The Planet Saving Potential of Compost

Recently, I received a query from Finian Makepeace, the co-founder of the dynamic, LA-based, soil carbon activist group, "Kiss The Ground". This diverse group aims to inspire five million new farmers to embrace sustainable food production over the next five years. They formed after my first major presentation in LA three years ago, and they are now generating meaningful change around the globe.

Their intention is to address a serious imbalance, which involves an alarming decline in young people interested in growing food. In fact, the average age of those involved in the most important profession of all, is now over 60. Who will feed us if this trend continues? We desperately need to rediscover the fun in farming and reclaim the passion and purpose in food production.

It is quite clear that this will never involve extractive, chemical monoculture. As young people recognise the profound link between soil health and human health, they may choose to place a toe in the water. When they realise that soil health is planetary health and that global warming can be reversed by sequestering carbon in the soil as humus, new farmers are born.

Anyway, back to Finian's recent request. He asked if I could provide some guidelines for the content of a proposed new video about the profound benefits of compost. I have included both his questions and my responses below.


Finian: Could you please provide suggestions for a compelling narrative about compost and its importance to all of us?

Graeme: It is essential that the narrative contain references to benefits of compost that resonate way beyond the home gardening or organic farming community. The focus should be on both personal benefits and planetary benefits.

From a personal perspective, compost reintroduces the diversity of microorganisms that ensure optimum nutrition delivery to our food. The nutrient value of our food has declined in direct correlation to the decline in soil carbon. There is a microbe behind every mineral and the higher their humus home base, the greater the nutrient density of our food.

From a planetary perspective, compost offers much more than the stable carbon it contains. It delivers the cellulose digesting organisms that are sorely missing in many soils. These creatures can then begin some serious carbon sequestration.

Finian: Is increased biodiversity an important part of this story?

Graeme: Nature is about biodiversity. Compost contains over 30,000 different species of organisms with many billions in a single handful. Many of these creatures are lacking in our soils. They have been seriously compromised in the extractive, chemical agriculture model. This new workforce can provide disease resilience, nutrient density, improved soil structure and most importantly, it provides food for earthworms. If we can reintroduce earthworms into our soils, then they will build humus. Earthworms can compost four times more rapidly than conventional plant decomposition in the soil. They are a critical key to fast-tracking carbon sequestration.

Finian: I wonder if you could offer your top five benefits of compost as a potential guideline for the video script.

Graeme: Okay, here they are in no particular order:

  1. Compost adds stable carbon to a soil but, most importantly, it is a triggering mechanism for carbon creation. It is a hugely important tool to counter global warming.

  2. Compost is the greatest tool to create a disease resistant soil and resilient plants. This seriously reduces the need for chemical intervention, which offers a much better outcome for both animals and humans and, of course, the health of our soils and planet.

  3. Water is the new gold. Compost, and the humus it contains, is the single most effective water management tool. A 1% increase in organic matter, generated by compost additives, dramatically improves water retention. In fact, it means that in each hectare, the soil can now hold 170,000 litres more water than was previously possible. This equates to 17 litres in a single square metre. There is significantly less evaporation (unlike the potentially huge water losses from large dams), there is no carbon footprint when pumping the water to the fields, and the plant roots can access the stored moisture as they need it.

  4. Compost helps detoxify soils that have been chemically contaminated. The compost carbon isolates chemical and heavy metal residues and reduces their likelihood of contaminating our food chain.

  5. Compost can seriously increase the nutritional value of our precious food. The humus it contains is the only storage system in the soil that can stabilise and help retain all minerals. As mentioned earlier, humus also houses the microbes that deliver these minerals. However, the nutrition link does not end there. This microbial life also produces a range of nutrients, including B vitamins, that support plant life and those who consume those healthier plants.

Finian: Thanks Graeme. Just a couple more questions. All compost is wonderful, but what do you consider to be the very best compost?

Graeme: In my opinion, vermicompost is the very best compost out there. In one study in Australia it was found to be twenty times more effective than the second best compost, which was based on cow manure.

Finian: There are several commercial composting techniques. Which do you favour?

Graeme: I strongly believe that aerated static piles are much more sustainable than windrow composting with machines. There is very little energy required with the simple caged blower fans that suck and blow oxygen through the pile. There is also no loss of CO2, moisture and nutrition, which is a feature of windrow composting.

However, the most important benefit of aerated static piles relates to the creation of a fungal dominated compost, which is not possible with the windrow technique. Beneficial fungi prefer minimum disturbance and when they are regularly sliced and diced with the turning machines, they tend to disappear. These are amongst the most important creatures on our planet at this point in time. They produce stable carbon, which keeps CO2 from returning to the atmosphere for 35 years, and they are missing in most soils. It is essential that we endeavour to produce more fungal dominated composts to restore the planet-saving, carbon-building potential of our soils.

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