CO2 foot­print

In animal hus­bandry and fer­tilis­er man­age­ment

The main focus for achiev­ing climate pro­tec­tion targets is on finding replace­ments for fossil energy sources. But renew­able ener­gies can only prevent more CO2 from being released into the atmos­phere and thus avoid increas­ing our CO2foot­print. With biochar it is also pos­si­ble to bring the carbon back into the soil from the CO2-con­t­a­m­i­nat­ed atmos­phere.

During car­bon­i­sa­tion of biomass, as the pro­duc­tion process for biochar is also called, about half of the carbon con­tained in the biomass is bound in the biochar over the long term. This is another reason why it is impor­tant to pay atten­tion to the quality of the coal used for biochar. Biochar is not just crumbly bar­be­cue coal with a new label. Cer­ti­fied biochar may only be pro­duced from certain biomass using climate and envi­ron­men­tal­ly friend­ly carbonisation/pyrolysis process­es. Only then is it free of car­cino­genic sub­stances and mil­lions of hectares of forest are not simply “charred” while thou­sands of tons of CO2 are released. In clean process­es, at least 50% of the carbon con­tained in the biomass is stably bound in the biochar and can thus be returned to the soil and removed from the atmos­phere. Cer­ti­fied biochar is a real benefit for the climate and the soil.

Nitrous oxide

Nitrous oxide (N2O) is a green­house gas that, accord­ing to the Federal Envi­ron­ment Agency, is around 300 times more harmful to the climate than carbon dioxide (CO2) and 12 times more harmful than methane. Nitrous oxide reflects the heat reflec­tion of the earth’s surface and pre­vents it from escap­ing into space. The heat is released back into the earth. In addi­tion, nitrous oxide damages the ozone layer. This pro­tects plants, animals and people from radi­a­tion damage and also reg­u­lates tem­per­a­ture.

Agri­cul­ture in par­tic­u­lar makes a sig­nif­i­cant con­tri­bu­tion to the release of nitrous oxide into the atmos­phere. The main sources are the high use of nitroge­nous fer­tilis­ers and animal hus­bandry. If too much fer­tilis­er is used, or used at the wrong time, the nitro­gen cannot be com­plete­ly absorbed by the crops and is released into the envi­ron­ment. Part of the excess nitro­gen is released into the atmos­phere as nitrous oxide.

However, if the soil con­tains biochar or if biochar is added to the fer­til­iz­er, nitrous oxide emis­sions are sig­nif­i­cant­ly reduced (see, for example, Kammann 2012, Uni­ver­si­ty Geisen­heim). In various plant­i­ng exper­i­ments with biochar in the lab­o­ra­to­ry and in the field, up to 60 percent less nitrous oxide was released. The researchers explain the effect with the storage capac­i­ty of plant coal. It can absorb up to five times its own weight of water and the nutri­ents dis­solved therein. This means that nitro­gen is no longer avail­able for the microor­gan­isms that nor­mal­ly metabolise the nitro­gen into nitrous oxide. It is stably bound in the numer­ous, small pores (< 100 nm) of plant coal and is released back into the envi­ron­ment only slowly and in small quan­ti­ties.

Methane

Accord­ing to the Federal Envi­ron­ment Agency, methane (CH4) is 25 times more harmful to the climate than carbon dioxide (CO2). Just like all other green­house gases, methane reflects the heat reflect­ed from the earth’s surface and pre­vents it from escap­ing into space. The heat is released back into the earth.More than one third of the world’s output comes direct­ly or indi­rect­ly from live­stock farming, mainly from large-scale farming of cattle and sheep. As rumi­nants, they produce large quan­ti­ties of methane in their stom­achs during diges­tion and release it again by “burping and farting”. In addi­tion, methane is released as fer­til­iz­er in agri­cul­ture through waste­water and sewage sludge treat­ment and the appli­ca­tion of sewage sludge.

Here too, biochar as a feed addi­tive can reduce methane emis­sions (see, for example, Schmidt 2016, Ithaka Journal). Biochar has an adsorb­ing effect in the diges­tive tract of animals, i.e. it binds nutri­ents and toxins very effi­cient­ly. It has there­fore been known for cen­turies in animal hus­bandry as an emer­gency treat­ment for indi­ges­tion and poi­son­ing and is used there as a non-digestible carrier. In the animals’ diges­tive tract, however, biochar not only has a detox­i­fy­ing effect, but also increas­es feed effi­cien­cy through its electro-bio­chem­i­cal inter­ac­tion and reduces methane for­ma­tion through nitro­gen binding.

Ammonia

The volatil­i­sa­tion of ammonia (NH3) is one of the most impor­tant causes for the loss of nitro­gen (N) in soil-plant systems world­wide. Nitro­gen does not remain in the air, and rain causes nitro­gen to flow back, which in turn pro­motes the for­ma­tion of highly climate-dam­ag­ing nitrous oxide emis­sions, the acid­i­fi­ca­tion of soils and the accu­mu­la­tion of nitro­gen in water.

The large-scale release of harmful ammonia emis­sions occurs above all in agri­cul­ture. It is caused by the micro­bial decom­po­si­tion of animal excre­ments in barns and fields when liquid manure is used as fer­tilis­er. The pungent smelling gas is not only harmful to the envi­ron­ment, but is also harmful to the animals in the stable, as it irri­tates their mucous mem­branes, attacks the lungs, weakens the immune system and even accu­mu­lates in the blood of the animals (see Schmidt 2012, Ithaka Insti­tute).

If biochar is used as a litter and feed addi­tive, nitro­gen losses can be sig­nif­i­cant­ly reduced. Biochar can absorb up to 5 times its own weight in water and binds toxins and nutri­ents very effi­cient­ly. The nitro­gen binding and the con­tin­u­ous drying of the bedding deprives the microor­gan­isms of their nutri­ent basis and thus reduces the toxic ammonia evap­o­ra­tion (see Schmidt 2012, Ithaka Insti­tute).

Recent con­tri­bu­tions on the green­house effect

Reduc­ing CO2-emis­sions with biochar

About 10 percent of EU CO2 emis­sions could be offset by more pro­duc­tive use of biomass and plant residues through pyrol­y­sis. This is the con­clu­sion of Prof. Bruno Glaser from the Uni­ver­si­ty of Halle and author of the article “Biochar use…

Why biochar does not decom­pose

There is great research inter­est in carbon © bound by pyrol­y­sis (car­bon­i­sa­tion), due pri­mar­i­ly to the poten­tial role of biochar (charred biomass) as a long-term carbon sink in soils and sed­i­ments. This is because biochar resists micro­bial…

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