In this issue we highlight some recent developments in the climate controversy. The first story revisits Australia’s ongoing brush with coal mining. The graphs referred to capture the trends which are worth studying. We also take a dive into the amazing story of the soil microbiome. Then we ponder how regenerative/ecological agriculture can become mainstream.

An even bigger coal-ition?

Federal environment minister Tonya Plibersek approved three coal mine expansions recently in a step described by conservationists as reckless and the antithesis of climate action. The Australian Conservation Foundation said the three projects, all in NSW, would generate more than 1.3 billion tonnes of greenhouse gas emissions in their lifetime. The approvals come after conservationists, independent MPs and senators have been negotiating with the government over its delayed reforms to environmental laws including calls for the climate impacts of projects to be considered as part of Federal assessments.

Tania Plibersek has approved Whitehaven Coal’s plan to extend underground mining for 13 more years until 2044 at its Narrabri site, while Mach Energy’s mine at Mount Pleasant has been extended until 2048. In defending the decision Plibersek said the mines were not new projects and the emissions from them would be considered under the government’s safeguard mechanism designed to cap and reduce emissions from major polluting sites. Gavin Mcfadzean, climate program manager at the Australian Conservation Foundation, said it is grossly irresponsible to be approving coal mines when scientists across the globe and the International Energy Agency have repeated calls for no new coal and gas projects, if we are to have any chance of having a safe climate.

Where are we up to with climate action? The following linked article carries a message for us all and graphs in the article don’t lie. In particular take a look at the recent climate disasters in November 2023, or later:

An ecological awakening?

Related to the story about starting or extending coal mining leases comes the following interview with Bill Plotkin who is an American depth psychologist and wilderness guide. This interview between Plotkin and interviewer Nate Hagan of the Great Simplification program covers the deeper aspects of life that help explain why we do what we do. The focus in this interview is on the need for an ecological awakening if we as a world society are going to emerge from the turmoil that exists today. If you enjoy this interview and want more in a similar vein, please consider adding your name to his circulation list. Interestingly, the program interview is called Ecological Awakening: A Path Towards Holistic Adulthood.

What does ‘living soil’ mean to you?

While Bill Plotkin’s background is human development, including the emergence of the soul, the next guest draws us back to an earthly plane – the soil. The beauty of regenerative agriculture is that it deftly places emphasis on the practical and the abstract, no remainder. Here is Dr Christine Jones’s take on how to create flourishing soil microbiomes. [Source]

Soil is an extraordinary, under-appreciated and misunderstood ecosystem. Soil health not only underpins agricultural productivity but also influences watershed function, water quality and the atmospheric water cycle, a key driver of earth’s climate. The abundance, vitality and diversity of life in the soil is linked to the abundance, vitality and diversity of almost every other living thing, including birds in the sky and the critters that dwell in rivers, lakes and the margins of the sea. In short, to heal the planet we must heal our soil. To heal soil, we need to understand it.

Sometimes the smallest things can have the biggest impacts. In parallel with research into the human gut microbiome, understanding and supporting the functioning of the soil microbiome is being increasingly recognised as the future for agriculture. Microbes, too small to be seen with the naked eye, are fundamental to almost every process that takes place in soil. Chief among these is the formation of water-stable aggregates. Aggregates provide the ‘crumb’ structure that makes soil porous and friable, like a sponge, enabling water to infiltrate and be stored for later use. Good structure also makes it easy for plant roots to grow. Soil aggregation requires a great deal of work on the part of microbes – and that requires a ton of energy. What form of energy do soil microbes use … and how do they obtain it?

The energy for soil building is derived from photosynthesis, which takes place in the chloroplasts of green leaves. During photosynthesis, light energy from the sun, carbon dioxide from the air and water from the soil are transformed into biochemical energy in the form of sugars. Some of these sugars, laced with a potent brew of carbon-based plant signals, are transferred to the soil microbial community in the form of root exudates. The entire process is termed the Liquid Carbon Pathway (see Jones’s article, Liquid Carbon Pathway).

It’s all part of a virtuous circle. Root exudates provide energy and messages to the microbes that not only form aggregates, but also solubilize and transport plant nutrients. The more extensive the roots and the more rapid the flow of exudates, the more abundant the microbes, the faster the improvement in soil structure, the better the infiltration and the higher the nutrient availability, all of which combine to improve conditions for plant growth. Well-aggregated soil is also less prone to erosion and/or waterlogging. Having water move downwards in soil rather than horizontally across the soil surface provides a perennial base flow of clean filtered water to rivers and streams.

BUT… it is important to note that soil building does NOT occur if large quantities of water-soluble nitrogen or phosphorus are placed in close proximity to seeds. The ready availability of these essential elements reduces the requirement for plants to provide root exudates to support nitrogen-fixing and/or phosphorus-solubilizing microbes. Reduced root exudation has many unintended consequences. Not the least of these is that the microbes that would normally produce glues and gums to form water-stable aggregates are not supported. Soil loses its structure and becomes compacted. No amount of applied nutrient can counteract soil compaction. An alternative approach is to apply a low rate of a biological stimulant to seeds prior to planting. This has the effect of enhancing the flow of root exudates, improving soil structure in the rhizosphere. Biostimulants include – but are by no means limited to – natural products such as vermiliquid, compost extract and fermented seaweed.

Where do beneficial microbes come from?

One of the reasons biostimulants can be very effective when placed on seeds is that the majority of microbes in the rhizosphere (the soil surrounding plant roots) originate from plant seeds, rather than from the soil itself. Seeds contain hundreds of species of bacteria, archaea, fungi and protists. When a seed germinates the microbes multiply and move into the new roots and the soil surrounding the roots. The plant forms its own microbiome, distinctly different from the microbiome of bulk soil. The presence of microbial stimulants can enhance this process.

As the plant grows and develops, microbes that originated in the seed continue to multiply and colonise the newly formed stems, leaves and flowers. Microbes are eventually incorporated back into seeds in readiness for the next generation.

As is the case for water-soluble N and/or P fertilizers, seed-applied fungicides and insecticides disrupt the extremely important communication that normally takes place between germinating seeds and their microbes. The most effective protection against pests and diseases is a flourishing soil ecosystem that supports symbionts such as mycorrhizal fungi and a wide diversity of invertebrates including earthworms and beneficial insects.

Why is plant diversity important?

Microbes function best in teams (consortia) representing a wide variety of functional traits. The rhizosphere microbiome created by plant roots is distinctly different for each plant family. Hence the greater the diversity of plant families in crops, pastures and horticulture, the greater the diversity of microbes and the more robust the entire ecosystem.

It is difficult to build a house with only plumbers or electricians or carpenters or bricklayers. A faster result can be obtained by assembling a team with a diversity of skills. And so it is with soils. The tradies for soil building come with the plants. The greater the number of families represented in a plant community, the greater the skill base and the better functioning the soil.

Results from the Jena Biodiversity Experiment showed soil beneath plant communities comprising at least four plant families was significantly deeper and better-structured, with higher nutrient status and improved water-holding capacity, compared to the same soil beneath a low diversity of plants. Plant diversity also had a highly significant effect on the sequestration and stabilisation of soil carbon.

A key finding to emerge from the Jena Experiment was that the intermingling of plants from at least four plant families significantly increased the exudation of carbon compounds into soil, supporting higher microbial biomass. The greatest increases were in beneficial soil fungi.

Why are soil fungi important?

While bacteria play vitally important roles in soil, including the solubilization of minerals such as phosphorus and the transformation of inert atmospheric nitrogen into plant available forms, they are largely reliant on plant-associated fungi to deliver energy from plant roots. There are many types of soil fungi. Some are seed-associated and form part of the plant’s inherent microbiome, others are opportunistic saprotrophs, while others, such as mycorrhizal fungi, are soil-dwelling obligate symbionts. Irrespective of the type, all forms of beneficial plant-associated fungi transfer energy to the bacterial communities involved in nutrient acquisition and stress tolerance. Soil fungi are also fundamental to the formation of water-stable aggregates.

Mycorrhizal fungi are of special significance. These symbionts provide the infrastructure for the trading of goods and services below ground. Plants connected via common mycorrhizal networks are able to exchange minerals, trace elements, energy and biochemical signals. Mycorrhizal fungi also transport water to plants in dry times. Fungal hyphae extend beyond plant roots and access micropores too small for roots to penetrate. Plant diversity stimulates colonisation by mycorrhizal fungi.

The microbial community a plant encounters at the germination stage can have a large influence on subsequent growth, via mechanisms including nutrient acquisition, resistance to pests and diseases and plant tolerance to stresses such as drought. Creating opportunities for plants to acquire microbes from neighbouring plants from different families or legacy microbes from preceding multi-species covers, can improve productivity and resilience. The more frequently multi-species are grown, the better the result. Replacing a warm-season mix with a cool-season mix and then another warm-season mix and so on, with different species in a different place each time, increases the microbial diversity in the entire plant community and all plants become fitter.

In pasture situations it is becoming increasingly common for annuals to be sown with perennials to provide high soil microbial diversity in the initial stages of establishment. The annuals eventually fall away, but the early diversity gives the soil microbiome a boost and gets it off to a good start. It is important to ensure that at least four families of perennials remain once the annuals have finished.

Other factors contributing to progressively improved outcomes in diverse plant communities include the deepening of soils, better aggregation, enhanced infiltration, higher moisture retention and an increased abundance of earthworms. These benefits are cumulative and create positive feedback loops.

And vice versa. Under continuous wheat or corn or soy – or perennial pasture containing only grasses – soil microbial diversity, plant health and soil function often decline over time. In addition to the detrimental effects of monoculture on microbial diversity, the microbiome of many of today’s plant cultivars has been simplified by decades of excessive fertiliser and pesticide use. Who could have known monocultures were so detrimental to soil health? In our attempts to simplify agricultural production we’ve reduced the complexity that gives soil its vitality.

Restoring richness and vibrancy to the below-ground soil ecosystem through above-ground plant diversity – combined with reduced inputs of toxic chemicals – is fundamental to improving the productivity and resilience of agricultural systems and ultimately, human and planetary health.

Christine Jones PhD
www.amazingcarbon.com

Mainstreaming regenerative/ ecological agriculture

Advancing Eco-Agriculture (AEA) is a United States organisation that has as its goal making regenerative agriculture mainstream by 2040. The person who created this vision and is working hard to achieve it is agronomist John Phelps. The IEA is linked to the AEA and will be passing on its helpful hints through our communication channels. The article linked below outlines the six essential aspects of creating a regenerative/ecological environment. The six aspects are directed towards market gardening but in reality, they apply to all forms of agriculture.

IEA Annual General Meeting

At the recent AGM the Board positions for 2024-25 were filled. The IEA is led by a member-elected Board, currently comprising 11 volunteer Directors. The Board meets monthly as a collective for online Zoom meetings and also as separate working group sub-committees advancing specific areas of IEA work. Go here - https://www.ecoag.org.au/board - to see our new and reinstated Directors.

Join the Institute of Ecological Agriculture

If you are interested in joining the Institute, then the pathway to doing so is simple. Just go to https://www.ecoag.org.au/membership and fill out the form.

If you are not sure about joining but would like to receive the Newsletter, go to https://www.ecoag.org.au/news and fill out the form.

If you are not sure about the IEA and need reassuring, best go to our Position Statement and see what it says: https://www.ecoag.org.au/position-statement.

If you are interested in becoming accredited within the framework of ecological or regenerative agriculture, please visit the following: https://www.ecoag.org.au/accreditation.

Sharing the good oil!

The Newsletter needs to circulate through the Australian rural community. It provides a different and important worldview on farming. Help the organisation to grow by circulating it to your friends or to people whom you think would benefit from it!

Editor: Kerry Cochrane
Design & presentation: Tony McKenzie