Microgravity Drip Irrigation: Innovative Way to Get “More Crop Per Drop”

Water scarcity solutions, especially those solutions that allow for continued food production while reducing water use, are a critical component of coping with reduced water availability now and into the future. We interviewed Dr. Manoj Shukla about a current research project of his using microgravity drip irrigation technologies from Israel on an experimental farm in Southern New Mexico.

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Transcript

Sarah LeRoy: Welcome to Come Rain or Shine Podcast of the USDA Southwest Climate Hub and the USGS Southwest Climate Adaptation Science Center or Southwest CASC. I'm Sarah LeRoy Science Applications and Communications Coordinator for the Southwest CASC. 

Emile Elias: And I'm Emile Elias, director of the Southwest Climate Hub.

Here we highlight stories to share the most recent advances in climate, science, weather, and climate adaptation and innovative practices to support resilient landscapes and communities. 

Sarah LeRoy: We believe that sharing some of the most innovative forward thinking and creative climate science and adaptation will strengthen our collective ability to respond to even the most challenging impacts of climate change in one of the hottest and driest regions of the world.

The contents of this podcast are for informational purposes only, and should not be interpreted as endorsement for any of the products, technologies, or strategies discussed. 

Today we are speaking with Dr. Manoj Shukla, professor of Soil Physics in the College of Agricultural Consumer and Environmental Sciences at New Mexico State University. Dr. Shukla began studying innovations in water use efficiency about 10 years ago with curtailment of Colorado River Water to some irrigators last year, this topic is critical and timely. Water scarcity solutions, especially those solutions that allow for continued food production while reducing water use are a critical component of coping with reduced water availability now and into the future.

In his current research project, Dr. Shukla is applying irrigation technologies from Israel on an experimental farm in Southern New Mexico. If these technologies prove promising as they seem to be so far, then they could be helpful across the arid Southwest and even in the eastern part of the United States, where more farmers are choosing to irrigate their crops.

Dr. Shukla, thank you for joining us today to talk about the novel irrigation options you are investigating. Perhaps you can start us off by telling us what microgravity drip irrigation is and how this system is different from conventional drip irrigation. 

Manoj Shukla: Thank you, Sarah. Thank you for having me and providing me this opportunity to talk about the new system, which we started working with in 2020, right when the Covid hit.

And at that time there was the whole lot of discussion about should we start with this project or not? And, and we thought that, you know, Covid might be just a temporary phenomena of two or three months, so we decided to go ahead and, you know, start that project, but we never regretted it. We are really happy that we, we did that.

So with regard to the microgravity drip irrigation system, just as the name suggests, it is a system where water flows through the drip tapes due to gravity. And we do not need any extra pressure or energy or pump, so it only flows because of the gravity and we are able to irrigate the crops. Now the system has been developed by a company from Israel.

The name of that company is N-Drip, N-Drip Solutions. And they also have a head office in Phoenix, Arizona from where they are able to cater to the most of the state here. And plus they have very good, efficient service. So, you know, they often visit us here in Las Cruces and in other parts of, of the country.

So if I have to tell you the main difference between the microgravity, drip irrigation system and the conventional drip system, then I will say that in a conventional drip system, you have to have a pump you have to have a filter, and then you need electricity connection. So there has to be power right at the farm. Since microgravity system works with only gravity, and therefore, you know, you only need like a tank, a small tank where you can create a head.

And as long as that head of water is a little bit more than a foot, about, you know, 36 to 40 centimeters, that water is enough for irrigating most crops.

Sarah LeRoy: Excellent. Thank you. Could you also give us an overview of the work that you've been doing at New Mexico State University using microgravity drip irrigation?

You know, what are you studying and what have you found so far?

Manoj Shukla: I, I think this is a very important question for us also to answer. So, you know, as I told you earlier that we started working with the microgravity drip irrigation system in 2020. And what we did with that we got all of the system components from the N-Drip company for free, and we installed it at the New Mexico State University's Leyendecker Science Center.

And what we did, you know, we took a 2.5 acre of field and we divided it it into two units. And in one of the unit we planted about 108 pecan trees. So they were all one year old pecan roots. And then on the remaining unit we planted 16 rows of chile. And for 2020 and 2021, we grew chile. And in 2022, and this year in 2023, we are going to we have, so 2022, we, we chile replaced by the silage corn and we will continue with the silage corn this year.

Now with regard to your question, that what exactly we are trying to study. Let me just very briefly tell you that it's a common knowledge that we have a severe water problem, especially in the Southwest United States and also in Southern New Mexico. And what is happening is that, you know, we are under severe drought and therefore surface water availability for irrigation has significantly decreased.

 Now in order to grow crops, you have to provide water. So if there is less surface water available, you have to pump more from the groundwater and therefore to, to sustain the agriculture in the valley. And, and as well as to sustain really the human life here in the valley. We have to utilize, there is no option but to utilize our water more efficiently.

So, you know, we have several objectives for this study. One of the major objective was to create a site for outreach so that, you know, there has to be a place with this new technology where these stakeholders can come and see the system in action. And simultaneously, if they have any questions or concerns, there are people who can address those questions and concerns.

Our second objective was to demonstrate that microgravity drip irrigation system actually works for both tree crops, for example, pecans, because you know, the Southern New Mexico is a pecan country. We have at least 60% of our agricultural land is is with pecans. And therefore we wanted to show them that, you know, the trees actually survive using this system.

We planted 108 trees and we only lost two. 106 trees came back the next year. So that was the thing that we want to demonstrate that it works for both row crops as well as the tree crops. And our third objective was to demonstrate the increases in the water use efficiency of the row crops. So we have you know, done this, shown that chile production is, can be sustained and maintained at the same level, even using much less water.

Emile Elias: Excellent. Thank you so much. I'm curious about why you chose to switch from chile the first two years to silage corn more recently. Was that just part of your experimental design or was there another reason? 

Manoj Shukla: Yeah, yeah. This is a good question. So generally, crop rotation is a better alternate for sustaining productivity of production.

So, you know, if you go chile, chile, chile, chile, then you know, you do not maintain the productivity levels and that is why, you know, just as part of the rotation, we went with chile and corn. 

Emile Elias: Excellent. Thanks. That was just something that came up as you were talking. I'm also curious about the economics.

So as I understand it, this microgravity drip irrigation system you've been working with has substantial cost savings over a regular drip irrigation system. So am I correct in that and can you say a little bit about that?

Manoj Shukla: So, you know, let me definitely tell you here that I'm not an economist, so. Means, you know, but still, you know, whatever discussions I had with the N-Drip company, because this is a question which is being asked almost every time, you know, we are talking to the reporter or talking with, you know, growers or stakeholders generally what I'm told by the N-Drip company.

That the installation cost of a microgravity drip irrigation system is around $900 to $1,000 per acre for row crops. However, with the tree crops that number goes down to close to $700 to $800 per acre. Now when you compare this to the conventional pressurized drip irrigation system, that system can cost you anywhere from $2,500 per acre to $2,800 per acre.

Emile Elias: Excellent. So based on the company's analyses and, and that you know about, and some of those estimates, there could be a considerable cost savings, potentially. Great. All right. So I'm also curious about some other possible benefits of using this type of irrigation system as compared with conventional irrigation.

Manoj Shukla: So, you know, so far from our result what we have seen, that when we were growing chile what we did, you know, we had, we divided our 16 rows into two sections of eight rows each. And, you know, the eight rows were provided irrigation, which, which was equal to the reference evapotranspiration for that week. And the other eight rows, we are provided 80% of the reference ET.

And in both the scenarios we saw that chile growth and the yield, they were either similar or even higher as compared to a furrow irrigated field located in Leyendecker Science Center. But if you look at in terms of the water application, we applied anywhere from 150 millimeters to 200 millimeters less water than compared to a furrow irrigation system.

So, and, and we do believe that, you know, there is more opportunity to even more reduce the water use and still get the same type of yield. A similar thing is also true for the pecan trees. We did not irrigate the pecan trees as often as probably maybe when it is under flood irrigation. And, and still we could see that, you know, our plant our pecan trees grew as much or even more than any other comparable farm where, where, you know, you are you are growing the pecan trees under flood irrigation system.

Emile Elias: Excellent. So what I'm hearing you say, I just wanna reiterate, is that you had similar yields while using less water with this irrigation system. 

Manoj Shukla: That that's correct. You know, similar or even slightly higher. 

Emile Elias: Excellent. Great. I think that's a really important point when we're talking about our semi-arid landscape in the Southwest.

So thanks. 

Sarah LeRoy: So my next question is in regards to maintenance and durability of the systems. So how do traditional drip irrigation systems and the microgravity system that you've been working with measure up to each other in regard to, you know, their maintenance and durability longterm? 

Manoj Shukla: This is a very important question.

And so both systems have problems whenever the water quality is very poor and that water quality could be either due to the suspended particles or it could be due to the dissolved ions. So, you know, in, in, you know, with that respect, you know, both have the same type of problem or disadvantages.

The other problems which both systems face is that sometimes, you know, roots tend to penetrate into the, the pipes through the drippers. So, and especially that happens when you are not irrigating for several days and, and then, you know, all of a sudden that surface soil layer is, is drier. So the roots try to enter those, enter through the, through the drippers.

And, and that causes the problem of number one, it decreases the uniformity of water application and even it can sometimes completely stop the irrigation. And and, and that could be a, could be a big problem with regard to the survival of that of that plant or, or the plants around that area.

As far as the durability is concern. I think both systems are highly durable. Once in a while we do see that the wild animals, they might chew onto the pipes, especially when the pipes are very close to the soil surface or they are right on the soil surface, but it happens with the, with the both systems and, and that is why both systems really need a supervision.

Somebody has to walk along the roads to make sure that drippers are flowing and, and there is no leakage in this system. 

Sarah LeRoy: Thanks for that. And just building on this idea of maintenance and, and durability in conventional drip irrigation systems. There te there can be a buildup of hard water deposits. You know, you mentioned water quality and in conventional systems, people you know, often use sulfuric acid to address this problem.

So is hard water deposits or is that a problem in this microgravity system? Can sulfuric acid be used to address the problem or would it damage the system? 

Manoj Shukla: So to answer your question, yes, the hard water is a problem for both systems. Especially if you are running the drippers today and then you are not running it for a week or so.

The little bit advantage with both systems is that, you know, you often run your drippers. You really do not wait, say for example, for a surface irrigation of flood irrigation. You wait for 15 days for the second irrigation both conventional and micro gravity drip system. You have this option of applying water more frequently and that can, you know a little bit tackle this problem of clogging because of the hard water.

As far as the use of dilute sulfuric acid is concerned. Both systems use it. Microgravity system also uses it and there is absolutely no problem with regard to the acid damage. Even sometimes people also use hydrogen peroxide because if, you know, Southern New Mexico has a problem of, you know, brown algae sometimes in the groundwater. 

And hydrogen peroxide is something that can completely kill it, you know, not just, you know, and it dissolves it so that, you know, it simply goes out of the dripper and, and it does not clock those, those, those drippers. But one thing I would definitely like to tell you, although we have not conducted any separate research on this, but the way the dripper in the microgravity drip irrigation systems are designed that essentially when water is flowing in the pipe in this direction, the water inside the dripper actually enters as a backflow system. And, and therefore suspended impurities, there is a less likelihood of those clogging, the clogging, the dripper.

Whereas, you know, in a conventional system, water simply just goes and, and comes out of the, of the dripper. So this new design in my opinion, should help little bit more with regard to the clogging problems. 

Sarah LeRoy: Excellent. And so, I mean, what we've talked about so far, it seems like there are a lot of positives for, for the system in in the arid Southwest.

And so I'm wondering, you know, do you think there are any drawbacks or aspects of this technology that you think might limit adoption in this area or region? 

Manoj Shukla: Yeah, this is a good question. You know, so there are two types of drawbacks. One is the system drawback and the another is associated with the people.

So with regard to the system, I do not see any drawback. Of course, you know, if your field is, has a very high slope, large slope, then you know both systems will not work because you know, all that water will drain very rapidly to the end. But you know, over time these pipes get filled up and therefore, you know, you will also be able to irrigate the crops which are on the up slope.

So, and the other thing is that, you know, both systems require your field should be leveled. So if the, as long as the grower has this option to level, therefore, which most of them have, so I really don't think that, you know, any, any of these there is any problem with regard to either the equipment or the system as such.

And we have now demonstrated that both system work on, you know, tree crops. They all work in row crops. They even work under alfalfa. Previously, there was that the people thought that alfalfa or sandy soils, drip irrigation system will not work. But you know, there are several units installed on that on sandy soil and also under alfalfa.

And we have shown that both systems work. So I really do not see that. The problem that I see, or the drawback that I see is in the attitude of the people. Because, you know, sometimes when you are following a certain system for an extended period of time, it is not easy to change your attitude or change your practice.

So that seems to be the only drawback if people can be a little bit more open-minded and they will evaluate this new technology and if they evaluate the cost and benefit with regard to making these changes. I think then that drawback can also be eliminated. 

Emile Elias: Excellent. Yeah, thank you. Thanks for that.

We often find that when talking to stakeholders about new technologies, and that's kind of what you were talking about now, is sort of the human component of adoption of something new or you know, diffusion of innovation. We find that even a short conversation can sometimes bring up angles or ideas that we hadn't previously thought of.

So in your interactions with farmers that you've talked with and you mentioned that your site is really a site for outreach as well. Have you heard of ideas that you hadn't previously thought of? So have you had any conversations that led to new ideas or aha moments that you can share with us?

Manoj Shukla: This is a very good question and I think yeah, definitely interacting with the growers.

Some of the things that came up was that that, you know, what is the discharge of the dripper and based upon the discharge of the dripper, how much water will be needed by a pecan tree when it is like six year old versus a pecan tree which is like 30 year old. So those are the things which definitely gave us the idea so that, you know, we can think about how many drip lines will be needed, based upon the size of the tree or the life of the tree, or in other words, you know, based upon the, how far along are the root systems. So those are some of the things which, you know, when, when we were talking to the growers that, that made us think. 

The other thing that or it was also a somewhat of a concern of the growers that probably drip system will not work when there is salinity problem in the soil and that also make us think about it, that the solution to salinity problem is usually applying more water so that you know, salts can leach below the root zone. So essentially, the drip system can also be, both systems can also be used. What we will have to do is that, you know, we'll have to apply little bit more water than is actually needed by the crop.

And this extra water will definitely be useful to leach our soil and, and so that the, the production will not suffer. And this also, you know, made us think about it, that we can also run this system in combination with a flood system. Say for example, if EBID, Elephant Butte Irrigation District, which actually provides all the surface water to the farmers here, if they provide us the water, which is generally very clean, you know, their salinities are very low, you know, less than 400, 500 parts per million.

So that water, if we get early in the growing season, maybe first apply that water as flood irrigation so that you know you are able to leach your salts and subsequently you can use this microgravity or conventional drip system, whichever you are comfortable with, and you can still have a significant amount of cost savings.

And next year you can repeat that same cycle so you are able to maintain the salinity levels. So, yeah, you know, these are some of the things that we actually started thinking about it after talking to stakeholders. 

 Sarah LeRoy: Excellent. And I wanted to follow up on something you mentioned in one of your previous answers about people being you know, reluctant to change.

And, and trying to get people on board with, you know, trying a new technology. And so I'm wondering what you, and you've touched on this a little bit, but what do you think the incentives are for producers to implement these irrigation technologies and, you know, instead of just continuing business as usual, particularly if they currently rely on groundwater?

Manoj Shukla: Yeah, so this is really very important for the producers and number one, the way this drought started, we thought that, you know, it's a cyclic process and maybe in next eight to 10 years we will again have you know, good rainfall and, and good snowfall and, and you know, it'll continue because it usually has followed a cyclic pattern.

But it did not happen for the last 20 years. Now, there are certain crops and there are certain minimum amount of water that is required for irrigation. So you know when farmers are pumping the water now, this gives them an opportunity to use the microgravity or conventional drip, drip system, whichever they are comfortable with microgravity is cheaper.

So, you know, probably might be a better way for them to go. And, and what they can do that they can they will be pumping less because, you know, this system you know, results in some water savings. So when they are pumping less, what will happen is that not only they are applying this groundwater, which is definitely more saline or brackish than the surface water that we get through EBID.

But number two, there are also cost savings with regard to the energy with the electricity to run those pumps. And maybe for one growing season, it not, it may not be that significant, but you know, over time, like in a 10 year, 15 year span, those costs their costs could be significant. The other important thing is that, you know, just because they are applying less water, which is more saline than the surface water, the salinity buildup in the soil will also be less, and therefore they will get much greater leaching efficiencies during the next season when they are getting this cleaner water from EBID.

So, so overall, and since the production is either the same or higher it does make a lot of sense to save water because you know that water will definitely help them either, you know, expand on their farm. You know, maybe they can plant some more trees or they may plant some other crop in, in the area that, that they have at their disposal. 

So, so, so that's what, you know, I will say that, you know, there are multiple benefits. You know, saving water for everyone, you know, probably increasing their irrigated agricultural area. And number three, saving on the electricity costs. 

Emile Elias: Those are some great incentives and it, it's fun to think about the creativity here, right?

It's, there are many different options. Flood irrigate first, then use microgravity, change crops. It's, it's really, it sounds like it's very individualized and pretty, pretty expansive in different solutions. You also have another part of the same research project that I wanted to talk about where you used polypropylene trays called Mitra Trays for the pecan trays. Mitra or Mitra? Not sure. And can you tell us a little bit about those? What are they, how are they set up in a field and what do they do?

Manoj Shukla: Yeah, so there is another Israeli company and the name of that company is Tal-Ya and Tal-Ya Company has come up with these trays.

And I think if I step back and talk to you about, you must have heard about pole planting in the state of New Mexico where the trees were planted and you know, something was done so that water from the ground, groundwater can wick come up so that those trees survive. So, and then simultaneously the other option is that If you can somehow make sure that, you know, whatever rain falls on that area, if all that can be diverted towards the tree, that might also help these trees to survive and grow.

So, Tal-Ya Company came up with this idea and they had this polypropylene tray, which is actually called as Mitra. Mitra trays, and if you if you are from India, Mitra essentially means friend, but I'm not really sure if that's what they meant with Mitra. And so what happens is that, you know, these trays have a, a big hole right in the center, and you can very easily put that, you know, tray at, on, on the soil surface.

And right in the center of the tray, there could be a pecan tree. So whatever water that is falling, that will all be diverted towards the center of the tree to the root zone. And since these trays cover the soil, Therefore, not only they improve the microclimate under the tray, and you can see that, you know, the evaporation will decrease.

Simultaneously what happens is that these trays, you know, keep the soil cooler so you know, you don't see that much temperature fluctuations because now the solar radiations are not hitting the ground. Ground directly. And at the same time, they also suppress weeds. No weed grows and, and therefore, literally when, at the end of the year, if you want to see, and you know, you take those trays out because it's very easy to take them out.

 You can literally see that your soil looks much different than the surrounding soil. And, and when that happens, you know, definitely those trees grow a little bit, you know, mold and their canopy development is much higher and eventually, you know, probably you might get the fruits a day or two year earlier. So these trays have a, have a large potential of of not only protecting the tree, but also making it grow faster and more. 

Emile Elias: Excellent Mitra trays, friend trays is how I'll think of them now.

Sounds like they have a trifecta of benefits, which is directing water to the tree, keeping the soil cooler, suppressing leads, so, and maybe even more things. There's probably more benefits as well. Excellent. That's great to know about. I hope to come out to one of your field days or demonstration days and, and see those myself.

And also given that pecan trees and pecans are such an economically important crop in Southern New Mexico, have you seen much interest in these trays from local producers? What are people saying about the friend Mitra trays?

Manoj Shukla: So the, during the field days several pecan growers several chile growers, they came to visit us at the Leyendecker Science Center.

Plus every year, you know, New Mexico State University has these field days for the stakeholders and growers. So people did come at that time and also many of the NGOs came. And when people see this system, most of the people like it in fact, the system was installed on two farmers field in New Mexico, and there was also some interest shown by the local pecan growers here.

One thing that some of the pecan growers thought that this system will be particularly useful to them in the nursery. Because people had the concern that if their trees are like, you know, 60, 70 year old tree, they may or may not adopt to that new system. But certainly, you know, when they are producing their seedlings, that's where they are.

 So since this is a very new system only like, we have the oldest site in the United States. 2020 was the first time ever in the US that system was installed and, and we were able to have a demonstration site. We do believe that, you know, over time and with companies major focus is right now concentrated in Arizona. From this year onwards, they will be much more focused here.

And, and I'm really, really hopeful that stakeholders will get, you know, a lot of attention to that. Just wanted to point out one other thing. That last year, the president of the Pecan Grower's Association of Mexico, he actually came here to see this this, the microgravity system in action and he's planning to bring some pecan growers this year in 2023 when we will be doing the installation in the field.

So we, we really, we, we are hopeful that soon there will be more stakeholders and more people will be using it in their farm. 

 Emile Elias: Excellent.

Is there anything that we haven't asked you today that you wish we would've asked? Is there anything we didn't touch on related to the research that you're doing?

Manoj Shukla: You, you asked really good questions very important questions. Probably the only thing that you did not ask is that how it contributes to the mission of education. Because as you know, that New Mexico State University is a land grant university, and therefore we have all three missions, of course, extension, outreach, research, and the teaching is a very important component.

So this demonstration site also serves a educational site, not only for the graduate and undergraduate students of NMSU, but this site can also serve as educational site for K to 12 students. Those students can come and see the system in action and probably, you know, they will have a much better idea where food comes from.

Cuz you might know that when this question was proposed to, several of our middle schoolers, their answer was from a grocery store. So, so, so we do believe, the other thing is that these graduate students, when they work on this system in the field, like the very first student her name is Hannah Fernandez.

She's going to graduate hopefully this semester with a master's degree where she worked on the chile farm, which which was irrigated using microgravity drip systems. A technician has worked on that and several of the undergraduate and graduate students who worked on this project, they learned quite a bit about not only the system, the crops, the soils and irrigation technology.

So it is also it is also helping New Mexico State's third mission of teaching as well. 

Emile Elias: Excellent. Thank you. We like to end our conversations by asking the experts that we get to speak with what gives them hope for the future. So now we'd like to ask you what gives you hope? 

Manoj Shukla: So, what gives me hope?

So the thing that gives me hope is that that when I came to the state in 2005, I moved here from Columbus, Ohio. And at that time I think it wasn't even considered a good idea to talk about drip irrigation system with the farmers. But now if you look at here, you know, not only there are several farms, chile farms, which are under conventional drip system, but you know, there are also alfalfa farms and other farms where growers are actually using the conventional drip system.

So this clearly shows that you know, the people or stakeholders and the growers of the area are smart and they are ready to change their practices if they are convinced that the, the system will be beneficial to them. And I, I'm really hopeful that, you know, over time more and more people will buy into the new technologies and more and more people will adopt to this technology.

And together, you know, we'll make sure that we can live in this area. We don't have to migrate, just be because there is no more agriculture and the water quality, air quality is so bad that it's it's not possible to live here in this area. So, yeah. 

Emile Elias: Aw, that was an excellent answer. Thank you for that thoughtful answer.

And if people only remember one thing from our conversation today, what is the one thing that you would like people to remember? 

Manoj Shukla: So I will say water is the basis of life. Use it but not overuse it.

 Emile Elias: Excellent. That's a great note. That's a great note to end on. Thank you so much, Dr. Shukla, for speaking with us today about your research.

I can see some real clear benefits, so thank you.

Manoj Shukla: Oh, thanks a lot. Thank you for having me.

Emile Elias: Thanks for listening to Come Rain or Shine podcast of the USDA Southwest Climate Hub 

and the USGS Southwest CASC. If you liked this podcast, don't forget to rate or review it and subscribe for more great episodes. A special thanks to our production crew, Skye Aney and Reanna Burnett. If you want more information, have any questions for the speakers or would like to offer feedback, please reach out to us via our websites.