The 'All About Soil Carbon' event held in Bairnsdale and Tambo Crossing was a major success with 150 participants attending.
Over 150 people from across the state came together for two days to learn all about soil carbon from internationally renowned and highly respected groundcover and soils ecologist Dr. Christine Jones. The event hosted by Landcare East Gippsland, Greening Australia and Evergraze was held in Bairnsdale on Monday 20th and the second day on a property in Tambo Crossing on the Tuesday 21st July.
Dr. Jones has a wealth of experience working with innovative landholders to implement regenerative land management techniques that enhance biodiversity, increase biological activity, sequester carbon, activate soil nutrient cycles, restore water balance, improve productivity and create new topsoil. During both days the stark message delivered by Dr. Jones was that “agriculture in Australia is on its knees” which resonated with the audience. Attendees who were mostly from dairy and beef production with some sheep and cropping where keen to learn how Australian agriculture can recover from ever increasing inputs and lowering production levels.
Dr. Jones told the audience that agriculture in this country needs to be fundamentally redesigned. Our farming systems are quickly depleting the very resource that we rely on for our survival – our soils. The most meaningful indicator for the health of the land, and the long-term wealth of a nation, is whether soil is being formed or lost. If soil is being lost, so too is the economic and ecological foundation on which production and conservation are based.
Carbon is the basic building block for life. Over millennia a highly effective carbon cycle has evolved to capture, store, transfer, release and recapture biochemical energy in the form of carbon compounds. The health of the soil - and therefore the vitality of plants, animals and people, depends of the effective functioning of this cycle.
Over 95% of terrestrial diversity is in the soil. In order for this life to flourish, the soil ecosystem requires fuel in the form of carbon (from green plants) and ‘habitat’ in the form of high root biomass. Further, the soil surface requires year-round protection from erosion and temperature extremes (both highs and lows).
Dr. Jones managed to keep the large audience captivated for hours as she explained how the most basic but significant process of photosynthesis or how grassy plants convert carbon dioxide from the air into soluble carbon in the plant. Unlike trees which store carbon in the wood of the plant, grasses store carbon in the soil in the form of the long lived, stable carbon compound humus. Dr. Jones repeatedly reminded the audience during the two days that the first rule to building soil carbon is “do no harm”.
The mycorrhizal fungi which lives in the soil and breaks down nutrients and minerals to make them available for plants has a symbiotic relationship with grassy plants. Fungi acquire their energy in a liquid form, as soluble carbon directly from actively growing plant roots in exchange for nutrients. This is the driver for soil carbon accumulation. By this process they are actively drawing down atmospheric carbon and turning it into humus, often quite deep in the soil profile, where it is protected from oxidation.
Unfortunately when soluble fertilizers are applied to pastures the grasses no longer require this symbiotic relationship with fungi and will not longer supply the liquid carbon through the roots. This human intervention halts the accumulation of soil carbon.
Periodically bare soils generally contain only half the organic carbon of similar soils in the same region under perennial cover. As a result they have poorer structure, lower soil water-holding capacity and reduced nutrient levels. Soil benefits in many ways from the presence of living plants year-round, due to reduced erosion, buffered temperatures, enhanced infiltration and markedly improved habitat for soil biota.
The key is to maintain ground cover and keep grasses long and green for active and deep soil carbon accumulation. Dr. Jones says by active grazing management you can manage your pastures for the grasses you want and not the weeds you don’t want, while rebuilding your soils. Dr. Jones explained how ‘pulse’ grazing tall grasses by large mobs of stock for short periods of time (2-3 days depending on stocking rates) and giving paddocks long periods of rest. This will keep roots under the soil actively growing and maintain healthy soil biology and therefore soil carbon accumulation. Leaving grasses with enough length (approx 3cm minimum) will allow pastures to produce more energy and recover quicker thus producing more biomass. Dr. Jones refers to those leaves as ‘solar panels’ for the plant. Significantly, it is the photosynthetic capacity of living plants (rather than the amount of dead biomass added to soil) that is the driver for soil carbon accumulation.
Across Australia there are farmers already producing the same or better yields with markedly reduced reliance on fossil-fuel based chemicals. Biology-friendly farming technologies can reduce on-farm input costs as well as lowering the regional and national carbon footprint. The formation of new topsoil is a biological process. It cannot be achieved through the application of synthetic fertiliser, pesticides, fungicides or insecticides, all of which have negative impacts on soil life.
Dr. Jones’ message was clear that the longer we delay undertaking changes to land management, the more soil will be lost, exposing an increasingly fragile agricultural sector to escalating production risks, rising input costs and vulnerability to climatic extremes.
A widespread misconception in the Australian community is that the carbon lost from our deeply weathered and fragile soils cannot be put back. The good news is - it can! Putting the carbon back will require the adoption of regenerative farming and grazing methods that result in the active formation of new topsoil. Carbon cannot be sequestered in soils if the forms of land management that cause carbon losses are continued.
For more information about Dr. Jones and soil carbon visit www.amazingcarbon.com