Soil Health

Exploring The Vital Link - Soil To Life

It’s All About Soil / The Importance of Soil

“ We know more about the movement of celestial bodies than about the soil underfoot ”

– Leonardo Da Vinci

Although the above quote is a couple hundred years old now, it highlights a crucial gap in human knowledge, one that exists to this day. While a lot has been learned since then, the number of discoveries which continue to be made tells us that we are still only scratching the soils surface.

Studying nature is extremely difficult because of the sheer number of variables and the interactions between them. Scientists generally use a reductive approach, in other words, to break a system down into its fundamental pieces, and study that aspect in isolation. Unfortunately, this is seldomly representative of the real world, and it has led us to many false conclusions or misunderstandings about how these natural systems really work.

At Talborne Organics, our philosophy is to be humble in front of nature, marvel at the complexity and beauty in its design, and accept that we cannot and should not try to control it. We believe in learning from nature and solving nature’s challenges with nature’s solutions.

We are enthusiastic about learning from other people, and we share our knowledge openly. We don’t claim to know it all, but in the 22 years of Talborne Organics experience we have learnt a lot, in theory and in practice. In this section we aim to share some basics of soil and plant nutrition which all growers need to know and understand.

Understanding Soil

To better understand what soil is, and how it works, it is useful to break it down into its 3 parts:

Until recently, Soil biology has been the most overlooked aspect of soil and agriculture, yet it is surely the most important. For millennia, plants, soil microbes, insects and other diverse forms of life have lived together and developed incredibly complex & synergistic ecosystems. Bacteria and Fungi are the most basic building blocks of the soil food chain. They perform critical functions such as:

  • Nutrient cycling, including fixing atmospheric Nitrogen into forms that can be taken up by plants
  • Breaking down organic matter
  • Releasing nutrients that are bound in parent rock / sand particles
  • Transporting water and nutrients to the plant from areas outside of the plant’s root zone
  • Protect plants from disease causing pathogens.
  • Produce plant vitamins and growth stimulating hormones
  • Many, many more.

There are many other players in the soil food chain, each being essential to the functioning of the ecosystem. These include Protozoa, Algae, Invertebrates such as Nematodes and Earthworms, and various other insects.

It has been estimated that up to 7 billion microbes live in one tablespoon of healthy soil, yet they are so small that we cannot see them with the naked eye, so often their roles and importance are overlooked.

For example, Nematodes, are tiny worms which are often thought of as a disease-causing pest, but while a certain group of them do damage plant’s roots, many species of Nematodes have very beneficial functions in soil, some of which predate (eat) and therefore control the populations of crop damaging Nematodes.

If you attempt to remove the most abundant animal on earth by number, your soil will lose a key layer of the food chain, thus nutrient cycling and other important functions of the soil will be severely disrupted.  

Application of chemicals that are harmful to soil biology such as synthetic fertilizers, pesticides, herbicides & nematicides severely disrupt the natural biological balance of the soil ecosystem, which leads to other problems that can only (temporarily) be fixed with more chemicals until the topsoil becomes lifeless and infertile, turns to dust, and washes or blows away resulting in loss of topsoil to erosion.

As with all things in Nature, the balanced cycle of nutrients determines the cycle of life.

The 5 “fundamental” elements sustaining all living things on earth are:

  1. Carbon
  2. Oxygen
  3. Hydrogen
  4. Nitrogen
  5. Phosphorous.

There are however, 94 elements that occur naturally which are essential for Plant Health and approximately 60 elements occurring in the human body, most of which have origins in our food, and therefore in our soils. (now including synthesized elements 118 in the periodic table)

Since the invention of synthetic fertilizers, there has been a focus on only the Major Nutrients that are required by plants: Nitrogen (N), Phosphorus (P) and Potassium (K).

The importance of the other 27 nutrients which are essential for Plant Health have been neglected. Every day new research is unlocking the importance of minor and micronutrients (trace elements) in plant and crop health, as well as in human health. If these nutrients are not available in sufficient quantities in the soil, then it is likely that they will be deficient in the plant. Therefore, it is essential that soils contain the correct balance of nutrients, in the required quantities.

When harvesting crops, we remove the nutrients (elements) which were extracted from the soil to produce nutrient-dense crops. Some of these Nutrients are replenished through natural cycles, especially where soils are healthy, but others result in soil deficiencies.

But excesses of any nutrient can be equally harmful. Often the overapplication of synthetic Nitrogen will cause plants to grow too quickly, resulting in “soft growth” which makes the plant vulnerable to pests, diseases, and environmental stress. Excesses of some nutrients can block the absorption of other crucial nutrients in a plant. A common example of nutrient toxicity is seen where farmers apply too much animal manure. Because the quantity applied is generally based on meeting the amount of Nitrogen required, they can accidentally end up with too much Sodium & Phosphate. Excess Phosphate restricts the uptake and absorption of Iron (Fe), Manganese (Mn) and Zinc (Zn) in the plant. Talborne Organic fertilizers do not contain animal manures in their formulations.

Soil pH is also important because if soil is too acid or alkaline, it prevents uptake of certain nutrients. pH can also affect soil biology as Bacteria prefer a more alkaline pH and Fungi prefer a more acid pH.  New research concludes that plants create the conditions for fungi to thrive in the soils.  Suggest to remove the pH chart as it is old fashioned.

Every grower should aim to balance the nutrient requirements of crop with the available nutrients in the ground, correcting deficiencies, and excesses. 

Soil, leaf and sap analysis are wonderful tools to ensure this balance is achieved. Talborne strongly recommends that growers continuously monitor their soils and keep a record of their interventions to optimise the uptake of nutrients that their crop requires.

Fertilizer which does not supplement the soils deficiencies to meet the crops requirements or too low levels of nutrients, means a compromised yield, poor quality, and wasted budget.

Too much fertilizer or the incorrect balance of nutrients for the crop is a waste of money and can even cause toxicity – again leading to poor yields and quality.

Soil is made up of mineral particles, organic matter, water, air and living organisms. The mineral particles are a mixture of sizes. The larger particles are sand, and the smaller particles are called silt and clay. The size and composition of these particles gives the soil a physical property that determines many other properties such as water retention, nutrient leaching, cation exchange capacity (CEC), aeration, compaction, and many others.

Understanding the type of soil that you are planting in is essential for planning your crop nutrition requirements. For example, soils that mostly contain sand and very little clay or silt are known as sandy soils. These soils allow for water to drain very quickly and are prone to losing nutrients to leaching. In order to help these soils’ maintain their nutrients, replenish with organic matter like compost and natural organic fertilizers.

Another example of physical properties impacting on crop health: Soils that contain a lot of clay will become easily compacted limiting root development. Poor drainage can create anaerobic conditions that could lead to pathogenic microbes becoming dominant in the soil, causing plant diseases like root rot. Soil scientists and agronomists will be able to provide more insight into how these factors affect your farm.

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What is Healthy Soil?

Soil health is defined as the continued capacity of soil to function as a vital living ecosystem that sustains plants, animals, and humans. Soil does all this by performing five essential functions:

  • Regulating water – Soil helps control where rain, snowmelt, and irrigation water goes. Water flows over the land or into and through the soil.
  • Sustaining plant and animal life – The diversity and productivity of living things depends on soil.
  • Filtering and buffering potential pollutants – The minerals and microbes in soil are responsible for filtering, buffering, degrading, immobilizing, and detoxifying organic and inorganic materials, including industrial and municipal by-products and atmospheric deposits.
  • Cycling nutrients – Carbon, nitrogen, phosphorus, and many other nutrients are stored, transformed, and cycled in the soil.
  • Providing physical stability and support – Soil structure provides a medium for plant roots. Soils also provide support for infrastructure such as buildings and protection for archaeological treasures.
  • Maximize presence of Living Roots
  • Minimize Disturbance (Physical and Chemical)
  • Maximize soil Cover
  • Maximize crop Biodiversity

As world population and food production demands rise, keeping our soil healthy and productive is of paramount importance. By farming using soil health principles and regenerative systems that include no-till, cover cropping, and crop rotations, more and more farmers are increasing their soil’s organic matter and improving microbial activity.

As a result, farmers are sequestering more carbon, increasing water infiltration, improving wildlife and pollinator habitat—all while harvesting better profits though reduced inputs and better yields.

  • South African soils are extremely degraded mostly due to unsuitable farming methods. The depleted state of South African soils revealed by research in 2020 as follows:

    Total South African Hectarage: 123.4 Million

    Arable land suitable for farming estimated:  11-15%

    Soils Organic matter (Soil Organic Carbon):  below 0.5% is  58%

    Soil Organic Carbon lost for every cultivation Cycle: 7 – 10%

    Loss of Soil Organic Carbon on 1st Tillage of virgin Soils: 20 – 40%

    Low Soil Organic Carbon levels in South African Soils are due to:

    • Regular tilling (ploughing) of soils for Industrial Agriculture.
    • Low productivity and biomass production due to low fertility and fertilizer inputs.
    • Removal of crop residues by burning or animal grazing.
    • Monoculture, mainly maize with no crop rotation

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Copyright 2022 by Talborne Organics (Pty) Ltd.
Terms & Conditions / Privacy Policy / Sitemap