MAKE
OUR SOIL GREAT AGAIN
It appears
increasingly clear that agricultural soils are a resource wrongly apprehended
by past generations of farmers, and ultimately unintentionally, or rather
unconsciously damaged.
The Green
Revolution, with its good intentions, has solved many of the food security
problems in the world, at least at the level of production.
But its
reductive vision, and the excessive proportion of inputs (pesticides and
fertilizers), and the spectacular improvement of productivity that followed in
the first years, have made that most of farmers forgot some foundations of our
great activity.
The
awakening is brutal, with sometimes dramatic findings, terrible erosion
problems in some places, soils that have sometimes lost their structure, a soil
reduced or destroyed soil life, a microbial activity at half-mast, in short,
fertility losses that become compelling under certain conditions.
But nothing
is lost, most mistakes are recoverable, and the oldest experiences of changing
farming practices show that it's always possible to go back and combine
productivity needs with respect for ecosystems, and especially the recovery of
our soils.
I
propose this text, published in spring by David R. Montgomery, in the British
edition of the digital magazine The Conversation, under the title (parody of
the slogan of Donald Trump during his election campaign) "Make our soil
great again".
Make our soils great again
By
David R. Montgomery
Professor
of Earth and Space Sciences, University of Washington
“Most of us don’t think much about
soil, let alone its health. But as Earth Day approaches, it’s time to recommend
some skin care for Mother Nature.
Restoring soil fertility is one of
humanity’s best options for making progress on three daunting challenges: feeding
everyone, weathering climate change and conserving biodiversity.
Widespread mechanization and
adoption of chemical fertilizers and pesticides revolutionized agriculture. But
it took a hidden toll on the soil. Farmers around the world have already
degraded and abandoned one-third of the world’s cropland. In the United States,
our soils have already lost about half of the organic matter content that
helped make them fertile.
What is at stake if we don’t
reverse this trend? Impoverished trouble spots like Syria, Libya and Iraq are
among the societies living with a legacy of degraded soil. And if the world
keeps losing productive farmland, it will only make it harder to feed a growing
global population.
But it is possible to restore soil
fertility, as I learned traveling the world to meet farmers who had adopted
regenerative practices on large commercial and small subsistence farms while
researching my new book, Growing A Revolution: Bringing Our Soil Back to Life.
From Pennsylvania to the Dakotas and from Africa to Latin America, I saw
compelling evidence of how a new way of farming can restore health to the soil,
and do so remarkably fast.
Workshop on cover crops, weed
management and no-till practices at the Stark Ranch in Gainesville, Texas.
These farmers adopted practices
that cultivate beneficial soil life. They stopped plowing and minimized ground
disturbance. They planted cover crops, especially legumes, as well as
commercial crops. And they didn’t just plant the same thing over and over
again. Instead they planted a greater diversity of crops in more complex
rotations. Combining these techniques cultivates a diversity of beneficial
microbial and soil life that enhances nutrient cycling, increases soil organic
matter, and improves soil structure and thereby reduces erosive runoff.
Farmers who implemented all three
techniques began regenerating fertile soil and after several years ended up
with more money in their pocket. Crop yields and soil organic matter increased
while their fuel, fertilizer, and pesticide use fell. Their fields consistently
had more pollinators — butterflies and bees — than neighboring conventional
farms. Using less insecticide and retaining native plants around their fields
translated into more predatory species that managed insect pests.
Innovative ranchers likewise showed
me methods that left their soil better off. Cows on their farms grazed the way
buffalo once did, concentrating in a small area for a short period followed by
a long recovery time. This pattern stimulates plants to push sugary substances
out of their roots. And this feeds soil life that in return provides the plants
with things like growth-promoting hormones and mineral nutrients. Letting cows
graze also builds soil organic matter by dispersing manure across the land,
rather than concentrating it in feedlot sewage lagoons.
Soil organic matter is the
foundation of the soil food web, and the consensus among scientists I talked
with was that soil organic matter is the single best indicator of soil health.
How much carbon could the world’s farmers and ranchers park underground through
soil building practices that incorporate plant residue and stimulate microbial
activity? Estimates vary widely, but farmers I visited had more than doubled
the carbon content of their soil over a decade or two. If farmers around the
world did this, it could help partially offset fossil fuel emissions for
decades to come.
Soil restoration will not solve world
hunger, stop climate change, or prevent further loss of biodiversity. No single
thing can solve these problems. But the innovative farmers I met showed me that
adopting the full suite of conservation agriculture practices can provide a
better livelihood and significant environmental benefits on conventional and
organic farms alike.
Restoring fertility to degraded
agricultural soils is one of humanity’s most pressing and under-recognized
natural infrastructure projects, and would pay dividends for generations to
come. It’s time for a moonshot-like effort to restore the root of all
prosperous civilizations:
Our soil, the skin of the Earth.”
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