Prof. Garrison Sposito, soil scientist at UC Berkeley, talks about water and soil, the inputs organic and chemical that are often added to soil, soil stewardship, agriculture and food security.

Transcript

Speaker 1: Spectrum's next

Speaker 2: [inaudible]. Welcome to spectrum the science [00:00:30] and technology show on k a l x Berkeley, a biweekly 30 minute program, bringing new interviews featuring bay in scientists and technologists as well as a calendar of local events and news.

Speaker 1: Good afternoon. My name is Brad swift and I'm the host of today's show. Today we continue our interview with Professor Garrison [inaudible], the Betty and Isaac Barsha, chair of Soil Science in the College of natural resources at UC Berkeley. [00:01:00] Professor [inaudible] is an active teacher and researcher at Berkeley. This is part two of two professors. Pacino talks about the interaction of water with soil and the various inputs, organic and chemical that are often added to soil. He addresses soil stewardship and the challenges ahead for agriculture and food security.

Speaker 3: You talked a little bit about the interaction of water and soil. It seems very crucial. So the study of [00:01:30] soil is very tied up in water then?

Speaker 4: Yes, and I think the, uh, because of being in California, we may not, not understand that as well as we should because California has very large irrigation systems. One of the things, one of the very first things that Hilgard did when he came to this state to work was to go see a man named Kearney who lived around Fresno. And Kearney had the idea that if water were applied to the soils of the San Joaquin Valley, they might be used to grow crops [00:02:00] because the rainfall was very limited. I mean, you could grow crops that way, but not very many. And Hilgard actually assessed those soils and told him what the problems would be in doing that. And Kearney then began to irrigate the first one to do so and made a fortune doing this. So we have a lot of irrigated land in California for agriculture. And as a result, it doesn't seem as obvious to us that most of the world doesn't irrigate.

Speaker 4: 80% of the agriculture in the world is rain fed. Two thirds of the food in the world [00:02:30] is produced by rain fed agriculture. So when you start looking around at places that are less high tech than California, it's actually rainwater that's making the world go around. So the question then is how does rainwater move through soil? How can we optimize its management in use and so forth, and not surprisingly relatively little is known about that because the places where the knowhow exists to study water and soil are the places where irrigation often gets done. And so typically all it has been studied in [00:03:00] the past is how much water do you have to have in the soil at the start of the growing season to make sure you get through it with a decent crop. And you'll hear things about this in the news where they'll say assessment of the water content in the Midwest is such that the corn crop will be less this year or more or whatever.

Speaker 4: And the same is true anywhere else. So now a number of people are beginning to realize that we have to learn a lot more about how water behaves in soil before we can really truly expect to do very much about agriculture in that use. [00:03:30] Now this is important because the rain is falling on the soil. It has two places to go. One is maybe three, let's say three at one place is it can just evaporate right back up in the air, which isn't going to help anything unless it goes through a plant. If you could make it go through a plant first before evaporating, then of course you're doing agriculture. Another thing it will do is percolate downward and way down into what we call groundwater into the water that's stored way deep in the earth and so that's a loss. A third thing it can do is move over the land [00:04:00] surface or just underneath the land surface laterally towards some creek or river or whatever.

Speaker 4: So that's it. Now obviously then what you want to manage is keeping the water in place long enough to get it through the plants you want so that they will grow and produce whatever it is you're interested in. So that turns out to be a really important deal about which we don't know as anywhere near as much as we should. With irrigation, you're applying huge amounts of water. In fact, they're, the problem usually is what to do with the wall. Excess water that [00:04:30] comes off afterward, often full of salts and various other things you don't want. So it's a totally different problem. We're here. It's taking something that's very erratic. First of all, rain doesn't come like irrigation where you can order it up and get it applied. So you've got to worry about the fact that it comes sporadically and they're dry years in wet years and all of that. And then you've got to know how it's stored in soil on which kinds of quote choices this soil is going to make in terms of whether it will evaporate runoff or percolate downward and so [00:05:00] on. So it's a big deal. But I would say that given the global situation in agriculture, we really haven't begun to study what we should

Speaker 5: [inaudible]. This is spectrum on k a l X. Today's guest is Gary [inaudible] Ceto, the soil scientists that you see Berkeley. This next segment covers inputs to soil.

Speaker 4: [00:05:30] This gets into the idea of how do you judge soil? What's what's considered productive, nonproductive. A lot of it comes down to these characteristics you were just describing with the water. The ability to hold water. Yes. However, I want to say that the phrase good soil, which is strictly an agricultural phrase or bad soil for that matter, people talk about good soil and what they mean is something they can grow crops on the they want to grow at the rate they want to grow them, et cetera. [00:06:00] Here's a very insightful essay by Gary Snyder, the poet and ecologist who's a local figure called good, wild, sacred and it's about soil and he talks about agricultural soils being called good and wild soils, soils that are under the forest or soils out in the desert, and then sacred soils have to do with native Americans and others who regarded certain areas of soil as as sacred sacred sites.

Speaker 4: Well, from the point of view of nature, there is no bad soil because nature simply [00:06:30] adapts to whatever is there. The water supply, the nutrients, everything else and what grows is what you see and it's fine. It's an equilibrium with whatever is provided and nature doesn't mind. Problem comes and the value judgment comes in that humans do say what they want from a soil. We're talking about domesticating that soil. So it'll do what we want in the same way that you break a horse, so to speak, to do what you want. But that wild soil is actually just as good as soil is. The soil is domesticated [00:07:00] and in many ways it may be better because it's an equilibrium where the global environment has to be. Whereas we may, by virtue of doing things to soil to make it, you know, to harness it, you might say make it into a soil that is not in equilibrium with the global environment, could be harming the global environment in some ways.

Speaker 4: So a good soil, well, what most people mean is it's a soil that behaves the way we want it to for some particular use. And that use may be as simple as dumping some waste onto it. And of course a good soil could be [00:07:30] one that you can build on if you take everything off and build a house on it. And that's good too. Mostly they mean agriculture or some kind of thing. They want to grow in the soils and trees or whatever, or yard, whatever. And in which case they mean I want to domesticate this soil. I don't want it to be wild. Such ends up involving a lot of inputs. It does energy inputs as well as material inputs. And of course a lot of ways, and I think this is something which people should keep in mind because the use of fertilizer [00:08:00] is certainly an example of this in the water too.

Speaker 4: These are examples of technologies. After all, there's a fertilizer technology and that's where it comes from. And there's a water technology that delivers a water that we need to water in excess of what rain might provide. So here's a way to say that so-called second law of thermodynamics for every technology there is a pollution for every technology there is a pollution. Science. People know what I'm talking about and they say the second law would means that there is no such thing as truly [00:08:30] free energy. It always costs you some losses. Heat. That's really what I'm saying here. So if people would keep that in mind, every time they adapt a technology to what they want to do, there's going to be a pollution. And they ought to think about that. In the case of fertilizer, it's the runoff of the excess fertilizer into the waterways or somewhere where it's gonna cause a problem.

Speaker 4: They might apply chemicals to kill things. They want to kill weeds with chemicals. So all of these technologies are problems and they're inputs. You're quite [00:09:00] right now with nitrogen, which is essential to any kind of plant we can think of and certainly to agricultural plants. Nitrogen is used to make protein and that's absolutely essential in the, in the time of the first world war for a totally other reason, because they wanted to make something for munitions. Humans learned how to convert the nitrogen in the air to an active form, a reactive form of nitrogen that could be used for any, any reaction and a fertilizer is one kind of reaction. [00:09:30] So we can make nitrogen fertilizers now out of the air. It's called the Harvard process. Michael Pollan's called that the single biggest revolution in modern agriculture and it probably is now. Okay, fine. You can do that.

Speaker 4: It doesn't stop the pollution problem, but it says effectively you've got this huge, huge reservoir of nitrogen that you can eventually with enough energy fueled by oil, no doubt convert into reactive nitrate. And we're doing this and we're actually producing a huge amount of reactive nitrated NXS. [00:10:00] It's running into the world's waterways and causing all sorts of problems because a fertilizer in one place as a fertilizer somewhere else. If it's not fertilizing the corn in the Midwest, it's fertilizing the plankton in the Gulf of Mexico and causing them to bloom and cause all sorts of problems there. The same is not true of phosphorus and potassium. They're the other big three. The big three are nitrogen, phosphorus, and potassium that plants, all plants need to grow well. Those two have to be mined and there are limited supplies [00:10:30] and they're not being recycled. We have a huge amount of phosphorus running off with erosion.

Speaker 4: Phosphorus tends to attach itself to particles and it goes with the particles when they erode and there's huge amounts going into the bottom of the ocean. Now, potassium is somewhat like that. So what we've got our limited supplies. I've heard estimates that the u s phosphorus minds will run out by the middle of this century. In fact, that the next period of time between now and 2050 is the biggest deal for us. All right now [00:11:00] in terms of thinking through these issues of where are we going to get future phosphorus, if our minds run out? Obviously once you start thinking about recycling or not wasting so much a potassiums the same way. Right now, countries are battling over putout so called potash mines. They're battling over this because they can see it's running out. You can't make it out of the air. There's no way to do that. It's gotta be mined out of the rocks.

Speaker 4: And that's a huge problem because nobody has thought of a way to grow plants without the p and the K [00:11:30] as they call it, potassium, phosphorus, and potassium. So yeah, those are big inputs. Fossil fuels are an, are a big input too, but actually there's more of them around than these others and we're not, well, we are wasting them, but, but we're not wasting them in the same scale. And this is partly because people don't really think about these things very much. They just think about maximizing yield. So their tendency is to put as much as possible on the ground figuring that if the plant doesn't use it well, it'll go away soon.

Speaker 2: [00:12:00] [inaudible] you are listening to part two of a two part interview with Gary [inaudible], a soil scientist at UC Berkeley. The show is spectrum and the station is k a l ex Berkeley.

Speaker 3: [00:12:30] Well in terms of the ongoing viability of large scale agriculture, is there a way to maintain a status of that or is there always going to be at some point in need for input?

Speaker 4: Well, the way these systems are managed, they are high input systems typically. Now, uh, that's true in this country and that's true in places like Brazil where they have these large scale farms. A lot of the world is much smaller scale. A lot of the world, [00:13:00] it depends on rain fed. Agriculture to live is much smaller scale, but these big systems do produce an awful lot of product corn and soybeans. Actually I think about three quarters of the agriculture. In the world is used to raise animals. So that means a quarter of it's actually growing food that people eat right from the plant and the rest is used either as grass that they're growing cause agriculture means past year or crop. Right now we have about 12% of the earth [00:13:30] surface. It isn't ice covered in cropland and that's often very intensively farmed people who are experts estimate we can go another quarter of that to 15% and if we go beyond that we'll have so messed up the global system that we won't be able to sustain it at all.

Speaker 4: So we're pretty close to a tipping point. Crop Land is 12% the rest that's in agriculture, which I think is nearly 40% of the land is in grasses and the grasses are were used to grow animals. [00:14:00] So right there that you can raise a question, well maybe there's too much being expended on growing animals. How much do we really want or need of this right away. Then you're going to cut down on the large scale stuff just to kind of think this through a little bit. Cause if only a quarter is being used to grow food from the plants and it seemed like a huge amount, maybe that is sustainable. So in other words, moving from animal protein to plant protein could be a good way to go to it. Think about this, [00:14:30] people say, well yeah, but you know, animal protein is really balanced. His and the world wants it.

Speaker 4: I mean it's not, it's not going the other way. It's not going down. It's going up. There are more countries that one animal protein and they have more and more the means to get it one way or the other. So there's a thing to think about right there. If you want to point a finger then you can say, well animal raising is probably doing the most harm right now to the agricultural use of land. And maybe that needs to be thought through in a different way. So that's an important consideration. But [00:15:00] I, I know no one who's thought seriously about this that thinks that large scale agriculture, the way it's done now could just be expanded to the rest of the world and would be sustainable. It's probably not sustainable even in the United States.

Speaker 5: [inaudible] you were listening to spectrum on k a l x Berkeley professor Gary [inaudible] is our guest. This is part two of a two part interview. [00:15:30] Professor Ceto is discussing how to be a good steward of the soil

Speaker 4: or a way to be a good steward of soils for people who are in forestry or in agriculture, people who are managing watersheds. Sure there is, and thinking again about it as an ecosystem, it's really the same story. If you want a person can think of his own yard, [00:16:00] where his home is as this ecosystem to manage to think about and there are ways of being a good steward. Let's take for just soil. First of all is to respect the soil for what it is. So yeah, there is a way to be a good steward and I think most people, they're interested in a good soil, not a wild soil. To them wild means uncontrollable. It means it doesn't do what I want when I want it to do. I want it to produce a grass. It looks unhealthily green. For example, a blue grass, which would never be grown here anyway, instead of some grass that could be adapted [00:16:30] to the area.

Speaker 4: Or I want to grow ornamentals that probably shouldn't be grown either and on and on. And the basic idea is respect the soil for what it is. Don't think of a bad soil as a wild soil fact. That's the natural state. And thirdly, soil health is correlated with a humus. Do everything you can to keep the humans, which means a healthy biology. It means inputs of organic matter if you're using it in some fashion to grow things or whatever you do. It's common sense kinds of things at all. Really good farmers [00:17:00] know people who are small scale farmers and who live from the land that they have. They understand these things so they, they get this, but it doesn't have to be a farm. It can be your own yard that you're the steward of and keeping it well. And if you've got kids teaching your kids about what's in that yard, but it's very basic. It isn't complicated. As long as the poisons from your neighbors don't get into your yard in any, on the run off from their fertilizer and all. That's an issue. If you live close together, then let's, it's [00:17:30] true with any ecosystem that anyone has to manage their ways to look after it.

Speaker 4: Now the UN is going to meet in Rio, does summer, well in June actually it's the real plus 20th summit to talk about sustainability. Yeah. Nations and there will be presented there some guidelines for what are called planetary boundaries. It means, for example, don't let the global crop land get above 15% of the total land areas, so we don't go over tipping point, don't [00:18:00] let the nitrogen levels in the ocean and all the other places we're putting nitrogen in. It shouldn't be get above certain levels, don't let the CO2 grow any more than this, et Cetera, et cetera. They're going to try to get the UN to adopt these worldwide as guidelines for countries to think about. So the first step toward this being a, you can find it online, it's called planetary boundaries, and if it's a document which they're going to present. So people are thinking about this all over the world who have good minds and are concerned.

Speaker 4: So what's happening and soil [00:18:30] is part of this because of course soil conservation is what's going to keep the agriculture going and anything that's being done to degrade that soil or just lose it, lose it by erosion. And we have so much of that going on, you know, just going out in the ocean. It's just unfortunate because that's, you know, it takes so long to replace that. It is not going to be like five years. It's going to be thousands of years to replace it. So we have to wake up to these things. I don't want to, I want you to think I'm an alarmist or anything. There's time, [00:19:00] but we would be foolish not to think about these things carefully. Everybody has a stake in this. They need to get educated on it and think about it. Is there anything about soil that you wanted to, uh, to bring up that I haven't quizzed you about?

Speaker 4: You know, I, one thing I was talking about this to my department head who happens to be a soil scientist and pathologist and uh, he's working with others now to bring up the point that soil is a national security issue. It isn't obvious [00:19:30] that that's true at first and except when you start thinking about food now, when could it raise the question of the farm bill? The farm bill actually isn't called the farm bill when it gets passed as a law. It's called the Food Security Act because food is seen as a matter of national security and it is, well, soil is necessary to reduce food. And so the ability for the United States, for example, to take advantage of these incredibly rich soils that I hope we don't ruin is [00:20:00] a security issue. Our ability to do that enhances our security if we're going to import a huge amount of food because we can't grow it ourselves, that's a security issue just like it is for oil.

Speaker 4: We would say oil is a security issue. We have a certain amount of coal which is a lot. We have a certain amount of oil but not a lot and some natural gas. We wouldn't hesitate to say that that's a national security issue. We're, we're well endowed way better than many countries, especially with coal. Likewise with rich soils, we are well endowed. We we're so fortunate [00:20:30] in that respect. We tend to use them as if they're gonna last forever and so in that sense I would say that soil is a national security issue at least for the preservation of the food supply and people need to think of it that way. Thanks very much professor supposed to, you know for coming on spectrum,

Speaker 6: you're welcome.

Speaker 5: If you missed the broadcast of part one of our two part interview with Professor Gary [00:21:00] [inaudible] or any other spectrum show. They are now available as podcasts at iTunes university and easy link to the podcast is on the calyx website under programming in the spectrum description, the regular teacher of spectrum is to mention a few of the science and technology that's happening locally over the next few weeks. Lisa [inaudible] joins me for the calendar.

Speaker 6: Physics relates to everything that we do. A new exhibition opening this Saturday, [00:21:30] June 2nd at 1:00 PM at the Lawrence Hall of science shows how a visit to a local skate park can demonstrate important physics principals. Learn the science behind extreme sports at Tony Hawk, read science and see how skateboard legend Tony Hawk joins forces with physics to make 900 degree revolutions admit air right up vertical walls and even fly over rails. Tony Hawk along with fellow professional skateboarders will perform an exciting demonstration [00:22:00] on a specially designed vertical skate ramp set up just outside the hall and visitors can explore over 25 interactive experiences. Spaces Limited and tickets are required. The Lawrence Hall of Science is located at one centennial drive in Berkeley. For more information, go to their website, www.lawrencehallofscience.org

Speaker 1: Two unusual planetary events will happen on consecutive days, a partial lunar eclipse, June 4th and the transit of Venus on June 5th [00:22:30] on Monday, June 4th view the partial lunar eclipse in the wee hours of Monday morning from the observatory deck of the Chabot Space and science center at 10,000 Skyline Boulevard in Oakland. The eclipse will be most visible from 2:59 AM to 4:03 AM engage in a conversation with astronomers and knowledgeable volunteers. As you witnessed the moon's passing behind the earth. For more information, go to their website. Shabbos space.org

Speaker 6: East Bay Science cafe [00:23:00] presents inside dinosaur bones. What bone tissues reveal about the life of fossil animals. For hundreds of years, scientists have examined fossil bones to learn about the life of the past. Recently, a wealth of new information about the lives of dinosaurs and other extinct animals has come from an unexpected source. Fossilized bone tissues. Come explore the insides of fossils and learn what that tells us about the evolutionary history of animals still alive today. The Speaker is Sarah Werning, a [00:23:30] phd candidate in the Department of integrative biology at the University of California Berkeley. Her research explores how changes in bone tissues in the fossil record reflect the evolution of growth and metabolic rates in reptiles, birds, mammals, and their ancestors. This takes place Wednesday, June 6th from seven to 9:00 PM at Cafe Valparaiso, part of the La Pena Cultural Center at 31 oh five Shaddock avenue. Berkeley Nightlife

Speaker 1: [00:24:00] is the California Academy of Sciences Weekly Adult Program where they feature music, cocktails and themes, special exhibits for guests 21 and over. It happens every Thursday. The theme for the June 7th nightlife is sustainable catch in honor of world ocean's Day. There will be sustainable seafood cooking demos by local restaurant tours, talks on white sharks, Galapagos fishes, deep sea diving, and coral reef fish. Robert Murray's film. The end of the line [00:24:30] from the SF ocean film festival will be screened and DJ CEP, founder of one of the longest running dubstep parties. In the U s dub mission. We'll be making music. June 14th night. Life theme will be turtle power play teenage mutant Ninja Turtles. Find out how to help the sea turtle restoration project talk with sea turtle researcher Jay Nichols and visit ray bones Bandar and his display of sea turtle skulls. There will be a special dive [00:25:00] show in the Philippine Coral Reef and the film sea turtle spotlight in the planetarium at six 30 music by DJ Jay Sonic. Visit www.cal academy.org/events/nightlife now, the news

Speaker 6: alarmed at the sudden losses of between 30 and 90% of honeybee colonies since 2006 scientists, policymakers, farmers, and beekeepers have posted many theories as to the cause of bee colony [00:25:30] collapse disorder such as pest disease, pesticides, migratory beekeeping, or some combination of these factors. A study from the Harvard School of Public Health that will appear in the June issue of the Bolton of insect tology indicates that the likely culprit in sharp worldwide declines in honeybee colony since 2006 is Imidacloprid, one of the most widely used pesticides. It's the second report to link that pesticide to the mysterious bee. Die-Offs. Imidacloprid [00:26:00] is a member of a family of pesticides known as neonicotinoids introduced in the early 1990s bees can be exposed in two ways through nectar from plant or through high fructose corn syrup that beekeepers use to feed their bees. Since most us grown corn has been treated with imidacloprid.

Speaker 6: It's also found in corn syrup. Members of the Harvard Group led by biologist Alex Lu, a specialist in environmental exposure said they found convincing evidence [00:26:30] of the link. Lou and his researchers conducted a field study in Massachusetts over a 23 week period after which 15 out of 16 treated hives died. His experiment included pesticides amounts below what is normally present in the environment. Those exposed to the highest levels of the pesticides died. First, the hives were empty except for food stores. Some pollen and young bees with few dead bees nearby. When other conditions cause hive collapse such as disease or past, many [00:27:00] dead bees are typically found inside and outside the effected hives. These beyond producing honey are prime pollinators of roughly one third of the crop species in the United States including fruits, vegetables, nuts and livestock feed such as Alfalfa and clover. Massive loss of honeybees could result in billions of dollars in agricultural losses. California's almond crop is one of the most vulnerable

Speaker 1: well science daily reports that the results of a new US Geological Survey study conclude [00:27:30] that faults west of Lake Tahoe referred to as the Tahoe Sierra frontal fault zone pose, a substantial increase in the seismic hazard assessment for the Lake Tahoe region of California and Nevada and could potentially generate earthquakes with magnitudes ranging from 6.3 to 6.9 a close association of landslide deposits and active faults also suggests that there is an earthquake induced landslide hazard along the steep fault formed range front [00:28:00] west of Lake Tahoe using a new high resolution imaging technology known as bare Earth Airborne Lidar, which stands for light detection and ranging combined with field observations and the modern geochronology lidar imagery allows scientists to see through dense forest cover and recognize earthquake faults that are not detectable with conventional aerial photography. USDS scientist and lead author James Howl says that although the Tahoe Sierra [00:28:30] frontal falls zone has long been recognized as forming the tectonic boundary between the Sierra Nevada to the west and the basin and range province to the east, it's level of activity and seismic hazard was not fully recognized because dense vegetation obscured the surface expressions of the faults using the new lidar technology has improved and clarified.

Speaker 1: Previous field mapping has provided visualization of the surface expressions of the faults and has allowed for accurate [00:29:00] measurement of the amount of motion that has occurred on the phone. Fox

Speaker 5: [inaudible] music character new show is Bible stone, a David from his album folk and acoustic. It's made available through a creative Commons attributions license 3.0 production assistance by Rick Karnofsky and Lisa catechins. Thank you for listening to spectrum. If you have comments about the show, please send [00:29:30] them to us via email. Our email address is spectrum dot k a l [email protected] join us in two weeks at this same time.

Speaker 2: [inaudible].

---

Hosted on Acast. See acast.com/privacy for more information.