How to Treat our soil

In the “What is compost” section we touched on the importance of a soils ability to provide air, water and nutrients to plant roots. When we consider how to treat our soil, we must acknowledge that plant health is strongly influenced by soil. In this section we will aim to discover what conditions promote the ideal growing environment.

Aerobic vs Anaerobic:

Aerobic soil and Anaerobic soil refers to different conditions of oxygen availability within the soil environment. Aerobic = oxygen rich. Anaerobic = oxygen poor.

Here are three reasons how aerobic conditions affect soil health:

1.     Nutrient availability: Aerobic soil conditions promote efficient nutrient cycling and availability. Beneficial aerobic microorganisms thrive and decompose organic matter, releasing plant available nutrients.

2.     Efficient organic matter breakdown: Aerobic soil conditions promote the activity of earth worms, fungi and other beneficial microorganisms. The increased efficiency of the decomposition process leads to increased humus content and thus the formation of more stable soil aggregates. 

3.     Soil biological activity: The increased presence of oxygen in aerobic soils increases the number of these beneficial organisms. These organisms are essential in the decomposition of organic matter, nutrient uptake and disease suppression. An increase in biological activity is related to more profound symbiotic relationships with plants.

An aerobic environment contributes to the ideal conditions in which a plant will grow most vigorously. As we know, increasing biological activity within our soil by using compost will lead to improvements in soil structure. Improved soil structure is characterised by increased aggregate stability and porosity, which in turn increases the potential exchange of air and water between soil and plants.

As we now understand why soil structure is important for plant health, we can focus on how to treat specific soils to achieve desirable results.

Dig or no-Dig?:

As we are well aware, soil structure is the key to plant health. Digging and turning soil disturbs the soils complex structure.

When we analyse why humus is good for the soil, we discover that it acts as a binding mechanism between the mineral particles that create the soil profile. When the aggregates formed in the presence of humus are let to mature, the bond which they create becomes increasingly more stable. You can begin to understand that the humus (which is a by-product of micro-organism activity) is vital for the well-being of the soil. Humus cannot be further broken down by microorganisms but rather provides nutrients for plant growth. With a no-dig approach we are able to maintain aggregate stability and therefore soil structure.

The chosen approach to your garden should be related to the long-term outcomes associated with regenerative practices.

To help you determine which approach is suitable for you we created a list of advantages and disadvantages for each.

Dig: The Dig approach involves the traditional methods that involve turning and cultivating the soil using spades, shovels and hoes.

Advantages:

-       Digging can break up compacted soil, improve aeration and facilitate root penetration.

-       Weeds can be controlled easily by disruption of their root systems

-       Allows for organic matter or soil amendments to be mixed deeper into the soil profile.

Disadvantages:

-       Can disrupt soil structure, beneficial soil organisms and expose soil to erosion.

-       Stimulate the growth of weed seeds by bringing them to the surface

-       Nutrient loss by increase decomposition of organic matter when brought to soil surface.

No-Dig: The No-Dig approach involves minimising or preventing soil disturbance. The no-dig method concentrates on long term outcomes and promotes building healthy ecosystems within the soil.

Advantages:

-       Soil structure is preserved, which promotes excellent exchange of air and water, soil biodiversity and water retention.

-       Organic matter retention through accumulation, this improves fertility and water retention.

-       Weed suppression by means of physically blocking sunlight and germination.

-       A reduction in soil erosion by improving soil structure and thus minimising surface run off

Disadvantages:

-       Long term results due to minimal disturbance techniques. Can make soil amendment slower.

-       Weed control is more difficult due to inability to disturb surface.

Ultimately, as the key to plant health is soil structure, it is important to recognise the effects of disrupting the soil profile and structure. By minimising the disruption, we are supporting an improvement in the health of our garden.

Both techniques have their advantages and disadvantages. Here at Green For You, we firmly believe that the most attractive part of gardening is that there is never one correct method or way to do something. We believe in experimentation and that hard work always pays off. So… go for it, try something new and see what happens?

Methods to Improve specific soil types:

The following soil restoration methods will involve both the traditional dig approach and the more modern no-dig approach. Use them as you will, any action will be better than no action!

Refer to the table below and choose the solutions appropriate to your specific soil type.

If you would like to determine what soil type you have in your garden, you can refer to the “Soil testing” learning resource available on this website.

Here is a simple and important rule: All soils need organic matter. To summarise the table above:

Sands: Need organic matter to provide body and assist in water retention.

Clays: Need it to help improve structure and to provide drainage.

Soil amendment techniques:

The following are examples of soil amendment techniques that follow regenerative and sustainable practice, these include;

-       Liming agents (Lime, dolomite) to correct soil acidity and make pH more alkaline.

-       Acidifying agents (Sphagnum peat moss) to reduce the pH of alkaline soils.

-       Gypsum (Calcium carbonate) to improve structure in soils of high clay content.

-       Organic fertilisers to adjust fertility levels and quantity of nutrients within soil.

-       Organic matter application (compost and animal manure) to improve soil structure, texture, water holding capacity, nutrient density and pH. Effect on soil pH dependent on source of organic matter.

-       Sand to improve permeability and aeration.

-       Wetting agents (surfactants) used to improve hydrophobic soils.

-       De-compaction to allow for less restricted root movement, increased water permeability, drainage and gaseous exchange.

In situations where plants are displaying evidence of poor growth or indication of pest and disease the first step in management is to perform a soil pH test. The restoration of soil health and specific techniques to implement will be determined by the test results. Essentially, soil restoration is the process of improving the structure, microbial life, nutrient density and overall carbon levels within the soil.

Bear in mind, plant selection is your best friend when it comes to dealing with un-desirable soils. Plants will cause nutrients to accumulate within the soil profile, add organic matter by naturally decomposing, control erosion and improve structure by root penetration.

Conducting a soil test as outlined by Green For You will help identify suitable plant species based on specific soil conditions and environmental factors. The implementation of a well thought out planting schedule will cause a gradual and consistent regenerative effect on the undesirable soil. This will make soils more productive, suitable and tolerable for a large variety of plants.

We hope you have found these learning topics to be informative and easily digestible. We aim to provide information this information to you so that you can make informed decisions that have a positive impact on our environment. We will continue to update and expand our learning topics to ensure the best and most up to date information is available to you.