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Evolution and InnovationSave Biodiversity...Rise

Soil & Ecosystems

Soil and Ecosytems
Soils are a crucial part of plant growth. Soil is taken for granted since just about everything seems to grow in soil. Many students don't recognize the importance of a good quality soil in determining plant growth.
Soils are composed of three particles -- sand, silt and clay. An ideal soil will contain 45 percent mineral particles, 5 percent organic matter from decomposing plant and animal material, 25 percent water, and 25 percent air spaces
The Soil Food web...

 

Soils are rich ecosystems, composed of both living and non-living matter with a multitude of interaction between them. Soils play an important role in all of our natural ecological cycles ? carbon, nitrogen, oxygen, water and nutrient. They also provide benefits through their contribution in a number of additional processes, called ecosystem services. These services range from waste decomposition to acting as a water filtration system to degrading environmental contaminants.

The diversity and abundance of life that exists within the soil is greater than in any other ecosystem. A handful of soil can contain bil­lions of different organisms that play a critical role in soil quality to support plant growth. Although we understand the vital services that these organisms provide by breaking down organic debris (plants, animals, and other organic materials) and recy­cling nutrients, scientists have only begun to study the rich and unique diversity that is a part of the soil ecosystem.

Ecological Cycling

Each ecological cycle is unique, although similar elements can appear in more than one cycle. While most move between the atmosphere (air), hydrosphere (water), lithosphere (land) and biosphere (living things), other nutrient cycles are limited to movement between rocks and soils and plants and animals. However, even the nutrients from these limited cycles, such as potassium, calcium, phosphorus and magnesium, are essential for life.

Water and nitrogen resources, both essential to all living things, stay constant within their cycles ? meaning their only change is in the forms they take. The water cycle is very dynamic as water can change from vapor to liquid to snow to ice. Soils role in this process is through infiltration, storage, and transpiration. Nitrogen, which makes up more than three-quarters of the Earth's atmosphere, must be broken down into other forms in order to be used by living organisms. It is within the nitrogen cycle that soil bacteria converts nitrogen into usable elements (called nitrogen fixing) for plants, animals and humans before it is eventually returned to the atmosphere.

Oxygen is unique in that it not only has its own cycle, it is often integrated into elements within other ecological cycles, as water (H2O), carbon dioxide (CO2), iron oxide (Fe2O3), and many others. Within the biosphere, photosynthesis is the key driver of theoxygen cycle as plants take in carbon dioxide and expel oxygen for animal and human use. Additionally, in water, oxygen is constantly being dissolved and consumed by microorganisms leading to balance.

The carbon cycle is by far the cycle of greatest interest due to its importance in both climate change and global warming. Soil plays a critical role in this cycle since the majority of carbon in the atmosphere comes from biological reactions within the soil. The biological/physical carbon cycle occurs over days, weeks, months, and years and involves the absorption, conversion, and release of carbon by living organisms through photosynthesis, respiration, and decomposition. The geological carbon cycletakes place over hundreds of millions of years and involves the cycling of carbon through the various layers of the Earth. A large amount of organic carbon sinks to the ocean floor to be buried into the Earth's crust. It is thought that more carbon dioxide is stored in the world's soils than is circulated within the atmosphere. Throughout the Earth's history, the release of CO2from deep below the surface occurs as a geological event, such as a volcanic eruption.

Ecosystem Services

Aside from its participation in various biogeochemical cycles and nutrient exchange, soil provides a number of other critical ecosystem services. These services differ from other ecosystem benefits in that there is a human demand for the natural assets and/or benefits. Several important benefits are listed below.

Soil is a natural protector of seeds and plants. Within a soil ecosystem seeds can disperse and germinate. The soil provides a physical support system for plants, while both retaining and delivering nutrients to them. This, in turn, provides humans and other animals with a source of food as well as resources for potential medicinal or other goods. In addition, soil can both hold and release water, thereby providing for plant growth, flood control, and water filtration and purification services.

Soils also play a central role in the management, processing and detoxification of a variety of wastes, both natural and man-made. Soil organisms decompose many organic compounds, such as manure, remains of plants, fertilizers and pesticides, preventing them from entering water and becoming pollutants. Human activity adds a wide variety of substances to the environment, some of which are hazardous or toxic. As long as the concentration is not greater than the ecosystem's ability to handle it, microorganisms in the soil can degrade or detoxify many of these substances, rendering them harmless to humans, animals, and the environment.

“The nation that destroys its soil destroys itself.”
 –Franklin D. Roosevelt, 1937
 
America has not heeded the warning Roosevelt issued nearly 80 years ago. Precious soils are being decimated daily by misguided reliance on industrialized agriculture and synthetic chemicals, which disrupt its delicate ecosystem.
The soils are poisoned with chemical fertilizers and pesticides, and allowed to wash away from overfarming, overgrazing, and erosion. Once teeming with life, our prairies and grasslands are being turned into lifeless dust fields.
The PBS documentary “SOS: Save our Soil,” part of its Food Forward series,1 highlights a few “food rebels” who are finding innovative ways to create a more sustainable food system, including making humus compost out of grass stubble and turning chicken litter into biochar.
The top six inches of soil are the most precious yet least understood ecosystem on Earth. In order to appreciate its importance to our very survival, you first must understand the role carbon plays in maintaining the ecological balance of our entire planet.
Conventional agriculture that relies on tilling and monocrops decimates the top soil and is responsible for massive losses every year. So much so that some predict that most of the topsoil in the US will be lost in the next two generations.
Have We Forgotten We’re Carbon-Based Life Forms..?
All life on earth is carbon-based, yet we seem to ignore carbon’s importance. Even soil microbes need carbon to flourish, which is why slow and steady carbon depletion from our soils will inevitably lead to ecological collapse.2,3 Deprived of carbon and critical microbes, soils become sterile; devoid of the microbial ecosystem.
The problem of carbon depletion in soils is not limited to the US. The world’s cultivated soils have lost 50 to 70 percent of their original carbon, much of which has been oxidized upon exposure to air to become carbon dioxide (CO2).4
One of the largest factors driving this carbon depletion problem is the food/agriculture industry, particularly tilling, lack of cover crops, monocropping, genetically engineered (GE) crops, and their massive dependence on synthetic chemicals, which quickly decimate topsoil.
Meanwhile, carbon dioxide emissions continue to rise. In 2012 alone, 35.7 billion tons of this greenhouse gas entered the atmosphere.5 Some CO2 is absorbed by the oceans, plants, and soil—healthy soil is a bountiful carbon reservoir.
Scientists have recently discovered how organic carbon is stored in soil—it binds only to certain soil structures. Soil's capacity to absorb CO2 is directly related to its health; therefore, soil preservation and restoration needs to be incorporated into today's climate models.6
Why Restoring Carbon to Soils Is So Important...!
Much of the focus on reducing greenhouse gases revolves around reducing carbon emissions, but now that we’re armed with rapidly expanding knowledge about carbon storage in soils, greater attention should be paid to carbon sequestration and soil restoration.
Carbon sequestration refers to taking the carbon from the atmosphere and putting it back into the soil, in a stable form of organic matter.
Many scientists say that regenerative agricultural practices can turn back the carbon clock, reducing atmospheric CO2 while also boosting soil productivity and increasing its resilience to floods, pests, and drought. Today, just three percent of North America’s tallgrass prairie remains, resulting in a massive loss of soil carbon into the atmosphere.
According to Yale:7
“The importance of soil carbon—how it is leached from the earth and how that process can be reversed—is the subject of intensifying scientific investigation, with important implications for the effort to slow the rapid rise of carbon dioxide in the atmosphere.
Scientists say that more carbon resides in soil than in the atmosphere and all plant life combined; there are 2,500 billion tons of carbon in soil, compared with 800 billion tons in the atmosphere and 560 billion tons in plant and animal life.
And compared to many proposed geoengineering fixes, storing carbon in soil is simple: It’s a matter of returning carbon where it belongs.”
According to Rattan Lal, director of Ohio State University’s Carbon Management and Sequestration Center:8
“The top priorities are restoring degraded and eroded lands, as well as avoiding deforestation and the farming of peatlands, which are a major reservoir of carbon and are easily decomposed upon drainage and cultivation...Bringing carbon back into soils has to be done not only to offset fossil fuels, but also to feed our growing global population. We cannot feed people if soil is degraded.”
Soil’s Favorite Food: Humus...!
Several game-changing farmers are addressing this problem. California farmer John Wick, who calls himself a “carbon farmer,” is making humus compost. Wick is the co-founder of the Main Carbon Project in Nicasio, California. Carbon-rich organic matter is what gives soil its water-retention capacity, its structure and fertility, so the objective is to add high-quality, sustainable organic matter back into the soil—and humus compost fits the bill. Wick makes humus compost from biomass such as corn stalks, wheat, and oat straw, soybean stubble, manure, and clay, plus three microbial inoculants. This is not ordinary compost, but closer to the naturally occurring humus that forms on forest floors.
Humus and Compost Are Two Different Things
It’s important to realize that compost and humus are different. Compost is organic matter that’s been decomposing to the smallest particles. Finished compost is only halfway to humus, which is a more effective and matured form of carbon. Humus is not a layer of soil but a component in soil—there is no such thing as a “humus layer.” Even though commercial products are sold as humus, the vast majority is really only finished compost, as true humus is only formed in nature.9 This is presumably why John Wick calls his product “humus compost,” which is as close as we can get to true humus.
Through photosynthesis, a plant draws carbon out of the air to form carbon compounds. What the plant doesn’t need for growth is exuded through its roots to feed soil organisms. Over time, these organisms (mostly bacteria and fungi) break down organic matter into smaller and smaller molecules until most of the usable chemicals in the organic matter have been extracted by the microorganisms and made available to the plants.
When all of the “good stuff “ is used up, the remaining material is called humus in a process is known as humification. Humus consists mostly of carbon in complex molecules or aggregates, and because microorganisms cannot further decompose it, it’s extremely stable—humus can persist in soil for hundreds and even thousands of years. This is in contrast to "active" topsoil carbon, which is in continual flux between microbial hosts and the atmosphere.
Humus Gives Soil Its Ability to Store Water and Nutrients
Scientists don’t yet fully understand humus, but they’ve been able to identify some of the characteristics that make it so highly beneficial, including the following:
Like a big sponge, humus can hold up to 90 percent of its weight in water
Because of its negative charge, many plant nutrients stick to humus (nitrogen, calcium, magnesium, phosphorus, and others), preventing them from washing away and acting as nature’s slow release fertilizer
Humus massively improves soil’s structure, making it loose and friable and helping plants root by providing them better access to nutrients, water, and oxygen
Humus may help “filter” toxic chemicals out of the soil, much like carbon-based water filtration systems filter toxins out of your water
You can build your soil’s humus content by top coating—not tilling—your soil with organic matter, such as woodchips, manure, and compost. Tilling should be avoided as it destroys soil’s intricate structure. Many innovative farmers and agricultural scientists have found ways to turn animal and human waste into fully finished, healthy compost—you can’t get much more sustainable than that! And it really packs a punch—in one case, a farmer who topped his soil one time only with one-half inch of manure compost got 25 to 50 percent more plant growth for four years.
Turning Chicken Poop into Biochar
Biochar is another way to add stable, long-lasting carbon to your soil. Biochar is created by slowly heating a biomass in a low-oxygen environment, such as a kiln, until everything but the carbon is burned off, and then putting it into the ground. Historically, fire has been the driving force of the earth’s carbon cycle. Natural fires started by lightning burned large swaths of plants and trees, returning the carbon back to the soil in the form of charcoal. Today, most societies take steps to prevent wild fires and greatly restrict burning practices.
Midwest poultry farmer Josh Frye has figured out a way to do what fires do, by transforming chicken poop into biochar using green technology with minimal emissions. Just like the scientists who successfully turned human urine into fertilizer, this is one more example of how waste can be turned into a useful and sustainable product with the potential for improving our food system and reducing environmental impacts.
Increase your soil Health with woodchips
A great, cost-effective alternative to compost or biochar that will radically improve the nutrient quality of your foods is mulching with wood chips. I learned about wood chips during my interview with Paul Gautschi. You just lay down uncomposted wood chips on top of your garden—using whatever is available locally, typically a combination of leaves, twigs, and branches. The chips break down gradually and are digested and redigested by a wide variety of bacteria, fungi, and nematodes in the soil, which is exactly what happens in nature.
After a year or so, you’ll develop lush soil underneath the chips that will happily support trees, vegetables, or whatever else you’re trying to grow. The longer you leave the chips on and the deeper you heap them, the thicker your topsoil will be. Wood chips also reduce your weeding by more than 90 percent, because the weeds that do grow are very easy to pull out by their roots. Wood chips drastically reduce the need for watering and eliminate your need for fertilizers, and they provide excellent insulation for your plants and soil, moderating the temperatures in both summer and winter.
Woodchips are a very concentrated form of biomass and can form massive amounts of humus if allowed to compost properly. I have personally put on over a half a million pounds of woodchips on my quarter acre of landscaping and am starting to see excellent results on my four dozen fruit trees, berry shrubs, and vegetables. The chips eliminate the need for irrigation and fertilizers, reduce weeds, and serve as earthworm magnets. The earthworm population on my property has literally exploded.
You Can’t Be Healthy Without Food from Healthy Soil
One of the more insidious aspects of the industrial food system is that, as soil becomes sicker and less able to perform its functions, farmers become increasingly dependent on the chemical technology industry—they become trapped. The use of glyphosate begins a downward spiral, making it necessary for farmers to use more and more herbicides, pesticides, and synthetic fertilizers that kill soil microbes. Especially if they’re using genetically engineered (GE) seeds. Weeds become resistant to glyphosate, so farmers must use more weed killers.
Crops become nutrient-deprived, so they’re forced to increase their use of synthetic fertilizers. Weeds and bugs become superweeds and superbugs... and on and on in a vicious cycle. The best way to avoid this trap is to refrain from using agrochemicals in the first place. Any organic farmer will tell you that they’re growing SOIL, not food—a properly cared for soil will take care of growing your food. The key is to use regenerative soil techniques instead of factory farming approaches, which are degenerative.
 
The answer to world hunger is not GE foods or fuels, but rather reverting to ecologically rational and sustainable agricultural practices, with an emphasis on supporting small local farmers. In a comprehensive global report entitled “Agriculture at a Crossroads,” IAAST (International Assessment of Agricultural Knowledge, Science and Technology for Development) gave high-tech farming a dismal two thumbs-down.10,11 Resistance to revamping the food system can be expected from a few mega-corporations whose pockets are lined by the chemical technology and pesticide industries, but as a consumer, you have a great deal of power as you vote every day with your wallet.
 
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