How could biochar change the fate of marginal soil in Nepal

Biochar is a carbon rich product that is produced by pyrolysis (heating in incomplete or partial absence of oxygen) of biomass at relatively low temperature (<700°C). Normally, a forest fire exceeds 800°C and a simple visible fire is already nearly 600°C. Biochar is very light carbon product. Biochar has been called Bio-Char, Charcoal (अंगार) or biomass derived black carbon, Agri-Char etc according to purpose of use. However, biochar is different from other because of the intention to incorporate in soil for agricultural and environmental benefits. Thus during the production of biochar special care are taken to optimize plant beneficial properties. It is also important to use the word ‘biochar’ in the scientific world to have consistency in research work and standardize the product.



A direct translation of biochar in Nepali will be 'Jaibik Angar' (जैविक अंगार) or can we give it a new name?- कृषि अंगार!! The char or charcoal (अंगार) is the same black portion, other than ashes, that is remained in our local wood-fire stove. Generally we call it COILA ‘कोईला’. The name which we might have wrongly adopted from the mine driven coal, in hindi ‘कोईला’ or in Nepali ‘गोल’ ( :-D ), because they are very similar in appearance. However, the structural and chemical properties of coal and biochar are very different. 

The use of charcoal (अंगार) is very ancient. They were mostly used as a fuel. Use of charcoal in agricultural field (now we change the term to Biochar ok !!), however, were not known to scientist until recently. The whole idea of using biochar in agricultural field surfaced when scientist discovered hectares of land filled with biochar like material across the Amazon river basin inside Amazon forest. Due to the time and environmental factors the material is blended with soil forming a typical dark color that local people call dark-earth or ‘Terra-Preta’. Those lands were modified by the pre-columbian Amazionian civilization, the latest were 800 years ago, to produce food. It is still so rich in nutrient that locals excavate to sell it as pot-soil. Amazon forest was once thought to be uninhabitable because of the adverse climatic condition for agriculture until archeological findings proved once it was home for millions.

Impression of how biochar would actually look and the modified land in Amazon River basin. 

Biochar is recently a huge interest for everyone mostly because of its two attributes. Firstly, most of the carbon in biochar is relatively stable in the soil. For example, the annual average turn over rate of the fine root system is 50% for different ecosystems i.e 50% of carbon stored in such roots will go to the atmosphere again within a year making decomposition a serious drawback for efficient carbon sequestration with biomass. But, biomass, during thermal decomposition (actually the degradation during heating is also decomposition) under absence of oxygen, attain a chemical structure making most part of biochar more resilient (>100 years) to decomposition in soil. This property makes biochar one of the potential tools to mitigate climate change through carbon sequestration in agriculture soil. Secondly, biochar has shown dramatic effects on plant production. The effects have been explained as a result of increased micronutrient and nutrient availability, increased microbial activity, increased water holding capacity, reduced soil toxicity etc. However, there are also results with no significant effects on plant production or reduced performance while biochar was applied. Until 2011, 50% of researches were positive, 30% were negative, and 20% were indifferent regarding growth and yield (Spokas, 2011).

Importantly for us, biochar could be a way for improving marginal or low yielding soil. Despite overwhelming researches showing good characteristics of biochar, more research has to be done on this relatively new material. But it is already clear that biochar can help to increase water holding capacity of soil. Some reports have suggested water holding capacity as the major feature of biochar to improve crop performance. Retention of moisture in the soil is the most important function to improve and keep on overall biological function in the soil. More biological function increases quality of soil.

Despite intruding attributes of biochar it is very important for us to think how it works in Nepalese context. Commercially biochar is produced in a special pyrolysis chamber in controlled condition. There could be chance of some business with such commercial production of biochar in Nepal. However, the production of biochar should not be the destruction of forest. Biochar materials could be straw, other plants biomass and manure as well. Biochar from sewage and waste  might not be more inconvenient in Nepalese context. It is also more controversial because of the possible metal toxicity it could add.

In Nepal, a more strategic approach to produce biochar could be by utilizing the places where wood is burnt everyday. Biochar could be produced commercially in ‘road side hotels’ where decent amount woods are burnt every day anyways. Engineers have developed energy efficient stoves which can produce biochar as a byproduct and that are also smokeless. Such a program is already underway in India and countries in Africa, South America and Asia Pacific. A lots of organizations are also working in Nepal to install clean stove. The clean stove program intends to install a smoke free and energy efficient stoves in homes. A general consideration on adding up objective of producing biochar by such clean stoves program will fit better in our system. These stove programs should consider producing biochar. There has been a huge investment by Global Alliance for Clean Cooking Stoves on such programs. We could make good use of such worldwide program. More concrete information on biochar, stove to biochar programs, various research programs and other biochar activities can be found in International Biochar Initiative (IBI). This organization is an umbrella organization which is also working on to standardize quality of biochar. 


Before any such programs, it is important to investigate and compare how biochar works on sloppy lands of Nepal or how biochar would react to the torrential monsoon in our place. Because biochar is very light, when incorporated, it will loosen the soil. And because it is light the monsoon could sweep away decent portion of biochar from soil wasting time and money. Although it is expected that there will be bonding between soil particles and biochar due to physicochemical and biological interaction in time, it is important to investigate its stability in soil in the early days. (a research question) 

A concept of biochar production, use and research

The above illustration is a concept on how an organization might work with biochar and connect with researchers. A preliminary research is necessary on the effectiveness of such programs. Even though we could start with biochar on the basis of reports and experiments done away from our home, it is very important to have the biochar quality tested in our own labs with our own resources because the quality of biochar depends on the quality of biomass and pyrolysis temperature. A major draw back in our country is a poor connection and integration of researchers and program organizer which should be utterly solved otherwise there is less chance of improving or guiding the program towards the right direction.


It looks like we have yet another tool but a stronger one. Its on us how we can implement a plan to write the fate of our marginal lands. We should not be planning to plan a plan, always.


Gunadhish Khanal
Aarhus University,
Denmark.
References:
1. Lehmann, J., and J. Gaunt. 2006. Bio-char Sequestration in Terrestrial Ecosystems – A Review. Mitigation and adaptation strategies for 11(2): 395-419Available at http://www.springerlink.com/index/10.1007/s11027-005-9006-5.


2.Lehmann, J., M. Rillig, J. Thies, and C. Masiello. 2011. Biochar effects on soil biota-A review. Soil Biology and (May): 1-25Available at http://linkinghub.elsevier.com/retrieve/pii/S0038071711001805.


3.Jeffery, S., F.G. a. Verheijen, and M. van der Velde. 2011. A quantitative review of the effects of biochar application to soils on crop productivity using meta-analysis. Agriculture, Ecosystems 144(1): 175-187Available at http://linkinghub.elsevier.com/retrieve/pii/S0167880911003197.