Benefits Of Biochar For Your Organic Garden
- holds onto nutrients until the plants need them. Biochar increases what is called the ‘Cation Exchange Capacity’ (CEC) and ‘Anion Exchange Capacity’ (AEC) of your soil. Plant nutrients carry either a positive or a negative charge. The surface of the biochar has areas with either a positive or a negative charge. So for example positively charged plant nutrients (ions) like Calcium or Magnesium are attracted to the negatively charged sites of the biochar where they stay in a loose connection until the plant roots need them. The same happens with negatively charged nutrients e.g. Nitrates or Phosphates with are attracted to the positive sites on the biochar.
- holds onto water and increases the water-holding capacity of the soil significantly. It acts like a sponge absorbing water into its porous structure. This is very important nowadays with climate change causing hotter summers and droughts more frequently. Biochar will help to make your garden more resilient to water shortages.
- provides shelter for beneficial soil microbes which help to grow healthy plants. The cell structure offers a habitat for beneficial soil bacteria, microbes, and fungi. All these critters pee and poo…and are thus providing fertilizer for our plants. They also function like our gut microbiome and help to protect plants from pests and diseases.
- prevents leaching of nutrients during heavy rain and therefore less fertilizer is needed
- holds on to toxic heavy metals and reduces their effect
- helps to improve the soil structure of heavy soils, sandy soils, and sticky clay.
So...What is Biochar And What Makes It Magic?
Biochar is any organic matter that has been pyrolyzed. During pyrolisis the organic matter is roasted without oxygen at a temperature around 350°C. You can use all sorts of organic waste materials like e.g. garden trimmings, wood shavings, straw, twigs…any plant material that comes free and is non-toxic!
During the roasting process, the organic matter doesn’t burn down to ashes because there is no oxygen available. This preserves the cell structure of the organic matter you chose for your biochar. These cell structures are like little chambers which offer a cozy home to microorganisms and nutrients once it is incorporated in your garden soil.
Don’t mix up biochar with charcoal! Although it might look similar it is not the same thing. Charcoal is produced at much higher temperatures with oxygen in the process. With biochar, the aim is to preserve the cell structures and pores of the organic matter so it can do its magic in the soil.
What Is Biochar And Is It A Fertiliser?
In short…no! In itself, biochar has no nutrients of any significance. It is simply a form of very stable carbon. So you might be wondering why and how this stuff can make such a difference to your garden. It mainly works in two ways.
1. Biochar can hold onto nutrients until the plants need them and prevent them from being washed away by rain or irrigation water.
2. Biochar gives soil microbes a cozy home and shelter from predators. It supports beneficial soil life which will help to improve plant health.
Why Biochar Is Good For The Climate
Biochar is a very stable form of carbon. It can stay in the soil without breaking down and being released as CO2 for a very long time. It is estimated that it stable for several hundred if not thousands of years! So by using biochar in your garden you are not only improving the productivity of your soil... but you are also taking the climate gas CO2 from the atmosphere. A true win-win! There is no better way to reduce your carbon footprint while growing more and better quality food.
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