Every summer something called the dead zone forms in the Gulf of Mexico.
It ranges from the size of Delaware to the size of New Jersey.
It’s a massive patch of water that doesn’t have enough oxygen for sea creatures to survive.
If you are a crab, or a fish, or a baby shrimp caught in the dead zone,
you die.
The problem starts thousands of miles away. When fertilizer gets applied to farmland,
some washes into the Mississippi River, where it will fertilize algae.
Look at what happens when you add fertilizer to ocean or lake water.
You can see the algae loves the fertilizer.
It all blooms at once, then dies, and then decomposes.
And in that process, it sucks all the oxygen out of the water.
That is bad news for those dear, sweet baby shrimp.
No seriously it’s really bad
for them and the people who depend on them for a living.
Fertilizer pollution causes problems even before it gets to the ocean.
It can contaminate drinking water, or even turn into suffocating smog.
And it’s a big contributor to global warming.
The federal government has spent billions of dollars a year to fix the problem,
but nothing’s changed.
The thing that makes this problem so tricky is that we can’t live without the pollutant
that’s causing these dead zones.
Without nitrogen and phosphorus, we can’t grow food.
Before industrial fertilizer, the naturally occurring fertilizer,
know by it's technical name,
"poop,"
determined a farmers’ yields, and thus their wealth. If you were a French farm girl
back then, you dowry was calculated not in acres of land but instead in the pounds of
manure your animals could provide. Wars were fought over nitrogen-rich guano.
Most scientists say that for all the problems with too much fertilizer,
a world with too little would be even worse. Bloodier, hungrier, and
The trick with fertilizer is to maximize crop growth and minimize the algae growth.
But how?
Well, the most promising solution is simple: just planting stuff on open soil.
It's called a cover crop.
Most farms in the U.S. look like this in the winter and spring.
A lot of rain tends to fall during those seasons, and all that water washes away nutrients and soil.
With cover crops, it’s more like this:
Cover the soil with rye grass, clover, or really any kind of plant, and they will provide
a buffer, slowing down raindrops, sucking up nutrients,
and holding soil in place with their roots.
What’s really exciting about cover crops is that they may provide a win-win for farmers
trapping nutrients to improve soil, while also reducing pollution and flooding downstream.
And so cover crops are booming
the number of acres planted with them increased 50 percent in recent years.
But even after all that growth, cover crops only cover this much of American farmland.
So … what if it looked more like this?
That’s what happened in one small watershed in northern Indiana. The results were dramatic.
In the spring, when the cover crops were growing,
the fields turned into sponges. The amount of water flowing off fields fell by half,
lowering both nitrates and phosphorus.
But it took a lot of time and money to cover the equivalent of 600 football fields.
Imagine expanding that to the entire Mississippi River basin.
But it’s likely that 70 percent of the land won’t be filled with cover crops without
some major prodding. We’ll probably need regulations, enforcement, and incentives,
as well as new technology — you know, the kinds of tools we’ve used to rein in every
other pollution problem we’ve conquered.
Until we get there, growing food is just going to come with a cost:
Those baby shrimp, and the entire gulf coast.