Biochar is a form of charcoal used to improve soil nutrition and growing conditions. It can be made from woody biomass that has been heated and charred with a restricted supply of oxygen, a process called pyrolysis. It captures atmospheric carbon, locking it into the soil for hundreds of years.
Knowledge of biochar has been around for millennia. Studies of soil at sites throughout the Amazon Basin suggest that ancient Amazonian civilizations made a primitive type of biochar and added it to the soil to help grow their crops.
According to recent studies, they found that with the addition of small percentages of biochar, tree health was vastly improved. Not only did 60% more transplanted trees survive; they displayed significantly increased photosynthetic efficiency, better growth, and a larger canopy area.
When using a biochar material for the first time, trying a new way of applying biochar and/ or a new rate of application, you should always start on a small scale (for example with two or three trees) and never try a new technique on a large area, before you have observed positive results. Also, while no recommended application rates for biochar can be given at this time, biochar should be applied in moderate amounts to soil. Rates around 1% by weight or less have been used successfully so far in field crops.
Biochar should ideally be applied to an area of soil that tree roots will eventually utilize to take up nutrients, i.e. the “drip line”. The drip line refers to the area you would get, once the tree has reached its mature size, if you drew a circle on the soil corresponding to the size of the tree’s crown. To apply biochar to the entire drip line it is necessary to work it into the soil beyond the tree’s planting hole, and this is not always possible.
For tree establishment, it may be possible to broadcast and incorporate or band apply biochar over the entire planting area or within each tree’s drip line, and add more biochar in planting holes. Broadcasting can be done by hand on small scales, or on larger scales by using lime/solid manure spreaders or broadcast seeders. Incorporation can be achieved using any plowing method at any scale, including hand hoes, animal draft plows, disc harrows, chisels, rotary hoes, etc. Moldboard plowing is not recommended as it is unlikely to mix the biochar into the soil and may result in deep biochar layers. When working with fine, dry biochar, wind losses during application and incorporation can be significant and precautions must be taken to minimize this. Moistening the biochar after weighing it is an easy way of controlling dust.
Arbor Hills Tree Farm will be working with Nebraska Forest Service this Spring to test the Bio Char products on selected tree planting sites.
For more information please click and contact Arbor Hills Tree Farm.