How To (Literally) Save Earth

Soil is the literal foundation for much of
life, yet we treat soil like… well, like dirt. Maybe that’s because, most of the time, soil
takes care of itself; decomposing plants and animals and degrading bedrock produce new
soil at roughly the same pace that wind and water erode it away But this balance between soil formation and
erosion is easily tipped. For millennia, the tiny Pacific island of
Mangaia was covered in a thin layer of fertile soil, but after humans arrived around 2000
years ago, their slash-and-burn agriculture exposed the soil to the elements. Over several centuries, rain and wind swept
virtually all the nutrient-rich topsoil from Mangaia’s hillsides and concentrated it
in just a few arable valleys, which people viciously fought over. With less land to grow crops, people resorted
to alternative food sources like rats—and even each other. We’re doing the same thing throughout the
world today – not the part where we eat each other, but the part where we farm the soil
away. That’s because we make for agriculture by
clearing away deep-rooted native vegetation and use hoes, plows, and tractors to loosen
the soil, making it easier for wind and rain to sweep away. And we grow mostly shallow-rooted crops that
are no good at holding onto soil, and that get stripped away during harvest, leaving
fields bare for much of the year and at the mercy of the elements As a result, the world’s farmlands lose soil
50 times faster than new soil can form. That extra erosion adds up to about 8 billion
pickup trucks of soil moved annually from fields to places like the bottoms of rivers
and behind dams – which are less convenient for farming. That soil loss reduces global crop yields
by as much as if we took a California-sized swath of farmland out of production every
decade. Fortunately, we know how to bring erosion
back into balance with the rate at which soil forms: plow less often, and after harvest,
leave plant parts behind or plant so-called cover crops to, well, cover the soil as protection
against water and wind. We can also incorporate trees or native plants
that keep soil in place year-round. Putting strategies like these in place can
cut erosion by as much as 95 percent, helping keep crop yields high in the long run. But in the present, they can hurt yields,
because adding other vegetation to farm fields means less room for crops. As a result, we’ve been slow to make these
soil-saving strategies the norm. If we can’t keep the farmable soil on our
farms, human civilization won’t immediately implode, but we might end up fighting over
the patches of land where that soil ends up, like the Mangaians, but on much, much bigger
islands. And, speaking of soil, this video was sponsored
by Soylent, a line of nutritionally-complete, convenient foods that actually take less Soy-l
to produce because many of their core nutrients, including omega-9 fatty acids, come not from
plants grown in fields but from algae grown in fermentation tanks. Their newest product, Coffiest, reimagines
breakfast as a coffee-flavored, algae-fueled meal in a bottle to help kickstart your day. Plus Soylent has partnered with the World
Food Program USA to donate a meal to someone in need for every case of Coffiest they sell. Go to soylent dot com slash earth, that’s
s-o-y-l-e-n-t dot com slash E-A-R-T-H or click on the link in the description to get 10%
off of your first month’s worth of Coffiest. Thanks, Soylent!


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