permaculture

[Lawrence London <lfljvenaura@gmail.com>]

Soil & Water Benefits of Biochar | US Biochar Initiative
http://biochar-us.org/soil-water-benefits-biochar

Soil & Water Benefits of Biochar Biochar Enhances Crop Yield, Enriches Soil
& Protects Water

Why Biochar?— Amending Soil with biochar is modeled after a process begun
thousands of years ago in the Amazon Basin, where islands of rich, fertile
soils called *terra preta* (dark earth) were created by indigenous people.
Anthropologists speculate that cooking fires and kitchen debris along with
deliberate placing of charcoal in the ground resulted in soils with high
fertility and carbon content. These soils continue to "hold" carbon today
and remain so nutrient rich that they have been dug up and sold as potting
soil in Brazilian markets.

Soil's Best Friend— Because of biochar's physical and chemical nature, it
has a unique ability for attracting and holding moisture, nutrients, and
agrochemicals even retaining difficult to hold nutrients like nitrogen and
phosphorous. Nitrogen tends to run-off regular soils, upsetting ecosystem
balance in streams and riparian areas. Biochar also holds gasses; recent
research has proven biochar-enriched soils reduce carbon dioxide (CO2) and
nitrous oxide (NO2) emissions by 50-80%. NO2 is a significant greenhouse
gas, 310 times more potent than CO2.

*[image: a microscopic view of biochar's surface]Biochar's *immense surface
area and complex pore structure (a single gram can have a surface area of
over 1000 square yards) provides a secure habitat for micro-organisms and
fungi. Certain fungi form a symbiotic relationship with plant root fibers
and this allows for greater nutrient uptake by plants. There is speculation
that this fungi may play a part in *terra preta's* ability to regenerate
itself.

Persistency in Soil— It is undisputed that biochar is more persistent than
any form of organic matter commonly applied to soil. Because of biochar's
long-term persistence in soil (more than 2,500 years and counting), all the
associated benefits of nutrient retention, water retention and overall soil
fertility are longer lasting than with common fertilizers alone. Biochar,
comparitively inert, doesn't break down like other organic soil amendments
and resists chemical and microbial degradation, especially when buried.

[image: fertilizer truck in a field]Biochar reduces soil acidity decreasing
liming needs but does not actually add nutrients. Biochar made from manure
is the exception; it retains a significant amount of nutrients from its
source. Because biochar attracts and holds soil nutrients, it reduces
fertilizer requirements - something common organic matter cannot do. As a
result, fertilization costs are minimized and fertilizer (organic or
chemical) is retained in the soil for far longer. Chemical fertilizers are
typically fossil-fuel based, thus biochar provides additional indirect
climate change benefits by reducing fertilizer needs.

[image: a crop of biochar enhanced corn][image: a crop of unenhanced
corn]Enhanced
Crop Yields— When added to soil, biochar improves plant growth and enhances
crop yields, increasing food production and sustainability in areas with
depleted soils, limited organic resources, insufficient water and/or access
to agrochemical fertilizers. Not all soils react the same to biochar and it
frequently can take up to a year to see results. On poor soils with low
carbon content, many studies have shown biochar can increase crop yields up
to four times, like the corn plots pictured on the right and below.

[image: research corn field amended with biochar]

Research presented at a recent American Chemical Society annual meeting
suggests that biochar plus chemical fertilizer yields increased growth of
winter wheat and several vegetables by 25-50% compared to chemical
fertilization alone. Soil Science Society of America experiments found that
biochar supplemented with fertilizer outperformed fertilizer alone by 60%.

It is important to note that not all biochar is the same. The key chemical
and physical properties of biochar are greatly affected by the type of feed
stock being heated and the conditions of the pyrolysis process. For
example, biochar made from manure will have a higher nutrient content than
biochar made from wood cuttings. However, the biochar from the wood
cuttings is likely to have a greater degree of persistence over a longer
period of time. The two different chars will look the same but will behave
quite differently.