ShmoopTube

00:02

As we've made our way through this unit agriculture has gotten bigger and [Cornfield growing bigger]

00:07

better with every new technology introduced sure there have been some

00:12

environmental downers and the occasional racist theft of land welcome to America [Car drives by Welcome to America sign]

00:17

but mostly people have been farming to their heart's content big machines like

00:21

tractors and combines made farm labor way cheaper and faster and the sky was

00:27

the limit right and actually the limits turned out to be much closer than

00:32

that well by the 1940s agriculture was in trouble many problems in agriculture

00:37

were the long-term effects of industrial technology for example combines and [Combine drives by and crops appear]

00:42

tractors encouraged farmers to plant enormous fields of the same crop which

00:47

is called the mono cropping but mono cropping like shooting apples off a

00:52

person's head is a dangerous game mono cropping allows huge populations of [Woman aims bow at apple on a mans head]

00:57

pests to target that single crop it also exhausts the nutrients in the soil

01:02

because all the plants want exactly the same goodies and finally it leaves the

01:06

crop vulnerable to disease don't think plant diseases are serious well check

01:11

out Ireland circa 1845 it wasn't called the potato famine because the potatoes [Potato appears in a kitchen]

01:17

were starving why oh just a little fungus among us that came and turned the

01:23

nation's mono crop of potatoes into rotten black goop well beyond the

01:28

problems of mono cropping agriculture seemed to have hit its limits.....

01:33

all the easily farmed land was being farmed and farmers could only produce so

01:38

much food per acre better stop reproducing their humans no more octo [Woman with lots of babies]

01:42

moms the biggest limitation was our old friend nitrogen remember that stuff well

01:48

it's a basic nutrient that plants need to survive right? easily exhausted by

01:52

intensive farming phone you betcha well farmers all over the world had

01:56

different strategies for keeping the nitrogen in their soil some people use

02:01

the manure from their livestock to fertilize there field or sometimes they

02:05

just let the fields take a season off so that the little nitrogen making bacteria

02:09

could have a chance to you know giggety other people figured out the joys of [legume on stage singing]

02:15

legumes we're talking about stuff like beans peas nuts and clover but one of

02:20

the many awesome things about legumes is that they put nitrogen back into the

02:24

soil also they brought us peanut butter which is just awesome they also brought [Jar of peanut butter appears]

02:29

us pea soup the awesomeness of which is debatable the problem was that rotating

02:35

crops or letting fields rest took too much time and the amount of manure from

02:39

livestock couldn't keep up with the massive demand for crops brought on by

02:44

modern era people started looking further afield for their nitrogen like [Young girl looking through binoculars]

02:48

really far afield brace yourself for this one it turns out that bird poop and

02:53

bat poop have crazy amounts of nitrogen in them yep Guano that's bat poop it's

02:58

awesome fertilizer we're sure bats are super proud of their contributions well [Bat flys by a field]

03:04

companies from industrial nation started laying claim to the world's best sources

03:08

of guano which were mostly giant bat caves or islands with lots of birds

03:12

nesting on them in South America people collected poop and shifted back to [Man delivers Guano to woman]

03:17

farmers in Europe and the US it was a big business a gross business but

03:22

that it was big.....

03:25

well then maybe dog walkers would stop leaving it on this sidewalk

Full Transcript