Understanding Soil - Lets stop treating it like dirt!

As we started practicing city farming, we started undersatnding soil more and more. We understood that it is not just dirt ! After a lot of browsing and taking notes this is what I have compiled.

SOIL

Forests or meadows survive in a natural system, year after year by recycling available nutrients. Leaves fall off and break down; grasses and flowers grow bloom and fade; animals die and decompose –all life adds organic matter to the soil.

The cycle of growth and decay is often depicted as a wheel, where birth, growth and maturity take place above ground in the light, and the process of decay below the surface in the darkness, giving birth to life anew. If growth is faster than decay the wheel is broken, destroying nature’s balance. What lives eventually dies, and its substance returns to the soil to be recycled into new life. This is nature’s law of return. This is the cycle we are trying to create in our farm.

“Growth has been speeded up, but nothing has been done to accelerate decay. Farming has become unbalanced. The gap between the two halves of the Wheel of Life has been left unabridged, or it has been filled by a substitute in the shape of artificial manures (chemicals). The soils of the world are either being worn out and left in ruins, or are being slowly poisoned. The restoration and maintenance of soil has become a universal problem”---Sir Albert Howard, Farming and Gardening for Health or Disease. Faber and Faber London.

It is proved beyond doubt that healthy soil means healthy plants. When you build and maintain fertile rich soil in organic matter, you lay the groundwork for thriving plants/crops that can develop quickly, resist pests and diseases, and yield a bountiful crop.

Shortcomings of chemical fertilizers

Can synthetic chemical fertilizers provide a short cut to healthy soil and healthy plants? After all plant’s needs are fairly basic: air, water, light, warmth and balance of nutrients and minerals. So why not put some seeds in the ground, and apply the appropriate chemicals and reap the harvest?

That’s one possible approach to chemical fertilizers; such as NPK (Nitrogen, Phosphorus, and Potassium) formulations sold in garden supply stores. These fertilizers do provide most of the nutrients that plants need in an easy to use form. But these chemicals have a number of shortcomings.

1. Plants can absorb only a limited amount of nutrients at a time, much of these water-soluble products may be wasted and end up as run off during rain or watering.
2. Many chemical fertilizers provide a quick burst of nutrients but may leave the plants to draw on over the course of the growing season.
3. since petroleum products are needed to produce the fertilizers, they use up valuable non-renewable source of energy.
4. Chemical fertilizers don’t build or maintain healthy soil. Like a vitamin pill or injection they provide instant nutrition but none of the benefits that one would get by actually eating fruits and vegetables.

Soil has to be -- LIVE

If you watch carefully to see what nature does as she goes about her daily round of chores, it’s quite easy to start believing that the whole thing is a complicated, secretive conspiracy by soil micro-organisms to beget more soil micro-organisms. Nature’s first concern is always to build more topsoil, and protect it. It’s easy to see why: no topsoil, not much nature either. A single spade full of rich garden soil contains more species of organisms than can be found above the ground in the entire Amazon rain forest.
Although the soil surface appears solid, air moves freely in and out of it. The air in upper 8 inches of a well-drained soil is completely renewed about every hour. - Soil Factoids, US National Soil Survey Center.

The following article By Danny Blank, ECHO Farm Manager explains it all.
A fresh look at life below the surface

Too often farming and land use practices contribute to land degradation, resulting in food insecurity and poverty. This article takes a fresh look at what is going on in soil, especially in relation to soil organic matter and the organism it supports, how this life in the soil is impacted by our land practices and how it in turn impacts the productivity of our farms.

Soil Food Web Concept

The soil food web is essentially the community of organisms that live in the soil. Every agricultural field, forest, prairie or pasture has its own food web with a unique set of soil organisms. Healthy soils contain massive populations of bacteria, fungi, protozoa, nematodes, soil arthropods and earthworms. A teaspoon ( approx 1 gram ) of productive soil contains between 100 million and 1 billion bacteria. It contains around 25000 species of bacteria and 8000 species of fungi.

Just as plants we see above ground differ from place to place the ratios and diversity of soil organisms change with region climate vegetative succession, and soil disturbance. Grasslands and agricultural fields generally have bacterial dominated food webs while forests usually have fungal dominated soils. Healthy highly productive agricultural soils tend to contain about equal weights of bacteria and fungi.( Soil Biology Primer)

Soil life is dynamic and complex. Understanding this complex soil food web- the life in the soil- is critical to understanding how the plant world grows and flourishes. It is the foundation for knowing how to restore damaged lands, improve agricultural production and ultimately improve the health and livelihood of people.

Soil micro-organisms play a big part in supporting healthy plant life through

· nutrient retention and cycling,
· disease suppression
· improved soil structure,
· Water infiltration, absorption and holding capacity.

SOIL FOOD WEB FUNCTIONS

Nutrient retention: The ability of the soil to hold nutrients is often measured by what is called cation exchange capacity
(CEC) - a measure of a soil’s negative charge. (Usually in clays and organic matter) Rarely is soil organism mentioned with regards to nutrient retention.However in a healthy soil food web vast reserves of important plant nutrients are stored within the bodies of bacteria, fungi and other soil organisms.

· Eg: no known organisms are more concentrated in nitrogen than bacteria. Fungi are typically the second most concentrated in nitrogen than bacteria. Along with nitrogen they contain other critical plant nutrients- high levels of phosphorus, potassium, sulphur, magnesium, calcium etc….

· Decomposition happens exclusively by these two sets of organisms which in turn store nutrients from the decomposed organic matter in their own bodies, immobilizing nutrients and thereby reducing leaching.

· Another example is calcium. Calcium is held incredibly tightly by fungal hyphae in the soil. Without healthy fungal biomass calcium is easily leached through the soil.

· The presence of decaying organic matter in the soil - broken down leaves, roots, dead organisms’ etc- along with diverse populations of bacteria and fungi are the key to immobilizing and storing nutrients in the soil. These nutrient rich organisms then become the basis for critical cycling of nutrients.
· The C:N ratio for bacteria is around 5:1 and fungi is 20:1
· Nutrient cycling happens when other sets of soil organisms (primarily protozoa, bacterial and fungi feeding nematodes, micro arthropods and earthworms) are present to consume nutrient rich bacteria and fungi and release nutrients in plant available form.
· A healthy soil contains diverse species and huge populations of protozoa, beneficial nematodes, micro arthropods, earthworms. Eg. I gram of healthy soil contains 1million protozoa. Single protozoa with a C: N ratio of 30: 1 can consume 10,000 bacteria a day.
· Because the protozoa need less nitrogen, the excess is excreted in the form of ammonium ions. Ammonium ions are held much tightly to soil particles than are nitrate ions, the most common (and leachable) form of nitrogen in commercial fertilizers.
· This predator-prey relationship between protozoa and bacteria can account for 40-80% of nitrogen in plants.
· A similar relationship has been documented with bacterial and fungal feeding nematodes. With a consumption rate up to 5000 cells / min these beneficial nematodes ( unlike plant feeding types) Are thought to turn over nitrogen in the range of 20-130 kg/ha/yr contributing immensely to plant available nitrogen
· These rapid interactions and countless exchanges of nutrients between soil organisms occur in root zones of plants where the highest concentrations of organisms exist (because root exudates provide food for the bacteria and fungi which in turn attract their predators) Protozoa, nematodes micro arthropods and earthworms.
· Nutrient cycling by these predators also occurs with other valuable plant nutrients such as potassium phosphorus calcium sulphur and magnesium resulting in a less leachable form than what is usually applied in synthetic fertilizers.
· Other soil organisms are also involved in more direct forms of nutrient cycling. Nitrogen fixing bacteria convert air nitrogen into a useable plant form as they colonize roots of legumes.

Improved soil structure: Air and water dynamics.

· As bacteria populations increase they secrete glue like sticky materials that bind sand silt clay and small SOM particles into micro aggregates.
· Fungi bind the micro aggregates to form larger soil aggregates structures creating air and water passageways.
· Larger passageways are created by bigger mites and earthworms that burrow through the soil looking for food. Earthworms glaze the passageways they create with nutrient rich and active microbial active slime layer that greatly enhances water holding capacity and soil structure.
· Earthworms and many soil arthropods also shred organic matter grazing on the micro-organisms present and then excreting the nutrients in plant available form.

Pest and disease Suppression

· Soil organism break down toxic compounds in soil, produce plant growth promoting hormones and chemicals, out compete and suppress disease causing organisms and buffer soil pH.
· When there is a healthy balance of microorganisms in the food web, pest and disease can be competed or preyed upon.
· When a balance is not maintained micro arthropods whose main foods source is normally fungi foods may attack plant roots instead.

If we only knew that life below the surface is what supports life above the surface, many would find that in short time damaged lands can be restored to their productive potential without expensive inputs. Land care practice would change to be truly that, care for the land patterned after the marvelous and elaborate design in the meadows and forests that causes them to flourish.

Dr Elaine Ingham claims that over 100,000 soil samples that have been analyzed from around the world there was no shortage of any mineral in any soil necessary for plant growth. Most modern soil tests only reveal the soluble and or exchangeable forms of nutrients present, not the total extractable nutrient pool. These extractable forms of nutrients which can exist as enormous reserves in soil are often only made available through the soil organism. When soil biology is missing, then soils will largely be defined by the chemical and physical structure and texture.

What has been learned about the soil food web strongly indicates that the measure of a healthy soil should include the presence of organic matter and of a full supporting cast of bacteria, fungi, protozoa, beneficial nematodes, worms and arthropods. Organic matter is the food. Soil biology is the life that makes it happen. The remedy for so many damaged agricultural lands, especially in the tropics where solar radiation is intense throughout the year, is to keep the soil covered, no tillage practice rotation, maximize organic matter and reintroduce needed soil biology to bring breath and life back into the soil.
WE CAN THEREFORE SAY THAT OUR SOIL IS A LIVING SOIL INVOLVING THOUSANDS OF DIFFERENT SPECIES OF MICROORGANISMS IN A HIGHLY COMPLEX ECOSYSTEM.

This living soil makes its presence felt everywhere! After the first rains, on both sides of tarred city roads, on vast wastelands…. wild weeds growing on our farms. According to seasons- they grow, get trampled over, and decompose and gradually a new type of soil mix of well-composted material grows above the original layer of soil.

If we observe carefully and listen we realize that there is no conspiracy at all but a beautiful symbiotic relationship where the tiniest microbe has an important role to play in this Cycle of Life. It’s a beautiful story waiting to be heard. So watch out pay your respects, and give tender loving care to the almighty microbe!

Prof Dabholkar observed keenly, listened and heard the stories that nature had to tell him. He simplified the complexities of nature so that they can be explained to the common man, the farmer in rural areas.

He firmly believed that by connecting natural resources with human resources, even the last person in the country can be made self sufficient. Thus people with help of resources found within one’s environment like Soil, Sunlight Water can enrich human life. Through results of his experiments Prof Dabholkar has enlightened the masses and shown that assured calculated results can be obtained if basic principles of preparing nutrient rich nursery soil, harvesting maximum sunlight through canopy management and monitoring proper root growth are followed. He termed this science Natueco Science.

What is Natueco Farming ?

Natueco farming means Natural eco-friendly farming. It follows the principles of eco-system networking of nature in our farming system. It is different from organic or natural farming both in philosophy and practice. It offers an alternative to the commercial, heavy chemicals used in farming. It emphasizes harvesting the sun through a critical application of scientific inquiries & experiments that are rooted in the neighborhood resources.

Natueco Farming emphasizes `Neighborhood Resource Enrichment' by `Additive Regeneration' rather than total dependence on external, commercial inputs. The three relevant aspects of Natueco Farming are as below.

1. SOIL

Enriching soil by --
· Recycling the biomass available in our surroundings
· Establish a proper energy chain.

2. ROOTS

Development and maintenance, of white root zones for efficient absorption of nutrients.

3. CANOPY

Harvesting the sun through proper canopy management for efficient photosynthesis

Natueco Science is based on our current needs of farming in situations where the soil has been heavily depleted. This is one of the fastest methods for regenerating a dead soil into a live soil, full of nutrients in a tropical country like India. (For temperate countries please see below). Natueco farming emphasizes regeneration of the land using local inputs and minimizing the dependence on external, commercial inputs. Natueco farming improves the plant vitality and quality by understanding and enriching the health of the soil, the roots and canopy management to harvest the maximum sunlight. Natueco farming does not suggest usage of even herbal pesticides. Instead it depends on perfect plant health to keep away pests


The soil serves several functions to the plant. It gives support to the root, supplies nutrients and moisture and provides air circulation to the roots. Only a healthy soil will stimulate an excellent root system, leading to a healthy canopy and ultimately the maximum harvest. Natueco farming, if properly followed will result in the quickest regeneration of topsoil.

Let us study in detail how we can prepare our own soil by using the resources available in our environment.

The Natueco Principles of Soil Management.

In nature it takes 100 – 500 years for humus to be formed in natural forests. Today with erosion, the decline of natural forests and chemical farming, the earth has been depleted of humus. We can produce this humus, termed Nursery Soil, in just 30-100 days through the understanding and application of nature’s processes. A good Nursery Soil consists of 50% well decomposed black biomass (organic part) and 50% activated mineral topsoil (inorganic part) by volume.

. It is a black, light material containing ligno proteins that can be broken into small fragments or crumbs. It has a very good water holding capacity of twice its own weight. The Nursery Soil provides support and delivers water and nutrients to the plant in the most efficient manner. A liter measure of a good Nursery Soil should weigh about 400 grams. A greater weight implies that the mineral content is high.
Before learning and understanding the technique we need to understand the components of SOIL. Detailed in the next post.