Today I'm going to talk to you guys about dirt.
Although the dirt we walk on
is only a one-meter thin layer of the Earth's crust,
all living things depend on that layer to survive.
The soil is our reservoir
for storing and moving all the nutrients, liquids, and gases
needed for life.
While we have depended on soil
since the beginning of civilization,
we still know surprisingly little about it.
For example, few can tell us what exactly soil is.
We know that good soil looks and feels like
this dark brown spongy cake that smells fresh,
but the exact composition of that cake is still a mystery.
After all, a single teaspoon of soil
contains more distinct microbes in it
than all the humans on planet Earth,
so, it's a really complicated substance.
Another basic thing that we don't know
is what's called the soil nutrient budget.
Underneath our feet,
what is the current level of acidity, carbon, nitrogen,
and other nutrients?
We need to know that,
because whenever you grow food,
you extract these nutrients from the soil
as a kind of price that you have to pay.
And if we're going to pay back our debt,
we need to put those nutrients back into the soil somehow.
Unless you keep the nutrient budget balanced,
farmers are not going to be able to continue producing
the food that we eat.
Over time, I realized the true value of soil.
So, I decided to build my own tech company named QED.
We focus on Africa,
because the future of Africa's food security
depends crucially on its agricultural growth.
And we know that Africa's soils
are also suffering the most right now
from widespread nutrient depletion and from erosion.
That’s why the Africa Soil Information Service
was created back in 2009,
to develop clever strategies
to collect the data about the soils of Africa.
We definitely can't say that we solved this problem,
but I just want to share a simplified story
about what QED has done so far.
It's really expensive to collect soil,
and so you only want to collect soil measurements
in places that actually matter to farmers,
where you have some crop lands
and you have some houses.
If you want to find those kinds of places efficiently,
we built an app called GeoSurvey,
and this is a crowd-sourcing software
for analyzing satellite imagery.
Users are shown random maps of the Earth,
and they can trace all the croplands and the houses.
We trained the computer with enough examples to do this for us.
So, thanks to the millions of submissions sent to GeoSurvey,
we can see the computer automatically marking up entire countries.
Armed with these kinds of maps,
now we have a strategic game plan
for places that our field team should target
to most efficiently collect the soil.
Traditionally, soil scientists use a process that's called wet chemistry,
and if you're running a national survey,
that can easily cost you millions of dollars to do.
So, to make this more affordable,
we use infrared spectrometers,
which are 10x cheaper and only run on the cost of electricity.
What they do is they shine infrared light on the soil,
and then by measuring the reflections of that light,
surprisingly we can predict certain nutrients quite well.
The increased affordability of this kind of method
allows us to collect much more data than previously available.
We need governments to take a renewed interest in soil.
Most of the world's poorest people are employed in agriculture.
Their whole livelihood hinges on the fertility of that soil,
and they do the best they can with the tools that they have,
but these farmers can't control changes to their entire landscape,
or what kinds of fertilizers they can access.
But if we use soil data, governments can design soil conservation efforts.
They could guide the private sector
to develop the right fertilizers for improving farmer yields
and farmer incomes.
If we want to build really high accuracy maps of soil and plant health,
we're going to need a lot, lot, lot, lot more data,
and that's going to require serious moonshot innovation.
So first of all,
it's really expensive right now to be collecting soil samples,
shipping them from the field to the lab.
And secondly,
while the instruments we've been using are cheaper than before,
they're still a bit too expensive and delicate
for many rural and remote areas.
If we're going to move forward,
I suggest we channel this punk science movement
to develop low cost, handheld sensors
that can get everybody involved with science.
This thing is made from components
that you guys all know about, PVC pipes.
I got a razor blade in here,
AA batteries, raspberry pie,
DVDs for diffraction gratings,
and of course,
you've all got this super computer sitting in your pocket,
which interfaces to produce an instant spectrogram.
I challenge the next generation to do better than us,
and make this even cheaper and more scalable
to collect data at scale.
As a child,
I dreamed about being an astronaut,
so I studied things like physics,
and later actually worked on telecommunications at NASA.
Nothing in my life up to this point
ever suggested that I’d be talking about dirt.
But over time I realized
that there’s actually no need to leave this planet
because one of the greatest mysteries of this universe
is literally right underneath your feet.