June 28, 2024
minute read

Biochar Basics: Environmental Protection

Biochar can be a powerful tool in protecting the environment within and around farms. Through sorption, biochar can decrease atmospheric ammonia emissions, limit nitrate leaching and runoff, decrease phosphate pollution and remediate contaminated soils effectively. This is because of its exceptionally porous structure at multiple scales and vast surface area.

Environmental Effects

Nitrate leaching can be reduced by adding biochar to the bulk soil, as biochar decreases surface runoff and leaching from fertilisers. Not only does this protect surrounding waterways from nutrient pollution, but also ensures that valuable nitrogen is retained in the soil and accessible to crops. In temperate climates like the UK, studies have found that biochar can decrease nutrient runoff by up to 28%, limiting diffuse pollution and soil degradation.

Applying biochar to soils polluted with contaminants can also limit the uptake and incorporation of contaminates into the edible parts of the crops by as much as 64%. When used effectively, biochar remediates degraded soils by improving soil structure, adding and retaining nutrients, and increasing soil carbon.

Some studies have even shown that biochar can decrease theodour from manure stores by over 50%!

How Does Biochar Protect the Environment In and Around Agriculture?

Effective Adsorbent

Biochar captures urea and ammonium on and within particles, which prevents volatilisation, nitrification, and ammonification. This means lower ammonia and greenhouse gas emissions, and reduced nutrient leaching from soil.

Absorption vs Adsorption in biochar
Biochar both absorbs and adsorbs nutrients. This ebables it to increase nutrient retention in the soil and availability to crops.

Traps Contaminants

Some soil contaminates effectively stick onto biochar surfaces through adsorption, immobilising them and preventing uptake by crops.

Improves Soil Structure

Biochar can improve soil structure, increase water retention and hold nutrients preventing loss through leaching and runoff, in turn protecting water courses and improving nutrient retention in Nitrate Vulnerable Zones (NVZs).

💡Using Biochar Effectively for Environmental Protection

Biochar can be utilised to improve environmental protection by targeting different pollutants or contaminates. Application methods and biochar types should be selected according to the desired effect.

  • At low dose rates (<1 t ha-1),biochar can contribute to environmental protection, especially when co-applied or added to potential pollutants such as fertilisers. When mixed with nutrient inputs, low application rates can partially mitigate nutrient loss through leaching and runoff.
  • Biochar should be used in accordance with farm management best practices to further improve environmental protections.
  • Tailored and certified biochar, which is free of contaminants and toxicants, can be added in various methods and doses to improve the impact of biochar on controlling pollutants. Activated biochars may also have improved absorbency.
  • Higher dose rates (>10t ha-1) are likely required to limit nutrient leaching and remediate contaminates in the bulk soil over multiple years.
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