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For human purposes not all dirt is good dirt, call us high maintenance, [Piles of dirt with bad, decent and OK signs in them]

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call us needy or just say we have way high standards we humans want our dirt to [Man examines a pile of dirt and celebrates with a fantastic sign]

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be fertile which means it has to have the right combination of things to grow [Man on a motorbike covers man with sign in mud]

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awesome crops. Well fertile soil has to have the right

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nutrients like nitrogen and potassium it also can't be too salty or too acidic [Scientist eats the dirt and spits it out because it is too salty]

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and it has to have good structure so that roots can move around and pick up [Plant grows]

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water finally it needs the right critters and good bacteria, you know kinda [Bacteria underground]

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like a probiotic yogurt though eating any kind of dirt isn't necessarily a good

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option for those in search of probiotics. Well farming the same soil over and over [Tractor driving over soil]

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again depletes it of nutrients and plant food farm a place too hard and it will

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turn to dust don't believe us ask all the folks who lived through the Dust Bowl [People appear out of a dust cloud]

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in the 1930s or don't they're still pretty cranky about that of all the

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factors that affect fertile soil nitrogen is one of the biggest without

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nitrogen plants can't do their plant magic and turn sunshine into food or [Nitrogen atom saying it is one of a kind]

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pull minerals and nutrients out of the dirt so let's figure out where our

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favorite little chemical comes from turns out there's a thing called the

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nitrogen cycle. It's not a motorcycle made of nitrogen though wouldn't that be cool so [Nitrogen atom riding a motorbike in a classroom]

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where does the nitrogen cycle start well nowhere in particular it's a cycle [Hamsters on wheels]

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so there's no beginning and no end and yeah we know deep... Alright we'll start

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talking about poop. Yep the waste of animals and plants decomposes which puts

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Nitrogen into the soil. This is why farmers sometimes intentionally fill

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their fields with manure shockingly enough they don't just enjoy the smell [Farmer shoveling manure into a field]

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Next friendly neighborhood bacteria in the soil converts the plant and animal

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poop into the kind of nitrogen that plants can use plants then binge on the [Bacteria smiling]

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nitrogen in the soil and grow like weeds or like you know whatever kind of plant

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they are. After that people in animals mercilessly eat the plants we're [Strawberry plants growing]

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like vampires. We can't help how we have to feed well [Humans and a monkey run by and destroy the plants]

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after the feeding frenzy animal and plant residues return nitrogen to the

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soil again and the cycle is complete. Well nitrogen from the atmosphere [Rain lands on the soil]

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gets into the soil via rain then atmospheric nitrogen can be

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converted into plant friendly nitrogen by legumes. And no legumes is not

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the French word for various types of bubblegum. Legumes are plants like [Woman in a sweet shop]

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alfalfa, clovers and soybeans. Well now that we've got science we can see how

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nitrogen matters to history. Every new piece of agricultural technology helped [Farmers next a nitrogen atom statue]

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us grow crops or raise critters at least a bit more efficiently. But as a whole

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they haven't always benefitted the nitrogen cycle. Plenty of Agriculture's [Poster of the nitrogen cycle falls to the ground]

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history has been about finding new sources of nitrogen and moving nitrogen

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around in places we need it most there was literally a war over guano aka bat [Men in suits and sunglasses exchange a briefcase and money]

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poop, because guano is so nitrogen rich you know what they say one bat's poop is

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another man's treasure...

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