Biochar: Soil Health, Clean Energy and Ecopreneurship

After more than a year of liv­ing with the pan­dem­ic, many of us could be think­ing about the future of jobs and what kind of changes we might see in the world. The belief in “job secu­ri­ty” has been shak­en up with many indi­vid­u­als los­ing their jobs in small and large com­pa­nies all over the globe. While the pan­dem­ic has been a time of immense suf­fer­ing, it also presents an oppor­tu­ni­ty for us to rethink aspects of our life that we have hith­er­to been pur­su­ing in an “auto” mode. In fact, we need to have a re-look at our aspi­ra­tions. For instance, is get­ting a job in a dream com­pa­ny real­ly going to secure our future finan­cial­ly? Should we think of ways to be self-reliant in mak­ing our own liveli­hood by cre­at­ing things or ser­vices that are of val­ue to oth­er mem­bers of soci­ety and the envi­ron­ment? This arti­cle looks at an inter­est­ing oppor­tu­ni­ty for “eco­pre­neur­ship”, which refers to the appli­ca­tion of sus­tain­able entre­pre­neur­ial prin­ci­ples to solv­ing envi­ron­men­tal prob­lems and is some­thing that has been gain­ing pop­u­lar­i­ty in the recent times.

An ancient mys­tery

Around 2500 years ago, long before Christo­pher Colum­bus voy­aged across the Atlantic to Amer­i­ca, a great civ­i­liza­tion thrived in the Ama­zon­ian rain­for­est in the con­ti­nent of South Amer­i­ca. How such a civ­i­liza­tion could have exist­ed had been a mys­tery to sci­en­tists because the Ama­zon­ian soils did not con­tain the nutri­ents nec­es­sary for grow­ing crops.  The Ama­zon­ian soils were not just defi­cient in nutri­ents; they did not con­tain com­pounds that could hold on the nutri­ents, even if added by humans. Adding fer­til­iz­ers to the soil does not work, because rain wash­es away the nutri­ents from the soil. So how did the Ama­zon­ian peo­ple flour­ish? Their secret was the knowl­edge of prepar­ing a dark soil called ‘ter­ra pre­ta’. Unlike mod­ern tech­niques of soil fer­til­iza­tion, the use of ter­ra pre­ta allows the soil to remain fer­tile for hun­dreds to thou­sands of years.

Sci­en­tists have still not dis­cov­ered the exact “ingre­di­ents” and the meth­ods of prepar­ing ter­ra pre­ta known to the Ama­zo­ni­ans. What sci­en­tists do know is that ter­ra pre­ta con­tains unusu­al­ly high amounts of a car­bon-rich com­pound known as biochar (or char­coal), from which it gets its black colour.

Com­par­i­son of (Left) Ama­zon­ian ter­ra pre­ta soil (Right) Soil nor­mal­ly found in the Ama­zon Basin. (Image Cour­tesy: Bruno Glaser et al. 2001)

What is biochar?

Biochar is a fine-grained, car­bon-rich, high­ly porous prod­uct that is formed from heat­ing wood or plant bio­mass in an envi­ron­ment with lit­tle or no oxy­gen. This process is called pyrol­y­sis. Pyrol­y­sis is dis­tinct from burn­ing or com­bus­tion, which takes place in the pres­ence of oxy­gen. Wood or plant mate­r­i­al con­sists main­ly of two com­pounds known as cel­lu­lose and lignin. These com­pounds are made of car­bon, hydro­gen and oxy­gen. When wood is sub­ject­ed to pyrol­y­sis, cel­lu­lose and lignin break down. The hydro­gen and oxy­gen atoms form water, while car­bon atoms are left­over. The left­over car­bon is called biochar.  Biochar can be seen in slow, smoul­der­ing fires, for exam­ple, at the bot­tom of an extin­guished camp fire.

Biochar pro­duc­tion in India is not new; it has been prac­tised since ancient times by Indi­an farm­ers and the meth­ods are part of tra­di­tion­al knowl­edge. In Tamil Nadu, for instance, pyrol­y­sis is car­ried out in earth kilns. Wood logs and plant roots are stacked in lay­ers and the stack is cov­ered with moist earth. A chim­ney or a vent is made to allow gas­es to escape. The earth kiln is an easy and low-cost method of char­coal pro­duc­tion. Wood logs are con­vert­ed into char­coal inside the earth kiln in 3–4 days.

Tra­di­tion­al earth kiln in Tamil Nadu

 

(Image cour­tesy: Srini­vas­rao and Jeyara­man et al. 2013. NICRA Bul­letin)

A piece of biochar

(Image cour­tesy: K.salo.85 — Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=29973096)

Mod­ern indus­tri­al meth­ods of char­coal pro­duc­tion make use of metal­lic drums, retorts and con­ver­tors, which recov­er the gaseous byprod­ucts of pyrol­y­sis for oth­er uses.

How can biochar mit­i­gate the eco­log­i­cal cri­sis of today?

Glob­al warm­ing due to green house gas (GHG) emis­sions has result­ed in cli­mate change and extreme weath­er pat­terns, which are threat­en­ing food secu­ri­ty glob­al­ly. The most effec­tive way to absorb the car­bon diox­ide in the atmos­phere is by seques­tra­tion of car­bon both in trees (eg: afforesta­tion) and in the soil, as they act as ‘car­bon sinks’.

Car­bon seques­tra­tion and soil fer­til­i­ty:

Mak­ing biochar is one of the most effec­tive car­bon seques­ter­ing meth­ods as this form of car­bon stays in the soil for many years and is resis­tant to chem­i­cal trans­for­ma­tion. The key prop­er­ty of biochar that makes it effec­tive for soil amend­ment is its high­ly porous struc­ture, which is respon­si­ble for water reten­tion, nutri­ent bind­ing and serves as a habi­tat for soil micro-organ­isms.

Research shows that pro­found changes in micro­bial com­mu­ni­ties occur in biochar amend­ed soils. Biochar amend­ment leads to bet­ter reten­tion of both nutri­ents and car­bon and min­i­mizes loss. Biochar also influ­ences the diver­si­ty and abun­dance of micro-organ­isms col­o­niz­ing its sur­faces and their activ­i­ties, in a way that con­serves the resources with­in the soil sys­tem.

To give an anal­o­gy, biochar is like the house which holds all fam­i­ly mem­bers and their mate­r­i­al resources togeth­er, and pro­vides the space for each mem­ber to per­form their activ­i­ty effi­cient­ly, so that the fam­i­ly as a whole can run suc­cess­ful­ly.

Porous struc­ture of biochar (Micro­scop­ic view), UK Biochar Research Cen­tre

(Image cour­tesy:  http://www.nakanoassociates. com/biochar/)

Solu­tion to crop burn­ing:

Agri­cul­tur­al residues such as straws of rice, wheat, mil­let, sorghum, puls­es, oilseeds and coconut shells, ground­nut shells, etc are usu­al­ly burnt as it is a fast way to clear the field for fur­ther land prepa­ra­tion and plant­i­ng. Burn­ing leads to the release of GHGs and dan­ger­ous air pol­lu­tants, in addi­tion to loss of valu­able bio­mass and nutri­ents. The avail­abil­i­ty of bio­mass in India is esti­mat­ed to be about 500 mil­lion tons per year. A por­tion of these residues are uti­lized as fod­der for farm ani­mals and a por­tion is burnt. About 93 mil­lion tons of crop residues are burnt each year in India. In Pun­jab alone, about 70 to 80 mil­lion tons of rice and wheat straw are burnt annu­al­ly.

Prepar­ing biochar from agri­cul­tur­al residues can be a pow­er­ful alter­na­tive to crop burn­ing.  Burn­ing a plant con­verts the plant’s car­bon into car­bon diox­ide which goes into the atmos­phere. But pyrol­y­sis retains the plant’s car­bon as biochar and is returned to the soil.

Clean ener­gy bio­fu­els as byprod­ucts:

Pyrol­y­sis meth­ods can be tweaked to yield dif­fer­ent pro­por­tions of biochar and bioen­er­gy prod­ucts such as bio­fu­els and syn­gas, which can be used as clean fuel for gen­er­at­ing elec­tric­i­ty and heat­ing appli­ca­tions.

Reme­di­a­tion of heavy met­als:

Biochar and acti­vat­ed char­coal, in par­tic­u­lar, have been found to be effec­tive in seques­ter­ing tox­ic heavy met­al con­t­a­m­i­nants from the soil.

Thus, we see that biochar has sev­er­al appli­ca­tions, not only in terms of “fix­ing” impor­tant envi­ron­men­tal chal­lenges, but also in terms of enrich­ing soil health and fer­til­i­ty for gen­er­a­tions to come. These appli­ca­tions open up ample entre­pre­neur­ial oppor­tu­ni­ties for those who have pas­sion and ener­gy to make a change and also become self-reliant. An exam­ple of an inno­v­a­tive prod­uct devel­op­ment chal­lenge is the design of effi­cient wood stoves that make biochar while also pro­vid­ing heat for cook­ing. Anoth­er exam­ple is pro­vid­ing ser­vices to farm­ers in terms of help­ing them max­i­mize eco­nom­ic ben­e­fits through biochar pro­duc­tion at the indi­vid­ual or com­mu­ni­ty lev­el. Cre­ative think­ing, hands on exper­i­men­ta­tion and con­tin­u­al­ly engag­ing with the stake­hold­ers, such as farm­ers, are impor­tant fac­tors for suc­cess in entre­pre­neur­ship.

 

 

Ref­er­ences

Mich­e­lovic (2009). Ancient Soil Chemists of the Ama­zon. Link: https://www.acs.org/content/dam/acsorg/education/resources/highschool/chemmatters/articlesbytopic/sustainability/chemmatters-feb2009-biochar.pdf

Ch, Srini­vas­rao & K.A., Gopinath & Govin­dara­jan, Dr & Dubey, A.K. & Wakud­kar, Har­sha & Purakayastha, Tapan & Pathak, Dr Suren­dra & Jha, Pramod & Rajkhowa, D.J. & Man­dal, Sandip & Jeyara­man, S. & Venkateswar­lu, Ban­di & Sik­ka, Alok. (2013). Use of Biochar for Soil Health Man­age­ment and Green­house Gas Mit­i­ga­tion in India: Poten­tial and con­straints. Link: https://www.researchgate.net/publication/259657894_Use_of_Biochar_for_Soil_Health_Management_and_Greenhouse_Gas_Mitigation_in_India_Potential_and_constraints

Glaser B. (2007). Pre­his­tor­i­cal­ly mod­i­fied soils of cen­tral Ama­zo­nia: a mod­el for sus­tain­able agri­cul­ture in the twen­ty-first cen­tu­ry. Philo­soph­i­cal trans­ac­tions of the Roy­al Soci­ety of Lon­don. Series B, Bio­log­i­cal sci­ences, 362(1478), 187–196. https://doi.org/10.1098/rstb.2006.1978

Glaser, Bruno & Hau­maier, Lud­wig & Guggen­berg­er, Georg & Zech, Wolf­gang. (2001). The ‘Ter­ra Pre­ta’ phe­nom­e­non: A mod­el for sus­tain­able agri­cul­ture in the humid trop­ics. Die Natur­wis­senschaften. 88. 37–41. 10.1007/s001140000193.

Jin, H. (2010). Char­ac­ter­i­za­tion of micro­bial life col­o­niz­ing biochar and biochar-amend­ed soils. Link: https://ecommons.cornell.edu/bitstream/handle/1813/17077/Jin,%20Hongyan.pdf;jsessionid=5A617A8821CE293422EA67C708723F8D?sequence=1

McLaugh­lin, H. (2016). An Overview of the cur­rent Biochar and Acti­vat­ed Car­bon Mar­kets. Link: https://www.biofuelsdigest.com/bdigest/2016/10/11/an-overview-of-the-current-biochar-and-activated-carbon-markets/

Moses, N. V. (2013). Here’s how ‘black gold’ is giv­ing India’s farm­ers new hope and try­ing to save the plan­et. Link: https://yourstory.com/2013/08/heres-how-black-gold-is-giving-indias-farmers-new-hope-and-trying-to-save-the-planet/amp