and 14 days after treatment and also at the end of the growing season, and we also collect the seeds from the soil surface following harvest of the crop, but I'm not really gonna talk about the seed collection right now, I'm mostly gonna focus on the weed control ratings. So these are the results for our weed location here in Lafayette, that's the location that we actually established all the other locations with all the weed species were established by the University of Missouri and other collaborators, but for giant ragweed as you can see here in the picture within an hour after treatment, those plants are starting to wilt already. Again this is a system that provides very quick results in terms of weed control. Again, you can get some instant gratification. You can tell exactly where you use this technology fairly quickly. Now if you look at results 14 days after application, we have the non-treated control here on the left. And one thing that I forgot to mention is that we actually use inter row cultivation a few weeks prior to this experiment. So we control most of the weeds between the soybean rows, but we still have a bunch of weeds growing within each one of those soybean rows as well. So at 14 days after the experiment was established, we see that the non-treated control is almost taken over by weeds. If you look at the weeds zapper at miles per hour and also at five miles per hour, we can see that we have very good activity of the weeds zapper on giant ragweed about 90 to 95% control. And again, that was very impressive for us. We also compared that with rope wick application with one pass of dicamba, and we see that dicamba and the rope wick system was also very effective. Giant ragweed weed is very sensitive to dicamba herbicide maybe even more sensitive than soybeans themselves, so the rope wick was very effective at controlling giant ragweed. And these results slides are actually from the University of Missouri They were nice enough to share these results with me. These is some of the research that they presented at the North Central weed science meeting in the center of 2021. These are the results for the giant ragweed site, and as you can see for giant ragweed control the weed zapper for both three miles per hour and five miles per hour was very effective. About 90% control of giant ragweed seven days after treatment as seven days after treatment though, the rope wick with dicamba only provided about 75% control of giant ragweed. And that is because dicamba is a synthetic auxin herbicide. It works slowly so at seven days after treatment a lot of those plants are still alive, but if you fast forward to the end of the growing season, we can see that the weed zapper maintain its efficacy but the one pass of the rope wig application was actually close to a hundred percent control giant ragweed. So even though we didn't see that initial response as good as we saw with the weed zapper, at the end of the growing season we had almost a 100% control using dicamba and rope wick system. Now, if you look at the other amaranthus species, other pigweeds, including waterhemp and Palmer, there was a few locations where they studied the effect of the weed zapper on waterhemp and palmer and there was a wide range of results here. We see that in Illinois, we had only about 10 to 15% control waterhemp and other locations we had as much as 80% control, kind of a similar story for palmer amaranth as well. And according to Jacob one of the reasons that we saw such low control of waterhemp in Illinois is because this was the first location where they ran the weed zapper in 2021. And there was not much of a high differential between the soybean canopy and the waterhemp plants. So they were not able to get good contact with those weeds and that's one of the reasons likely why the efficacy of the weed zapper was so low. So it might be a little bit of a high differential problem there. The weeds probably were not tall enough, but also maybe waterhemp and palmer are not as great candidates for weed zapper, they may have lower moisture content compared to giant ragweed. Also if you look at the plants, giant ragweed has a lot of foliage, a lot of large leaves close to he growing point that might promote more contact with the weed zapper. But if you look at water hemp and Palmer amaranth, they not necessarily always have a lot of biomass on the upper part of the plant. So maybe the contact with the boom was not as great as it was for giant ragweed. Similar story for velvetleaf this was a weed that was only tested in Nebraska in 2021, they also tested a few treatments with dicamba as opposed emergence for comparison. And you see that the treatments with dicamba and glyphosate were very effective in controlling velvetleaf leaf, but all the treatments where we use the weed zapper a post emergent treatment, we only have anywhere from 15 to 30% control of velvet leaf at the end of the growing season. And velvet leaf it seems to be one of those weeds that's more problematic for using the weed zapper, it has lower moisture content, it has a lot of fiber, so it may not be a good candidate for using this technology. Especially as it gets close to maturity. And these results here is looking at the end of the season control for all species across all different sites where they tested, the weed zapper in 2021. And as you can see in giant ragweed was the one that we saw the most efficacy for the weed zapper system, Palmer and waterhemp was a little vulnerable, might be due to the high differential that wasn't there in some of those locations and for giant Foxtail and velvetleaf again, those weeds have lower moisture contents. And in the case of giant Foxtail most of the time, the vast majority of the plant biomass is below the crop canopy. So it'd be harder to get good contact with the weed zapper boom for giant Foxtail and other grasses. So just to summarize here, what we learned from this research is that the first point is that the speed of electrocution didn't seem to affect the efficacy of the weed zapper at least in the research trials that we conducted. But again we only tested at three and five miles per hour, I'm sure if we had tested the system at seven, nine, 10 miles per hour, maybe we've seen some different results as we run that unit at a faster speed, we gonna see more variability of results. About the efficacy was highly influenced by weed species, again it goes back to water content and plant structure. If you have a lot of foliage close to the top of the plant, you're gonna have better contact with the unit and is gonna result in higher efficacy. And the one thing to keep in mind with using the weed zapper is that you need sufficient high differential between the weeds themselves and the crop canopy to get good control. And that goes back to you have competition up to the point that you use the weed zapper. If you use the weed zapper late, you're gonna control the weeds So you're not gonna recover the weed potential that you lost, but it's still a great strategy for reducing the seed bank for the following growing season. This is mostly what I have for today, again this is my contact information and Bill's, and I'll be happy to take any questions you might have. - [Girish] All right. Thanks Marcello. So everyone feel free to go ahead and drop your questions into the Q and A. And if you haven't opened the Q and a, there's actually been several questions asked and answered already. Bill was working in the background to answer some of those. So while folks are coming up with their own, I'll just start plugging you with some that I came up with along the way. So I've heard from a folks looking at vegetable systems that it's often requiring maybe two, three, or even four passes. So how many passes do you think let's say in a soybean operation, how many passes were to be required? And how easy is it to assess the efficacy of, you know, how that first pass did? How do you know that you need more passes than one? - Right? Yeah, I think that answer really depends on the weather conditions too that year. Some years you get one flush and then it turns right and we don't get a second flush of weeds. And also how much you wait to do that first pass, you know, if you do a pass right after those weeds just passed the crop canopy, you might still have some weeds there below the canopy that will need a second application soon enough. But again if you wait too long, you're already losing yield as well. So it's a tough situation sometimes you have to evaluate how much of an infestation you have and if it's worth waiting or not for that first pass. - [Girish] So is there a time when the density of the weeds is too high, you just don't have enough voltage generated. So, you know, if you have that differential in the weed and the crop canopy and you're going through, can you essentially overtax the weed zapper so that you're not getting good kill? - Right. From what I've seen, the answer if you have had infestations that you have to run slower. So it's just one of those things you can probably still get through the field, but you might be running a fairly low speed. You have to compromise the speed to get a good activity if you have a very dense infestation. So might have to run to two miles per hour or something like that. It really depends on how heavy it is and what ways there are, again for grasses it seems that you really need to slow down because you don't have as good contact with the foliage as you get with some of the broad Leafs like giant ragweed. - [Girish] So again folks, I'm just gonna keep going through my questions. I'd rather answer yours. So go ahead and put your questions in the Q and A Does dew or rain on the leaves either help or hinder the weed control with this. - So that's a question I actually asked for the researchers at Missouri, and they say that it doesn't seem to be that big of a deal. Again you have installation from the tires and stuff like that. So it's not like you gonna get electrocuted if there's due in the field or anything like that. And a little bit of moisture is actually probably better than not having any moisture and being too dry. So I guess as long as it's not too excessive from what I heard from Missouri, it should be fine. - [Girish] I've still got no questions in the Q and A, so I guess I'll ask one more. Is there a certain ratio required of horsepower per with the boom or kinda what's the minimum horsepower required to run this? - So I've seen some resources from the company old fashioned manufacturing, they're the ones that make the weed zapper and they send a recommendation or something between 150 to 255 horsepower for the PTO. And that's just so you can run the units in having infestation without like taxing your system too much. So, but again that's outside of my expertise with the equipment, but that's some of the resources that I found. - [Girish] Well, Thank you, Marcello and Bill for sharing with us today. Really appreciate that was really interesting. - Thank you.