When specifying soil enhancement, typically following decompaction Biochar is always recommended, typically combined with other forms of organic material such as agricultural compost or mulch. However, we are often asked, what is biochar, and how does Biochar work?
What is Biochar?
Biochar is a very pure form of charcoal that has a high carbon content and is now produced using modern and high-tech kilns. However, biochar is not a new technology, in fact, evidence of biochar use has been found in Mayan settlements dating back to 1000-750BC!
The organic material used to produce the biochar, typically wood but also other combustible plants such a straw, wheat etc. It is burned in a kiln with highly restricted airflow and oxygen content. In many modern kilns the gases that are given off by the burning wood are collected and fed back into the kiln to reduce the amounts that are given off into the atmosphere.
Although all the talk of burning wood to make biochar doesn’t sound very environmentally friendly, in fact biochar, as it doesn’t decay, is a great way of permanently sequestering carbon into the ground.
1kg of biochar is the equivalent to 3kgs of carbon dioxide being removed from the atmosphere!
What does biochar do when added to the soil?
As well as being a great way for carbon to be sequestered into the soil, biochar improves the structure of the soil, aeration, water holding capacity and nutrient retention within the soil.
Our chosen supplier of biochar products is Carbon Gold (https://www.carbongold.com/) whose products are also organic and have added mycorrhizal fungi, Trichoderma, seaweed and wormcasts!
Mycorrhizal fungi is a symbiotic organism that works with the root systems of plants to increase the levels of water and nutrient uptake by the plants root system,
Trichoderma is a specialist fungi that feed on soil borne pests in order to defend its host plants root system.
Seaweed contains a number of trace minerals and organic compounds that promote healthy plants.
Wormcasts are full of healthy bacteria and organic humus to encourage healthy and vigorous root growth.
All of the above combine to increase the ability of the tree to uptake water, nutrients and minerals from the surrounding soil, meaning a healthy, more vigorous tree that is less susceptible to pests and disease.
How should biochar be applied?
For all urban and residential trees, where possible, biochar should be applied at the planting stage, directly into the planting site. Studies (https://www.carbongold.com/1-acre-2000-trees-0-losses/) on orchard trees (Where typically soils are heavily compacted and depleted of nutrients from intensive growing cycles) have shown up to 100% success rate on newly planted trees, compared to losses of up to 20% on trees planted without
However it is not too late to apply biochar to mature trees, for this application we would undertake radial de-compaction around the tree loosening the soil in the top 15-30cm and apply a mixture of biochar and agricultural compost or rotted wood chips to the top of the soil.
Studies have shown that trees treated with the above applications can increase resistance to a variety of pests and diseases including Ash Dieback (Hymenoscyphus fraxineus) and Honey Fungus (Armillaria mellea).