The Benefits and Applications of Biochar as a Soil Additive

Biochar is a highly porous and a high-surface area charcoal substance that differs from other charcoals intended for soil use and is shown to provide benefits in agriculture. It is produced under certain conditions, such as limited oxygen, that are optimised to ensure it has the characteristics that are useful in agriculture.

Here we take a deeper look into all aspects of Biochar application, including what the product is, its benefits and effects and application.

What is Biochar?

Biochar is engineered charcoal that sequesters carbon and improves soil structure, moisture retention and nutrient availability. The Australia and New Zealand Biochar Researchers Network define Biochar as a product that is rich in carbon produced through the heating of biomass in an oxygen limited environment. 

The Benefits and Effects of Using Biochar in Soil

There are many benefits to using Biochar in soil, the overarching point being that it can help to promote plant growth. 

Biochar has many effects on the properties of soil and these are outlined below:

  • Biochar provides an immediate increase in soil carbon that can last for anywhere between centuries and millennia;
  • When fertiliser is added following the application of Biochar it is more effective than application on its own;
  • The organic chemicals in Biochar appear to have a benefit on germination of seedlings and establishing plants;
  • Biochar produced from manure sources has a mineral count that is higher when compared with that taken from woody sources, and supplies the soil with more nutrients;
  • The application of Biochar has the potential to suppress soil-borne diseases;
  • Perhaps the most dramatic property, the increase of soil-moisture retention, delaying plant wilting for 1-2 weeks beyond control trials.

Biochar is a Powerful Tool to Help Combat Climate Change

Biochar is a powerful yet simple tool in the combat against climate change. When organic materials decay greenhouse gases, including methane and carbon dioxide are released into the atmosphere. Charring the organic material effectively fixes carbon into a more stable form.

When Biochar is added to soil, the carbon is sequestered. Estimations are that by using this method in agriculture there is the potential to be able to reduce global emissions of carbon by as much as 10%1. 

In summary, not only does Biochar aid in the growing of crops and plants, it can also help in combating climate change. 

The Application of Biochar

The simplest Biochar application method is to spread it evenly onto the top of the soil and work it into the soil. In cases where using the product on perennial crops or orchards, it may be applied to the soil surface and then covered over with additional organic materials. Alternatively, it can be mixed and applied with mulch or compost or applied in the form of liquid slurry, if it is finely ground. Use of Biochar this way at large scale can be done with a hydro mulcher. 

When used as a component of compost, Biochar increases microbial activity while reducing nutrient loss through the composting process. During the process it becomes packed with nutrients and covered with microbes, with better overall pH-balance than compost produced without Biochar. 

If Biochar is allowed to dry out, dust mask and gloves should be worn when applying.

Biochar can be used in numerous applications, including, but not limited to:

  • Perennial plants – including fruit orchards;
  • Horticultural crops – including planting out or preparing raised beds;
  • Tree crops – Biochar can be applied directly around their root ball and incorporated into the soil;
  • Tree establishment – Biochar may be applied in bands in top soil in addition to planting holes;
  • In seedling raising mix;
  • Gardening, turf grass and landscaping - Biochar may be used in all aspects of the landscaping environment. 

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