Soil Life & Carbon Answers to Global Warming in Our ‘Root Cellar’ by Mike Amaranthus, Ph.D.

From the food we eat, to the air we breath, to the clothes we wear, humans depend on the thin covering of the earth’s surface we call soil. Arguably this thin and fragile layer of living topsoil is the Earth’s most critical natural resource. Soil is literally the “root cellar” for the planet, a storage area that feeds us and protects us in emergencies. It nurtures life in both forest and field and carves intricate paths that link the health of the land, sea and atmosphere. Lately there has been tremendous attention given to carbon sequestration. Five to ten years ago, few had heard of or cared about the concept. Carbon se- questration has suddenly become a hot topic because carbon in the air combines with oxygen to become carbon dioxide, Root system of a rye crop inoculated with compost tea and mycorrhizal fungi — this a greenhouse gas that contributes to area is rich in feeder roots, soil organisms and soil carbon. global warming. Soils are key players in the process of more of the carbon to the atmosphere Oregon State University. “It holds water, storing (sequestering) and recycling car- as CO2 through respiration, although preventing drought and floods, it sup- bon. According to Canada’s Department some will be stored within their bodies ports the living soil organisms that hold of Agriculture and the Environment, until they die and decompose. Finally, the key to sustainable plant growth, and soils contain more than all the carbon as plants and animals decay, instead of it is a reservoir of carbon that plays a key in the atmosphere and three times more escaping as carbon dioxide, a significant role in global climate change.” than is stored in all the Earth’s vegeta- portion of their carbon becomes part of Soils can contain a wide range of or- tion. Soil microbes break down decaying the organic component in soils through ganic matter. Most topsoils range from plant and animal matter in the process the activities of essential soil organisms. 1 to 20 percent organic matter. The best of creating fertile soils, and healthy soils These beneficial microorganisms work agricultural lands have loamy topsoil in containing billions of beneficial micro- to produce a substance known as humus, which there is a high concentration of organisms and vigorous root systems a stable, rich component of soil that is organic matter. Some of the richest in have become an important carbon sink, the color of dark chocolate and loaded the world were found in the Great Plains binding up carbon that might otherwise with carbon. of the central United States, where pe- enter the atmosphere. rennial grasses, their roots systems and The carbon absorbed from the at- HISTORY LESSON associated soil organisms over thousands mosphere by plants and animals can When frequent tillage is introduced, of years built up deep layers of carbon- take several paths before it re-enters the long chains of carbon that are the es- laden topsoil. They form continuously, air as carbon dioxide. When a plant or sence of humus are converted into car- but very slowly. Only about one inch of animal dies, it is broken down by soil bon dioxide, which releases into the soil is formed every 500 to 1,000 years, microorganisms. As the microorganisms atmosphere. Soil depleted of the humic so loss of good topsoil is a serious issue consume the organic matter, they release fraction is more prone to erosion, loss of that has led to the rise and fall of civili- some of the carbon into the atmosphere microbial diversity and a breakdown of zations. in the form of carbon dioxide. Some is structure and can support fewer animals The great early civilizations of Meso- destined for longer-term storage in roots and plants. “Organic matter is the elixir potamia, for example, arose because of and in the bodies of plant-eating or car- of microbial life in the soil,” explains Dr. the richness of their soils, and collapsed nivorous animals. Animals then return Dave Perry, professor and ecologist at because of declines in soil quality. Poor

Reprinted from March 2008 • Vol. 38, No. 3 Endomycorrhizal spores such as these are deposited beneath the soil surface and do not rapidly recolonize agricultural sites once they have been lost. land management and excessive irriga- tion caused soils to become increas- ingly degraded and unable to support the Fertile Crescent civilizations. Ancient Greece suffered a similar fate. The phi- losopher Plato, writing around 360 B.C., attributed the demise of Greek domi- Mycorrhizal filaments in the soil extract nutrients and water and leave deposits of nance to soil degradation: “In earlier carbon-rich glomalin. days Attica yielded far more abundant produce. In comparison of what then from the time of Alexander the Great to they actually live inside the plant, such was, there are remaining only the bones Napoleon. as beneficial mycorrhizal fungi. Their of the wasted body; all the richer and Today, we are facing many of the threads penetrate into the root and se- softer parts of the soil having fallen away, same issues: removal of native vegeta- cure sugars provided by the plant to fuel and the mere skeleton of the land being tion, over-harvest, dwindling supplies their growth. In exchange, these same left.” What Plato likely did not recognize of fresh water, overworked soils and filaments radiate out from the root into is how much carbon had washed away sprawling population growth. Our poor the surrounding soil where they capture from these Greek soils. management of the land has resulted nutrients and water and transport these In the New World, similar processes in serious warning signs. Widespread materials back to the plant. It is esti- were unfolding. Harvard Professor Syl- agricultural pollution of lands and seas, mated that mycorrhizal fungal filaments vanus Morley concluded back in the accelerated topsoil loss, damage to fish explore hundreds to thousands of times 1930s that the great Mayan Civilization and aquatic life, pesticide buildup in our more soil volume than roots alone. of Mesoamerica collapsed because they bodies, and rapidly declining nutritional Endomycorrhizae, also known as ar- overshot the carrying capacity of the value of food have become environmen- buscular mycorrhizae, are the symbiotic land. Deforestation and erosion exhaust- tal problems of immense importance association of fungus and root that oc- ed their resource base. Mayans died of that are directly related to soil. Now is cur on more plant species than all other starvation and thirst in mass, and others the time to bring attention to the criti- types of mycorrhizae combined. They fled once-great cities, leaving them as cal role our management of soil plays have been observed in the roots of more silent warnings for generations to come. in another environmental issue of great than 1,000 genera of plants representing UCLA professor Jared Diamond, au- significance: global climate change. some 200 families. It has been estimated thor of the books Guns, Germs and Steel that more than 85 to 90 percent of the and Collapse, argues that most inhabit- FIRST LESSON estimated 400,000 species of vascular ants of Easter Island in the Pacific died How do we stop the degradation of plants in the world form arbuscular because of deforestation, erosion and our soils? The answers can be found in mycorrhizae. These include most grains, soil depletion. In Iceland, farming and nature below the soil surface in our “root vegetables, fruit and nut trees, vines and human activities caused about 50 percent cellar.” A favorite habitat of microbes is turf grasses. of the soil to end up in the sea, explains near and in the roots of plants. Although Benefits of mycorrhizae include: Diamond, concluding, “Icelandic society many of them live throughout the soil, • Improved nutrient and water uptake; survived only through a drastically lower up to 100 times more live close to the • Improved root growth; standard of living.” Not surprisingly, the roots of plants. • Improved plant growth and yield; practice of destroying soils by torching This area near the roots is called the • Reduced transplant shock; watersheds or salting farms and fields rhizosphere, the thin layer of soil sur- • Reduced drought stress. has been employed by armies in warfare rounding the roots. Some microbes have Some modern agricultural practices such a close relationship with plants that reduce the biological activity in soil.

Reprinted from March 2008 • Vol. 38, No. 3 A granular mycorrhizal inoculant (left) and a mycorrhizal inoculant coating on wheat seed.

Certain pesticides, chemical fertilizers, tered in via existing irrigation systems. (with the exception of the brassicas). intensive cultivation, compaction, or- The goal is to create physical contact Glomalin (produced by the endomycor- ganic matter loss, and erosion adversely between the mycorrhizal inoculant and rhizal fungal group Glomus, hence the effect beneficial mycorrhizal fungi. An the crop roots, and the type of applica- name) is produced by endomycorrhizal extensive body of laboratory testing in- tion depends upon the farmer’s equip- fungi established on a plant’s roots. The dicates that the majority of intensively ment and needs. Inoculants that are fungi produce glomalin from carbon managed agricultural lands lack ade- concentrated and contain several species they trade for other nutrients and water, quate populations of mycorrhizal fungi. of mycorrhizal fungi produce the best apparently to seal themselves and gain Farming widespread areas affects the results. The cost of inoculation generally enough rigidity to carry materials across plant/mycorrhizal relationship in two ranges from $7 to $17 per acre. the air spaces between soil particles. fundamental ways. First, it isolates the Sara F. Wright’s discovery of glomalin plant from beneficial mycorrhizal fungi CARBON-RICH SUPERGLUE is causing a complete reexamination of available in natural settings. Second, it Mycorrhizae also perform another soil organic matter. It is increasingly be- increases a healthy crop’s need for water, service for the ecosystem that has only ing included in studies of carbon storage nutrients and soil structure. recently come to light. The USDA pub- and soil quality. Once lost from a farm, endomycor- lished a report by Don Comis on work rhizal populations are slow to recolonize by Sara F. Wright and Kristine A. Nichols CO2 & GLOMALIN unless there is close access to natural that suggests a substance called gloma- In an earlier study, Wright and sci- areas that can act as a source of mycor- lin, discovered by Wright in 1996, does entists from the University of Califor- rhizal spores. Endomycorrhizal fungi do indeed “glom” onto a large amount of nia at Riverside and Stanford University not disperse their spores in the wind, carbon. The glomalin molecule is made showed that higher CO2 levels in the at- but must grow from root to root or be up of 30-40 percent carbon and repre- mosphere stimulate the fungi to produce dispersed by animals, so close proxim- sents up to 30 percent of the carbon in more glomalin. A three-year study was ity to healthy and undisturbed natural soil. It is a natural superglue that binds done on semiarid shrub land, and a six- sites may be necessary. Normally though, organic matter to mineral particles in year study was conducted on grasslands farmers seldom have the opportunity to soil. It also forms soil clumps — aggre- in San Diego County, California, using grow their crops immediately adjacent to gates — that improve soil structure and outdoor chambers with controlled CO2 undisturbed natural ecosystems. keep other soil carbon from escaping. It levels. When atmospheric CO2 reached Inoculating farmland soils with my- is in fact glomalin that gives soil its tilth 670 parts per million — the level pre- corrhizal fungi before, during or fol- — a subtle texture that enables experi- dicted for the middle to late 21st cen- lowing planting can improve crop es- enced farmers to identify great soil by tury — mycorrhizal fungal filaments tablishment, growth, yield and carbon feeling for the smooth granules as they (hyphae) grew three times as long and sequestration. Mycorrhizal inoculants flow through their fingers. Glomalin is produced five times as much glomalin are available in liquid, powder and gran- relatively stable in soils, lasting anywhere as fungi on plants growing with today’s ular forms and can be sprinkled onto from seven to 42 years. ambient level of 370 ppm. roots during transplanting, banded be- Endomycorrhizae form with nearly Longer hyphae help plants reach neath seed, used as a seed coating or wa- all the important agricultural plants more water and nutrients, which could

Reprinted from March 2008 • Vol. 38, No. 3 help plants face drought in a warmer organic matter in the soil. Data from 23 and diseases were almost nonexistent. climate. The increase in glomalin pro- years of continuous research in side-by- Over time prairie soils built and main- duction helps soil build defenses against side fields is conclusive: the organic sys- tained deep and carbon-rich productive degradation and erosion and boosts its tem has shown an increase in soil carbon topsoil. It is a soil legacy that helped productivity. Wright says all these ben- of 15-28 percent, compared to no in- make America prosperous. efits can also come from good tillage crease in the non-organic system. Dr. Da- Compared to perennial grasses, an- and soil management techniques rather vid Douds of the Agricultural Research nual crops such as wheat, corn, sunflow- than higher atmospheric CO2. “You can Service suggests that healthy mycorrhizal ers and sorghum have relatively shallow still raise glomalin levels, improve soil fungi populations in organic systems are root systems. The vast majority of an- structure, and increase carbon storage,” key to the increase in soil carbon. In ad- nual roots are confined to the top foot of she notes. dition, a recent study of energy inputs soil. These root systems die after harvest, Forests, croplands and grasslands conducted by Dr. David Pimentel of leaving non-vegetated soil exposed to around the world are potentially valu- Cornell University found that organic erosion of precious topsoil. Perennial able for offsetting carbon dioxide emis- farming systems use just 63 percent of root systems, on the other hand, com- sions from industry and vehicles. In the energy required by conventional monly exceed 6 feet in depth and main- fact, some private markets have already farming systems, largely because of the tain this living tissue year-round. This started offering carbon credits for sale by massive amounts of energy required to allows perennial grasses to be resilient owners of such land. Industry could buy synthesize nitrogen fertilizer. in the face of extremes of environment the credits as offsets for their emissions. The expectation is that these credits would be traded just as pollution cred- its are currently traded worldwide. Al- though such plans risk abuse by indus- trial polluters and are thus controversial, the importance of our crops, forests and grasslands in offsetting the environmen- tal damage caused by human technology is unquestionable.

SECOND LESSON Today most human food comes from legumes, oilseed crops and cereal grains. It is estimated that 80 percent of agri- cultural land is occupied by these crops. These human staples are relatively high in protein and calories and easy to store and transport, thus making them attrac- tive to both consumers and producers. A glomalin-rich soil inoculated with beneficial soil organisms. However, these annual crops must be grown from seed every year, generally using fossil-fuel intensive cultivation This is big news. Organic farming and to sprout into action when warm and fertilization methods. To maintain with help from mycorrhizal fungi can temperatures, water and nutrients be- annual yields, farmers are faced with take massive amounts of carbon dioxide come available. Deep perennial grass- growing input costs for seed, fuel, fertil- out of the air. If all 160 million acres of root systems and associated mycorrhizal izer, pesticides and herbicides. All these corn and soybeans in the United States fungi reduce fertilizer losses, conserve practices, including tillage, consume or were converted to organic production, water, and boost the soil’s storage of release large amounts of carbon dioxide the reduction in atmospheric CO2 could carbon. Roots and mycorrhizal fungi into the atmosphere. In addition, ero- translate to: pump carbon-rich plant sugars such as sion and runoff from these intensively • 57.7 million cars off the road (25 glomalin into the soil, feeding beneficial cultivated lands can pollute freshwater percent of nation’s cars!); soil organism that conserve and access supplies and degrade the soil. • 773 billion car miles not driven. soil nutrients. Data from the Rodale Institute’s long- Let’s look at nature’s “root cellar” as Perennial roots themselves become a running comparison of organic and an example of how the system works — root cellar of stored carbon. Deep root conventional cropping systems confirms for example, a native tall-grass prairie in systems capture and utilize more rain- that organic methods are far more effec- the Midwest. These prairie systems were water than shallow root systems, thus tive at removing carbon dioxide from productive year after year and needed no reducing off-site movement of water and the atmosphere and fixing it as beneficial fertilizers, pesticides or herbicides. Pests nutrients. In addition, perennial grasses

Reprinted from March 2008 • Vol. 38, No. 3 do not have to be planted every year, production of high-yield perennial grain thus reducing consumption of fuel by crops, if successful, could have a major farm machinery. Perennial root systems positive impact on both the environ- and associated mycorrhizal fungi tie up ment and the sequestration of carbon in soil resources, discouraging invasions of the root cellar. weeds. Pesticide, herbicide and fertilizer Acres U.S.A. is the national journal of use is greatly diminished, which again CONCLUSIONS sustainable agriculture, standing virtually lowers the amount of fossil fuels needed Hidden underground in our planet’s alone with a real track record — over 35 years of continuous publication. Eash on the farm. Greater root depths, longer root cellar, nature has given us a tem- issue is packed full of information eco- growing seasons for roots and mycorrhi- plate to help us resolve a variety of consultants regularly charge top dollar zal fungi let perennials sequester carbon serious environmental issues, including for. You’ll be kept up-to-date on all of at a rate 50 percent higher than an annu- global warming. Often overlooked and the news that affects agriculture — regu- lations, discoveries, research updates, ally cropped field. underappreciated, the living soil holds organic certification issues, and more. For all of these reasons, plant breed- the key to the future. Vigorous long- ers both in the United States and in- lasting root systems and associated tiny To subscribe, call ternationally have initiated breeding fungal threads can accumulate and store 1-800-355-5313 programs to develop wheat, sunflower, vast amounts of carbon. Are we destined (toll-free in the U.S. & Canada) sorghum and intermediate wheatgrass as to relive the mistakes of previous civili- 512-892-4400 / fax 512-892-4448 perennial grain crops. While still in the zations or are we wise enough to learn P.O. Box 91299 / Austin, TX 78709 early stages, plant geneticists such as Wes from natural systems? It’s time to exam- [email protected] Jackson in Kansas are making progress. ine our root cellar for solutions. Or subscribe online at: The Land Institute, a nonprofit founded www.acresusa.com by Jackson, has discovered that of the 13 Mike Amaranthus is president of Mycorrhizal Applications Inc., P.O. Box 1029, Grants Pass, most widely grown grain and oil seed Oregon 97528, phone 541-476-3985, fax 541- crops, 10 are capable of hybridization 476-1581, e-mail [email protected], web- with perennial relatives. The widespread site www.mycorrh izae.com.

Reprinted from March 2008 • Vol. 38, No. 3