Sunday, January 21, 2007

The Scoop on Dirt (A Review)


Last September, E/The Environmental Magazine, published The Scoop On Dirt: Why We Should all Worship the Ground We Walk On by Tamsyn Jones. It is beautifully written, but settles into a tired view of soil. As a soil scientist, it irks me that this essay flubs the opportunity to celebrate the unfolding understanding of this dark and patient resource. An expectation of higher aspirations is created by the title and the opening prose.

It’s one of nature’s most perfect contradictions: a substance that is ubiquitous but unseen; humble but essential; surprisingly strong but profoundly fragile. It nurtures life and death; undergirds cities, forests and oceans; and feeds all terrestrial life on Earth. It is a substance few people understand and most take for granted. Yet, it is arguably one of Earth’s most critical natural resources—and humans, quite literally, owe to it their very existence.

From the food we eat to the clothes we wear to the air we breathe, humanity depends upon the dirt beneath our feet. Gardeners understand this intuitively; to them, the saying “cherish the soil” is gospel. But for the better part of society, dirt barely gets a sideways glance. To most, it’s just part of the background, something so obvious it’s ignored.

Even among the environmentally minded, soil sags well below the radar of important causes. But the relationship between soil quality and other aspects of environmental health is intricately entwined. What’s more, it’s a relationship that encompasses a vast swath of territory, from agricultural practices to global climate change, and from the well being of oceans to that of people.

Ultimately it works into a description of Third World soil erosion, chemical burn-out and exhausted productivity. We are told that without aid from the powers that be, the soil, and those it supports, will suffer. I accept that on face value, without hesitation. Third World nations are requesting training in soil management and nutrients to replenish their exhausted soil. We should help them in this.

There is also a short Part II essay, covering factory farms and sustainable farm management. Sidebars provide information on desertification, sludge, the NRCS, soil science as a vanishing skill, and a John Havlin interview.

There is much to like about this piece. Soil seldom gets such professional treatment. However, because it is so well-written – she is a journalist after all – one may not easily spot that some of the observations are presented as foregone conclusions, yet are not supported or warranted. Most of the first 20 paragraphs are full of solum-esque richness. By the end at the 60th paragraph, all the good will banked during the beginning of the essay has been mortgaged by hyperbole...

"Only 8% of our land is arable. This means...", as the context amplifies, that the remaining 92% is "too inhospitable to support our species." (paragraph 8)

"...the practice of destroying soils by torching ... has been employed by armies..." (paragraph 21)

...and mind numbing oversimplification.

"...soils are eroding faster than they can be rebuilt." (paragraph 29)

"The fastest soil regeneration is 200 years, but it can take a million years". (paragraph 30)

The more I learn about soil, the more disservice I see in this type of "Soil Erosion for Dummies" pablum. For one it implies that, absent man's influence, all soils naturally improve with time. Only the young ones do. Nature is not so kind to old soil and soil management must be guided by this fact.

What qualifies as "soil regeneration"? It has always bothered me that regenerating the living processes in the topsoil and regenerating substratum soil mass from the bottom up are treated as not worth differentiating. Still. 80 years, 500-1000 years, or more years to regenerate an inch of soil: You can tell people any number you want, everybody in the know understands its just a theatrical device. A million years is highly theatrical. It implies waiting for a climatic shift or a geologic system reboot.

From a great beginning, the essay wears down to looking at the world through the eyes of a soil science seemingly frozen in time. Conspicuous by its absence are post 1950s discoveries like terra preta and glomalin, discoveries that hint at workings of soil health beyond our current understanding. I choose these examples because they hold the promise of achieving unprecedented soil vitality in the arable soils most of concern in the essay.

Terra preta [updated link (1/29/07)] has been actively researched since the early 1960s. It is a key component of carbon negative fuel production. Terra preta is made by adding charcoal to soil, but total soil carbon continues to build long after additions of charcoal stop. Charcoal producing household wood-gas stoves designs are available. Simple and efficient, these can be used to establish terra preta nova on a scale that matches the Third World's soil carbon crisis. Larger adaptations of the process are being developed commercially. A solar furnace (pdf) alternative is promising.

Glomalin was discovered in 1996. Produced by fungi from carbohydrates supplied by plant allies, glomalin holds 1/3 of global soil carbon, and in a recalcitrant form to boot. It dramatically improves soil health. Low soil nutrient status tends to favor its production, as plants are encouraged to fuel and hydrate their fungal allies in exchange for phosphorus. Perhaps a similar process is supported in terra preta, and accounts for the mysteriously rising tide of soil carbon.

Without a celebration of the ongoing exploration of soil, one is left with the impression that soil scientists have long since exhausted the soil of its potential for significant and exciting discovery.

My final beef is with the John Havlin interview. Why do our soil science leaders continue to get sucked into overplaying the agriculture card? Maybe Charles Kellog should have pounded SSSA a little harder back when he had a chance.

"Many people have the vague notion that soil science is merely a phase of agronomy and deals only with practical soil management for field crops. Whether we like it or not this is the image many have of us." Charles E. Kellog, A challenge to American soil scientists: On the occasion of the 25th anniversary of the Soil Science Society of America. Soil Science Society of America Proceedings, 25(6):419-423, 1961.





1 comment:

Craig Mackintosh said...

Hello Philip

Thanks for your comment on my site. I shall look into the items you've mentioned when I get a spare minute.

I also started on Tamsyn's article with excitement. I hadn't seen anyone waxing so poetic on soil for quite some time. It was a joy to see. But, like you, the further I delved into the article, the less inspired I became.

I must keep an eye on your site!

Kind regards

Craig