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Oct 122010
 

(The article below has been adapted from Chapter 2, “Population Pressure: Land and Water,” in Lester R. Brown’s book Plan B 4.0: Mobilizing to Save Civilization (New York: W.W. Norton & Company, 2009). Brown is the president of the Earth Policy Institute.)


Lester Brown

The thin layer of topsoil that covers the planet’s land surface is the foundation of civilization. This soil, typically 6 inches or so deep, was formed over long stretches of geological time as new soil formation exceeded the natural rate of erosion. But sometime within the last century, as human and livestock populations expanded, soil erosion began to exceed new soil formation over large areas.

This is not new. In 1938, Walter Lowdermilk, a senior official in the Soil Conservation Service of the U.S. Department of Agriculture, traveled abroad to look at lands that had been cultivated for thousands of years, seeking to learn how these older civilizations had coped with soil erosion. He found that some had managed their land well, maintaining its fertility over long stretches of history, and were thriving. Others had failed to do so and left only remnants of their illustrious pasts.

In a section of his report entitled “The Hundred Dead Cities,” he described a site in northern Syria, near Aleppo, where ancient buildings were still standing in stark isolated relief, but they were on bare rock. During the seventh century, the thriving region had been invaded, initially by a Persian army and later by nomads out of the Arabian Desert. In the process, soil and water conservation practices used for centuries were abandoned. Lowdermilk noted, “Here erosion had done its worst….if the soils had remained, even though the cities were destroyed and the populations dispersed, the area might be re-peopled again and the cities rebuilt, but now that the soils are gone, all is gone.”

Wind and water erosion take a toll. The latter can be seen in the silting of reservoirs and in satellite photographs of muddy, silt-laden rivers flowing into the sea. Pakistan’s two large reservoirs, Mangla and Tarbela, which store Indus River water for the country’s vast irrigation network, are losing roughly 1 percent of their storage capacity each year as they fill with silt from deforested watersheds.

Ethiopia, a mountainous country with highly erodible soils, is losing close to 2 billion tons of topsoil a year, washed away by rain. This is one reason Ethiopia always seems to be on the verge of famine, never able to accumulate enough grain reserves to provide meaningful food security.

Soil erosion from the deterioration of grasslands is widespread. The world’s steadily growing herds of cattle and flocks of sheep and goats forage on the two fifths of the earth’s land surface that is too dry, too steeply sloping, or not fertile enough to sustain crop production. This area supports most of the world’s 3.3 billion cattle, sheep, and goats, all ruminants with complex digestive systems that enable them to digest roughage, converting it into beef, mutton, and milk.

An estimated 200 million people make their living as pastoralists, tending cattle, sheep, and goats. Since most land is held in common in pastoral societies, overgrazing is difficult to control. As a result, half of the world’s grasslands are degraded. The problem is highly visible throughout Africa, the Middle East, Central Asia, and northwest China, where the growth in livestock numbers tracks that in human numbers. In 1950, Africa was home to 227 million people and 273 million livestock. By 2007, there were 965 million people and 824 million livestock.

Nigeria, Africa’s most populous country, is losing 351,000 hectares (867,000 acres) of rangeland and cropland to desertification each year. While Nigeria’s human population was growing from 37 million in 1950 to 148 million in 2007, a fourfold expansion, its livestock population grew from roughly 6 million to 102 million, a 17-fold jump. With the forage needs of Nigeria’s 16 million cattle and 86 million sheep and goats exceeding the sustainable yield of grasslands, the northern part of the country is slowly turning to desert. If Nigeria continues toward its projected 289 million people by 2050, the deterioration will only accelerate.

Iran, with 73 million people, illustrates the pressures facing the Middle East. With 8 million cattle and 79 million sheep and goats—the source of wool for its fabled rug-making industry—Iran’s rangelands are deteriorating from overstocking. In the southeastern province of Sistan-Balochistan, sand storms have buried 124 villages, forcing their abandonment. Drifting sands have covered grazing areas—starving livestock and depriving villagers of their livelihood.

Neighboring Afghanistan is faced with a similar situation. The Registan Desert is migrating westward, encroaching on agricultural areas. A U.N. Environment Programme (UNEP) team reports that “up to 100 villages have been submerged by windblown dust and sand.” In the country’s northwest, sand dunes are moving onto agricultural land in the upper reaches of the Amu Darya basin, their path cleared by the loss of stabilizing vegetation from firewood gathering and overgrazing. The UNEP team observed sand dunes 15 meters high blocking roads, forcing residents to establish new routes.

China faces similarly difficult challenges. After the economic reforms in 1978 that shifted the responsibility for farming from large state-organized production teams to farm families, China’s cattle, sheep, and goat populations spiraled upward. While the United States, a country with comparable grazing capacity, has 97 million cattle, China has a slightly smaller herd of 82 million. But while the United States has only 9 million sheep and goats, China has 284 million. Concentrated in China’s western and northern provinces, sheep and goats are destroying the land’s protective vegetation. The wind then does the rest, removing the soil and converting productive rangeland into desert.

China’s desertification may be the worst in the world. Wang Tao, one of the world’s leading desert scholars, reports that from 1950 to 1975 an average of 600 square miles turned to desert each year. By century’s end, nearly 1,400 square miles (3,600 square kilometers) were going to desert annually. Over the last half-century, some 24,000 villages in northern and western China have been entirely or partly abandoned as a result of being overrun by drifting sand.

China is now at war. It is not invading armies that are claiming its territory, but expanding deserts. Old deserts are advancing and new ones are forming like guerrilla forces striking unexpectedly, forcing Beijing to fight on several fronts.

Soil erosion often results from the demand-driven expansion of cultivation onto marginal land. Over the last century or so there were massive cropland expansions in two countries—the United States and the Soviet Union—and both ended in disaster.

During the late nineteenth century, millions of Americans pushed westward, homesteading on the Great Plains, plowing vast areas of grassland to produce wheat. Much of this land—highly erodible when plowed—should have remained in grass. This overexpansion culminated in the 1930s Dust Bowl, a traumatic period chronicled in John Steinbeck’s novel The Grapes of Wrath. In a crash program to save its soils, the United States returned large areas of eroded cropland to grass, adopted strip-cropping, and planted thousands of miles of tree shelterbelts.

The second major expansion came in the Soviet Union beginning in the mid-1950s. In an all-out effort to expand grain production, the Soviets plowed an area of grassland larger than the wheat area of Australia and Canada combined. The result, as Soviet agronomists had predicted, was an ecological disaster—another Dust Bowl. Kazakhstan, where the plowing was concentrated, has abandoned 40 percent of its grainland since 1980. On the remaining cultivated land, the wheat yield per acre is one sixth of that in France, Western Europe’s leading wheat producer.

A third massive cropland expansion is now taking place in the Brazilian Amazon Basin and in the cerrado, a savannah-like region bordering the basin on its south side. Land in the cerrado, like that in the U.S. and Soviet expansion, is vulnerable to soil erosion. This cropland expansion is pushing cattle ranchers into the Amazon forests, where ecologists are convinced that continuing to clear the area of trees will end in disaster. Reporter Geoffrey Lean, summarizing the findings of a 2006 Brazilian scientific symposium in London’s Independent, notes that the alternative to a rainforest in the Amazon would be “dry savannah at best, desert at worst.”

Civilization depends on fertile soils. Ultimately, the health of the people cannot be separated from the health of the land.

(Conserving and rebuilding soils will be covered in the next Plan B 4.0 Book Byte.)


Jul 212010
 

By Harriet Blake
Green Right Now

Count yourself lucky if you live in a part of the country that has rich organic soil.

Dirt in the Midwest and Mid Atlantic states tends to be easy to work with, while soil in warmer, drier Southwestern states requires some help.

Soil enriched with organic materials will improve the toughest, dry dirt.

However, even if you live in an area with hard-to-work clay soil, there’s something that will enrich your dirt: organic matter, or compost. You can buy compost products at area garden centers, but consider taking advantage of what falls from your area’s trees. They provide free organic matter every fall.

Composted matter improves soil structure and drainage, says Texas A&M extension horticulturalist Keith Hansen. Compost also “promotes better root growth and increased absorption of rainfall and water, and helps reduce runoff, pollution and the loss of essential plant nutrients,” he said.

Soil organic matter helps a garden thrive. Good soil, as described in Organic Gardening from Rodale Press, has a high amount of organic matter, a loose, crumbly texture and a dark brown color. Organic additions to your dirt will make plants resilient, bigger and resistant to bugs and disease.

There are more than 20,000 kinds of soil in the United States, according to the U.S. Department of Agriculture, but the three basic types are clay, sandy and loam. The differences arise from an area’s climate, topography, parent material and biological factors (plants, animals, micro-organisms and humans).

Clay and sandy soil require additional organic material, such as compost or peat moss. Loosen up the soil by tilling or using a spade. Tilling compost, especially into clay soil, is essential before putting in a landscape, says Daphne Richards, a county extension agent with Texas A&M.

“Organic matter in the soil breaks up those hard, compacted clay lumps and allows air and water to flow through the soil, while also feeding beneficial microorganisms.” For already-established lawns that require “amending,” she suggests applying compost annually as a thin top dressing, allowing the grass to grow up through it. Clay soil takes a long time to absorb water, so water it slowly. The USDA advises watering only as fast as soil absorbs the water.

The addition of organic material in sandy soil also keeps water from running through the soil too quickly, which allows plants to absorb more moisture.

Loam soil, which is considered the best, is a combination of sand, silt and clay. It absorbs water easily and has the ability to retain it for plants to use later.

Bed preparation is key to any good landscape, according to landscape architect — aka the  Dirt Doctor – Howard Garrett. “Without good bed preparation,” he says, “plants will struggle.”

Garrett recommends first removing unwanted vegetation. Get rid of weeds and grass, and toss

Dry or sandy soil needs a boost from organic matter you till into it.

them into a compost pile.  Don’t till the soil when it is wet, as this will eliminate air spaces that are important to good soil life, he said.

It’s important to raise beds to promote drainage. Moistening the soil before planting is key, but don’t make it so wet that the soil becomes muddy. For a new bed with no grass or an existing bed, Garrett advises adding 4 to 6 inches of compost, organic fertilizer, volcanic rock sand or powder and dry molasses. Then rototill, fork or air spade to an 8-inch depth. For a new bed located in a grass area, the existing sod should be removed to about 1½ inches and then add all of the above plus horticultural cornmeal. (Cornmeal can stop the germination of weed and grass seeds in the mix.)

After the beds are set, take pot-bound plants and gently loosen their root balls, taking care not to tear the root system. Dip the balls into water and put them into moist plant beds.

Adding compost tea – a low-strength natural fertilizer – is effective on many pests or problems,  including black spot on roses. The plants should be set so the top of the root ball is even or just a bit higher than the soil level. When a plant sits too high, its upper roots dry out.

Make sure you add 2 to 3 inches of organic mulch after planting. Annuals and perennials need a thin layer of compost, while shrubs and ground cover benefit from mulch made of native tree trimmings.

Once your dirt is established, maintain its health by watering at the right time of the day, using the right fertilizer, mowing and using natural alternatives to keep pests away.

Watering in the early morning or night is best, as water evaporates when you use it during the day. Don’t water when it’s windy, so you can direct the water where it’s needed.

Fertilizing is important because plants need nitrogen (for healthy green growth); phosphorous (to help roots and seeds develop and avoid disease); and potassium (to allow root development and prevent disease). If applied correctly, these nutrients are absorbed by the plants and very little is absorbed by ground or surface water.

Because soils differ, having your soil tested to find out what type of fertilizer is needed is a good idea. Your local or state extension service should be able to help.

Remove weeds, fertilize when soil is damp, then water again to get fertilizer to roots.

Remember to fertilize when dirt is damp, then water again after the application. This helps the fertilizer go directly to the roots instead of remaining on top of the soil where it can be blown away or washed away by rain.

When mowing – you’ve heard this before – leave the clippings on the lawn. They will decompose and provide natural nutrients for the grass. Also, don’t cut the grass too short during hot weather – you won’t need to water as much.

Natural alternatives for pesticides save money and are, of course, better for the environment. Spraying plants with non-detergent insecticidal soaps, garlic, hot pepper, a teaspoon of liquid soap in a gallon of water, used dishwater or a strong stream of water will help remove insects from your vegetation.

Also consider including plants that naturally kill bugs among the flowers in your garden. Some of these are mint (kills ants and aphids); onion (kills bean leaf beetles, spider mites and mice); garlic (kills flea beetles); French marigolds (kills root knot nematodes); and prostrate rosemary (kills slugs).

Everyone in the organic gardening movement can’t say enough about composting. The Dallas-based Clean Air Gardening news site notes that adding compost not only improves soil fertility but provides food for microorganisms to keep soil healthy and balanced. Nitrogen, potassium and phosphorus are made naturally by the feeding of microorganisms.

Understanding how to make and use compost is good for everyone. With landfills overflowing, composting provides an alternative to throwing away organic waste. Why toss away materials when they can be used to help your garden and lawn grow and thrive?

Copyright © 2010 Green Right Now | Distributed by GRN Network

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Jul 192010
 

By Francesca Rheannon
Green Right Now

Biochar has emerged over the last couple years as a ray of hope on the otherwise bleak horizon of the planet’s environmental future. It has been hailed as a possible solution to climate change, world hunger, and rural poverty — though doubts are being raised in some quarters.

Last year, some of the world’s most eminent biochar experts gathered for a biochar conference at the University of Massachusetts-Amherst to discuss this ancient technology that is getting a new look by scientists, governments and investors.  To the packed audience, this promising technology sounded like a panacea for a whole host of problems. Biochar, the speakers said, could soak up large amounts of carbon from the atmosphere, supercharge soil fertility to feed the world’s hungry, promote jobs and economic opportunities for farmers, safely get rid of animal and plant waste, heat buildings greenly, and slash the kind of fertilizer use that is creating vast dead zones in coastal waters from nitrogen runoff.

“We see the synergisms in terms of food security, energy security, rural economic development and climate change working together,” the USDA’s David Laird explained between conference sessions. Laird runs the biochar research program at the agency’s National Laboratory For Agriculture and The Environment in Ames, Iowa.

Created by burning plant matter or animal wastes at low temperatures (pyrolysis), biochar has been around for centuries. The ancient indigenous civilizations of the Amazon may have supported their large populations on the rich soil, called “terra preta”, they created when they made charcoal – soils far more fertile than even those naturally occurring in the rainforest. These soils not only yield more crops, they also – critically for our warming planet — store carbon, sequestering it in the ground where it can be kept safely out of the atmosphere for hundreds or even a thousand years.

But can what the ancients did be replicated today?

Critics charge that the Amazonian terra preta was built up slowly over centuries in a process we still don’t understand. They question whether we know how to make biochar stable enough to sequester carbon over the centuries we will need to bring the earth’s atmosphere back within pre-fossil fuel era limits.

Biochar and the carbon cycle (Image: Cornell University)

But Cornell soil scientist Johannes Lehmann, author of the definitive scientific study of biochar, said in an interview last week that the evidence is getting stronger that biochar can store carbon in the soils safely over the long term.  “Biochar is stable,” he says. “Charring prolongs the life and increases the stability by 1.5 and 2 orders of magnitude; instead of half of the carbon in the soil decomposing in ten years, it will take a thousand years to decompose.”

How long it really takes depends on where you are, Lehmann cautioned. “For a leaf falling in Alaska, the carbon will normally stay in the soil in a hundred years (without charring); in Nigeria, it will only stay a week,” he says “but the critical point is that charring increases stability everywhere.”

David Laird says the problem is that biochar is not a simple system. “We think of charcoal and immediately we think of having a barbecue in the backyard and a bag of charcoal. But the reality is, there are many different forms of charcoal.” There’s good char and bad char, he told me – and what may be good on one type of soil may be bad for another – something biochar entrepreneurs need to know to make sure they use the right kind of char under the right conditions. “We need to think about char by soil, by crop, by climate interactions, and ultimately optimize systems that work.”

But other problems may not be so easily remedied by providing better scientific information to entrepreneurs.  Climate change journalist George Monbiot set off a fierce debate last year when he lambasted biochar as more hype than hope and charged that “charleaders” like NASA climatologist Jim Hansen and scientist James Lovelock (creator of the Gaia Hypothesis) would be “pyrolising the planet in the name of saving it.”

The problem stems not so much from the science as from the business model for biochar. Bringing biochar into the market for trading carbon credits – which is being considered by the United Nations Framework Convention on Climate Change (UNFCCC)  for inclusion in UN Certified Emission Reductions (CER) and Clean Development Mechanism (CDM) – would kickstart biochar production on an industrial scale. It would create a market for biochar carbon offsets that polluters would buy. That means biochar companies would need enough biomass to fuel their furnaces – and their bottom lines. That could mean more than a billion hectares worldwide devoted to biochar.

Where would the biomass on such a massive scale come from? From monocultural tree plantations, which could take over arable land, be carved out of existing natural forests, or displace pastoralists and nomads from so-called “marginal” lands – lands that don’t have a commercial value on the global market, but that provide habitat for diverse species and sustenance for the largely poor people who depend on them. And if native forests are cut down to feed biochar furnaces, their ability to capture carbon out of the atmosphere will be lost.

Johannes Lehmann says carbon trading mechanisms must look at the full life cycle of the biochar getting the credits. For example, is it displacing natural forests without replacing them? Is it being transported long distances using fossil fuels? Is it using more energy to produce char than it saves? Is it staying long enough in the soil? He advocates using agricultural waste, like rice straw in India, which is already being burned but not being turned into char or being returned to the soil.

But biochar doesn’t have to be produced on a large-scale commercial basis in order to accomplish the wonders for which it’s been touted. Small farmers all over the world can pyrolize their agricultural waste, turn it into energy for heat and use it to enhance soil fertility. Small-scale biochar technology is not expensive – you can build a tin-can pyrolizer in your garage, and backyard inventors are creating models that can be used on the small to medium scale for farms and communities.

Municipal governments can use it to turn garbage into compost and energy. Portable biochar furnaces could, for example, be leased from local manufacturers in western states to turn forests devastated by the pine bark beetle into usable fertilizer. (They may have to compete with those who want these dead pine trees for biofuel).

The real question is: Will biochar become a feedstock for profits by global companies who use their clout to water down or kill environmental regulations? Or will it be a feedstock fueling solutions to humanity’s most pressing problems? The jury is still out.

For more about biochar see these resources:

Francesca Rheannon writes about sustainability and corporate social responsibility. She is a contributing writer for CSRwire.com and co-manages the CSRwire blog, Talkback. She is also host and producer of the weekly radio show and podcast, Writers Voice.

Copyright © 2010 Green Right Now | Distributed by GRN Network


Jul 182008
 

By John DeFore

Conservation minded farmers might naturally assume it’s wise to get the most out of what’s available; if post-harvest waste material can be used in biofuel production, it seems to make financial and ecological use to sell it.

Not necessarily, according to a scientist at Washington State University who is urging farmers in her region to leave the waste where it falls.

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