30: Water – History of Irrigation Transcript
Hallie: Hello and welcome to One to Grow On. A show where we dig into questions about agriculture and try to understand how food production impacts us and our world. My name is Hallie Casey and I studied and currently work in agriculture.
Chris: I’m Chris Casey, Hallie’s dad. Each week we pick an area of agriculture or food production that confuses a lot of people and get Hallie to explain it to us. This week we’re focusing on water.
Hallie: The history of water.
Chris: I know what this is.
Hallie: Do you?
Chris: Yeah, I know what water is. There’s been a lot of stuff that we’ve talked about like I have no idea what that is. I know water is.
Hallie: What is it? [Laughs].
Chris: It’s a liquid and it’s made up of an oxygen molecule and two hydrogen molecules bonded together. Hey, astute listener. Editing Chris here. If you’re thinking, hey, wait.
A water molecule is made up of one oxygen atom and two hydrogen atoms because atoms make molecules, you’d be right.
Hallie: One time when I was in grad school, I didn’t have to, but I wanted to make an animation for a presentation about how passive water transport happens in plants and so I did this whole lovely animation and I realized at the end I had built the molecules backwards, so there was one hydrogen and two oxygen. [Laughs].
Chris: I remember that.
Hallie: It was deeply embarrassing.
Chris: Also, the famous Rime of the Ancient Mariner. Water, water everywhere, and all the boards did shrink. Water, water everywhere nor any drop to drink, but this is water that I’m guessing plants drink.
Hallie: Yeah, we’re going to talk today mostly the history of irrigation. This is going to be a two-parter, so today it’s the history of irrigation and how we’ve used water in agriculture. Then the next time we’ll talk about how we are currently using water in agriculture and it’s going to be heads up less fun.
Chris: Okay. Are we going to talk about California politics?
Hallie: In the next one, yeah.
Chris: Really? Okay.
Hallie: Oh, yeah for sure.
Chris: I remember seeing those signs driving down highway 5.
Hallie: Oh, yes. Talk about the signs that we saw. This is when we were moving me into grad school.
Chris: Right. We were driving you up to Davis and there were signs outside of farms that said the government caused the drought and it just sort of boggled my mind.
Hallie: For those of you who’ve never been to California, there’s a lot of great parts of California. Highway five North of LA is not a great part of California. It’s a pretty bad part of California.
Chris: It’s one of the worst drives I’ve ever taken.
Hallie: It’s really, really bad and you just basically drive and it’s just expanses of farmland forever and ever. Even if you’re driving through Kansas or something, people talk about how flat Kansas is. You got stuff like trees in Kansas like you can see a tree line. Northern California, Central Valley, there is no trees. It’s just flat tomato fields, zucchini. It’s really terrible.
But you do see these very bizarre billboards that are talking about no water, no food, and stuff like that. But that is for the next episode. Right now we’re just going to talk about history. Fun, fun history.
Chris: All right. History of irrigation.
Hallie: Yes, we are just going to be talking about irrigation in regards to agriculture. I’m not really going to be talking about landscape plants, not going to be talking about recreational irrigation stuff like turf grass and golf today.
Chris: Sorry, Vikram.
Hallie: Yeah, if you want to hear us talk about turf grass, we did a whole episode about it. We start from patron Vikram Pilliga.
Chris: It’s true.
Hallie: Irrigation started in prehistoric times, right? We have a lot of records of irrigation because this is what made civilization possible. We’ve talked a lot on the show about how agriculture is what shifts people throughout many different histories around the world from hunting and gathering to being able to be stationary and do things like build buildings. Irrigation is a really huge part of that.
The first evidence we have in the prehistoric record of irrigation is around 10,000 BCE, which is pretty much when a lot of people started farming throughout the world in different places. Very early civilizations in the Fertile Crescent really got a handle on irrigation in some super cool ways. This is mostly like Egypt and Mesopotamia, which is what present day Iran and Iraq is. They were able to use floodwaters from the Nile, the Tigris and the Euphrates to irrigate their lands.
Chris: You need all that water to water all the plants.
Hallie: Yeah, you got to have water to water the plants. It’s extremely important and these people in ancient Egypt and Mesopotamia were able to divert floodwaters into their fields, so that’s like irrigation.
Chris: When you say divert, did they literally just dig trenches and the water would start going that way?
Hallie: Actually in ancient Egypt is where we see the first instance of a canal that was invented by a people called the Hyksos who lived in Egypt. They weren’t technically Egyptian, but they were as some medic people that lived in Egypt for a while and they invented canals.
Hallie: Very cool.
Chris: The V-nation should be very thankful.
Hallie: Yeah, it’s true. Except they’re not really anymore because they’re sinking. The canals are causing some trouble for Venice.
Chris: So are rising tide waters. Anyway, back to irrigation.
Hallie: There was also evidence in ancient Egypt that they use gauges to measure tide waters so that they would be able to track when the tides would rise on the river. They would use things like steps or cylindrical gauges to make predictions about when the floods would come.
Chris: Oh, like when you cross low water crossing and there’s a little pole with numbers etched on it, that kind of thing?
Hallie: Yeah, kind of like that.
Chris: Nice. Did they have a sign that said turn around, don’t drown?
Hallie: I wouldn’t think they would know. [Laughs]. That’s something that we have here in Texas because we have a lot of flooding. We have a lot of flash floods that happened like extremely quickly.
Chris: It’s true and we have a lot of low water crossings that get flooded very quickly in those situations.
Hallie: In ancient Egypt, they also came up with the concept of a Shadoof, which is basically a bucket on a lever and it’s the first evidence we have of people physically moving water.
Chris: How? Like a bucket on a lever that they carried or the water got moved from where to where in this bucket?
Hallie: They were able to irrigate basically farmland that wasn’t on the flood plain by moving it in a bucket. It was instead of like diverting water that was already going to be flooding these flood plains so that it was flooding it more efficiently, they were actually able to get farther out from the rivers flood plains, using a Shadoof a bucket and a lever. Ancient Egypt also, we see the first evidence of a water wheel, which is like the first use of irrigation technology that does not require human labor.
Chris: That’s awesome.
Hallie: Extremely awesome.
Chris: Water wheels isn’t something I normally associate with ancient Egypt.
Hallie: It’s extremely awesome mostly because prior to this, a lot of it was slave labor because it was human labor and that was the cheapest available. The invention of a water wheel is extremely huge. Also, windmills were generally a big thing. We’re going to talk about windmills a little bit throughout. We’re going to kind of bounce around talk about Rome, talk about China. There are windmills throughout history. In many places, we don’t really have like an origin of the windmill story. A lot of people thought about windmills in many different places.
Chris: Wow. They’re just everywhere, so that makes sense though. I mean, everyone’s figuring out ways to grow their food and grind up the grain and eat it. It kind of makes sense that everyone would have similar ideas on how to do it.
Hallie: Exactly. It’s similar to a water wheel and it doesn’t use human labor, but not really an origin story there.
Chris: Don Quixote couldn’t slay them all.
Hallie: He could not [laughs]. Particularly in ancient Egypt to kind of wrap up the canals were extremely important in Egypt’s ability to grow as an empire and as this huge civilization. The canals themselves were culturally very important. They were often decorated with art or with images of a Pharaoh and they really ended up symbolizing a lot from what we can tell the Egyptian people to like wealth and being fertile and having fertile fields and being able to grow food, which is amazing. Irrigation is super important as is agriculture. We love to see it.
Chris: It is. It makes sense that you’ve got all this water that you’re able to divert and so it’s easier to have access to food. When it’s easier to have access to food, you have a population center that grows more and yeah, that’s really cool.
Hallie: You mentioned Venice earlier. Moving on to the Roman Empire, they also had canals. They in fact copied Egyptian style canals.
Chris: Oh, I had no idea.
Hallie: Being an empire they were able to appropriate a lot of technologies from their conquered peoples and this included canals.
Chris: I remember seeing some of the obelisks when we were there.
Hallie: Exactly. [Laughs]. Yeah.
Chris: Some stuff appropriated. Some outright stolen.
Hallie: Yeah, in terms of technology much more appropriated because it would be pretty hard for you to move the canal, but they were also very into pipes, particularly led pipes which now in retrospect, hindsight being 2020 led, not the greatest thing to build a pipe out of, but pipes in general, huge for Rome.
Chris: Super useful. Super great way to move water around.
Hallie: Totally. The Romans as a people, as an empire were extremely good at agriculture and this is definitely one of the things that allowed the empire to grow as much as it did was that they really were able to grow food very efficiently and this included irrigation. Pipes were a big part of that. Canals were a real part of that and aqueducts were something that not only helped agriculture, but aqueduct and pipes also helped the growth of what we consider really like the first city centers where you really had things like the Roman bath houses and people were able to live close together and they had running water and indoor plumbing and there were fountains on squares and people had access to safe water generally, which was very huge.
Chris: When did they start throwing money in the fountains?
Hallie: I couldn’t tell you.
Chris: Okay. That makes sense though. I mean, it goes back to the irrigation and agriculture fostering access to food and a population center.
Hallie: Totally. We’re going to see a lot of that in this episode. We also did see reservoirs in Rome. They put them down like below mountains so that when the snow melted, they were able to capture that water instead of it just all going either out into the ocean or it being put into groundwater.
Chris: That’s smart. I had no idea that reservoirs had a strategic placement like that.
Hallie: I mean today, some of them do. Not all of them. Usually today, most of our snow melt goes into surface water, so it naturally goes out into rivers. But I can imagine if you are in Southern Europe, the ocean is very close to you. If it goes out to the river, the river is going to be going to the ocean. That’s not where you want your fresh water.
Chris: Also now, if we need to fill a reservoir and we have access to water that we can pump into it for later, we have that technology now. Back then when they didn’t have a technology to pump water around, putting it at the base of a snow melt is great a idea.
Hallie: For sure. More on Mesopotamia. I mentioned this earlier, but going a little bit more in depth on Mesopotamia, there were the Hanging Gardens of Babylon. We don’t really know how this worked. It seems like they definitely existed and they definitely needed irrigation, but we have not yet been able to figure out what irrigation technology they used for the Hanging Gardens of Babylon, which is extremely cool, which was around like circa 600 BCE.
Chris: Maybe it was prehistoric hydroponics.
Hallie: May be. I don’t know. I really want to know.
Chris: [Laughs]. When we invented the time machine to stop the spread of the Asian Chestnut, then we can also go back and check out that.
Hallie: [Laughs]. Yes, go see the Hanging Gardens of Babylon. I would love to. That would be wild. The Mesopotamians also invented something called a komet, I think is how you pronounce it, which is basically an underground tunnel that brought water from a well to somewhere else. Today, we have things like subsurface irrigation pipes, which is kind of comparable. But this was particularly for transporting water from one area to another, which we have tons of pipes in Mesopotamia 550 BCE twenty-five hundred years ago almost.
Hallie: More than. Pretty wild.
Chris: This is really cool. I’m thinking about sanitation because we think about how ancient sanitation practices weren’t what they are today. They didn’t know as much about things like germs and whatnot, but clearly what they had was good enough to create these population centers and create easier access to food and water and stuff like that that was good enough for life.
Hallie: I mean, particularly for Rome, having running water was huge. Having access to clean, running water was extremely important in Mesopotamia and we’re going to talk about China here in a second and then Egypt, we did see like population centers, but it wasn’t in the same way where it was definitely this is like a city center, like what we would modern day recognize as a city.
It was more like you had more people who were doing less farming closer together and then like the further out you got, it was like just farmers. Whereas Rome, you really had a very close concentration of people who were not at all farming, which is very cool for back then. But the ability to transport water is definitely linked in with a civilization’s ability to thrive because you’re able to grow your population if you’re able to grow more food.
Chris: All right. You mentioned China.
Hallie: Yes, I mentioned China. There is a lot of technology that was created in China, but one that is like particularly cool around irrigation is something that and I think this is how you pronounce it, the Dujiangyan water irrigation system, which was invented in the third century BCE, long time ago, still in use today.
Chris: Like being used for irrigation.
Chris: Wow. That’s awesome.
Hallie: Extremely cool. This guy, Lee Bang he was a hydrologist. The emperor at the time, asked him to go look at this because the main river ran through this city/province, the Sichuan Province and it was flooding a lot, which was causing a lot of issues naturally. So he had this hydrologist go out there.
I don’t know what a third century BCE hydrologists looks like, but I guess it’s just a guy who thought a lot about water. He went out there and he thought about how we can make this river not flood. Basically, it was a system of terraces and canals and it still exists today and right now today it irrigates like 600,000 hectares of farmland. It’s basically a method of using natural topography to control the spring snow melt off of the Dujiangyan Mountain that’s like right pushup behind the city. It was like, the snow was melting and the river was flooding so they terrorist it and they added canals and that just slowed the water down immensely so that it was able to percolate down into the soil and you weren’t seeing flooding.
Chris: That’s amazing, so it serves two purposes, both irrigation and flood control.
Hallie: Absolutely. Extremely cool.
Chris: Real quick. Do you know off the top of your head the conversion of acres to hectares?
Hallie: Yes, I do. It is one hectare to every 2.47 acres.
Chris: Okay. So 668,000 hectors times 2.4 acres is a lot.
Hallie: A lot of land.
Chris: It’s a lot of freaking land. Are people able to look at the staff and say, “Hey, let’s do that.” Or I guess this is sort of unique to this region.
Hallie: The idea of using natural topography to slow water down generally is something that has been used for a long time in lots of different places. A lot in Southeast Asia, definitely in South America, the Inca people and people before them, which we’ll talk about here in a second, used it. In the Andean region because they had mountains and they had to get some flat land that the water would slow down percolate into and that they would be able to cultivate easily. That idea has existed in many different forms, in many different places, but this is like one example of it that has one like lasted so long and two is just extremely effective and they’re using the snow melt from one mountain to irrigate just such a huge area. It’s like a really incredible example.
Hallie: One really cool thing. This was right before we had gunpowder because it was third century BCE. What they did was they alternated, heating and cooling rock in order to like break the canals open.
Chris: What do you mean? Oh, you mean there’s a rock in the way and so they would heat the rock up and then they’d cool the rock down and then the rock would crack and water would flow through.
Hallie: Yeah, basically. I mean, it was like kind of on a mountain side part of this hydrology landscaping. They had to like basically break through a lot of rock in order to like build canals and that’s how they would do it.
Chris: By that point, they’d figured out not only irrigation, but thermal expansion I guess.
Hallie: Right which is so cool.
Chris: That’s very cool.
Hallie: Yeah, and some researchers today think that like this irrigation system fundamentally changed the culture of the Sichuan Province and Chengdu, which is the largest city in the Sichuan Province because it was so much easier to farm. It’s always been easier to farm in the Sichuan Province because this hydrologically minded irrigation system is still functioning. It has been functioning there for like more than 2000 years. There are so many fewer disasters. You have fewer floods, so people were just able to be more laid back. You had fewer worries on your mind and so it changed how people interacted with each other and the world.
Chris: That’s awesome.
Hallie: It’s so cool. Irrigation is amazing.
Hallie: I mentioned a second ago talking about South America.
For different reasons including that there was not ever the same kind of research effort from the European, like “institutions of research” put into the North and South American ancient cultures as there was a huge research effort, both in the Fertile Crescent and in ancient China from these massive academic institutions in Western Europe. Then of course there was a genocide that arguably is still happening today against indigenous people for the past 500 years and there was a massive knowledge loss. Unfortunately, we do not know a lot about ancient irrigation in the Americas, but we do know some things. The Hohokam people in what is today considered Arizona made a very complex system of canals that carried water from the Salt River to their farmland between 850 and 1450 Common Era.
Chris: Okay. It could be argued that, I mean, they didn’t do it first, but they also invented canals on their own.
Hallie: Yeah, totally. On the Eastern side of the US, there were several different Mound Building cultures and there is some evidence that topography change influenced irrigation as well. The Chimu people in what is now mostly Peru also had canals and this allowed their culture to flourish until they were then conquered by the Inca. Then in modern day, Central America, what is mostly Mexico now, the Aztec also had Chinampas. Do you know about Chinampas?
Chris: I’ve never heard of the Chinampa.
Hallie: They are super cool. They still exist today, although they are no longer floating. Basically, they would have cane plants that they would lie down and they would build up a huge mound of organic matter in the middle of a lake and then they would be able to plant crops on that. Mostly they would have a lot of Chinampas and circled [inaudible], which is where Mexico City is now, which was like the Aztec capital.
Chris: Okay. Help me with the visual on this Chinampa real quick. You got a lake full of water. You lay down a cane plant, which means what? You make a raft out of.
Hallie: No, it’s basically you lay down a lot of cane plants on the bottom of the lake until the bottom of the lake is now above the lake. So it’s like this huge mound of just organic matter, like cane plants and sometimes other plants, but they used a lot of cane because it grows in lakes.
Chris: When I hear cane plant, I think of sugar cane, but this can’t just be any sort of cane plant.
Hallie: Yeah, like a reed.
Chris: Oh, okay like reeds and sort of lake bound grasses, things like that. Cool. Then when they build that up, they put dirt on top of that?
Hallie: It was mostly organic matter that had broken down. The lakes would flood and you would get, I mean, there’s some evidence that it was a lot of what we now call night soil, which is human excrement, which has lots of good organic matter, minerals, nutrients, but we don’t really use it anymore.
The lake would flood and it would bring more stuff in from surrounding areas. You would also get some soil that washes some sediment, but it was a lot of organic matter and then they would just be able to farm on top of that. That’s a cool technology. It’s not terribly scalable in terms of irrigation. It’s kind of a cool thing that doesn’t really exist anywhere else as far as we know.
Chris: Well, much like they had to break the reeds down to put them in the lake, we have to break this episode up into parts.
Hallie: In order to put it into a lake.
Chris: Yes, or in order to have a midroll, which we’re going to do now. We’ll be back soon.
Chris: Hello, listener. Welcome to the break.
Hallie: Dad, I would like to thank our starfruit level patrons, Lindsay, Vikram, Mama Casey.
Chris: Shianne. Thank you all so much.
Hallie: Thank you so so much.
Chris: Thank you to our newest patron, Tim.
Hallie: Thank you so much, Tim. Also, if you’re interested in the agriculture industry, Tim runs one of the best agriculture podcasts out there. You should definitely go check him out. Future of agriculture is the name of his podcast.
Chris: Yeah, it’s great. Also, he makes great dad jokes or at least he should. Don’t limit yourself, man.
Chris: Also, we have a listener survey we would love for you to fill out.
Hallie: We do. I spent a really long time putting this listener survey together.
Chris: But it won’t take a really long time for you to fill it out.
Hallie: It won’t. It’ll only take you like 10 minutes, but we really want to know more about you for many different reasons. It’s helpful for us as we try and grow the show to one, know how you listen to the show, what you like about the show, what works, what doesn’t and also we are collecting a little bit of demographic info so that if we want to start selling ads, we have that info that we can then take to sponsors.
Chris: Also, mostly in the survey what we want to see is what you get out of the show, what you enjoy listening to most. We know what we like producing and we want to try to focus on a few things and make sure you get the most out of it that you can.
Hallie: Honestly, this would be incredibly helpful. If you could go to onetogrowonpod.com/survey and take 10 minutes of your time, you can tweet at us afterwards and we will personally thank you. At the beginning of the survey, we also ask name and email. You can be totally anonymous, but if you leave your name and email, we will enter you into a raffle to win some stickers and a handwritten thank you note.
Chris: Yeah, but like she said, if you want to take the survey anonymously, the name and email are optional. You can just skip that page.
Hallie: It’s onetogrowonpod.com/survey. One more time. That’s onetogrowonpod.com/survey. 10 minutes of your time would mean so much to us.
Chris: Thank you very much and now back to the episode.
Hallie: Back to the episode.
Hallie: All right we’re back. Do you have a nature fact for us?
Chris: I do. This is going to be nature fact with help from Hallie. For Christmas, I was gifted a book called Banana: The Fate of the Fruit That Changed the World by Dan Koeppel.
Chris: While we were at the party, I started reading it and it’s really kind of so far cool, interesting read. But one of the things he wrote in here was that the banana was a berry and it’s the world’s biggest herb and I’m like, what the hey man? What do you mean? First of all, please explain to me how it’s a berry.
Hallie: Oh my gosh. I did a whole Ask One to Grow On about this.
Chris: Oh, did we do? Do we have an episode doing this?
Hallie: Yes, it’s called what is a berry?
Chris: Okay and you talked about the banana.
Hallie: I think I talked about the banana yeah. Bananas, tomatoes, blueberries.
Chris: Wait. Is the tomato a berry?
Hallie: Yes, I will refer you to the Ask One to Grow On as per my last email.
Hallie: The Ask One to Grow On episode what is a berry. You can refer to that.
Chris: Okay. All right. I will go back and re-listen to that and listener, if you want to go listen to that too it’s called what is a berry?
Hallie: Also, if you have any additional questions listener, you can hashtag #askonetogrowon on Twitter and Instagram and I will see it and answer it.
Chris: I’m guessing it’s not because it comes in a bunch of bananas that it’s a berry.
Hallie: No, definitely not.
Chris: Okay. That was the only thing I could think of, but I’ll check. Why is it a herb?
Hallie: I wouldn’t really call it a herb because we use the word herb colloquially to mean things like herbs and spices and many of the herbs that we use in the kitchen are not actually herbaceous. They’re referring to the word herbaceous. Basically, we categorize our plants in many different ways. One of them being woody versus herbaceous plants. Woody plants have things like lignin.
Chris: I was going to answer that.
Hallie: Woody plants have lignin. They have bark. They have wood tissue on the inside, which is like old xylem tissue, basically. Our herbaceous plants like bananas and papayas and grasses don’t have that woody tissue. They never develop any kind of lignin. They don’t develop wood. They don’t develop bark or cork. If you cut into a banana plant or like a grass plant or a papaya plant, it’s just like fleshy gooeyness on the inside.
Chris: Even on the stock?
Hallie: Right. Yeah, there’s like no woody part. There’s no dry part. It’s just gooey flesh. They also aren’t really able to grow outwards so they’re like the same size round all the way up kind of like bamboo. Bamboos are grass so it’s herbaceous. It’s like the same size around forever. You’re going to have a 20 year old banana plant. It doesn’t really get bigger around because they’re not able to build that cambium layer that pushes it out and builds wood on the inside. Does that make sense?
Chris: It does. Cool. All right. Tara tara tata nature fact.
Hallie: [Laughs]. Okay. That’s kind of talking about when things first came about, like who was thinking about canals and how all these different technologies first were thought of.
After that, technology was transferred, things became pretty unified around much of the world until the 18th century. Not a lot happened. We thought of canals and we got some pipes and we’re like, all right. This is working for us until we really were trying to scale up due to colonialism. The British Empire was expanding greatly and they were trying to get more people. In order to have more people, you need more food and they had all of these people that they had just subjugated and so they had a lot of really cheap labor. We had a lot of technological advances that was then dubbed the second agricultural revolution. What I would now call the agricultural revolution because the first agricultural revolution is like the beginning of agriculture. Not really revolutionizing anything you’re like inventing it. So like beginning of agriculture and then the agriculture revolution. But if you look it up in textbooks it is termed as the second agriculture revolution. It’s a bone epic. That’s like we started draining fens and bogs to get water. We also invented the hose as well in the 1870s.
Chris: Hang on. The hose as in the hose that water comes out of?
Chris: Oh, okay. Not the plural of hoe.
Chris: Which makes sense in this context which we’re talking about.
Hallie: The plural of hoe like the tool a hoe was invented definitely before the hose, like the long thing that water comes out of. Hose was amended in 1870s. That’s pretty recently.
Chris: Wow. Yeah.
Hallie: In the 1900s, in the America rural people didn’t really have access to electricity, so you didn’t really have electric pumps. Once people got electricity, they were then able to pump water, which was closer to the 1950s. In 1952, a guy called Frank Zybach invented center pivot irrigation, which completely changed the game for particularly the Great Plains in the US.
Chris: Oh, I can guess from the name is that when we’re driving out in the country and we see these long, I don’t know basically sprinklers on wheels that stretch out from a center point and look like they sort of drive around in a circle watering things.
Hallie: Yeah, pretty much. You basically have a big, long arm that has sprinklers on it that runs the radius of a circle. The hub of it is in the center of the circle and then the spoke goes out the radius of the circle and then it’s able to move around in a circle. Basically you’re using very little energy in order to irrigate this circle and it’s a very large area generally. If you’re flying over farmland, oftentimes you’ll see like circles and that is what that’s from. That’s from the center pivot irrigation system.
Chris: Actual crop circles as opposed to things that people call crop circles.
Hallie: That’s true.
Chris: Anyway, that takes us to what?
Hallie: In 1965, a person called Simcha Blass is attributed as inventing drip irrigation. This is kind of questionable because drip irrigation is basically using passive irrigation and that has existed for a long time. There’s a concept called an oya where basically you use terracotta. Basically, you fill something that is terracotta up with water and then because the terracotta is permeable that water can be drawn out through the terracotta itself. It’s similar to drip irrigation and that’s existed in China and that’s existed in Spain for a long time and then it was used by indigenous people, but in 1965, there was an Israeli agronomist who put a lot of pieces together. In Germany, there was an underground pipe that basically there were very small perforations on the pipe and so the plants were able to slowly draw water out of the pipe. Then in 1965, this Israeli agronomist took all these different pieces and added a drip emitter and “invented” what we now call modern day drip irrigation. Although he didn’t invent the drip emitter for sure, but the concept of passives or slow release irrigation has existed for a long time.
Chris: It sounds like he made a decent innovation on an existing concept.
Hallie: Yeah, for sure which is huge. People really are moving a lot more towards drip irrigation not because you use less water, but because you use less water per plant, which is good. A lot of people talk about how drip irrigation ends up using less water. It doesn’t necessarily. You end up using about the same amount of water, but you’re able to grow more plants if that makes sense.
Chris: Yeah, more efficient watering practices.
Hallie: Kind of. Yeah.
Chris: Great. How does that work?
Hallie: Drip irrigation?
Chris: Well, why are you able to use less water per plant?
Hallie: Basically, drip irrigation is you have a thin plastic. We call it a ribbon. It’s a very thin flexible plastic pipe that you lay along the ground and you have little holes that are punched into it and you have little emitters and the emitters control how much water comes out, so you’re able to slow release a gallon an hour or half a gallon an hour basically in drops. It like very, very slowly releases this irrigation, so you’re not irrigating to the left of your plant or to the right of your plant. You’re irrigating a very localized spot. That’s basically why. It has mixed uses. There are some ways that it’s not as good as things like sprinkler irrigation, but you end up with yes, more efficient irrigation technically. Today, 38% of irrigated land is irrigated with groundwater. 62% is irrigated with surface water. 69% of all water withdrawal globally is for agriculture.
Chris: That’s not a figure I would have thought of that’s a lot. Wow.
Hallie: It is a lot. The highest percent is an Africa and Asia. This number has increased dramatically over the past hundred years. I mean, earlier I was talking about how people weren’t really pumping water in the early to mid-20th century. Now, pretty much everyone is able to pump water because we have things like solar technology. Slap a solar panel on it. You don’t have to be hooked up to the grid. It can just pump away. Then worldwide, only 20% of cultivated land is irrigated. But the land that is irrigated produces 40% of the food supply.
Chris: Okay. That sounds like a pretty significant percentage. Do we know how the rest of the land gets water if it’s not irrigated?
Hallie: It gets watered by the rain and if the rains don’t come, then the food doesn’t grow.
Chris: Oh, wow. Bummer. Okay. So it’s either rain or irrigation.
Hallie: Yeah, pretty much. Sometimes like in some places you do still have flood irrigated areas, but it’s much less common mostly because there are a lot of dams now that control rivers and we don’t really want rivers to flood anymore because we have a lot more people. It can be very dangerous if rivers flood. It’s much less common to have flood irrigated.
Chris: Cool. To sum up irrigation is really cool. Not only super important, but like critical innovation for people to go from a sort of hunter gatherer lifestyle to agrarian and somewhat city centered lifestyle.
Hallie: Yeah, for sure.
Chris: People came up with it all over the world and been doing it for a very long time.
Hallie: Today, it is such a huge part of how we globally use water as a people, as a species. It is an immense part of how we use our water.
Chris: That’s where most of our water goes it sounds like.
Hallie: Yeah, 69%.
Chris: That’s the history of irrigation. Come back for the next episode where we’ll talk about.
Hallie: Next week, we are going to talk about climate change and we’re going to talk about policy change and we’re going to talk about the future of irrigation in two weeks.
Chris: Thanks for listening to this episode of One to Grow On.
Hallie: This show is hosted by me, Hallie Casey and Chris Casey.
Chris: It is produced by Katherine Arjet and Hallie Cassie.
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Chris: Be sure to check out the next episode in two weeks.
Hallie: But until then, keep on growing.
Chris: Bye everybody.