Components of Healthy Soil for a Thriving Food Forest

Sprouting veggie beds at the Poomaale Collective, Coorg

In our food-growing processes, we often forget that there is an entire world that is teeming with life below our feet. The health and vitality of our plants are determined not only by what we do above ground but equally, if not more, by what is going on below. The ‘Wood Wide Web’ as it is often called is the beautifully complex, interdependent network of soil life, mycelium, plant roots and other natural elements that are in a relationship with each other. Understanding and strengthening these relationships is an important part of creating resilient growing systems.

Soil is where our food begins. The key to building resilient, self-sufficient food-growing systems – food forests – is improving soil health. The health of our crops above ground directly depends on the health of the soil and its components underground. Soil is as much alive as we are. It breathes, it consumes, it grows (or rather propagates growth), and the trick to understanding soil health is to treat it like a living being. It is the presence of life that makes soil different from dirt. 

Just any plant, animal or human needs nutrition to grow and remain healthy, soil needs it too. The combination of certain nutritional elements makes soil capable of growing and supporting plant ecosystems. Let’s look into what these nutritional elements are.

Components of Healthy Soil

1. Vitamin Water

Well, water is technically not a vitamin, but it sure is vital for all life forms. It pours life into anything it touches. A majority of the earth and all its living beings is water too. So, we won’t be wrong to say that soil and water are soulmates. Naturally, it is important for soil to contain water. The absence of water can dry up soil and make it unsuitable for life to grow within it. Water further acts as a solvent for other nutrients in soil and helps them travel from one part to another with its flow. 

2. Organic matter

Dead and decomposing matter like fallen leaves, vegetable waste, dead animals and insects, animal faeces – all add to nitrogen, phosphorus, and sulfur levels in the soil. 3-5% is considered as ideal carbon content in soil. This organic matter makes up the soil ‘humus’.

3. Air 

Another important element for life. Many living organisms, including humans, use air as a medium for oxygen intake. A similar story goes on underground as well. For oxygen to reach the microorganisms of the soil, airflow is important. Roughly about 50% of the soil volume contains air pores and these air pores contain gaseous elements – oxygen, carbon dioxide, nitrogen and water vapour – all of which are essential for the survival of the microbial life in soil. The microbial life in the soil continuously releases carbon dioxide during respiration. Therefore, it is all the more necessary for soil that is ‘well ventilated’ (aerated in this case) for oxygen to come in and carbon dioxide to go out.

4. Living organisms

All living beings – insects, worms, bacteria, algae and more – make up what is called the ‘soil food web’ –  web indicating a strong interconnection between all these living beings below the soil surface. According to the US Department of Agriculture, a teaspoon of soil contains 100 million to 1 billion microbes! These include simple fungi, bacteria, algae, protozoa, worms, arthropods and nematodes. The soil that is generally suitable for agriculture and deemed ‘fertile’ contains a higher concentration of microbes than non-agricultural land. 

5. Minerals 

Just like minerals are an important part of human nutrition, they’re important for plant nutrition as well. While most farmers focus on improving nitrogen and carbon content in soil for their undeniable health boost, other minerals (which are often overlooked) play a significant part in enhancing soil health too. All essential minerals work in harmony with each other and collectively improve soil health.

Carbon – the central element of all organic matter on earth.

Nitrogen – present in all plant and animal proteins. Proteins are the building blocks of living beings. Therefore, the soil that grows the food we eat, needs to have its own building blocks.

Calcium – restores ph balance in soil (shifts acidity to alkalinity) and forms an important part of the structural elements of a plant. The ideal Ph of soil is between 5.5 to 7.7.

Magnesium – the central atom of chlorophyll pigment, important for photosynthesis

Phosphorus – essential for the reactions at a molecular level like metabolism of sugars, energy transfer, cell division and more.

The Touch and Feel of Healthy Soil

A handful of soil – Shot at the Poomaale Collective, Coorg

Three important components are crucial to making up a healthy soil structure – sand, silt and clay. However, each of these components cannot support a healthy plant system all by itself. Hence, we only see humans and animals chilling on sand beaches and statues made out of clay. 

In order to support food-growing systems, these elements need to work together.

Sand – allows air circulation by creating larger pores in soil.
Silt – holds water well enough and creates small pores in soil.

Clay – holds water and nutrients extremely well but is poor for air circulation.

The mixture of these three components in adequate amounts makes up a healthy soil structure that is loose (for adequate air circulation), friable (can crumble easily under little pressure) and allows water to drain easily. ‘Loamy’ soil is ideal for the growth of plants. Considered extremely fertile – it is a mixture of clay, sand, silt, and additional organic matter. It can hold a large amount of moisture but also drains well. Hence, it is suitable for cultivation as the water goes all the way down to the plant roots without them being overwatered. 

How to Check Soil Health?

• The first check is a visual inspection of your plants. Is the growth of your plants as expected? Do the plants look good or are they facing the troubles of stunted growth or rotting? Healthy plants are a product of healthy soil.
• Check for water drainage/stagnation. Water stagnation at any point is not desirable. A well-draining soil is considered healthy.
• Look out for earthworms and other insects which contribute to the soil food web. Healthy soil is an invitation to these living beings and their presence is a reason to celebrate.
• How easy on the hand is the soil? Is it friable enough or lumpy/rocky? The ease of working around the soil is an indicator of its structural health.

Harvesting diverse farm fresh veggies from the FPZ (Food Production Zone) in the Hyderabad Farming Collective. 

What it Takes to Achieve Soil Health

Adding extra nitrogen to soil and fertilizers that contain deficient minerals have been in practice. But they do the work by spilling out of the natural soil ecosystem. When we introduce external inputs, we take on the burden of all the elements of the natural environments on our shoulders that otherwise share the load of making soil healthy.

We, at the Hyderabad Collective at Bodakonda village, are constantly trying to understand and evaluate our soils, to determine the best-growing conditions for our veggie plants. Building healthy soils takes time, consistent trials, and evaluation of the trials. Our field tests at the Hyderabad Collective tell us that our soils are predominantly sandy. While this makes them very well-drained, we ideally require a higher component of clay to help hold moisture for longer. Fortunately, some clayey soil was excavated during the creation of our lake. We saw this as an opportunity to experiment.

Our experiment will involve using different proportions of this clayey soil as an additive to our veggie beds, to evaluate whether this is helping the growth of our veggies. Find out how we are carrying this out at the Hyderabad Farming Collective.

Lake Soil Experiment carried out at the Hyderabad Collective

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