Nebraska Cover Crop & Soil Health Conference - Welcome and David Montgomery

University of Nebraska Eastern Nebraska Research and Extension Center Author

02/25/2019 Added

77 Plays

Description

The 2019 Nebraska Cover Crop and Soil Health Conference featured innovative speakers who have worked with cover crops extensively and shared what they have learned. There are many benefits to utilizing cover crops, such as improved soil heath and reduced erosion. It is the details of how and what to do that can present challenges. The focus of the conference was to provide information to growers who are in a corn/soybean rotation and to assist them in understanding the value of cover crops.

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[00:00:08.140]That there wasn't a registration fee.
[00:00:09.770]And so we do wanna acknowledge how that happened.
[00:00:13.030]Some of our sponsors, if you're in the room today,
[00:00:15.000]please stand for these different groups
[00:00:17.330]'cause we'd like to acknowledge you
[00:00:18.630]for helping make this event free for attendees.
[00:00:21.170]So, the Nebraska Soybean Board,
[00:00:24.790]is anyone here from the Nebras, 'kay,
[00:00:26.740]thank you, gentlemen.
[00:00:28.606](audience applauds)
[00:00:32.830]Lower Platte North NRD.
[00:00:38.030]'Kay, up front here, thank you.
[00:00:39.945](audience applauds)
[00:00:42.955]USDA Sustainable Ag Research and Education.
[00:00:46.690]I know Gary is a representative in the back.
[00:00:50.409](audience applauds)
[00:00:52.210]And then our partners with USDA NRCS.
[00:00:55.510]So thank you, Dan and our NRCS staff in the room.
[00:00:58.435](audience applauds)
[00:00:59.590]Stand up, NRCS.
[00:01:04.210]Also just a few other things.
[00:01:07.750]Doug Zalesky's gonna come,
[00:01:09.150]talk to you a little bit about what's going on here.
[00:01:11.270]He's the Director of the Eastern Nebraska
[00:01:13.620]Research and Extension Center,
[00:01:14.930]formerly called the ARDC, if you're used to calling it that.
[00:01:17.730]So a little bit of a name change.
[00:01:19.910]Doug is a Husker alum
[00:01:21.490]and earned a Bachelor's degree
[00:01:22.510]in animal science and production
[00:01:23.880]and a Master's degree in physiology
[00:01:25.500]and reproduction from Nebraska.
[00:01:27.800]And the Eastern Nebraska Research and Extension Center,
[00:01:30.420]there is some science around your table,
[00:01:32.520]does it leverage the strengths
[00:01:33.750]of existing resources across eastern Nebraska,
[00:01:36.680]including the university's Lincoln campus,
[00:01:39.350]deliver integrative research and extension programming,
[00:01:42.170]which is why we're here today.
[00:01:43.270]So with that, I'll turn the mic over to Doug.
[00:01:49.640]Thank you, Nathan.
[00:01:51.030]I'd like to welcome everybody here this morning
[00:01:53.400]to the Eastern Nebraska Research and Extension Center.
[00:01:56.190]It's great to see such a big crowd
[00:01:58.360]and it's great to see all the red.
[00:02:00.500]You're here on a special day.
[00:02:01.820]Nathan mentioned that it's not only Valentine's Day,
[00:02:06.060]but this is also for the University of Nebraska Lincoln
[00:02:09.580]Glow Big Red Day, Go Big Red, Glow Big Red.
[00:02:14.040]This is charter week for the University of Nebraska.
[00:02:18.500]We're celebrating 150 years of the being in existence.
[00:02:24.720]So there's a lot of events
[00:02:25.970]and a lot of things going on this year,
[00:02:28.360]this week in particular,
[00:02:31.300]but throughout the year to celebrate that milestone.
[00:02:35.020]So a couple things that are going on here,
[00:02:37.370]I know there was an email sent out to registrants
[00:02:40.010]to wear rad to day to help celebrate Glow Big Red Day.
[00:02:44.870]They're asking people to wear it,
[00:02:47.680]fly it, give it, whatever you can think of,
[00:02:52.260]light it up with red today.
[00:02:55.770]So we'll see a lot of that
[00:02:56.857]and it's great to see all the red here today.
[00:03:00.530]One of the things that's gonna happen,
[00:03:02.270]there are several things here today.
[00:03:03.710]We have out N 150 mascot, Flat Herbie, he's here.
[00:03:10.030]If you would like to get a picture taken with him,
[00:03:12.210]we'd love to have that happen.
[00:03:14.100]But you'll see him round the state all year long
[00:03:18.980]as the different events and things go on.
[00:03:21.240]So it's good to have him with us.
[00:03:24.270]Keith also bought some Nifty N 150 ice cream
[00:03:31.930]that was developed at the UNL dairy store on east campus.
[00:03:36.250]And Keith thought that it was fit
[00:03:38.630]to be able to serve some of that today at lunch.
[00:03:41.410]So you'll get to partake of that.
[00:03:43.810]Under the leadership of our chancellor Ronnie Green,
[00:03:48.240]the university has undertaken
[00:03:50.034]a big strategic planning effort in the last year and a half.
[00:03:55.417]And that has resulted in what's called the N 150 Report.
[00:04:00.000]If you would like to read that report,
[00:04:02.280]it is available online.
[00:04:04.910]Google UNL N 150 and it'll take you to that website.
[00:04:09.920]But it'll give you a good idea
[00:04:11.350]of where the university is headed.
[00:04:14.650]We're looking forward to all the changes and improvements
[00:04:18.390]that are outlined in this report.
[00:04:20.600]I'm gonna stop there.
[00:04:21.690]Have a great day.
[00:04:22.920]Good to have you here.
[00:04:24.010]And turn it back over to Nathan.
[00:04:27.610]Thanks, Doug.
[00:04:28.750](audience applauds)
[00:04:33.240]There's one more group here in the crowd
[00:04:35.070]that essentially is the committee or group
[00:04:36.930]that puts this program together.
[00:04:38.750]A lot of these members have been with us
[00:04:41.020]putting this program together for the last four years.
[00:04:43.260]So I would like them to stand
[00:04:44.900]and acknowledge their efforts
[00:04:46.070]in helping put today's program together.
[00:04:48.210]So Keith Gluen in the back, kind of our lead on this.
[00:04:53.450]There you go. (audience applauds)
[00:04:56.650]Didn't see Dolores, but she might be floating around.
[00:04:58.920]She really helps with some
[00:04:59.980]of the advertising materials and outreach.
[00:05:03.040]Gary Leswing in the back.
[00:05:06.626](audience applauds)
[00:05:08.730]Mike McDonnell.
[00:05:12.350](audience applauds)
[00:05:14.320]Paul Yah-sah.
[00:05:17.424](audience applauds)
[00:05:19.200]Dan Gillespie.
[00:05:21.925](audience applauds)
[00:05:23.140]And Jodie Sahf.
[00:05:26.962](audience applauds)
[00:05:29.126]Okay.
[00:05:30.320]Next I have the pleasure to introduce
[00:05:32.090]our first speaker of the morning.
[00:05:34.030]Got to pick him up from the Omaha airport last night.
[00:05:36.960]David Montgomery, he's a professor of geomorphology
[00:05:39.150]at the University of Washington in Seattle.
[00:05:41.840]He looks at the processes shaping the Earth's surface
[00:05:44.060]and how they affect ecological systems
[00:05:46.260]in human societies.
[00:05:47.920]He has written numerous books
[00:05:49.020]and has traveled around the world.
[00:05:50.690]We're delighted to have him here in Nebraska,
[00:05:52.900]it is first time here at this location in eastern Nebraska,
[00:05:55.990]so we're excited to hear him talk.
[00:05:57.740]And we're gonna have a great group of speakers
[00:05:59.520]that are really rock stars of soil health today.
[00:06:01.730]So we're excited about the program,
[00:06:03.130]and thanks, David, for making the trip from out west.
[00:06:06.860]No worries.
[00:06:08.463](audience applauds) Thank you.
[00:06:13.510]Can everybody hear me with the microphone set up?
[00:06:15.880]In the back, if you can hear me, wave.
[00:06:17.790]All right, sounds like we're good.
[00:06:19.450]Good morning.
[00:06:20.930]Well, thank you for the invitation to come out
[00:06:22.550]and talk about soil health.
[00:06:23.720]I'm a geologist by background.
[00:06:26.950]So I come to look at cover cropping
[00:06:29.160]and soil health and farming
[00:06:30.630]from a very different perspective
[00:06:32.010]than perhaps most of you.
[00:06:34.320]And what I'm gonna talk about is
[00:06:35.640]take you on a bit of a trip
[00:06:37.720]through my own intellectual journey
[00:06:39.100]over the last (sighs) oh, 12 or so years,
[00:06:41.690]thinking and writing about soil
[00:06:43.900]and how important it is for human societies
[00:06:46.750]through the course of the three books
[00:06:48.030]that are up, that were up on the screen a moment ago.
[00:06:51.560]And I don't know if we can go back to the slides.
[00:06:55.830]We'll get there?
[00:06:57.690]All right.
[00:07:01.690]But that first book, the Dirt one,
[00:07:04.030]is the one that got me into thinking about soil.
[00:07:06.410]It's the kind of book that you might expect
[00:07:08.240]a geologist to write about soil.
[00:07:10.010]It's very backwards-looking.
[00:07:11.250]It looks back through the history
[00:07:12.880]of civilizations around the world.
[00:07:15.030]And the one-sort of sentence summary,
[00:07:18.070]I'm not touching anything,
[00:07:19.220]so the one-sentence summary of that book is essentially,
[00:07:22.480]societies that did not take care of their land did not last.
[00:07:26.060]There's lessons there that come
[00:07:28.430]from the world of archeology and geology.
[00:07:30.790]And you might not be surprised to learn
[00:07:32.220]that a geomorphologist wrote that.
[00:07:34.010]Now, what is a geomorphologist?
[00:07:35.900]That's my specialty in geology.
[00:07:37.560]It's somebody who studies natural erosion processes.
[00:07:40.770]What shapes hills?
[00:07:42.210]Why hill are convex
[00:07:43.570]and you can actually fit parabolas to them mathematically.
[00:07:46.810]How high mountain ranges get,
[00:07:48.410]why are the Himalaya the size they are.
[00:07:50.410]That's the kind of thing that I study as an academic.
[00:07:54.560]But I was taught to think of soil
[00:07:56.070]as the stuff that covered up rocks.
[00:07:57.930]It was the stuff that got in the way
[00:07:59.560]of looking at the good stuff.
[00:08:01.270]And I've come to learn that that is
[00:08:02.540]a very, very wrong view of things
[00:08:04.930]and become much more interested
[00:08:06.860]in the idea of soil health as the future of agriculture.
[00:08:10.330]And that middle book, The Hidden Half of Nature,
[00:08:12.180]is one that I wrote with my wife.
[00:08:13.410]She's a biologist.
[00:08:14.850]I'm a geologist.
[00:08:15.890]You put those two things together,
[00:08:17.250]and that's essentially how you make healthy, fertile soil.
[00:08:20.660]That book focuses on the role
[00:08:22.240]of microbial life in soil fertility,
[00:08:24.350]the part of soil science that I was not taught
[00:08:26.990]in graduate school when I took soil science classes
[00:08:30.520]a few decades ago.
[00:08:32.110]And the third book, Growing a Revolution,
[00:08:33.920]I wanna focus on at the end of the talk,
[00:08:35.670]is really about how to take
[00:08:36.860]the lessons from that first book,
[00:08:39.190]the science from that second book,
[00:08:40.880]and how farmers around the world have been applying that
[00:08:43.830]to the problem of regenerating the fertility of soil
[00:08:46.640]and thereby making their farms more profitable.
[00:08:48.640]That's sort of how I came into looking at soils.
[00:08:52.130]And why would a geologist at first blush
[00:08:54.500]interested in writing a book
[00:08:55.870]about the history of land degradation?
[00:08:58.730]It's because if you look at the state
[00:08:59.960]of the world soils today,
[00:09:01.860]an awful lot of our agronomic lands
[00:09:04.270]are degraded to some extent, some to a very large extent.
[00:09:08.250]This is the UN's map of global soil degradation
[00:09:10.620]from about 15 years ago or so, if I recall correctly.
[00:09:14.120]It's painted with a very broad brush.
[00:09:17.410]Take the patterns you see up here
[00:09:18.830]in detail with a grain of salt.
[00:09:20.270]But the broad brush is what I wanna use
[00:09:22.460]this slide to emphasize.
[00:09:23.710]There's a lot of red and yellow on the map,
[00:09:25.960]as you can see.
[00:09:26.793]There's a lot of soils that are degraded or very degraded.
[00:09:29.260]And what does that mean?
[00:09:30.100]It means that their natural
[00:09:31.170]agronomic potential is compromised.
[00:09:32.900]We can't grow as much food off of them
[00:09:34.770]without chemical supplementation
[00:09:36.970]as you could have with their native soils.
[00:09:40.020]But I'd also like to point out
[00:09:41.050]that within any one of these red zones,
[00:09:43.590]you can also find farms that are rebuilding soil fertility,
[00:09:46.770]at what to a geologist is a frightening pace.
[00:09:48.990]So I like this slide because it lets me say two things.
[00:09:51.340]We have a global problem with the state of our soils,
[00:09:54.610]but there are also people around the world
[00:09:56.160]who are fixing it right under our noses.
[00:09:58.670]And that's where I wanna take you through,
[00:10:00.230]is that journ, sort of my education, if you will,
[00:10:03.450]or reeducation as a geologist, through this story.
[00:10:08.140]But where are we today?
[00:10:09.770]There's a UN Global State of the Soil report from 2015,
[00:10:12.970]just a couple of years ago,
[00:10:14.460]that in its executive summary concluded
[00:10:16.670]that we're losing about 0.3%
[00:10:19.340]of our global agricultural production capacity,
[00:10:21.930]our ability to grow food, each and every year
[00:10:24.410]to ongoing soil loss, the physical erosion of the soil,
[00:10:27.430]and soil degradation, the degradation
[00:10:29.890]of the fertility of the land.
[00:10:32.120]Now .3%, that's not a very big number, is it?
[00:10:36.160]It's pretty close to what I think
[00:10:37.600]I'm getting on my savings account these days,
[00:10:39.716](audience chuckles) you know?
[00:10:40.670]It takes years, it takes decades
[00:10:42.970]to actually notice the interest to pile up.
[00:10:45.690]But one of the things about being a geologist is,
[00:10:47.550]you start thinking about centuries
[00:10:49.100]as being really short time scales.
[00:10:50.790]And if you take that .3% and you play it out
[00:10:52.880]over the next 100 years, what do you get?
[00:10:55.000]We're on track to lose another third
[00:10:57.650]of our agricultural production capacity.
[00:11:00.490]If you add up all the farmland around the world
[00:11:02.360]that's already been taken out of production
[00:11:03.990]in places like Syria and Libya,
[00:11:06.380]to name some of the worst examples,
[00:11:08.670]we've already lost, yeah, 30 to 25,
[00:11:10.940]a quarter to a third of the world's farmland
[00:11:14.160]that was once worked,
[00:11:15.440]that we know from things like Roman tax records was worked,
[00:11:18.640]is no longer worked.
[00:11:20.520]If we're on track to lose another third this next century,
[00:11:23.430]that has the makings of a slow motion disaster
[00:11:26.290]as our population grows by a third in the next century.
[00:11:29.410]It's my contention that agriculture needs to change
[00:11:31.910]in some way over the next century
[00:11:34.520]to prevent those curves from intersecting.
[00:11:37.300]And the Dirt book was my entree to this,
[00:11:38.900]sort of to look back through history
[00:11:40.360]and thinking about
[00:11:41.193]how different societies have fared in the past.
[00:11:44.450]I started writing it thinking I wanted to write
[00:11:46.510]a history of soil erosion
[00:11:47.640]because I studied natural soil erosion.
[00:11:49.730]And I thought it'd be a great excuse
[00:11:50.920]to go visit ruins around the world,
[00:11:52.440]write about some of the societies that I'd seen.
[00:11:54.770]But as I started thinking about it in writing,
[00:11:56.480]I realized that of all the places
[00:11:58.010]I've worked around the world,
[00:11:59.090]that's one of the nice things about being a geologist is,
[00:12:00.940]you get to travel all over the world,
[00:12:03.320]societies that were developed on landscapes
[00:12:05.930]where I could tell that they had degraded their soil,
[00:12:08.570]those were generally the impoverished places.
[00:12:12.110]And I started putting the pattern together.
[00:12:14.250]And when you research back into the history of soil erosion,
[00:12:17.623]what you find is that it's not a new idea,
[00:12:20.110]that the idea that degradation of the land,
[00:12:22.210]degradation of the soil, had impacted
[00:12:24.050]the stability and longevity of ancient civilizations.
[00:12:26.860]Environmental history textbooks are full of that argument.
[00:12:30.490]But the general argument that you read
[00:12:32.710]is that deforestation led to loss of the soil
[00:12:35.640]that undermined a society.
[00:12:38.290]But when you actually go out
[00:12:39.230]and you look at the archeological record
[00:12:40.970]and you put the pieces together,
[00:12:42.550]you see a bit of a different story.
[00:12:44.030]Well, you do find examples from ancient Mesopotamia
[00:12:47.140]to neolithic or Bronze Age Europe,
[00:12:48.780]classical Greece, Rome, the southern United States,
[00:12:52.410]Easter Island, China, Angkor Wat,
[00:12:54.950]you can go right around the world,
[00:12:55.990]Mesoamerica and the Olmecs and the Mayans after them,
[00:12:58.780]there are strong connections
[00:13:00.030]between the degradation of the soil
[00:13:01.677]and the longevity, if you will, of civilizations.
[00:13:05.660]But the culprit turned out not to be the ax.
[00:13:09.410]It was the plow that followed.
[00:13:12.080]That was my attempt in the Dirt book
[00:13:13.460]to basically rewrite the environmental history
[00:13:16.150]of how we've treated land
[00:13:17.320]to bring in the idea
[00:13:18.810]that tillage was one of the major factors
[00:13:22.660]that helped undermine ancient civilizations.
[00:13:25.110]Slowly, of course,
[00:13:27.210]but inevitably.
[00:13:29.080]What is it about tillage that actually helped,
[00:13:31.836]led to soil degradation and erosion?
[00:13:33.450]Well, think about what the plow does.
[00:13:36.170]It inverts the soil.
[00:13:37.410]That makes it pretty good weed control,
[00:13:39.690]that's why it's been used for a long time.
[00:13:41.750]But it also means that the soil's gonna be bare
[00:13:43.770]and vulnerable to erosion by wind or rain
[00:13:46.000]for the time until the next crop
[00:13:48.190]or the next weeds come into that field.
[00:13:50.340]And that was as true in Roman days as it is today.
[00:13:53.960]And how many of you have ever gone out to a native prairie
[00:13:57.710]or up into the mountains into a native forest,
[00:14:01.110]below timberline, and not in the Arctic,
[00:14:04.740]and seen vast expanses of bare brown earth?
[00:14:09.000]You don't see it.
[00:14:09.833]Nature clothed herself in plants.
[00:14:11.170]And there's strong reasons for that
[00:14:12.640]that goes back to the initial colonization
[00:14:14.270]of the continents by land plants.
[00:14:16.090]And I'll get into a little bit of that a little later.
[00:14:18.180]But the basic problem with tillage is
[00:14:19.860]it leaves the surface of the soil bare
[00:14:21.830]and vulnerable to erosion
[00:14:23.770]for some time of the year.
[00:14:25.040]And that allows the removal of soil
[00:14:27.010]to race ahead of the rebuilding of soil.
[00:14:29.457]And you can think of soil
[00:14:30.790]as a society's natural bank account,
[00:14:33.290]the natural capital that we use to grow our food
[00:14:36.060]that fuels our very existence.
[00:14:39.170]And in that sense, it's not unlike
[00:14:40.930]our own individual bank accounts.
[00:14:42.900]And I know for a fact, because I've demonstrated this
[00:14:45.330]several times, that if you spend money
[00:14:46.880]faster than you make it, you go broke.
[00:14:49.740]You can burn through your savings.
[00:14:50.990]It's just a matter of time
[00:14:52.500]if those numbers are out of balance.
[00:14:55.200]So if we think of soil as a system that's the same way,
[00:14:57.540]it's produced from the breaking down of rocks
[00:14:59.420]and merging with organic matter, with biologic life matter,
[00:15:03.320]and that's your income.
[00:15:04.830]And if you look at expenses as soil erosion,
[00:15:07.170]if you lose soil faster than you make it,
[00:15:08.830]you're quite literally running out of it.
[00:15:10.900]It's happened to societies around the world in the past,
[00:15:13.710]just too slowly to ever become the crisis du jour.
[00:15:18.903]Let me tell you a bit
[00:15:19.736]about one of those societies in particular.
[00:15:21.310]I'm gonna spare you all the societies
[00:15:22.890]that I talked about in the Dirt book.
[00:15:24.740]But I'm gonna focus on classical Greece.
[00:15:26.920]Why classical Greece?
[00:15:28.180]Because a geologist named Tjeerd Van Andel
[00:15:31.620]and an archeologist named Chris Runnels
[00:15:34.240]put together the story of what happened
[00:15:36.010]to the landscape in southern Greece
[00:15:38.060]by doing studies that are called geoarcheology,
[00:15:40.790]where geologists work with archeologists
[00:15:42.370]to reconstruct the history of a place.
[00:15:45.050]So they did all the work for me,
[00:15:46.280]and I could sort of harvest a few of their figures.
[00:15:48.630]But the basic idea is that cycles
[00:15:50.230]of soil erosion and formation
[00:15:52.510]began in Ancient Greece in the Bronze Age,
[00:15:54.920]in several thousand years before the time of Christ,
[00:15:59.860]that coincided with the introduction
[00:16:01.320]of plow-based agriculture.
[00:16:03.110]So what happened in Greece?
[00:16:04.580]Well, this shows you a cross-section
[00:16:06.630]of the typical hillside
[00:16:08.300]that Van Andel and Runnels published back in the 1980s
[00:16:11.370]that show that from the time
[00:16:13.410]from the end of the last glaciation
[00:16:15.140]to the arrival of the plow,
[00:16:17.010]most of the time period we live in,
[00:16:19.310]called the Holocene, the last 10,000 years,
[00:16:21.940]you had open oak woodland on the hillsides,
[00:16:23.920]you had the thin soil,
[00:16:24.917]the sort of the brown stuff with the vertical stripes,
[00:16:27.080]about one to three foot thick soil,
[00:16:29.170]you had valley bottom deposits
[00:16:31.060]in the alluvium down at the bottom of the hillsides
[00:16:33.870]and over bedrock.
[00:16:35.270]And this is sort of the typical souther Greek landscape.
[00:16:38.090]Now, where do you think that people started farming
[00:16:40.370]once they came to this landscape?
[00:16:41.490]Down in the valley bottoms,
[00:16:42.430]where you had flat, relatively well-worked ground,
[00:16:44.930]where water was readily accessible.
[00:16:47.050]And as the population rose, the farms spread
[00:16:49.270]up onto the hillsides, onto steeper terrain.
[00:16:52.300]And by the height of the Bronze Age
[00:16:54.150]and then again in the Classical Age of Greece,
[00:16:55.900]green fields literally spread right up the valley sides.
[00:16:59.560]And if you go back and you read
[00:17:01.270]Roman literature that survived,
[00:17:02.710]there's four books that have survived from Roman times.
[00:17:05.250]Unfortunately they're all in Latin,
[00:17:06.810]but they have been translated.
[00:17:08.110]So you can read them.
[00:17:09.760]The Romans are very much into plowing
[00:17:11.250]as the Greeks were before them.
[00:17:13.650]So what happened is that the soils on those hillsides
[00:17:16.710]eventually ended up down in the valley bottoms.
[00:17:19.230]They got eroded off.
[00:17:20.450]A lot of the sediment was retained on the landscape,
[00:17:23.710]but not all of it.
[00:17:24.590]Some of it went out to build deltas into the Mediterranean.
[00:17:28.150]But the problem, of course, is
[00:17:29.670]that if you strip the soils off the hillsides,
[00:17:32.630]in a landscape where the population had developed
[00:17:35.380]to rely on farming on the whole landscape,
[00:17:38.210]you'd be able to support fewer people
[00:17:39.920]just farming on the valley bottoms
[00:17:41.330]than if you had soil still on the hillsides.
[00:17:43.600]You can still find Bronze Age agricultural implements
[00:17:46.240]up on the bare, denuded rocky hillsides of southern Greece,
[00:17:49.230]in places where you couldn't grow crops
[00:17:50.850]because there's no soil left.
[00:17:53.320]This is a relatively extreme example.
[00:17:56.670]But I like it because very few places in the world
[00:17:59.290]where you've had three civilizations
[00:18:00.880]occupying the same piece of ground in succession.
[00:18:04.190]And when you're a geologist,
[00:18:05.430]when you start getting into thousands of years,
[00:18:07.470]you start to feel comfortable.
[00:18:09.320]Those are, like, real units of time for somebody like me.
[00:18:12.720]So what we have here is the population density
[00:18:15.190]of a particular valley in southern Greece,
[00:18:17.210]the Southern Argolid,
[00:18:18.770]that Van Andel and Runnels put together back in the 80s.
[00:18:21.440]It goes from 6000 BC, so about 8,000 years ago.
[00:18:24.200]So we're going almost all the way back to the Ice Age,
[00:18:26.830]and we're looking at how many people were in that valley.
[00:18:29.640]In the Bronze Age, so you started out
[00:18:31.470]with the low population density,
[00:18:33.270]you know, a few hundred people.
[00:18:35.080]In the Bronze Age they got it up to a few thousand people
[00:18:37.540]when the advent of agriculture came from points to the east,
[00:18:40.470]the plow came to this landscape.
[00:18:43.110]They had a few thousand year run at it.
[00:18:44.540]Then there was a crash back down
[00:18:45.910]to sort of pre-agricultural levels in a dark age,
[00:18:49.410]another rise of population, the age of classical Greece,
[00:18:52.360]another dark age, and then the modern age.
[00:18:54.700]So a rise, crash, rise, crash, rise.
[00:18:56.827]And of course the question we all wanna know is,
[00:18:58.590]what happens next?
[00:19:01.530]There's two aspects of this curve
[00:19:03.910]that I actually find really interesting.
[00:19:05.770]One of them is trivial.
[00:19:07.740]Why does the amplitude grow over time
[00:19:10.320]through successive civilizations?
[00:19:12.370]Well, the answer, I think, is obviously technology.
[00:19:14.910]We have better technology today
[00:19:16.500]than we did in the Bronze Age.
[00:19:18.120]I've yet to find anybody who objects
[00:19:20.010]to me stating that as a fact.
[00:19:25.040]But what about the periodicity?
[00:19:26.490]Why a rise, crash, rise, crash, rise?
[00:19:28.490]And it's a few thousand years to come up,
[00:19:30.080]with a couple thousand down,
[00:19:31.670]you know, roughly order of a thousand years or two.
[00:19:34.490]What sets that periodicity?
[00:19:35.770]That got me starting to think
[00:19:37.210]about what controls longevity of agricultural civilizations.
[00:19:41.840]Now of course it turns out that,
[00:19:43.220]like any good academic, I thought I was on
[00:19:45.160]to a really neat, original idea,
[00:19:47.330]until I started reading the literature
[00:19:49.400]and realized that the idea was thousands of years old.
[00:19:51.826](laughs)
[00:19:52.920]Plato recognized the magnitude
[00:19:55.730]of the Bronze Age soil erosion event
[00:19:58.530]on the Greek landscape
[00:19:59.810]and its ability to support population.
[00:20:02.850]He wrote in a quote that's worth
[00:20:04.749]reading in full from one of his Dialogues
[00:20:07.360]that "The rich, soft soil has all run away
[00:20:09.237]"leaving the land nothing but skin and bone.
[00:20:11.397]"But in those days the damage had not taken place,
[00:20:13.917]"the hills had high crests,
[00:20:15.197]"the rocky plain of Phelleus was covered with rich soil,
[00:20:17.807]"and the mountains were covered by thick woods,
[00:20:19.587]"of where there are some traces today."
[00:20:21.680]What Plato was observing was evidence
[00:20:24.740]of the Bronze Age soil erosion event.
[00:20:27.150]He described things like pedestals,
[00:20:30.190]soil pedestals on the margins and in the middle of fields
[00:20:33.180]around trees that the farmers did not plow over
[00:20:35.980]because it was their lunchtime shade tree, for example.
[00:20:39.260]And they were now sitting a meter or so,
[00:20:41.290]several feet, above the surrounding fields.
[00:20:43.780]Now what Plato realized is that the tree
[00:20:45.920]had not raised the earth to build a pedestal,
[00:20:49.110]the earth had eroded from around it.
[00:20:51.430]He then went and looked at the miles of rivers
[00:20:53.370]around the Greek peninsula
[00:20:54.990]and noticed that the rivers flowing out of the forest
[00:20:57.620]flowed clean and clear,
[00:20:59.450]and the rivers flowing out of the plowed fields were muddy
[00:21:02.990]and the rivers were building deltas
[00:21:04.870]out into the Mediterranean.
[00:21:07.090]Has anybody ever been to the ancient port of Rome, Ostia?
[00:21:11.670]How close to the ocean is it today?
[00:21:14.360]It's not on the sea anymore, is it?
[00:21:16.320]It's a few miles inland.
[00:21:18.220]That few miles of new land represents the soils
[00:21:21.670]that were farmed off of the hills of central Italy
[00:21:24.490]building out into the Mediterranean.
[00:21:26.670]This problem was not unique to the Greek landscape.
[00:21:30.820]But Plato probably deserves credit
[00:21:32.510]for recognizing this problem.
[00:21:35.150]Now I'm gonna pick on my own home state of Washington
[00:21:37.240]for a few minutes, in part because this is closer
[00:21:40.090]to Washington State University
[00:21:41.440]and I teach at University of Washington.
[00:21:43.540]So I can get away with this.
[00:21:45.821]But this picture is why a geologist
[00:21:49.240]would think of tillage as a very destructive act,
[00:21:54.800]as a slow motion train wreck
[00:21:56.270]in terms of soil development and building.
[00:21:58.560]All these little, well, this is a winter wheat field.
[00:22:01.150]This is a photograph taken of a winter wheat field
[00:22:03.230]that was in the classical winter wheat fallow rotation,
[00:22:05.380]taken in the fallow periods after it had been plowed.
[00:22:07.790]And then rain happened.
[00:22:09.840]All those little channels that are cut into there,
[00:22:11.590]they're called rills.
[00:22:12.423]A geologist like myself doesn't,
[00:22:14.810]they're not, like, permanent landscape features.
[00:22:16.840]They could be erased by a single pass of the plow.
[00:22:19.050]They're an agronomic nuisance.
[00:22:21.150]But they can add up if they happen year after year.
[00:22:25.710]So this next slide's also from that same area,
[00:22:29.270]in the Palouse, it's a, you know,
[00:22:31.330]have beautiful loose and volcanic soils
[00:22:33.703]that are mostly wind deposited, somewhat steep hills,
[00:22:37.580]it's sort of an erosion engine
[00:22:39.470]once you take the native grasses off it.
[00:22:42.040]This shows you how those little rills can add up over time.
[00:22:45.130]The fence up there in the upper right
[00:22:46.510]is a fence that the farmer built around his water cistern
[00:22:49.500]back in 1911 when the land was first plowed.
[00:22:53.090]Between 1911 and 1961, nothing happened on this field
[00:22:56.610]other than it was in that wheat-fallow rotation,
[00:22:59.290]and then occasionally it would rain
[00:23:03.120]and those rills would form.
[00:23:05.640]By 1961, this bit of a cliff had developed
[00:23:08.250]around the, on this fence line.
[00:23:12.700]I'd sort of view them as sort of fence line cliffs.
[00:23:15.030]You can see similar things around some,
[00:23:17.290]well, I have a student who's now using laser surveying data
[00:23:21.010]to do this for the entire state of Iowa
[00:23:23.020]and look at sort of the offsets
[00:23:24.580]around pioneer cemeteries and other other places.
[00:23:27.740]How big an offset of this?
[00:23:29.100]How much erosion happened in the 50 years in between?
[00:23:32.030]Well, you can't really tell from this scale,
[00:23:33.730]but that's a five-foot high cliff.
[00:23:36.590]That's five feet of erosion in 50 years,
[00:23:38.770]that's about a foot every decade.
[00:23:41.545]That's about an inch a year.
[00:23:44.620]There's nowhere on Earth that soil forms that fast.
[00:23:48.870]Except in my wife's garden
[00:23:50.840]and on some of the farms that I've visited.
[00:23:53.860]But if you think about soil forming
[00:23:55.740]from breaking down rocks,
[00:23:57.790]it takes centuries to form an inch of soil.
[00:24:00.840]If you already have the mineral matter,
[00:24:02.610]you can build healthy fertile soil fast
[00:24:04.680]by adding the biology.
[00:24:06.300]But I'm getting ahead of myself.
[00:24:08.640]So there's nowhere on Earth
[00:24:10.070]that soil's forming that fast naturally.
[00:24:13.560]But I also hope you're sitting there, thinking,
[00:24:14.967]"Dave, that's a pretty extreme example, isn't it?"
[00:24:18.490]And my response to that would be, "Of course it is.
[00:24:20.987]"That's why I like to use it."
[00:24:24.270]How typical is it, though,
[00:24:25.570]is the question you should be asking.
[00:24:28.560]'Cause that's one corner of one field
[00:24:30.400]in one part of the country.
[00:24:32.490]So let's expand our scale a bit up
[00:24:34.560]and go and look at the magnitude of soil erosion
[00:24:38.170]in the last few 100 years, historical soil erosion,
[00:24:40.680]so soil erosion after the advent of western agriculture,
[00:24:45.760]from Virginia to Alabama in the hill country.
[00:24:48.500]That gray noodle is not the coastal plain,
[00:24:51.370]not the Appalachians, it's the hill country in between.
[00:24:54.393]It's sort of the rolling hills
[00:24:55.840]where you might expect erosion to potentially be a problem,
[00:24:58.800]'cause the steeper the slope,
[00:25:00.170]the worse the erosion problem will be.
[00:25:02.160]And that's simple physics and geometry.
[00:25:05.480]But notice four to 10 inches of soil erosion
[00:25:07.860]over most of the area,
[00:25:08.940]more than 10 inches in some areas.
[00:25:11.080]How big a deal is that?
[00:25:13.290]Well, if you go back and you read the original journals
[00:25:16.070]of some of the early plantation owners in this area,
[00:25:18.800]they only had six to 12 inches of rich black earth
[00:25:21.030]over the subsoil to begin with.
[00:25:23.030]So if we could erode off a third to all of the topsoil
[00:25:29.140]across a region that was once
[00:25:30.510]one of the early bread baskets
[00:25:31.960]of the North American colonies,
[00:25:34.040]think what the Greeks could have done
[00:25:35.150]with an 800-year run in southern Greece,
[00:25:36.750]or the Romans at a thousand-year run in central Italy.
[00:25:40.090]It starts to put into perspective the idea
[00:25:42.400]that long-term reliance on tillage
[00:25:45.020]can actually undermine the ability of the land
[00:25:48.870]to support agriculture in a pretty serious way.
[00:25:51.620]It just does it at a slow enough pace
[00:25:53.950]that it's hard to notice
[00:25:55.360]other than retrospectively over a lifetime.
[00:26:02.430]There's one other element to soil degradation
[00:26:04.920]that I should mention.
[00:26:05.753]So far I've been mostly talking about soil erosion.
[00:26:08.870]But I also went to one of these, a farm
[00:26:11.890]in that gray noodle of the Piedmont country
[00:26:16.600]in North Carolina as part of a TV show called Nova
[00:26:20.070]that I've done a few episodes for, little bits in,
[00:26:22.800]where I got a call from them at one point, saying,
[00:26:25.337]"We have this three-part series
[00:26:26.697]"on the geologic history of North America
[00:26:28.897]"and we're in final production and we realize
[00:26:30.727]"that we've kind of forgot something
[00:26:31.887]"that might be important.
[00:26:33.657]"Is there anything that you could do
[00:26:34.977]"to tell the history of soil in North America
[00:26:37.507]"in three minutes or less?"
[00:26:40.460]'Cause that's kind of like the time
[00:26:41.850]you can slot between commercials.
[00:26:45.210]And I basically said, "Well, let's go
[00:26:46.377]"to a tobacco plantation in North Carolina
[00:26:48.417]"and let's put out a white tablecloth,
[00:26:50.487]"and let's dig soil out of the conventional tobacco field
[00:26:56.397]"that had been farmed conventionally
[00:26:58.777]"for the last 100 years," that's the soil on the right,
[00:27:01.517]"and then let's look at the soil
[00:27:03.537]"on the neighboring field,
[00:27:04.947]"that had been a farm up until about 100, 120 years ago
[00:27:08.017]"and was then abandoned."
[00:27:09.310]And we know that 'cause there's trees
[00:27:10.610]about yay big in diameter growing on it.
[00:27:14.280]So we went, got that,
[00:27:15.690]put it on the white tablecloth right by it.
[00:27:18.212]And you notice there's a bit of a difference
[00:27:19.570]between these soils.
[00:27:20.960]It's the same parent material, it's the same climate.
[00:27:23.680]The only difference is the management.
[00:27:25.700]What's happened to it, what people have done to it
[00:27:27.810]over the last century.
[00:27:29.240]This one looks a lot like beach sand,
[00:27:31.550]and for a very good reason.
[00:27:33.020]It is beach sand.
[00:27:34.400]It's 10 million year old beach sand.
[00:27:35.870]It's Miocene-aged beach sand.
[00:27:37.890]The soil on the left has a lot more organic matter in it.
[00:27:40.830]The difference in color is organic matter.
[00:27:43.090]The difference in structure,
[00:27:44.070]you've got a lot of salts over here,
[00:27:45.710]you don't over there.
[00:27:47.747]Yet basically the soils are the same.
[00:27:49.520]If I took these samples and gave them
[00:27:51.020]to an undergraduate class of geologists
[00:27:52.950]and I asked them if they were the same soil,
[00:27:54.220]they'd tell me I was nuts.
[00:27:58.180]But technically they are.
[00:27:59.410]They're just different in the way
[00:28:01.630]that they've been treated over the last century.
[00:28:04.050]What we do to the soil can affect it a lot.
[00:28:07.280]And as you notice the difference
[00:28:08.410]in colors in that last slide,
[00:28:10.020]that was due mostly to differences in organic matter,
[00:28:12.720]in carbon in the soil.
[00:28:14.490]And if we look at what's happened
[00:28:15.790]over the last few centuries
[00:28:17.380]to North American farmland and rain soils,
[00:28:20.990]we've lost about 50% of the soil organic matter
[00:28:24.195]that they originally had as native soils.
[00:28:27.200]And one of the things I've been finding,
[00:28:28.530]one of the interesting things about coming
[00:28:30.010]and talking to conferences like this is
[00:28:31.133]that I've been finding that almost wherever I go
[00:28:33.420]across North America, I find the answer's about the same.
[00:28:37.160]We've taken soils that are, like, five or 6% organic matter
[00:28:39.850]turned into about two or 3%, or 8% into 4%, or 4% into 2%,
[00:28:43.800]we've lost about half of the organic matter in our soils.
[00:28:46.870]And as I'll talk about in a moment,
[00:28:49.060]that's essentially drawing down the batteries
[00:28:51.560]that power the biology
[00:28:53.530]that is really a key part of the engine of fertility
[00:28:56.940]that helps to drive productivity in soils.
[00:29:02.100]And I wanna emphasize
[00:29:02.980]this is not just a North American problem.
[00:29:04.690]How many of you had coffee this morning?
[00:29:09.280]Well, as part of writing Growing Revolution,
[00:29:11.660]that third book that I'm about to get to in a few minutes,
[00:29:13.930]I went and visited coffee country in Costa Rica.
[00:29:17.450]This shows you two soils from the heart of coffee country.
[00:29:21.390]I'll spare the village the name of the valley
[00:29:23.990]that it was actually in.
[00:29:25.250]But when you drive over the crest
[00:29:26.560]of the mountains in Central America
[00:29:29.490]and you look down into this valley,
[00:29:30.700]the river is flowing this color.
[00:29:32.900]It's flowing orange.
[00:29:34.640]And rivers aren't supposed to flow orange, are they?
[00:29:37.320]What's happening is, they're bleeding soil
[00:29:39.010]off of their coffee fields.
[00:29:42.500]This shows you in part the net result of that.
[00:29:46.020]If you go to the heart of the coffee plantations,
[00:29:48.010]the soil on the right looks like this over here.
[00:29:50.040]It's subsoil to the surface.
[00:29:52.500]The topsoil is quite literally gone.
[00:29:54.130]If you go to the native jungle right around it,
[00:29:57.180]this notebook there is for scale.
[00:29:58.413]It's about, oh, eight inches or so high,
[00:30:01.090]there's about a foot or more of black topsoil
[00:30:04.110]over the more orangy subsoil.
[00:30:06.860]It took 'em just a hundred years
[00:30:08.030]to lose their entire topsoil off this landscape.
[00:30:10.310]They've only been farming this for a hundred years.
[00:30:13.110]Again, it puts into perspective
[00:30:14.870]that the problem of soil loss
[00:30:16.680]and soil organic matter degradation
[00:30:19.590]can actually add up surprisingly fast.
[00:30:23.360]So far I've told you anecdotes,
[00:30:25.300]I've told you stories.
[00:30:26.140]I haven't shown you a whole lot of data.
[00:30:28.060]But, you know, I'm a research scientist.
[00:30:29.550]When I put the Dirt book together,
[00:30:31.100]I was very interested in understanding
[00:30:32.970]to what degree does modern data back up or refute
[00:30:37.350]the story that seemed to be coming into focus
[00:30:39.330]from the archeology and geology?
[00:30:41.900]So I went to the library for about a month
[00:30:43.650]and I gathered up all the data that I could find
[00:30:45.870]on how fast do natural environments erode,
[00:30:49.230]how fast do soils build naturally.
[00:30:51.200]And I boiled it all down into a single table.
[00:30:53.890]If you're really interested in the background to this,
[00:30:56.750]there's a paper in the proceedings
[00:30:58.020]of the National Academy of Sciences
[00:30:59.840]that has something like a 30-page Excel spreadsheet
[00:31:02.530]that has all background data in it.
[00:31:05.010]Nobody should ever have to compile this again.
[00:31:08.380]What I have over here are the different kinds
[00:31:09.980]of rates that I looked at.
[00:31:12.050]The numbers in parentheses are the number
[00:31:13.810]of peer-reviewed academic studies
[00:31:15.670]that I took data from
[00:31:17.160]to generate the averages over here on the right.
[00:31:19.900]If you wanna look at the full distributions,
[00:31:21.650]I published that in the original paper, too,
[00:31:23.270]but it's, you know, it's highly variable.
[00:31:25.670]But these are the averages.
[00:31:26.780]The medians, half the values I found are smaller,
[00:31:28.990]half are higher, are reporting the one right in the middle.
[00:31:32.440]Conventional farming, by which I mean in this paper
[00:31:35.940]tillage-based farming, everywhere from small plowed fields
[00:31:40.780]in the developing world
[00:31:42.640]to large mechanized operations in this country,
[00:31:46.220]average erosion rate a millimeter and a half a year.
[00:31:49.440]Now globally, that's a pretty small number,
[00:31:51.570]don't you think?
[00:31:53.180]Except that means it only takes 20 years
[00:31:54.910]to lose an inch of soil.
[00:31:58.570]If you look at how fast nature builds soils,
[00:32:01.910]the soil production rate is about 2% of a millimeter a year.
[00:32:05.230]That means it takes about a thousand years
[00:32:06.820]to build an inch of soil.
[00:32:08.700]That's the problem.
[00:32:10.780]Our rate of soil erosion is much higher
[00:32:13.110]than our rate of soil building,
[00:32:15.420]viewed through the thick, fuzzy lens
[00:32:17.890]and eyes of a geologist at a global scale.
[00:32:21.700]Natural landscapes, and over the long term,
[00:32:24.100]they erode at about the same pace as soil production.
[00:32:26.270]That makes sense.
[00:32:27.103]They should be in balance.
[00:32:29.160]They're not.
[00:32:30.740]The good news is that erosion rates
[00:32:32.520]under no-till farming are down
[00:32:34.380]much closer to long-term natural rates
[00:32:36.560]of soil building and soil loss.
[00:32:38.710]In other words, we know how to farm
[00:32:40.170]in ways that help to minimize the rate of soil erosion.
[00:32:43.870]It's by minimizing disturbance, it's by going to no-till.
[00:32:47.110]The bad news, of course, is
[00:32:48.073]that as we look around the world,
[00:32:50.140]that's still a minority of the world's crop land.
[00:32:54.630]Now so far I've given you all the data
[00:32:56.290]that it would take for you to calculate
[00:32:57.830]the longevity of an agricultural civilization
[00:33:00.250]on the back of your napkin.
[00:33:01.760]And if you want, feel free to follow along
[00:33:03.570]and check my math.
[00:33:04.840]But basically that net soil loss
[00:33:06.880]of about a millimeter a year,
[00:33:07.970]and I could argue for a millimeter and a half,
[00:33:09.940]means you could lose a half meter to one meter thick soil,
[00:33:13.210]about a one to three-foot-thick soil,
[00:33:14.930]in, you know, a thousand years.
[00:33:16.611](audio warps)
[00:33:19.827]One of the things I found in writing the Dirt book
[00:33:21.420]is the average longevity
[00:33:22.800]of agricultural civilizations around the world
[00:33:24.890]was about a thousand years, plus or minus.
[00:33:28.990]With a few really key exceptions.
[00:33:30.870]And I hope you're sitting there, thinking, "But what about?"
[00:33:33.910]'Cause what about the Nile and Egypt?
[00:33:37.130]Haven't they farmed there for thousands of years?
[00:33:39.540]The Tigris and Euphrates, the original Garden of Eden?
[00:33:43.660]What about the Indus and the Brahmaputra in India,
[00:33:46.000]where the early agricultural civilizations there developed?
[00:33:48.330]Or the rivers of lowland China?
[00:33:50.670]These are all places where farming has been practiced
[00:33:52.770]for thousands of years.
[00:33:54.650]Doesn't that blow my idea out of the water?
[00:33:56.570]Well, all those places are developed
[00:33:59.310]on major river flood plains.
[00:34:00.760]And the answer to the conundrum is hidden
[00:34:02.230]right there in that word flood plain.
[00:34:04.200]'Cause what happens on a flood plain?
[00:34:07.880]Anybody?
[00:34:09.108](audience member speaks off-microphone)
[00:34:10.370]It floods!
[00:34:13.511]And does the flood water come clean?
[00:34:16.900]No, it comes with the soil eroded off of,
[00:34:20.290]you know, your upstream neighbors,
[00:34:21.670]it comes with nutrients in the water,
[00:34:23.150]it comes with organic matter,
[00:34:24.240]it comes with tires and cars
[00:34:25.690]and whatever else is in the water.
[00:34:28.340]But if you look back around the world,
[00:34:30.460]if you wanna find agriculturally-destroyed landscapes,
[00:34:34.000]look upstream of those long-lived civilizations.
[00:34:37.870]Look in the Zagros Mountains,
[00:34:39.940]look in Somalia and Ethiopia,
[00:34:42.350]look in the Himalaya, look in eastern Tibet,
[00:34:46.700]western China, the original heart of agriculture.
[00:34:48.820]Those are all landscapes that are seriously denuded
[00:34:52.850]and whose topsoil subsidized the agricultural civilizations
[00:34:56.720]down in the flood plains and the deltas.
[00:34:58.860]There's a reason that those societies
[00:35:01.180]thrived on flood plains.
[00:35:02.950]You can get away with flood farming there, with the plow.
[00:35:07.160]Anyone know how thick a grain of sand is,
[00:35:11.060]or how large a grain of sand it,
[00:35:12.183]is a better way to put it.
[00:35:13.610]About a millimeter to two millimeters
[00:35:15.350]for medium to coarse sand.
[00:35:17.650]That long-term erosion rate with the plow-based agriculture
[00:35:20.060]of a millimeter and a half,
[00:35:21.010]you could offset it with the deposition
[00:35:22.640]of a single grain of sand every year.
[00:35:25.670]Those numbers could be in balance.
[00:35:27.150]In other words, there's parts of the landscape
[00:35:28.680]that are quite resilient to tillage.
[00:35:31.710]But it tends to be a small portion of the landscape.
[00:35:34.870]The river bottoms, flood plains.
[00:35:38.270]So this all started me,
[00:35:39.950]so I promise the depressing part of the talk is now over.
[00:35:43.940]What I wanna do is pivot to try and look at the question
[00:35:46.420]that writing the Dirt book made me wrestle with,
[00:35:48.520]which is, can we reverse the historical pattern
[00:35:50.480]of soil degradation?
[00:35:51.860]And I started looking into that
[00:35:54.650]in writing The Hidden Half of Nature,
[00:35:56.130]the book that Anne and I wrote together,
[00:35:57.980]that we started on in sort of an unusual manner.
[00:36:03.746]I was not accustomed to doing field work in my own yard.
[00:36:07.512]Was used to doing field work around the world.
[00:36:08.760]We bought a house back in the late 1990s
[00:36:11.350]that came with a side yard
[00:36:12.940]that had a vast expanse of lawn.
[00:36:15.300]And Anne is a biologist, she's a gardener,
[00:36:17.490]she wanted a garden.
[00:36:18.720]This is her chance to terraform
[00:36:20.300]and make whatever she desired.
[00:36:22.300]And so we pulled up that lawn
[00:36:23.750]and we discovered we had this,
[00:36:25.200]you know, the kind of rich, black earth
[00:36:27.250]that was the envy of farmers (audio skips) the world.
[00:36:33.250]No.
[00:36:35.460]We had crap soil.
[00:36:37.588]We had glacial till.
[00:36:39.220]Seattle is a place that was overrun by a glacier
[00:36:42.280]17 to 15,000 years ago.
[00:36:44.270]And this stuff was bits of Canada
[00:36:46.980]that were scraped off, pushed down to the Puget Sound
[00:36:50.380]and then overrun by a mile-high wall of ice
[00:36:52.950]that compressed it into nature's concrete.
[00:36:55.410]We didn't find a single worm below that lawn.
[00:36:58.970]We didn't find a single life form.
[00:37:00.590]I'm sure there were some bacteria and fungi there,
[00:37:02.700]but Anne realized that, if she was gonna make
[00:37:06.270]the kind of garden she wanted, we had to fix her soil.
[00:37:09.600]We had to turn that dirt into soil.
[00:37:11.630]And so she's the biologist.
[00:37:13.720]She decided that we had the mineral matter.
[00:37:15.530]What we needed was the biological part of soil.
[00:37:18.130]So she started, she painted her wheelbarrow up
[00:37:19.990]to sort of speed things along
[00:37:22.380]and started convincing arborists to give us the wood chips
[00:37:27.250]and adding organic matter
[00:37:28.520]from every source that we could find.
[00:37:30.870]And what she managed to do is turn this soil
[00:37:33.870]into this soil.
[00:37:34.840]This is from another Nova episode from last spring
[00:37:37.180]that they descended on our house to film.
[00:37:40.370]Our original soil, so we still have a little part
[00:37:43.240]that we didn't touch.
[00:37:44.540]It had about 1% organic matter.
[00:37:47.490]The few wood chips in there
[00:37:48.610]were sort of added as mulch later.
[00:37:50.290]This soil, which is typical of most the yard now,
[00:37:52.660]is about eight to 10% carbon.
[00:37:57.810]Huge difference.
[00:37:59.110]And it happened in about 12 years.
[00:38:01.660]Pretty fast, almost a percent a year of change.
[00:38:04.890]And it came from adding organic matter,
[00:38:07.110]layering compost and mulch in the yard.
[00:38:09.210]We didn't dig, we didn't disturb.
[00:38:10.940]Why?
[00:38:11.773]We were busy.
[00:38:12.640]We didn't have time to do that.
[00:38:14.350]And okay, we were a little lazy, too.
[00:38:15.810]But we basically added compost and mulch.
[00:38:17.760]And what we realized, and over the course of doing this,
[00:38:21.840]is that we were not the ones
[00:38:23.240]doing the lion's share of the work.
[00:38:24.480]A lot of the work was being done
[00:38:26.290]by the soil food web, the bacteria and the fungi in the soil
[00:38:29.930]that were consuming, breaking down the compost,
[00:38:33.630]the nematodes and arthropods were consuming
[00:38:35.930]the bacteria and fungi and then excreting their bodies,
[00:38:39.950]essentially manuring the soil from the inside out.
[00:38:44.460]Things like the worms that would chew up leaves
[00:38:46.950]and grind them and mix them physically with soil particles,
[00:38:49.930]and then the microbes, the campa bacteria here,
[00:38:52.690]the fungi here with the little hyphae
[00:38:55.210]connecting to a plant root,
[00:38:57.060]these guys are actually the engines
[00:38:59.640]that were processing a lot of that organic matter
[00:39:01.770]back into forms that could be taken up by plants
[00:39:04.380]when their bodies were consumed by their predators,
[00:39:07.750]nematodes and microarthropods that would consume these guys
[00:39:11.200]who are rich in things like nitrogen,
[00:39:13.100]phosphorus and mineral micronutrients that plants need.
[00:39:18.500]When these guys excrete their waste,
[00:39:20.930]they essentially are manuring the soil from the inside out.
[00:39:26.440]And Anne and I started to get fascinated
[00:39:28.130]by what's happening in the soil
[00:39:30.640]as the engine of rebuilding the fertility of our yard.
[00:39:34.790]And when we ran across papers
[00:39:37.220]that were talking about exudates
[00:39:38.940]flowing out of plant roots and into the soil,
[00:39:41.710]we realized that what we had been taught
[00:39:43.630]in graduate-level soil science classes
[00:39:45.550]about plant roots essentially being straws
[00:39:47.610]that could draw up the soluble portion
[00:39:49.720]of whatever nutrients were soluble in fluids
[00:39:53.720]was really only half the story,
[00:39:55.350]that roots were actually two-way highways, two-way streets.
[00:39:58.760]And we were quite literally shocked
[00:40:01.280]to learn from research journals
[00:40:03.810]that some plants will actually push out
[00:40:05.337]30, 40% or more of the material they produce
[00:40:09.870]through their ability to photosynthesize.
[00:40:11.510]They'll push it out of their roots and into the soil.
[00:40:14.180]Now, how many of us take 30 or 40% of our income
[00:40:17.800]and just go leave it on a street corner somewhere?
[00:40:20.160]And I'm not talking about taxes.
[00:40:21.650]That's a whole different story.
[00:40:26.100]No, why would plants basically be putting out that much,
[00:40:29.980]expending the energy to make exudates which,
[00:40:33.330]when you look at them, what are they?
[00:40:34.800]They're sugars, they're carbohydrates,
[00:40:37.460]they are proteins, they are fats.
[00:40:39.900]There's papers that have documented plants
[00:40:42.540]exuding lipids into the soil.
[00:40:44.860]So carbs, proteins and fats.
[00:40:46.290]What's that sound like?
[00:40:47.310]Food.
[00:40:48.601]Plants are pushing food out into the soil.
[00:40:50.640]Why would they do that?
[00:40:52.410]Well, it turns out that when you look at the zone
[00:40:54.760]called the rhizosphere, which is simply Greek
[00:40:57.270]for area around the roots of a plant,
[00:41:00.400]it's one of the nice things about Greek,
[00:41:01.570]it's pretty transparent once you know it,
[00:41:05.430]that in that rhizosphere,
[00:41:07.210]there's what Anne and I have termed a biological bazaar.
[00:41:11.070]It's a trading system
[00:41:12.820]where the plants are pushing exudates out of their roots
[00:41:16.670]and then in that purple zone of the rhizosphere,
[00:41:19.120]which extends about a millimeter to a centimeter
[00:41:21.300]around the tip of the roots of plants,
[00:41:23.100]there's an abundance of microbes,
[00:41:24.870]bacteria and fungi, that are essentially there
[00:41:27.870]to consume the smorgasbord,
[00:41:30.230]the banquet the plants are putting out into the soil.
[00:41:33.960]The zone around the roots of plants
[00:41:35.200]are some of the most life-rich zones on the planet.
[00:41:39.418]To put out those exudates into the soil,
[00:41:40.840]what happens to those exudates?
[00:41:42.700]Well, it's kinda like what happens
[00:41:44.070]when you put beer and pizza out at a university.
[00:41:48.130]The students come and they consume it.
[00:41:50.650]And then what do they do?
[00:41:51.710]They run off to the bathrooms.
[00:41:54.030]So what are all those microbes doing with those exudates?
[00:41:56.910]They consume them, they power their bodies,
[00:41:59.140]and they produce their own metabolites or waste products.
[00:42:03.690]When Anne and I read papers that documented
[00:42:06.000]that microbial metabolites living in the rhizosphere
[00:42:08.800]were consuming exudates and producing
[00:42:10.830]plant growth-promoting hormones
[00:42:12.610]for the particular plants
[00:42:15.780]that they were eating the exudates from,
[00:42:18.260]the lights went on.
[00:42:21.320]The plants are feeding the microbes
[00:42:22.620]because the microbes are sort of serving
[00:42:24.760]as off-shored chemical factories
[00:42:27.020]that are making things that are useful
[00:42:28.940]to the plants' health and defense
[00:42:30.660]that the plant can't make for itself.
[00:42:33.060]It is a partnership.
[00:42:34.690]The plants are feeding the microbes
[00:42:36.040]because the microbes are helping the plants thrive.
[00:42:38.100]And if the plants are thriving,
[00:42:39.230]they're producing more exudates that feed the microbes.
[00:42:41.330]It's a virtuous circle.
[00:42:42.590]It's a positive feedback.
[00:42:46.490]And that extends to the role of fungi in the soil,
[00:42:48.950]which by building their hyphae,
[00:42:52.238]and their microized little hyphae in particular,
[00:42:53.680]out into the soil.
[00:42:55.070]They essentially are functioning as miners and truckers
[00:42:58.260]that are gathering mineral elements from soil particles
[00:43:01.710]and they transport them back along their bodies
[00:43:04.130]to then exchange with the plants in exchange for sugars.
[00:43:07.640]Fungi can't produce sugars.
[00:43:09.520]They can't photosynthesize.
[00:43:11.650]They can metabolize things.
[00:43:13.710]They can reprocess dead things.
[00:43:15.910]They can't create new life from carbon and oxygen
[00:43:18.360]the way that photosynthesis can.
[00:43:20.090]So what they is, they've specialized
[00:43:22.690]in trying to get mineral elements out of the soil.
[00:43:25.870]There's some that will focus on phosphorus
[00:43:27.930]and other mineral micronutrients,
[00:43:29.620]things that in effect allow them
[00:43:31.890]to serve as root extensions for plants
[00:43:35.000]to get mineral, both major and minor elements,
[00:43:37.440]that the plant can't reach.
[00:43:39.150]And they're subsidized by the exudates.
[00:43:43.060]And those partnerships allow us
[00:43:44.460]to look at two different ways
[00:43:45.680]of thinking about a plant's diet.
[00:43:47.220]I hadn't thought about a plant having a diet
[00:43:49.310]when I started working on these books.
[00:43:51.600]I've now come to realize that wow,
[00:43:53.410]just like the way our diets impact our health,
[00:43:57.140]the plants' diets impact their health.
[00:43:59.580]And there's two ways to think about a plant's diet.
[00:44:02.740]You can actually grow large plants
[00:44:06.090]in relatively poor soil, so organic matter-poor soil,
[00:44:09.320]if you add enough major elements.
[00:44:11.240]Sort of the N, P, K that we know,
[00:44:13.290]well, at least for the N and P,
[00:44:15.150]we know that there's solid evidence
[00:44:16.790]that it can actually boost yields if they're.
[00:44:21.020]But what happens is that plants don't invest
[00:44:23.880]as much in their root system
[00:44:25.220]when they get an abundance of the major elements
[00:44:27.323]that they need for growth.
[00:44:28.810]The elements they need for growth
[00:44:29.747]and the elements they need for health
[00:44:31.140]are a little different at times.
[00:44:34.280]And you could run this experiment
[00:44:35.430]for yourself on corn plants.
[00:44:37.350]Ones in very fertilized plants in very poor soils
[00:44:41.758]are pretty easy to pull up by their roots.
[00:44:44.650]Much harder to do that to a corn plant
[00:44:46.690]that's grown in healthy, fertile soil
[00:44:50.050]that's rich in organic matter.
[00:44:51.400]So what you're missing out on
[00:44:53.500]in growing plants in relatively poor soil
[00:44:55.410]are the mineral micronutrients
[00:44:56.980]and those beneficial microbial metabolites
[00:44:58.860]'cause the plants are not investing
[00:45:00.140]as much in the root system,
[00:45:01.500]which means there's not as many exudates,
[00:45:03.480]which means that you're getting
[00:45:04.410]a different composition of life in the soil.
[00:45:08.450]If you're growing stuff in more healthy, fertile soil,
[00:45:11.160]you can basically, you may still need to fertilize
[00:45:13.810]to some degree,
[00:45:15.540]but you'll get a higher dose, if you will,
[00:45:19.280]of the mineral micronutrients
[00:45:20.480]and beneficial microbial metabolites.
[00:45:22.100]There's different ways to think, in other words,
[00:45:24.230]about how to actually benefit
[00:45:26.720]the health and growth of crops.
[00:45:30.890]So at that point, I was starting to think about,
[00:45:35.150]wow, if we could restore the fertility
[00:45:37.400]on our little scrap of north Seattle
[00:45:39.420]and do it in less than a decade,
[00:45:40.950]take 1% organic matter to pushing 10%
[00:45:43.710]across our whole lot,
[00:45:45.680]could these kinds of ideas and thinking
[00:45:47.610]actually work on fully operational farms at scale
[00:45:51.730]and on an economic basis?
[00:45:53.640]So I took six months off from teaching
[00:45:55.480]at the University of Washington
[00:45:56.940]and visited farmers around the world
[00:45:58.920]to try and ask that very question.
[00:46:00.620]And I selected farmers who had been pioneers
[00:46:04.359]in rebuilding the health and fertility of the soil,
[00:46:06.990]because as a geologist, I kinda suspected
[00:46:09.300]it would take a while
[00:46:10.610]and I didn't have the patience to actually run
[00:46:12.520]that kind of experiment myself.
[00:46:14.270]So I went to find people who had actually already done it.
[00:46:17.790]Thank you.
[00:46:19.780]And to basically share the answer at the start,
[00:46:23.260]I visited farms around the world
[00:46:24.710]that had rebuilt soil health.
[00:46:26.150]The people who had adopted the three principles
[00:46:28.090]of Conservation Agriculture
[00:46:30.030]were matching the yields of their conventional neighbors
[00:46:32.700]but using far less oil and chemical inputs to do it.
[00:46:35.680]That made them more profitable.
[00:46:37.890]And I'll share some of their stories
[00:46:40.010]with you in a minute.
[00:46:42.160]But briefly, what are those three principles
[00:46:43.930]of Conservation Agriculture?
[00:46:45.670]Well, it's minimal or no disturbance,
[00:46:47.900]which is essentially no-till,
[00:46:50.410]maintaining a permanent ground cover
[00:46:52.150]or maintaining cover crops,
[00:46:53.460]and adopting diverse rotations,
[00:46:55.387]or, you know, four or five crops
[00:46:57.820]or a great diversity in the cover crops.
[00:47:01.060]There were some of the farmers I visited
[00:47:02.380]who had just three cash crops
[00:47:04.350]but major diversity in their cover crops.
[00:47:06.710]And why are all these microbes on the screen?
[00:47:09.180]Because if you were to try and think of
[00:47:10.750]how you would devise a system of farming
[00:47:14.080]to cultivate the beneficial life in the rhizosphere,
[00:47:17.390]so it could actually do what it evolved to do
[00:47:21.000]for the plants that are growing there
[00:47:22.410]to support their health and their growth,
[00:47:24.590]what you would do is, you wouldn't disturb them,
[00:47:26.860]you would feed them, and you would plant
[00:47:30.240]a diversity of them
[00:47:31.370]so that there'd be a diverse community
[00:47:33.320]of microbes in the soil.
[00:47:34.920]The rationale for that is, well, minimal disturbance,
[00:47:37.340]how comfortable do you think you would be
[00:47:39.130]if somebody came by once a year,
[00:47:41.020]took the roof off of your house
[00:47:42.330]and stirred all your belongings up?
[00:47:46.220]You'd move pretty fast.
[00:47:47.710]The plow does that to soil life.
[00:47:49.580]The analogy is pretty good.
[00:47:51.700]So that's shelter.
[00:47:53.570]You can think of cover crops as food,
[00:47:55.320]getting organic matter back into the soil.
[00:47:57.110]Cover crops are a great way to do that.
[00:47:59.350]It also keeps the ground covered.
[00:48:01.050]And if you have living roots
[00:48:02.490]that are exuding into the soil at all times,
[00:48:04.890]what becomes soil organic matter?
[00:48:06.530]It's the dead bodies of those organisms
[00:48:08.400]that eat the exudates.
[00:48:09.870]If you don't have the exudates,
[00:48:10.940]you're not building the soil life,
[00:48:12.160]you're not gonna build the organic matter as much.
[00:48:14.220]And the diversity of crop rotations?
[00:48:15.860]Well, think about the functionality
[00:48:18.400]of a community of organisms in any setting.
[00:48:22.620]How dysfunctional would be an entire city
[00:48:25.570]made of geology professors be?
[00:48:30.155]Starve.
[00:48:31.980]Of course we'd argue to the end, but we'd starve.
[00:48:37.010]So there's basic reasons why those three principles
[00:48:40.490]work for cultivating the beneficial life in the soil.
[00:48:44.600]Those general principles do translate to other settings,
[00:48:47.190]and I'll share a few stories briefly with you in a minute.
[00:48:49.740]But the specific practices that farmers use
[00:48:52.180]in different regions need to be tailored to their farms,
[00:48:54.860]their landscape, their climate, their crops,
[00:48:57.360]their technology, their sociopolitical and economic systems.
[00:49:00.690]In other words, the general principles translate,
[00:49:04.510]the specifics of practices don't.
[00:49:06.990]That's why we need research,
[00:49:08.600]we need people to figure out how to adapt these principles
[00:49:11.150]to different places
[00:49:12.690]in ways that will work economically
[00:49:14.300]for farmers in those regions.
[00:49:19.340]And I will share with you very briefly
[00:49:21.810]a few of the people that I visited
[00:49:23.320]for writing A Growing Revolution.
[00:49:26.220]One of the first people I visited
[00:49:27.750]was Dwayne Beck at South Dakota State University
[00:49:30.360]at the Dakota Lakes Research Farm.
[00:49:32.457]I'd visited him in part because the cover of my Dirt book
[00:49:36.360]is a piece of agricultural machinery
[00:49:38.390]from the Dust Bowl days with dust blowing all over it.
[00:49:40.760]That was in his region, his back yard.
[00:49:43.320]And I wanted to go see what had happened to his region
[00:49:45.900]because I saw him give a talk
[00:49:47.180]to the World Congress on Conservation Agriculture
[00:49:49.730]where he'd said they converted most of the region
[00:49:51.740]around his farm into no-till.
[00:49:53.750]And in that way, they'd stopped the black earth
[00:49:55.610]from blowing whenever the wind blew.
[00:49:57.410]So I wanted to go see his farm.
[00:49:58.760]And he impressed me, they've been adopting no-till
[00:50:00.730]with cover crops and complex rotations
[00:50:02.770]sorta in that order progressively over the last few decades,
[00:50:05.680]figuring out how to make it work for them.
[00:50:07.820]And they've been able to reduce their diesel,
[00:50:09.250]fertilizer and pesticide use by more than half.
[00:50:12.840]And that got my attention.
[00:50:14.290]Because what are some of the big expenses on modern farms?
[00:50:17.380]Diesel, fertilizer and pesticide.
[00:50:19.400]So the next question obviously is,
[00:50:21.060]what happened to their yields?
[00:50:22.120]And notice they went up.
[00:50:23.210]They didn't go down.
[00:50:25.710]They didn't pay a yield penalty
[00:50:27.200]once they had restored the fertility of their land.
[00:50:29.180]Now, there can be a transition period
[00:50:31.120]that farmers I talked to talked about.
[00:50:34.400]But it was remarkably short.
[00:50:38.890]When I left Dakota Lakes, I asked Dwayne
[00:50:42.400]whether or not, he was working with farmers
[00:50:44.360]that were up to 20,000 acres.
[00:50:46.420]These were large mechanized North American farms.
[00:50:49.570]I asked him whether the kinda ideas
[00:50:51.060]behind what he was doing, the no-till with cover crops
[00:50:53.990]and more diversity in the rotations,
[00:50:56.430]would work for feeding subsistence farmers in Africa
[00:50:59.020]because that is where the real problem
[00:51:01.250]of feeding the world lies for the next 100 years.
[00:51:03.680]And he said, "Well, don't ask me about that.
[00:51:05.877]"I'm not a subsistence farmer in Africa."
[00:51:08.860]But he did say I should go talk to this gentleman here,
[00:51:11.410]Kofi Boa, who runs the Center for No-Till Research
[00:51:13.810]in Kumasi, Ghana.
[00:51:14.940]And I believe that he did his Master's in Nebraska.
[00:51:17.170]I think he's a Corn Husker.
[00:51:19.920]Notice his hat.
[00:51:21.090]Got Dirt?
[00:51:22.070]Get Soil.
[00:51:23.810]When I got out of the Jeep at his farm
[00:51:25.830]and saw that hat on him, I knew,
[00:51:27.137]"Okay, this is gonna be an interesting couple days.
[00:51:28.977]"He's thinking along the lines that I'm thinking of."
[00:51:31.420]And what he had done is, he'd basically taken the knowledge
[00:51:34.970]he gained about no-till doing his Master's here,
[00:51:38.030]went back to Ghana,
[00:51:39.670]and transitioned the people in his village
[00:51:42.070]from their traditional slash and burn style of agriculture
[00:51:44.660]to no-till with cover crops,
[00:51:46.360]and the diversity of crops they get in
[00:51:48.790]because they're farming small plots.
[00:51:50.850]This room would be about the size
[00:51:52.300]of maybe an average farm there.
[00:51:54.660]And they plant by hand, they bury everything by hand.
[00:51:57.500]So they can grow, like, six to eight different crops
[00:51:59.550]in the field at the same time.
[00:52:01.120]They get their diversity all at once.
[00:52:03.730]And what happened is that they basically shut erosion off.
[00:52:06.990]Notice this factor of, like, 20 decline in erosion rates.
[00:52:10.420]And what happened to their yields?
[00:52:11.560]Their corn yields tripled and their cowpea yields doubled.
[00:52:15.300]That's as good as the Green Revolution did.
[00:52:18.810]And there's a reason that the Green Revolution
[00:52:20.900]did not transform subsistence farming
[00:52:23.120]in places like the village where Kofi worked.
[00:52:26.920]Because the people there don't have money
[00:52:28.450]to buy a fertilizer for fertilizer-intensive seeds,
[00:52:31.200]they don't have money to buy patented seeds,
[00:52:32.930]they don't have much money to buy herbicides or pesticides,
[00:52:35.910]although they will if they need them.
[00:52:39.840]What Kofi did is, he taught them a different way
[00:52:41.520]to think about their land, think about their soil,
[00:52:44.880]to change their practices
[00:52:46.430]that gave 'em the same kind of boost in their yields.
[00:52:48.400]It fundamentally transformed the economy of his village.
[00:52:53.240]One of the other people I visited
[00:52:54.370]was this gentleman here, David Brandt,
[00:52:56.220]who runs Brandt Family Farm in Carroll, Ohio.
[00:53:00.840]He grows wheat, corn and soybeans
[00:53:03.270]for the North American commodity markets.
[00:53:05.170]But that's not all he grows.
[00:53:06.410]He also grows a very diverse mixtures of cover crops
[00:53:09.180]in between his cash crops.
[00:53:10.710]And this is him standing in one of those fields,
[00:53:13.210]modeling one of his tillage radishes
[00:53:15.310]which is pointing to his neighbor's soybean field.
[00:53:18.955]And notice the color difference.
[00:53:20.700]His, David's, field is nice and green,
[00:53:22.980]the soybeans are kinda yellow.
[00:53:24.760]Notice the green stuff in the field next door.
[00:53:27.610]Those are glyphosate-resistant marestail weeds.
[00:53:30.340]They've been sprayed three times the year I visited.
[00:53:32.390]They cannot be killed.
[00:53:34.130]They're a yield drag on his neighbor's farm
[00:53:36.290]and getting to be a serious yield drag.
[00:53:38.340]David doesn't have weeds.
[00:53:39.790]Well, he says he doesn't have weeds, he plants them.
[00:53:43.120]He calls 'em cover crops.
[00:53:46.050]And he terminates them in ways
[00:53:48.960]that allow him to be using those cover crops
[00:53:51.580]to grab mineral micronutrients and elements
[00:53:53.910]out of the subsoil with some of his deep-rooted covers,
[00:53:57.010]he brings it out into the body of his plants,
[00:53:59.040]he then kills those plants,
[00:54:00.340]which then rot under the soil
[00:54:02.020]and deliver those nutrients to the topsoil,
[00:54:04.440]where his cash crop then harvests them as fertilizer
[00:54:08.160]in the next season.
[00:54:09.460]He's basically turned weeds into an asset
[00:54:12.400]by managing them as cover crops.
[00:54:16.550]He also walked me through the economics
[00:54:18.120]of his neighbors' operation.
[00:54:19.380]His neighbors are full tillage, 200 pounds of nitrogen,
[00:54:21.740]two and a half quarts of Roundup an acre.
[00:54:23.850]They were losing, at four bucks a bushel,
[00:54:25.860]they were losing 100 bucks an acre.
[00:54:27.980]David is in the 20, 15 when I visited.
[00:54:32.290]David's been doing no-till for 44 years
[00:54:34.350]with cover crops added more recently.
[00:54:36.880]So he's not tilling, saving on diesel,
[00:54:38.620]he's using about an eighth of the nitrogen,
[00:54:40.410]a fifth of the Roundup.
[00:54:42.230]He's not an organic farmer.
[00:54:43.750]But I teased him that he was an organic-ish farmer
[00:54:46.590]because he was starting to use so little of chemical inputs
[00:54:50.610]that he was almost organic.
[00:54:53.860]He thought that was nice and funny.
[00:54:54.960]We had a good laugh about it.
[00:54:55.820]But what was even better was
[00:54:58.180]that he was a profitable farmer.
[00:55:00.640]He was making 400 bucks an acre
[00:55:02.270]when his neighbors were losing
[00:55:03.140]100 bucks an acre on the farm.
[00:55:05.140]And I checked the numbers for Iowa.
[00:55:08.290]The place I could find where there's actually a paper on it,
[00:55:11.340]that same year, 24% of the farmers in Iowa
[00:55:13.930]lost more than 100 bucks an acre on their corn.
[00:55:16.700]And to me, that suggests a real problem
[00:55:19.040]at the heart of agriculture.
[00:55:20.480]If commodity prices are so low
[00:55:22.190]and input prices are so high,
[00:55:24.000]the people working hard
[00:55:25.290]on some of the best land in the world
[00:55:26.710]could lose money the harder they work.
[00:55:28.410]They would have been better off
[00:55:29.590]planting a single pumpkin and harvesting it
[00:55:31.980]and selling it for Halloween.
[00:55:35.130]So why was David Brandt more profitable than his neighbors?
[00:55:38.590]Because this is the soil he was working today.
[00:55:40.730]This is the soil he started with.
[00:55:42.030]This is off of his neighbor's farm,
[00:55:43.370]if I recall correctly.
[00:55:44.710]It represents what David started with back in 1971.
[00:55:47.640]He transformed it into this.
[00:55:49.550]The difference, again, it's building carbon in the soil.
[00:55:53.300]You notice some structure difference in there as well.
[00:55:55.660]But the difference in the profitability for the farms
[00:55:58.860]is that David could get away with hardly using any inputs
[00:56:01.930]because he rebuilt the fertility of his land.
[00:56:03.627]And what I found so inspiring about it is,
[00:56:06.300]he rebuilt his land with intensive, profitable
[00:56:09.380]full production agriculture.
[00:56:11.390]It was just a different style of agriculture.
[00:56:15.195]One of the other people, inspiring people, I met
[00:56:17.640]was, Jay Fuherer is sitting here in the front row.
[00:56:20.120]I'm his warmup act today.
[00:56:21.500]So they'll be yours in a moment, I promise you.
[00:56:25.310]But what they've been doing at Menoken Farm
[00:56:27.500]in terms of advancing the ideas and concepts of soil health,
[00:56:30.720]you start talking to some of these early adopters
[00:56:32.730]and all roads sort of kinda lead back
[00:56:35.380]to some of these key individuals
[00:56:36.750]and the experiments that they were working with.
[00:56:38.770]One of the people that Jay was working with early on
[00:56:41.090]was Gabe Brown, who has been experimenting
[00:56:44.640]with adding livestock back to his landscape,
[00:56:48.580]not just the microbial livestock that David Brandt has
[00:56:52.230]but the real deal, these guys.
[00:56:55.690]And I'll just share with you briefly
[00:56:58.070]that he's been using a style of intensive rotational grazing
[00:57:03.060]where lots of little electric fences are put up,
[00:57:06.230]cattle are restricted to areas, graze 'em,
[00:57:08.440]and moved quite frequently.
[00:57:09.690]I'm not gonna go much into that today,
[00:57:11.320]but I wanna share with you
[00:57:12.800]what Gabe did to the soil on this particular field,
[00:57:15.140]where he's experimented with,
[00:57:16.650]it's a market garden where he grows cash crops for a CSA,
[00:57:22.130]he then brings in some of his cattle
[00:57:24.550]to graze off the crop stubble and then cover crops,
[00:57:29.950]chickens to get the bugs out of the cow patties,
[00:57:32.770]and what he's basically doing is,
[00:57:33.940]he's using cattle as self-propelled methane digesters
[00:57:37.250]to accelerate the process of his crop stubble
[00:57:40.100]and cover crop breakdown
[00:57:41.670]to return manure to the land.
[00:57:43.770]And what he's managed to do is,
[00:57:45.620]create soil that's about like this.
[00:57:48.683]The soil in his left hand,
[00:57:49.540]so that's the soil off the field I just showed you,
[00:57:51.040]that's the soil, the soil in his left hand
[00:57:52.628]is his neighbor's organic farm.
[00:57:55.920]Now which soil would you rather be farming?
[00:57:58.400]The one that's been treated organically
[00:57:59.870]or the one that Gabe, another one
[00:58:01.730]of these organic-ish farmers,
[00:58:04.295]who is a conventional farmer
[00:58:05.920]who has just weaned himself off of most inputs
[00:58:09.750]because he doesn't need them anymore.
[00:58:11.260]And now that he's turned his soil
[00:58:13.180]into stuff that looks like that.
[00:58:15.890]What's wrong with his neighbor's farm?
[00:58:17.310]His neighbor's organic farm?
[00:58:18.550]Well, nothing other than they plow too much,
[00:58:22.370]which limits the buildup of their organic matter.
[00:58:24.900]So the recipe that I came up with
[00:58:26.810]in writing Growing a Revolution is,
[00:58:28.010]ditch the plow, cover up and grow diversity,
[00:58:30.210]as, if you want advice for how to build soil health,
[00:58:33.360]you might put a little asterisk here,
[00:58:34.730]of, like, and maybe add cows, too,
[00:58:36.770]depending on how you do it.
[00:58:38.290]Bring the animals back into the equation.
[00:58:41.140]But these three things really translate
[00:58:44.670]into 180-degree opposite of the advice
[00:58:48.910]that's mostly been given to farmers
[00:58:50.590]for the last hundred years,
[00:58:52.100]in terms of intensive tillage,
[00:58:53.660]intensive chemical use, and growing one or two crops.
[00:58:58.010]That was the recipe for maintaining production with inputs
[00:59:02.160]but degrading the soil over the long run.
[00:59:04.590]From what I can tell, this is the recipe,
[00:59:06.790]the 180-degree turn in how we think about the soil,
[00:59:09.810]that would lead us to the idea of no-till with cover crops
[00:59:12.420]and then experimenting with diversity,
[00:59:13.870]whether in one's cash crops or in one's cover crops,
[00:59:17.130]and then experimenting with bringing animals
[00:59:19.320]back onto the land as well.
[00:59:20.410]I'm not convinced you have to
[00:59:21.580]bring animals back on the land to restore soil.
[00:59:25.650]David Brandt did it without livestock,
[00:59:27.930]or I should say without livestock
[00:59:29.510]other than microbial livestock.
[00:59:32.000]But I do think that livestock
[00:59:33.230]can be an accelerator of soil building
[00:59:35.360]and soil rebuilding,
[00:59:36.530]which for me personally is a 180-degree flip.
[00:59:39.070]If you'd asked me 10 years ago
[00:59:40.300]when I wrote the Dirt book about that,
[00:59:42.070]I would have given you the party line
[00:59:43.510]that livestock were destructive to the land
[00:59:46.060]and actually cause soil degradation or erosion.
[00:59:48.720]What's flipped in my mind?
[00:59:50.610]Well, the same kind of thing
[00:59:51.710]that's flipped in many of the farmers that I talked to
[00:59:53.730]in the way they look at the soil.
[00:59:55.500]I now think that the problem wasn't the cattle.
[00:59:58.360]The problem was how we managed the cattle,
[01:00:00.110]how we were thinking about how to manage the cattle.
[01:00:03.510]In any case, I should probably leave you there.
[01:00:05.420]I'm supposed to go, I think, til 10
[01:00:06.630]so I should probably leave you there.
[01:00:08.920]If anyone is interested in picking up copies of the books,
[01:00:11.610]I brought a few along with me.
[01:00:12.990]I'm happy to engage in questions
[01:00:14.670]and will be here all day.
[01:00:16.000]But if you wanna know the specifics
[01:00:17.680]of what to do on your farm,
[01:00:19.200]I think the next guy will be able to help you
[01:00:21.100]an awful lot more than I will be on that one.
[01:00:23.543](chuckles)
[01:00:24.730]Sorry, Jay. (chuckles)
[01:00:26.130]Anyway, thank you very much.
[01:00:27.640]If we have time for questions,
[01:00:28.600]I'd be happy to deal with some.
[01:00:29.965](audience applauds)
[01:00:35.790]We do have a few minutes for questions,
[01:00:37.520]but I'd ask that you ask for the mic
[01:00:39.150]so everybody can hear your question.
[01:00:42.240]So raise your hand and I'll run the mic over.
[01:00:44.480]Questions for Dave?
[01:00:46.000]Up front.
[01:00:50.130]What's your view on strip till?
[01:00:51.920]How detrimental is that, being the minimum till method?
[01:00:56.370]Well, you know, I would like to know more about it
[01:00:58.280]and see some studies on that.
[01:01:03.040]My gut is that it could actually be
[01:01:05.710]nowhere near as destructive as general tilling,
[01:01:08.830]so it'd be a lot better.
[01:01:11.060]My gut is also, it depends a lot
[01:01:12.450]on how it's oriented on the land.
[01:01:15.360]If you're basically, if it's broken up
[01:01:17.040]and you don't allow any runoff
[01:01:18.510]on the strips that are tilled to actually accumulate,
[01:01:21.430]it might actually work.
[01:01:22.320]I've seen, I've met some people
[01:01:24.370]who claim to have had really good success with it.
[01:01:27.770]I don't have a lot of experience with it.
[01:01:29.800]But if you think about the physics of soil erosion,
[01:01:32.870]breaking up the accumulation of runoff
[01:01:35.430]as it moves is a good way to do it.
[01:01:38.310]Keeping runoff from happening in the first place
[01:01:40.200]is the better way to do it.
[01:01:41.690]But strip tillage might be kind of a happy medium
[01:01:45.420]and I don't have enough experience with it personally
[01:01:47.330]to tell anyone whether it would work
[01:01:48.950]in their environment or not.
[01:01:51.030]But I think it's a really intriguing idea.
[01:01:52.930]And it makes some sense to me.
[01:02:02.090]So with sustainability being a big question,
[01:02:06.660]what's your opinion on how we transform
[01:02:11.705]from going economically sustainable
[01:02:13.860]to growing vegetative growth sustainably
[01:02:18.050]for a longer period of time?
[01:02:20.950]What actually turned me
[01:02:22.330]into a bit of an optimist that we could get
[01:02:24.300]to a long-term sustainable agriculture
[01:02:27.727]for the societal century kind of scale
[01:02:31.370]was that each (audio skips) farmers that I (audio skips)
[01:02:34.110]already made the transition
[01:02:35.450]were more profitable today
[01:02:37.410]than their conventional neighbors.
[01:02:39.210]And so to me I'd view a lot of the challenge
[01:02:41.770]of how to get to a more sustainable style of agriculture
[01:02:46.060]is first of all, if it doesn't work
[01:02:48.290]economically for the farmers,
[01:02:49.550]it's not going to be sustainable
[01:02:51.060]'cause it won't be sustained.
[01:02:53.490]And I think we need a lot of focus
[01:02:55.320]on how to get people through the transition
[01:02:57.710]because every farmer that I visit who had transformed
[01:03:02.780]essentially low organic matter soil,
[01:03:06.000]dirt we could call it,
[01:03:07.170]into fairly rich productive soil,
[01:03:09.370]once they were through that transition,
[01:03:11.200]they were more profitable than the neighbors.
[01:03:13.440]And so I think we need a lot of attention
[01:03:15.800]on how to actually pull off the transition period,
[01:03:18.550]'cause not everybody can necessarily afford
[01:03:20.720]to experiment or to take a hit for a year or two
[01:03:24.160]if there's a yield drag.
[01:03:26.640]I think we need more research
[01:03:27.880]on how to do that transition.
[01:03:29.600]A number of people I've talked to
[01:03:31.190]basically have looked at
[01:03:32.650]how to think about where in a particular rotation
[01:03:38.210]to bring covers in as a first step.
[01:03:40.770]And there's ways to do it that will work well
[01:03:43.180]and ways to not do it well.
[01:03:44.840]I think that for different regions,
[01:03:46.520]that has to be figured out,
[01:03:47.630]and that's where Extension folks
[01:03:49.160]and the NRCS folks ought to be a big help
[01:03:54.120]in figuring that kind of stuff out.
[01:03:57.840]One more question.
[01:03:59.500]We got one down here in the front.
[01:04:01.191](man speaks off-microphone)
[01:04:06.253]The question is, what percentage
[01:04:07.210]of the countries in the world cannot feed their population?
[01:04:10.910]That's a question I don't know the direct answer to.
[01:04:13.440]But I can give you some triangulation on it.
[01:04:16.500]If you look at the idea that North American farmers
[01:04:20.390]are feeding the world,
[01:04:21.580]it's actually a pretty big misconception.
[01:04:25.310]A lot of what we're doing is feeding livestock
[01:04:27.560]and the ethanol industry.
[01:04:29.917]You could argue all you want
[01:04:30.750]about whether we should be eating meat or not,
[01:04:33.250]but if you look at the energetics of it,
[01:04:37.113]it's energetically a lot more efficient
[01:04:38.340]if livestock are not eating corn,
[01:04:40.220]they're eating grass.
[01:04:41.670]There's all kinds of health benefits
[01:04:42.900]that will flow to us as well.
[01:04:43.860]So there's questions of sort of
[01:04:45.280]how the food system is set up.
[01:04:46.980]But the biggest question in terms of feeding the world is
[01:04:49.710]how Africa is gonna feed itself
[01:04:51.710]because they are the place where there's the big problem.
[01:04:55.680]And that's where most of the world's population
[01:04:57.960]is expected to actually grow.
[01:05:00.440]Almost every other country in the world,
[01:05:02.290]every other continent, is at stable population growth.
[01:05:05.410]And we currently produce enough calories
[01:05:07.560]to feed everyone in the world.
[01:05:10.080]The only reason there are hungry people in the world
[01:05:12.000]is a matter of distribution.
[01:05:14.550]The question of whether we'll be able
[01:05:16.160]to continue doing that
[01:05:17.520]with two or three or four billion more people,
[01:05:20.300]most of whom will be in Africa,
[01:05:22.310]is a huge question.
[01:05:23.910]So one of the reasons I went to visit Kofi in Ghana
[01:05:27.060]was the question of,
[01:05:28.420]how can we actually transition African farming
[01:05:31.560]into being able to feed Africa,
[01:05:33.910]and do it sustainably?
[01:05:36.210]To me, that's the really big question.
[01:05:38.330]I don't think there's really much of an issue
[01:05:39.900]in terms of feeding Europe, North America or South America.
[01:05:42.840]Asia could be another question.
[01:05:45.930]So-- Okay.
[01:05:47.420]That gets your question.
[01:05:49.160]David's gonna be around.
[01:05:51.170]Thanks, David, because he said he would stick around--
[01:05:54.370]Yep. Most of the day,
[01:05:56.340]instead of catching an early flight
[01:05:58.020]and getting back to Seattle for Valentine's
[01:06:01.420]and his wife.
[01:06:03.020]He's gonna stick around and--
[01:06:04.971]I was promised I was only getting
[01:06:06.400]in a little trouble.
[01:06:07.233]Okay, he'll be out in the hallway there.
[01:06:08.670]You can visit with him whenever you'd like during the day.
[01:06:11.040]Thank you very much for joining us here in Nebraska.
[01:06:14.080]Give him a nice hand.
[01:06:15.206](audience applauds)

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Nebraska Cover Crop & Soil Health Conference - Welcome and David Montgomery

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