This information applies to compost made by thermal composting, by worm-driven processes (cold-composting), or by static composting.

Generally the reasons growers use compost are:

  1. To add organisms to the soil.  This is not just limited to bacteria, but includes fungi, protozoa, nematodes and often micro arthropods.  If it is made correctly, compost will increase immunity to a host of diseases.
  2. To add foods to feed existing bacteria, fungi, protozoa, nematodes and micro arthropods. 
  3. To add structure to the soil.  Many types of compost contain physical structure components like coir (coconut fibre), clay, fibre, and chunks of wood.  These impart physical structure that allows oxygen to move through the material.  It is extremely important that air passageways are maintained in the compost.

Many people think of compost as a source of enzymes, hormones, and plant growth promoting materials.  While those materials are important, they do not maintain their efficacy for long in soil nor in compost.  Compost TeaWhat actually creates the enzymes, hormones, and plant-growth-promoting materials?  They are created by the bacteria, fungi, protozoa, nematodes and micro arthropods that make up the soil food web.  So, actually, what you want to be adding to your soil is the correct biology, because this will ensure the ongoing creation of more of the enzymes or hormones that your plants need to thrive.  One of our services is to create compost recipes tailored to your specific needs based on our findings after analysing your soil.

If you are growing plants in soils where the biology is not in a balanced state, you can only achieve plant growth by using toxic chemicals to try to overcome the diseases that will attack the stressed plants and by using chemical salt inputs to try to feed the plants the inorganic nutrients they need.  However these plants are then not healthy, they are stressed, and the nutrients the crop produces are not at optimum levels.  As such, when consumed by humans these crops are not delivering the highest levels of nutrients for their diet.  Of course, by adding chemicals, we are able to increase production of plant material in unhealthy systems - an example of this being crops grown in hydroponics systems.  But at what cost to water quality, human nutrition or the quality of our lives?  The long-term impacts of this method of farming are sure to be staggering.  SFI/SFI NZ can help rehabilitate you and your property from having a chemical dependency and guide you to achieving a natural balance in your soils.  This leads to improved productivity and can increase your land value.

Plants depend on beneficial micro-organisms in the following ways:

  1. to protect them from pathogens,
  2. to retain nutrients in the soil so they do not leach from the root zone, 
  3. to cycle nutrients into plant available forms (both predator-prey and mycorrhizal fungi work to achieve this), 
  4. to improve uptake of soil and/or foliar nutrients, 
  5. to break down pollutants in the soil, on aboveground plant surfaces or around the roots, and 
  6. to build the air passageways that enable air and water to penetrate deep into the soil and be retained.  In this way the plants roots can grow as deep into the soil as physiologically possible enabling them to obtain water and nutrients all year long, regardless of drought.

If the organisms that perform these key functions are missing, they need to be replaced.  A failure to do so will make you totally reliant on chemicals and the need to utilise scarce water resources in large quantities.

Compost biology

Compost organisms perform a number of important processes during composting.  But their relevance doesn’t stop there – those same organisms survive and live in soil, on leaf surfaces, and around roots, leaves, stems, blossoms, etc. They can create a protective layer on leaves, stems, blossoms, fruit and any above or below ground plant surface.

Bacteria and fungi – retain nutrients in the compost, and ultimately, in your soil too.  They can also perform the same function on your leaf surfaces, if you could somehow get compost to adhere to the leaves.  That is possible if you turn the compost into compost tea – refer to our sections on compost tea to learn more as well as to gain insight into our services offerings in this area.

Protozoa and nematodes – mineralise the retained nutrients held by the bacteria and fungi.  In compost, these mineralised nutrients serve to help other organisms grow and utilize the carbon sources in the organic matter put into the compost pile.

Bacteria and fungi build micro- and macro- masses in the compost as well while the protozoa and nematodes help build the larger pores in the compost.  So within a week or so, if you have the right biology in the compost, air passageways and water infiltration hallways have been built by these organisms.  Turning compost becomes less and less critical as the biology grows and forms structure for you.

The dynamic living system in compost is very much influenced by the foods you choose to put into the compost pile, the biology of the organic matter going into your pile, and by the effects of rain, wind, heat, sunlight, and pollution that occurs while you are composting.

There are numerous factors that have an effect on compost quality including the starting materials, moisture, aggregation, and temperature / turning.  Additionally, different plants or crops may require a more fungal or bacterial dominated compost.  It is imperative that the environmental conditions in compost are managed so that a high quality, pathogen-free compost is produced.

SFI can assist you to develop the compost that your soil and plants need.