Biostasy

The Theory of Biorhexistasy describes climatic conditions necessary for periods of soil formation (pedogenesis) separated by periods of soil erosion. Proposed by pedologist H. Erhart in 1951, the theory defines two climatic phases: biostasy and rhexistasy.

If I recall, H. Erhart figured this out while on the Congo river contemplating a low sediment load in a high rainfall, potentially highly erosive setting. Impressive. There is a soil science truism that clean water is hungry water, and can't wash across or through the land without taking some with. From a soil scientist's perspective, water is soil in highly dilute form. (So is air.)

Reading between the lines, I don't think Erhart had a research budget much beyond travel expenses. He simply deduced from what he knew of tropical weathering that the river had to be laden with dissolved minerals, calcium especially, washed from the soil by percolating rain water. Groundbreaking as that was in its own right, he didn't stop there. Using induction, he reasoned that when similar conditions dominated it ages past, rivers would have delivered abundant calcium to ancient seas subsequently (at the close of the age, perhaps) yielding vast limestone deposits. He saw these ages as lush, moist, and warm with accelerated chemical weathering accompanied by the formation of deep soils. Biostasy. Between periods of biostasy, he envisioned conditions dominated instead by physical weathering: severe fluctuations in temperature and moisture, sparse vegetation, shallow exposed soils, rivers choked with sediments, but with low solute content. This insight informs interpreting endokarstic sediments(Yves Quinif) in Europe where stalacite formation is observed to be greatest, and with least sediment, during interglacial periods due to higher dissolved calcium content, and less soil erosion.

Simply as a mental exercise, consider a scenario where atmospheric carbon dioxide hits 1200 ppm 200 years from now. In the context of biorhexistasy, what is going to dominate? biostasy, rhexistasy or will it be something well outside H. Erhart's elegant construct? Considering that the Congo and the sediment laden Nile coexist in the same age, it is certainly conceivable that biorhexistasy will continue to play out differently based on location, with neither dominating. But the undeniable effect of higher carbon dioxide is higher chemical weathering. So maybe rhexistasy during the transition, followed by biostasy.

(Recycled from nscss.org)

Make dirt more better

Soil has a problem. It is eroding faster than it is being made. That's a given in these times of relative geologic stability. Most soil was formed in depositional material. Without sedimentary deposits being exposed by tectonic processes, without substantial volcanic ash fall, without the continental glaciation producing silt, and without the global wind storms and cataclysmic post-glacial flooding to redistribute that silt, we basically have to wait on the next climate change re-boot for our next era of major soil replenishment. In these trying times on the downhill slide from peak soil resources, we'll have to make better soil from the soil that we have left.

Soil organisms help ranchers

Intense, low duration grazing builds soil vitality, and increases soil organic matter.

Formulaically, the process described by Manske is very simple; what happens as a result is not.

A rancher chooses three pastures on which to graze the cattle. Starting in the first pasture, the cattle graze for 15 days, and then move on to the next pasture. This is repeated and the cattle find themselves in the third pasture.

Once the cattle leave the first pasture, the soil organisms go to work, converting the organic nitrogen into mineral nitrogen and feeding the plants, building their crude protein.

“Just by changing the management from focusing on dry matter poundage to managing those soil organisms, you can increase the productivity of your land,” Manske said. (Source)

Well observed.

Rhizosperic soil can get awfully puny under long duration grazing. Topsoil pales and topsoil depth is lost, but not to sediment discharge or wind erosion. The in-situ transformation of topsoil to not-topsoil results in the discharge of soil carbon to the atmosphere. The good news is that, unlike wind erosion, water erosion, sheet erosion, or gully erosion erosion, this yet-to-be-named variant of topsoil erosion is reversible.

Home Buyers Will Pay for Soil, Won't Pay For Dirt

In 2003, the Snohomish County Public Works Department published a remarkable manual with a simple title: Building Soil (pdf). Promoting sediment-free stormwater, it encouraged builders to embrace the wisdom of retaining native soil and vegetation, and to question the value of turning soil into dirt for no good reason. From a building perspective, soil is a valuable construction material manufactured from a low cost/ low value soil resource feedstock. The thinking goes like this: Manipulating soil tidies up a site and adds value. Stormwater regulations interfere with the ability to add value, thus the disconnect.

Enter the Washington Organic Recycling Council which has a new site, www. buildingsoil.org, with a new and refreshingly non-regulatory spin for convincing builders to buy into the principles in the Building Soil manual. The pitch goes like this: Avoiding disturbance around the building footprint, in a sense, doing nothing, confers a marketable value on that soil resource.

New home buyers say they are happy to pay more for a healthy, easy to care for landscape – and that starts with the soil.

A timely message in a buyers' market.

Biofuel demand pencils out to damaged soil

Crop residue is not a waste. It is a precious commodity and essential to preserving soil quality.

Production systems must be developed so that ethanol produced must be at least C neutral if not C negative. Temptations [to mine soil vitality] aside, biofuels produced from crop residues may neither be free nor cheap.

Rattan Lal, SSSA President, has a timely message to his fellow Society members in the May issue of CSA News (regretfully subscription only). It is that we must take this opportunity to break the cycle of soil destruction that characterizes the rise and fall of civilized man. Biofuels adds unprecedented value to biomass production. Rattan Lal sketches out the numbers, comparing potential demand to crop residue available. With demand tracking above supply, the temptation is to mine the soil of its vitality. Rattan Lal observes that soil exploitation is the primary contributing factor to desertification.

Harvesting crop residues for use as fodder for livestock, residential fuel for cooking and heating, construction material, and other competing uses is a reality in sub-Saharan Africa, South Asia, China, and other developing countries. Therefore, it is not surprising that these are also the regions that have been plagued with severe problems of soil degradation.

With a severe decline in physical quality, degraded soils do not respond to fertilizers even if made available at a subsidized price. Adverse effects of none or low rates of applications of fertilizers and other amendments on agronomic production and soil quality have been exacerbated by the perpetual and indiscriminate removal of crop residues coupled with uncontrolled and excessive communal grazing.

The stubborn trends of low crop yields and perpetual hunger and malnutrition in sub-Saharan Africa and in regions of rainfed agriculture in South Asia cannot be reversed without returning crop residues to the soil and also supplementing them with liberal applications of other biosolids.

Rattan Lal has done an admirable job in this appeal to the his fellow SSSA members. He has included constructive comment on tools and processes available to make biofuels production compatible with maintaining soil vitality. But the undercurrent message is that those of us who love soil must involve ourselves in the process, the policy, and the public discussion of our transition to sustainable energy.

Leave comment or email me if you would like to request a copy of Rattan Lal's May address. Or better yet, join SSSA.

NRCS Assessment of US Land Use, Erosion, Wetlands

The USDA Natural Resources Conservation Service has posted results of their Natural Resources Inventory (NRI). Depicted are land cover and use, soil erosion, and wetland gains or losses for the 48 contiguous United States.

From 1977 to 1997, NRCS conducted the assessment every five years, in 2000, they began the transition to an annual assessment. The most recent data is from 2003 and reflects only conditions at that point, NRCS Chief, Arlen Lancaster says, "This is a snapshot, this is the number in terms of cropland, this is where we're at in terms of erosion," he says later this year they will be able to provide numbers that reflect the change from year-to-year.

Some findings:

1. The 48 contiguous states cover 1.9 billion acres and 71% of that, 1.4 billion is in non-Federal rural land uses. Of that 1.4 billion acres, 406 million is in forest land, 405 million is rangeland and 368 million is cropland.
2. Cropland acreage decreased 12% from 1982 to 2003. The net decline between 1997 and 2003 was 8 million acres, or about 2 percent.
3. Soil erosion on U.S. cropland decreased 43% from 1982 to 2003.
4. In 1982, 40% of all cropland was eroding above soil loss tolerance rates, that number declined to 28% in 2003.
5. Erosion rates on a per acre basis declined significantly between 1982 and 2003. Sheet and rill erosion on cropland dropped from 4.0 tons per acre per year in 1982 to 2.6 tons per acre per year in 2003; wind erosion rates dropped from 3.3 to 2.1 tons per acre per year.
6. There was a net gain in wetland acres on non-Federal rural lands between 1997 and 2003. Annual net gains between 2001 and 2003 were 72,000 acres per year, of which 44,000 acres per year were on agricultural lands.

The 2003 results look fairly encouraging. Erosion continued down. There was a net gain in wetland acres coming substantially from agricultural lands and a moderated trend of farmland loss. It fits with what I was seeing on the ground in those years. 2004, 2005 and 2006 might not be as good as 2001 - 2003. Funding for soil conservation and especially wetland construction was tighter after 2003. This was also at a time when tiling was on the increase, as I reported earlier. The farmland loss rate probably regained some steam with development activity. Any comments?

Technorati Tags: erosion land wetland farm soil government

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.

Technorati Tags: environment erosion news soil science

New Soil Science Licensing Website

Renewed soil science licensing efforts are underway in Washington State. Supporting them is a new website. Titled Soil Science Licensing, the site is available to become a clearinghouse for all soil science licensing efforts. It links to the best available information, including the list of soil science licensing boards maintained by the Soil WikiProject.

For now, the Soil Science Licensing site effort is strictly focussed on Washington state's efforts. The latest revision (pdf) (December 7, 2006) has been posted and I have one concern with the new wording:

The practice of soil science does not include design work, such as would be carried out by either engineers, as defined in RCW 18.43.020 or architects, as defined in RCW 18.08.320.

We need something along these lines, but the term "design work" is not specifically defined in the cited sections, but is referred to somewhat broadly. Is this going to be a problem? Perhaps someone with experience in one of the licensed states can comment.