What is Soil Health

A healthy soil is that which allows crops to grow to their maximum productivity without diseases and pests and without a need for supplementation.

A healthy soil is teeming with bacteria, fungi, algae, protozoa, nematodes, and other tiny creatures that play important roles in plant health.

How does a health soil look like?

Soil is not an inert growing medium – it is a living and life-giving natural resource. It is teaming with billions of bacteria, fungi, and other microbes that are the foundation of an elegant symbiotic ecosystem.

  • Soil bacteria produce natural antibiotics that help plants resist disease.
  • Fungi assist plants in absorbing water and nutrients.
  • Together, these bacteria and fungi are known as “organic matter.”
  • The more organic matter in a sample of soil, the healthier that soil is.

Indicators of a healthy soil



Soil color provides a tremendous amount of information. Soil color can tell us the amount and state of organic matter and iron oxide, age, and other physical processes. In general, the darker the soil, the higher the organic matter content. Soil is typically darkest in the uppermost layers of the soil profile, and it lightens as depth increases.


Soil structure is the arrangement of soil particles in different sizes and shapes. This determines the amount of pore space between particles. More pore space allows for greater water infiltration. Aggregate stability and soil texture affects soil structure.


Healthy soils are biologically active soils. The presence of earthworms, earthworm castings, dung beetles, etc., or evidence of their activity. Earthworms are major decomposers of organic material, and underground engineers. They create burrows through the soil profile, which increases porosity, enables water to move down and creates channels for roots. Earthworm excrement, known as castings, help increase nutrient cycling because pound-for-pound they contain significant amounts of nitrogen, phosphorus and potassium. Dung beetles take dung from the soil surface, roll it into a ball, lay their eggs in it and bury it deep in the soil to create a food source for their young and brings nutrient-rich organic material into the soil profile, which increases nutrient cycling and availability.


Rooting resistance indicated by “J” rooting, which means a plant root grows down to the resistance layer and turns some degrees because it cannot penetrate the resistance layer. In extreme cases, water infiltration is also halted at this layer, which limits the soil’s water holding capacity and ultimately exacerbates the effects of drought.


Smell of a soil can indicate its health. The earthy smell of a biologically healthy and active soil is the presence of an organic compound called geosmin, from the Greek, geo (earth) and osme (odor). Geosmin is an organic product produced by active soil bacteria. Essentially, if your soils are cycling organic matter, they will have that fragrant earthy smell. Soils can have other smells, but they are not associated with soil health. Soils absent of oxygen can have a rotten egg or sulfur smell. This is often a sign of poor drainage.


Chemical Indicators

pH: pH is an important indicator of soil health because if there is inadequate soil pH, crop growth can be impacted, and key nutrients may become less available. Additionally, soil pH can vary soil microbial communities.

Macronutrients: N, P, K, Ca, Mg, S are all macronutrients that are vital to plant growth. If these nutrients are not available in plant usable quantities, crop growth will likely suffer.

Micronutrients: Although necessary in smaller quantities than macronutrients, micronutrients are just as critical to plant growth. Typically, soils provide plants with enough necessary micronutrients.

Physical Indicators

Aggregate Stability: Soil aggregates that are held together tightly via root exudates, soil fungi, and inherent soil properties. They can be improved upon by creating environments for “biological glues” to be produced by plants and microbes by reducing tillage that physically breaks soil aggregates.

Available Water Capacity: Much of this depends on innate soil texture but can be impacted by the amount of soil organic matter and soil aggregation, both of which can increase water holding capacity.

Soil Compaction: High amounts of soil compaction mean less room for air or water in the soil, impacting water infiltration and drainage, plant root growth, as well as soil microbial communities. Being timely when driving large equipment on soils, as well as implementing deep rooting plants on the soil, can help alleviate this.

Biological Indicators

Soil Microbial Protein: Measures nitrogen from proteins being broken down in the soil which would then be available for plant uptake.

Active Carbon: Measures the carbon-containing compounds which are readily broken down by microbes as food. Active carbon is essentially a measure of the food stock available for microbes, which promotes nutrient availability and cycling.

OM: Organic matter influences water holding capacity, contains nutrients that can be broken down and made available, and provides food for microbes. Improving organic matter in the soil can be challenging but made easier by introducing conservation tactics like reducing tillage, adding other crops to a rotation, and using cover crops.

Respiration: Measures the amount of CO2 produced by microbes which can help indicate soil microbial activity.

What Are Fertilizers?

Fertilizers are food for plants: they provide nutrients for plants to grow and thrive. They are natural or artificial substance containing the chemical elements that improve growth and productiveness of plants. Fertilizers enhance the natural fertility of the soil or replace chemical elements taken from the soil by previous crops.

Types of Fertilizers

All types of fertilizers include any substance, living or inorganic which aids in plant growth and health.


“Organic fertilizer” or natural fertilizers refer to fertilizer that has gone through minimal processing, where nutrients are still found in their natural forms. This includes manure and compost, and purchased organic fertilizers

Inorganic fertilizers generally refer to fertilizers that are synthetic or artificial, and generally are manufactured from petroleum products (yes, fertilizer that is made from crude oil). They are minerals in concentrated form that are readily available to the plant. Unlike most organic fertilizers, they don’t need the help of the soil to break them down so the plant can utilize them. They only need the soil to hold them until the plant takes them in.


  1. Manure for the garden comes from cow, sheep, poultry and horses. Manure is known as a “complete” fertilizer; it has a lot of organic matter, but is it releases nutrients slowly Note: Beware of using fresh manure as a fertilizer because it can burn plants.
  2. Blood meal is dried, powdered blood collected from cattle slaughterhouses. It’s such a rich source of nitrogen that gardeners have to be careful not to over-apply and burn the roots of their plants. Apply blood meal just before planting to stimulate green leafy growth.
  3. Bone meal is finely ground bone. A by-product from animal slaughterhouses, it is a great source of calcium and contains up to 15% phosphate. Bone meal promotes strong root systems and flowering. It is often used when growing flowers, bulbs and fruit trees.
  4. Bat guano is protected by caves from leaching, so nutrients are conserved. It is rich in soluble nitrogen, phosphorous and trace elements. Usually powdery, bat guano may be used any time of year as a top dressing or diluted in a tea and used as a foliar spray.
  5. Shellfish fertilizer or shell meal is made from crushed bones or shells from crab or other shellfish. It is a great source of calcium in addition to phosphorus and many trace minerals. One benefit of shellfish fertilizer: it contains chitin which encourages the growth of organisms that inhibit harmful pest nematodes.
  6. Rock phosphate is a calcium or lime-based phosphate rock that is usually ground to the consistency of small crumbs. This rock powder contains over 30% phosphate and a large number of trace elements. Rock phosphate does not leach out of the soil, remaining unchanged until taken up by the roots.
  7. Greensand is an iron potassium silicate that gives the minerals in which it occurs a green tint. Mined from an ancient New Jersey seabed deposit of shells, Greensand is rich in iron, potassium and numerous micronutrients.
  8. Fish emulsion is a partially decomposed blend of finely pulverized fish. It can smell, although some deodorized versions have been developed. Like blood meal, it should be used sparingly in order not to burn plant roots.
  9. Urine from all animals including rabbits, human, cows etc


Inorganic fertilizers are synthetic chemicals. They usually contain only a few nutrients – generally nitrogen, phosphorus, potassium, sulfur and sometimes micronutrients, either singly or in combination, fully artificial and manufactured in exact doses These nutrients are in a form readily available to plants, a fast dose of nutrients, feeding your plants how you want and when you want. Their nutrient ratios are clearly printed on the bag,

Even though they are an almost perfect food source for your plants, they provide nothing for the soil, limiting their effectiveness in the long-term. There is also the very real risk of a toxic overdose of chemicals that leach arsenic, cadmium, and uranium into the soil, potentially affecting any growing fruits or vegetables.

Unlike the organic variety, inorganic fertilizer does not need to decompose over time to supply nutrients to plants

However, since they are lost from the soil quickly, you may have to fertilize plants several times during the growing season unless you use a specially formulated, slow-release type.


Inorganic fertilizers come in either single or multi-nutrient formulas that contain basic nutrients, such as nitrogen, phosphorus, and potassium. They can be fast release or slow-release formulas. Slow-release formulas contain larger molecules that are coated. They are made to break down slowly in the soil. A typical slow-release fertilizer releases nutrients over a period of 50 days to a year. This reduces the chance of burning the plant or root system.

Nitrogen Fertilizers

Nitrogen is a plan nutrient responsible for growth. This ingredient is useful in fertilizers, particularly during the middle stages of a plant’s lifespan, when it needs encouragement to continue to grow large and stem new leaves.

Examples include ammonium nitrate, potassium nitrate, calcium nitrate and urea. These fertilizers contain high levels of nitrogen. However, these inorganic fertilizers tend to increase the pH of the soil when you apply them. They increase the chances of burn and damage to seedlings.

Potassium Fertilizers

Potassium will help your plants to grow deeper and stronger roots. It can also help protect your plants from harm when they are deprived of other nutrients. This nutrient is vital for photosynthesis and has the ability to slow down any diseases that may infect your garden

Examples include potassium sulphate and potassium nitrate.  Also, muriate of potash, also known as potassium chloride. Muriate of potash is the most used potassium fertilizer. In some cases, plants may be sensitive to chloride. If a plant is sensitive to chloride, potassium sulphate, also known as sulphate of potash, is a better choice. It does not contain chloride. Potassium nitrate is easy to apply. This is because it does not pull moisture from the air. But it does slightly increase the pH of the soil upon application.

Phosphorus Fertilizers

Phosphorous is a nutrient that plants need continuously. Throughout their lifecycle, phosphorous help to strengthen the root system and stems of a plant. Flowering, seeding, and fruiting can all be improved with phosphorous.

Examples include superphosphates. It does not affect the pH of the soil upon application. Ammonium phosphates also come in water-soluble, granular forms.


Fertilizer comes in a few different forms. There is liquid, powder, and granular.

  • Liquid fertilizers are often diluted with water. Spreading them is like watering your garden, usually done with a hose attachment.
  • Soluble Powdered fertilizers also need water to be productive. Usually, they are spread by hand and watered to complete absorption or mixed with water and sprayed
  • Granular lawn fertilizers can easily be spread on top of soil. These nutrient pack granules will be soaked into your garden over time as you water it.

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