The waste product which could help mitigate climate change
Biochar can boost crop yields in poor soils and help stop the effects of climate change, study finds

Date:
August 4, 2021
Source:
University of New South Wales
Summary:
Biochar can boost crop yields in poor soils and help stop the
effects of climate change, study finds.



FULL STORY ==========================================================================
A product made from urban, agriculture and forestry waste has the
added benefit of reducing the carbon footprint of modern farming, an international review involving UNSW has found.


========================================================================== Visiting Professor in the School of Materials Science and Engineering at
UNSW Science, Stephen Joseph, says the study published in GCB Bioenergy provides strong evidence that biochar can contribute to climate change mitigation.

"Biochar can draw down carbon from the atmosphere into the soil and
store it for hundreds to thousands of years," the lead author says."This
study also found that biochar helps build organic carbon in soil by
up to 20 per cent (average 3.8 per cent) and can reduce nitrous oxide
emissions from soil by 12 to 50 per cent, which increases the climate
change mitigation benefits of biochar." The findings are supported
by the Intergovernmental Panel on Climate Change's recent Special
Report on Climate Change and Land, which estimated there was important
climate change mitigation potential available through biochar. "The intergovernmental panel found that globally, biochar could mitigate
between 300 million to 660 million tonnes of carbon dioxide per year by
2050," Prof. Joseph says. "Compare that to Australia's emissions last
year -- an estimated 499 million tonnes of carbon dioxide -- and you can
see that biochar can absorb a lot of emissions. We just need a will to
develop and use it." Biochar is the product of heating biomass residues
such as wood chips, animal manures, sludges, compost and green waste,
in an oxygen-starved environment - - a process called pyrolysis. The
result is stable charcoal which can cut greenhouse emissions, while
boosting soil fertility. The GCB Bioenergystudy reviewed approximately
300 papers including 33 meta-analyses that examined many of the 14,000
biochar studies that have been published over the last 20 years.

"It found average crop yields increased from 10 to 42 per cent,
concentrations of heavy metals in plant tissue were reduced by 17
to 39 per cent and phosphorus availability to plants increased too,"
Prof. Joseph says. "Biochar helps plants resist environmental stresses,
such as diseases, and helps plants tolerate toxic metals, water stress
and organic compounds such as the herbicide atrazine." The study details
for the first time how biochar improves the root zone of a plant. In the
first three weeks, as biochar reacts with the soil it can stimulate seed germination and seedling growth. During the next six months, reactive
surfaces are created on biochar particles, improving nutrient supply to
plants. After three to six months, biochar starts to 'age' in the soil
and forms microaggregates that protect organic matter from decomposition.

Prof. Joseph says the study found the greatest responses to biochar
were in acidic and sandy soils where biochar had been applied together
with fertiliser.

"We found the positive effects of biochar were dose dependent and also dependent on matching the properties of the biochar to soil constraints
and plant nutrient requirements," Prof. Joseph says. "Plants, particularly
in low- nutrient, acidic soils common in the tropics and humid subtropics,
such as the north coast of NSW and Queensland, could significantly
benefit from biochar.

"Sandy soils in Western Australia, Victoria and South Australia,
particularly in dryland regions increasingly affected by drought under
climate change, would also greatly benefit." Prof. Joseph AM is an
expert in producing engineered stable biochar from agriculture, urban
and forestry residues. He has been researching the benefits of biochar
in promoting healthy soils and addressing climate change since he was introduced to it by Indigenous Australians in the seventies. He says
biochar has been used for production of crops and for maintaining healthy
soils by Indigenous peoples in Australia, Latin America (especially in
the Amazon basin) and Africa for many hundreds of years.

Biochar has also been recorded in the 17th Century as a feed supplement
for animals. But while Australian researchers have studied biochar since
2005, it has been relatively slow to take off as a commercial product,
with Australia producing around 5000 tonnes a year. "This is in part due
to the small number of large-scale demonstration programs that have been funded, as well as farmers' and government advisors' lack of knowledge
about biochar, regulatory hurdles, and lack of venture capital and young entrepreneurs to fund and build biochar businesses," Prof. Joseph says.

In comparison, the US is producing about 50,000 tonnes a year, while
China is producing more than 500,000 tonnes a year. Prof. Joseph, who
has received an Order of Australia for his work in renewable energy
and biochar, says to enable widespread adoption of biochar, it needs
to be readily integrated with farming operations and be demonstrated to
be economically viable. "We've done the science, what we don't have is
enough resources to educate and train people, to establish demonstrations
so farmers can see the benefits of using biochar, to develop this new industry," he says.

However this is slowly changing as large corporations are purchasing
carbon dioxide reduction certificates (CORC's) to offset their emissions,
which is boosting the profile of biochar in Australia. Biochar has
potential in a range of applications. Prof. Joseph co-authored a
recent study in International Materials Reviews which detailed the
less well-known uses of biochar, such as a construction material,
to reduce toxins in soil, grow microorganisms, in animal feed and
soil remediation. UNSW has a collaborative grant with a company and a university in Norway to develop a biochar based anti-microbial coating to
kill pathogens in water and find use in air filtration systems, he says.

Stephen Joseph is a member of the Australian New Zealand Biochar
Industries Group. The Universities where he works have received grants
from both state and federal governments and from companies for the
development and testing of biochars. He has also assisted companies and
farmers develop fit for purpose biochars and equipment to make biochar.

========================================================================== Story Source: Materials provided by
University_of_New_South_Wales. Original written by Diane Nazaroff. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Stephen Joseph, Annette L. Cowie, Lukas Van Zwieten, Nanthi Bolan,
Alice
Budai, Wolfram Buss, Maria Luz Cayuela, Ellen R. Graber, Jim
Ippolito, Yakov Kuzyakov, Yu Luo, Yong Sik Ok, Kumuduni Niroshika
Palansooriya, Jessica Shepherd, Scott Stephens, Zhe (Han) Weng,
Johannes Lehmann. How biochar works, and when it doesn't: A review
of mechanisms controlling soil and plant responses to biochar. GCB
Bioenergy, 2021; DOI: 10.1111/ gcbb.12885 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210804123613.htm

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