As a resource on Biochar please look to Biochar Environmental Management Science and Technology edited by Johannes Lehmann and Stephen Josesph.

Because Biochar can be alkaline in its pH and when elevated temperatures over 400 C are used to generate it. In the more alkaline soil areas application might lead to issues with micronutrient inavailability especially in a alkaline high carbonate soil environment.

The use of biochar is most outstanding in the soil leached soil environment of low pH.

There is currently little regulation or labeling on biochar sales and it would prudent to have greater standardization and characterization of the products as they become more available. As far as sources most suitable one could consider the legume trees used as windbreaks as a viable resource. The thinning chipped and used for pyrolysis will provide a green energy resource and the residual can be strategically used for increasing the soil Carbon, Nitrogen and mineral contents.

A lot of work shows the substantial value of biochar for increasing crop performance but much of that work is at very high rates. A gap in the literature is determining the more optimized minimized rates which will optimize its use economically.

I believe a cover crop can increase soil carbon 500 to 1,500 kg C per hectare with the use of biochar at rates of 5,000 kg C per hectare will greatly increase the soil carbon and biological activity of soils it increases both mycorrhizal fungal activity and Rhizobial symbiosis. If I was trying to promote this the red depleted acid soils of the World would be primary target.

I would suggest alley crop systems of rotated field crops using legume trees as the biochar resource would be best overall test system for long term studies.

As a resource on Biochar please look to Biochar Environmental Management Science and Technology edited by Johannes Lehmann and Stephen Josesph.

Because Biochar can be alkaline in its pH and when elevated temperatures over 400 C are used to generate it. In the more alkaline soil areas application might lead to issues with micronutrient inavailability especially in a alkaline high carbonate soil environment.

The use of biochar is most outstanding in the soil leached soil environment of low pH.

There is currently little regulation or labeling on biochar sales and it would prudent to have greater standardization and characterization of the products as they become more available. As far as sources most suitable one could consider the legume trees used as windbreaks as a viable resource. The thinning chipped and used for pyrolysis will provide a green energy resource and the residual can be strategically used for increasing the soil Carbon, Nitrogen and mineral contents.

A lot of work shows the substantial value of biochar for increasing crop performance but much of that work is at very high rates. A gap in the literature is determining the more optimized minimized rates which will optimize its use economically.

I believe a cover crop can increase soil carbon 500 to 1,500 kg C per hectare with the use of biochar at rates of 5,000 kg C per hectare will greatly increase the soil carbon and biological activity of soils it increases both mycorrhizal fungal activity and Rhizobial symbiosis. If I was trying to promote this the red depleted acid soils of the World would be primary target.

I would suggest alley crop systems of rotated field crops using legume trees as the biochar resource would be best overall test system for long term studies.

What kind of substrates are best suited for biochar production?

Hard wood biomass which contain 10 per cent moisture content is best for biochar production.  In our experiment we had tried with 17 different soft and hardwood biomass and we concluded that the prosopis juliflora without bark biochar recovery is 30%. 

How could we regulate the quality of biochar ?

In order to regulate quality of biochar, biomass prior treated with following guidelines.

1. Collection of hard woods and remove barks to avoid lignin effects.

2. Immerse them in diluted acid (H2SO4) is required 

3. Dry the hard wood under sun and chop them in to small pieces (2.5- 5 cm)

4. Pyrolysis them at 350 degree C for an hour.

5. Resident time should be  8 hr.

6. Mill them with proper size and sieve for uniform biochar particle.

7. Apply to rhizosphere 

What are the parameters that guide the manurial value of quality biochar ?

Biochar decomposition rate is 0.03 % per year. If we apply one year it can able to help for 5-8 years in water and nutrient retention. 

How can we improve the manurial value of biochar?

Biochar structural pattern will be similar to biomass and the S,R,T pores will be utilized for loading of any nutrient. 

Is there any long term evaluation of biochar with reference to crop response and soil health assessment?

Few studies are available with mycorrhiza and biochar association.

What kind of substrates are best suited for biochar production?

Hard wood biomass which contain 10 per cent moisture content is best for biochar production.  In our experiment we had tried with 17 different soft and hardwood biomass and we concluded that the prosopis juliflora without bark biochar recovery is 30%. 

How could we regulate the quality of biochar ?

In order to regulate quality of biochar, biomass prior treated with following guidelines.

1. Collection of hard woods and remove barks to avoid lignin effects.

2. Immerse them in diluted acid (H2SO4) is required 

3. Dry the hard wood under sun and chop them in to small pieces (2.5- 5 cm)

4. Pyrolysis them at 350 degree C for an hour.

5. Resident time should be  8 hr.

6. Mill them with proper size and sieve for uniform biochar particle.

7. Apply to rhizosphere 

What are the parameters that guide the manurial value of quality biochar ?

Biochar decomposition rate is 0.03 % per year. If we apply one year it can able to help for 5-8 years in water and nutrient retention. 

How can we improve the manurial value of biochar?

Biochar structural pattern will be similar to biomass and the S,R,T pores will be utilized for loading of any nutrient. 

Is there any long term evaluation of biochar with reference to crop response and soil health assessment?

Few studies are available with mycorrhiza and biochar association.

Will biochar enhance acidity of soil and reduce the fertility ?

When biochar is made at temperatures over 400 C as the pyrolysis temperature increases the end product alkalinity increases in turn.

If you are in an acid environment from a soil say of less than 5.5 the liming effect of the biochar may be very useful as it could immobilize the solubility of iron, aluminum and manganese which can be toxic in acid infertile conditions.

However if your soil is neutral and the addition biochar pushes the soil pH to over 7.5 you will likely have conditions of Zinc and other nutrient deficiency. There is still a lot of work to be done but a start is to know your soil pH and other nutrients and add biochar in increments.

Soil pH is very critical to much of nutritional available for plants.

Excellent responses from my learned colleagues , Drs Hepperly , Manikandan , and Verghese . Why have I tossed up this question , knowing the fact , certain issues pertaining to biochar have been discussed . according to on estimate , as much as 373 million tons of biochars can be produced globally looking at the current  quantum of crop residues that are produced annually , and this has the potential of  sequestration of 0.55 Pg carbon dioxide per year in soils. Friends , just imagine the utility of biochars in residue management , and if you include the potential of animal residues plus sewage sludge , you can  conveniently arrive at some staggering figures .

Dr Hepperly , cant we regulate the pH of end product biochar by regulating the temperature of pyrolysis, since biochars have been reported to have pH ranging from 6.1 to as high as 11.2.

Dr Manikandan, appreciating your response, can you share any publication relating to standard protocol of biochar preparation.  

My question is addressed to Dr. Hepperly. What is the standard protocol of biochar development?

Dr Deka ,  Dr Shirgure and other learned colleagues . Biochars are formed when biological residues combusted at 600-800 0Cunder low oxygen , with resultant residue having low density and highly porous. Accordingly to classical review by Schmidt (2012) highlighting as many as 55 uses (1. Silage agent, 2. Feed additive / supplement, 3. Litter additive, 4. Slurry treatment, 5. Manure composting, 6. Water treatment in fish farming of biochars ,7. Carbon fertiliser, 8. Compost, 9. Substitute for peat in potting soil, 10. Plant protection, 11. Compensatory fertiliser for trace elements 12. Insulation, 13. Air decontamination, 14. Decontamination of earth foundations, 15. Humidity regulation, 16. Protection against electromagnetic radiation (“electrosmog17. Soil additive for soil remediation [for use in particular on former mine-works, military bases and landfill sites.] 18. Soil substrates [highly adsorbing, plantable soil substrates for use in cleaning waste water; in particular urban waste water contaminated by heavy metals] 19. A barrier preventing pesticides getting into surface water [Sides of field and ponds can be equipped with 30-50 cm deep barriers made of biochar for filtering out pesticides.]20. Treating pond and lake water [Biochar is good for adsorbing pesticides and fertilizers, as well as for improving water aeration21. Biomass additive, 22. Biogas slurry treatment 23. Active carbon filter, 24. Pre-rinsing additive, 25. Soil substrate for organic plant beds, 26. Composting toilets, 27. Micro-filters, 28. Macro-filters in developing countries

Divers Exhaust filters (29. Controlling emissions, 30. Room air filters) Industrial materials (31. carbon fibres, 32. plastics) Electronics (33. semiconductors, 34. batteries) Metallurgy (35. metal reduction) Cosmetics (36. soaps, 37. skin-cream, 38. therapeutic bath additives) Paints and colouring (39. food colorants, 40. industrial paints) Energy production (41. pellets, 42. substitute for lignite) Medicines (43. detoxification, 44. carrier for active pharmaceutical ingredients)45. Fabric additive for functional underwear, 46. Thermal insulation for functional clothing, 47. Deodorant for shoe soles 48. Filling for mattresses, 49. Filling for pillows 50. Shield against electromagnetic radiation ).

I am enclosing the PDF  for your referral please.  You can judge the multiple roles of biochars in soaamny broad  range of enterprises including various off- shoot disciplines of agriculture .

Dear Doctor Srivastava,

You are correct that precise control of the pyrolysis will change the end pH at higher temperatures the alkalinity of the end product is increased more.

When higher temperatures are avoided the advantages is less alkalinity and more retention of residual Carbon. At higher temperatures the yield of syngas can increase as well as yield of the more alkalinity in the residue. Alkaline products can also be blended to achieve end uses without extreme alkalinity. At the higher temperatures less char is produced.

The use of biochar is excellent with compost and in fact some of the highest performance we have observed in acid red piedmont low fertility soil was with the use of compost with biochar. It also is an excellent amendment for compost potentially.

The porous honey combed nature of the product provides something of a soil habitat for bacteria and fungi which might be less likely to survive in the bulk soil which represents something of an inhospital and naked environment.

Biochar has been demonstrated to stimulate both the Rhizobia and Mycorrhizal relationship.

Thanks Dr Hepperly for an excellent response . Endorsing your comments , let me add another piece of information dealing with type biochar obatained with different biological material and effect of temperature of pyrolysis .

The understanding of its chemical and physical properties, which are strongly related to the type of the initial material used and pyrolysis conditions, is crucial to identify the most suitable application of biochar in soil. A selection of organic wastes with different characteristics (e.g., rice husk (RH), rice straw (RS), wood chips of apple tree (Malus pumila) (AB), and oak tree (Quercus serrata) (OB)) were pyrolyzed at different temperatures (400, 500, 600, 700, and 800 ◦C) in order to optimize the physicochemical properties of biochar as a soil amendment. Low-temperature pyrolysis produced high biochar yields; in contrast, high-temperature pyrolysis led to biochars with a high C content, large surface area, and high adsorption characteristics. Biochar obtained at 600 ◦C leads to a high recalcitrant character, whereas that obtained at 400 ◦C retains volatile and easily labile compounds. The biochar obtained from rice materials (RH and RS) showed a high yield and unique chemical properties because of the incorporation of silica elements into its chemical structure. The biochar obtained from wood materials (AB and OB) showed high carbon content and a high absorption character. (Jindo et al . 2010. Biogeoscience 11: 6613-6621). Hope such information will lead to better understanding  on these issues.

Dr Srivastava this very good piece of information, how can we optimize the process of pyrolosis temperature and type of biological material, both affecting the physical and chemical properties of biochar. 

What kind of eco-logical services, long term biochar application on long term basis could offer?

Do you feel biochars are better alternative to slash and burn  method of agriculture land clearing adopted in humid tropical areas.

Pierlorenzo , you have tossed up some real mind blowing issues pertaining to biochar preparation . Kindly look into the central theme of my question , and you endorse it . I urge upon my learned colleagues to throw some more lights on such burning issues. Some of my colleagues , therefore , earlier raise this issue , can it be good supplement to traditionally used  Slash and Burn method of agriculture , popularly called Shifting Cultivation . Yes , I agree with you on these issues . Lets listen from our other colleagues , what they have to say about all these?

Carbon  level is increasing day by day in the atmosphere so I dont suggest this technology to improve soil health on the earth. There are many non destructive way to improve soil fertility.

It will be interesting to know, how come at such high temperature of pyrolysis, the biological properties of biochar could be expected. It is more like a physical amendment working in soil.

Biochar is created using a pyrolysis process by heating biomass in a low oxygen environment but at high temperature. Therefore, indigenous microbial population is depleted. I have my own reservation that biochar could not be a promising organic manures but it could be a good soil ameliorant.

Well  said Drs Deka , Ram and Malhotra , your concerns , to me as well , look genuine , but still biochar is widely recognized as an efficient tool of carbon sequestration and soil fertility improvements , however , most of the functions of biochar originate from its secondary functions , not through its own inherent properties. The chemical  nature biochar is yet to be defined precisely , because of variation in biochar properties on account  substrate subjected to pryrolysis and charring conditions. Presence of six carbon rings without any O or OH  , still makes  biochar environmentally doubtful preposition according to some researchers.  

Can any one of us endorse or refute these comments through some better response  

What kind of developments have taken place with regard to preparation of biochar. There is no doubt about biochar utility in agriculture.

Dear all, 

Australia was at the forefront of trying to translate terra preta knowledge into a commercially viable biochar supply chain. To achieve this, Federal and State governments, agricultural research and development corporations and private enterprises spent many millions of research dollars to improve knowledge about the production of biochar and its beneficial use in agriculture, i.e. its effects on soil properties and plant growth.

However, some 10 years after the biochar revolution began in Australia, nothing much has changed on the ground. Although scientific knowledge about the production and use of biochar has increased greatly, there was a failure to translate the aquired knowledge into large-scale production of biochar and its wide-spread agricultural and horticultural use.

The application of biochar to agricultural soils attracted much interest as a potential tool to sequester carbon, mitigate greenhouse gas emissions and to improve soil properties and agricultural productivity. Apart from increasing soil pH and reducing nitrous oxide emissions, probably the only unambiguous benefit of using biochar is its capacity to supply stable carbon compounds and increase soil carbon levels. Numerous research projects have shown that the use of biochar as soil amendment can supply macronutrients (N, P, K and Ca) and micronutrients (Mg, Zn), alter pH and cation exchange capacity (CEC), and modify pore structure, surface area and bulk density, which alters water and gas dynamics. However, despite this array of potential benefits, the unpredictable nature of plant growth responses across different soil-plant-environment systems prevented most farmers from using biochar.

Overall, biochar use trials resulted in positive, negative and neutral effects on productivity, depending on factors such as the type of biochar used (feedstock and pyrolysis conditions), the studied plant production system (annual/perennial, grain, pasture, vegetable etc.) and the growth resources provided (soil type, fertilisation, nutrient availability, moisture, temperature etc.). Positive effects of biochar amendments on crop yields were often shown in nutrient impoverished soils, in particular in highly weathered and acid soils and other poor soils, such as sands.

Predominantly unsatisfacotry crop yield responses, the risk of reduced herbicide efficacy and a lack of opportunity to monetise increasing soil carbon levels through the use of biochar prevented farmers from applying the product. Essentially, there is a lack of demonstrated economic benefits for farmers using biochar. The Australian Bureau of Agricultural and Resource Economics and Sciences demanded that, if biochar has negative or even neutral effects on agricultural soils and systems, there may be no argument for its use, and if it is beneficial to agricultural production, its use must also be of economic benefit to farmers.

For further information see also:

Agricultural and Environmental Applications of Biochar: Advances and Barriers. Eds.: M. Guo, Z. He, and M. Uchimiya. SSSA Special Publication 63, 2015

and 

Standardized Product Definition and Product Testing Guidelines for Biochar That Is Used in Soil (developed and published by Int. Biochar Initiative, for certification in USA and Canada only)

 Interesting Dr Deka . I was trying to look through some of the developments that have taken place with regard to preparation of biochar over  conventional dry pyrolysis . Another very distinct improvement has taken place for biochar preparation . The method is called hydrothermal carbonization (HTC) , first developed by Frederick Bergius (1913).   HTC is a thermo-chemical process where organic matter is converted into carbon-rich products called hydrochar under high pressure settings. Distinctive conditions for HTC are high temperature varying from 180C to 250C, pressure ranging from 2 to 10 MPa and presence of water as reaction medium, with a recovery arte of upto 90%.  I am enclosing a pertinent PDF  for further reading . this review is worth reading  for all of us , I can assure you all.

Thank you Anoop for the inter sting question as usual. In spite of lab and short-term field studies, many research works have been conducted on biochar over the last decades. I think your question needs to be  interpreted very cautiously, because comparing biochar and manure in terms of immediate yield  benefits and improvement in soil fertility is quite different.

First, although nutrient content of manures varies based on sources, they are generally superior than biochar. However, the negative and positive aspects of the two amendments need to be seen from their long-term effects on soil quality, crop yield and carbon sequestration potential. Thus, manures are rich in terms of nutrients and can give immediate yield benefits. However, at present,  agriculture faces great challenges from the impacts of greenhouse gas emission and climate change. Emissions from the decomposition of soil applied manures, composts and  any organic wastes are among the causes of climate change. This is especially evident in tropical agricultural soils where the rate of decomposition of organic matter is faster.

 Second, since biochar derived from the pyrolysis of biomass is recalcitrant, it should be seen from the perspectives of carbon sequestration and soil amendment.  It can be sequestered in the soil for hundreds of years to millennia. As we discussed in our previous debates, the nutrient content and effect of biochar on soil properties and crop productivity depend on the feedstock type and the pyrolyzing temperature. For example, wood biochars are usually lower in nutrient contents than manures and crop residues, but higher in pH and thereby better in the amelioration of acid soils. Regarding  temperature, biochars produced at higher temperature are more inert and porous, but lower in biochar yield than biochars produced at relatively lower temperature.

Third, the effects of biochar are slower and longer-term than other organic amendments. For instance, according to some studies the yields of crops have significantly increased since the second year of application without  additional  biochar. That means the positive effects of biochar on soils, plant growth and yield are seen in the long term.

Fourth, the positive impacts of biochar on soils and crop yield are more indirect than instead of supplying nutrients to plants. To mention a few, improving soil physical properties such as bulk density and water holding capacity; soil chemical properties, such as improving soil pH, CEC, nutrient retention capacity and nutrient use efficiency; soil biological properties, such as creating favorable habitats for microorganisms. In the long term, improved nutrient retention may decrease the amount of inorganic fertilizer applied to soils, especially nitrogen.  

Fifth, biochar can be used as an additive or bulking agent for composting. Biochar hastens the composting process; reduce the amount of nitrogen loss as N2O emission during composting.  In addition, compost plus biochar mixture has shown promising results in terms of crop yield and reduction of greenhouse gas commissions.  Overall, considering the problems we have now both in agriculture and environment, biochar will have a promising potential as soil amendment and mitigating climate change. 

Fascinating response Johannes , highly informative in the context of subject , we are discussing , whose impact is so varied on soil  health and crop productivity . In a way , I endorse your comments that despite so much of focus on biochar production and its use, ground reality has not changed to any discernable limit . You can further correct me , if I am wrong , biochar whether it is produced through dry pyrolysis at high temperature or hydrothermal carbonization  as wet  pyrolysis at high pressure , is predominantly highly recalcitrant in nature , so resistant to any kind of decomposition ( Evident from soil residence time of biochar claimed to be more than thousand years or so  ) including biodegradation , means least susceptible to microbial decomposition , means biochar will not act as susbstrate for any kind of microbes , then where from nutrients like P,K,Ca, Mg , Zn come , unless they are from the biochar itself.  Hoping to get your another fascinating response Johannes.

While comparing the effectiveness of biochar verses organic manures, Dr Getachew, do you feel it is the surface charge density of humate/fulvate that contribute better towards effectiveness of organic manures compared to stable charged density of biochar .

Well said Getachew through an articulative response  and very cautiously replied in a most impressive manner , appreciate your response wholeheartedly . I agree with about the  short term  response  of organic manures in soil fertility changes vis-à-vis crop productivity , but such responses are not so upcoming through biochar , simply because of recalcitrant nature carbon present in biochar . And this is the reason biochar acts more like a conditioner in terms of offering carbon sequestration on long term basis. Yes , you are , this is one area , we have failed to put check on emission of greenhouse gases vis decomposition of organic manures and other fertilizer-induced emissions. Is there any environmental concerns still remain to be addressed at , as to why biochar adoption at field is still at the miniscule level ? Can you throw some light on these issues?

 Dr Srivastava,

the previous Australian government invested considerable funds to 'Fill the Research Gap' concerning the potential for reducing / mitigating agricultural GHG emissions. One of the focal areas was the use of organic soil amendments as a means of sequestering soil carbon. In this context, the CSIRO has assessed C stability / C degradation of about 100 organic soil amendments, comprising manures, composts, biosolids, biochars and plant residues. Clearly, biochar was the most recalcitrant product, showing 'weighted medium residence time (in sand) of around 75 years, while the other organic soil amendments showed 3 – 8 yrs. So, biochar is recalcitrant, but not inert. Small fractions of biochar also break down, possibly resulting in nutrient release in a small way. I am doubtful about release of N, and this is more claimed on improving N mineralisation from the soil pool.

However, I don't want to get lost in academic discussions regarding small details. The bottom line is that the use of biochar has to deliver economic returns to the farmer over the short or long-term, otherwise it will not have a future as organic soil amendment. This is not to say that biochar will not find applications in niche markets or specialist applications, which have yet to be established (at least here in Australia).

Johannes , you are perfectly right in your claim .  You have given some useful account work done at CSIRO, Australia .

Incidently , our current  research has to address the very  burning issue of carbon sequestration , and unfortunately none of the organic manures have displayed their promise in this regard .  On the other hand , organic manures on a short term basis have been able to register their response on soil health  as well  as crop performance , where a farmer can visualize such responses on filed. But looking at the resilience time of biochars in soil , they hold promise towards long term sequestering of carbon  , but their nutrient release pattern is so much expended over years  that crop responses probably will be going unnoticed to farmers. Could it be multiples inoculation  with AM-centric  multiple microbial inoculation   to impose some instability to recalcitrant nature of biochar carbon , thereby , incurring some visible  crop responses  , either on short term basis or on long term basis. Is there any study at CSIRO , Johannes , to suggest , how much minimum  turnover time in terms of years should be taken as a standard period of valid evaluation of biochar impact , either on soil  quality or   sustainability in crop response.  

What kind of quality parameters be used to define the quality of biochar from soil health point of view.

yes, it may be and irrespect to other factors depends on material to be used for biochar production.

Kudos to Dr Srivastava. The biochar revolutions is not the soil lution but a powerful new tool in the toolbox. The addressing of climate and environmental concerns is by nature multi phasic. Biochar is best used in an agricultural systems approach that focus on the end results the nature and production of the good earth. In the nutritional approach we need our complete nutrition to be provided and stressed.

Biochar is particularly useful in combination with more labile factions and looking to symbiosis of the biology through legumes and the role of mycorrhizae which employ synergisms that simplified approaches have not been as effective in doing over a long run. Our research and problem solving while needing experts with specialization also needs a broad systems approach utilizing long term systems evaluation and evolution. We have just some of the ingredients without the big picture in many cases.

Dr Hepperly, dont you think we need to utilise the potential for AM -trap crops like maize, wheat, sorghum etc. Do you feel legumes are better suited for AM-diversity or such crops will add more towards creating better labile pool of soil carbon.

Dear Anoop

I wish you find a little about your question in this research paper

best regards

Ali Alhayany

Dr Hepperly , another very useful feedback at your end. I do agree with you , biochar by the virtue of highly recalcitrant form of carbon , that is least exposed to microbial decomposition , has seriousinability to inflict any favorable effect eith on soil health or on plant performance , if you are looking for such responses in shorter terms. Integration some labile sources of carbon accredition would do some value addition to biochar through use of crops like legumes coupled with AMFs. At thesame time , i do agree with reamrks of Dr Deka as well , who favours about the use of AM-trap crops. More or less similar observations were made by Dr biala Johannes from CSIRO, Australia. We surely need to address about ways and means to shorten the resilience time of biochar in soil , if we have to harness the potential benefits of biochar on crop performance , besides addressing environmental issue of carbon sequestration., which isalways a long term  issue. 

Dear Dr. Anoop Kumar Srivastava,

Thank you for sharing your question. I don't have enough information about this issue but I am enthusiastic to know more about it.

Regards,

Mehdi

Thanks Dr Hani for some interesting links and your very pertinent observations on biochars. Creating niche for beneficial microbes through biochar, is how far feasible on a short term basis to benefit th rcrops ? Presence of such a stable form of carbon will not be facilitating to microbes , since carbon supplied through biochar will not be available to those demnding microbes of the soil ? I will appreciate your feedback on these issues.

/

Dr. Hani and other colleagues, How would you distinguish between good quality biochar and bad quality biochar.

Sikha's question looks useful regarding the quality parameters of biochar. First, as it has repeatedly  been explained the quality of biochar relies on the feedstock type and pyrolyzing temperature. These two production factors greatly affect both the quality and yield of biochar. 

Second, both physical and chemical parameters may be used to characterize the quality of biochars. For example, density, as content, porosity water holding capacity of biochars can be taken as physical parameters. Organic carbon content, pH, plant nutrient content, nutrient retention capacity and stability in the soil can be use to characterize the quality of biochars. In addition, the concentration of heavy metals and other toxic substances are indicators of quality of biochars. I think if search for the document for biochar standards developed by the International Biochar Initiative, you may get sufficient information.

Thanks Dr Getachew. How do  we observe the completion of pyrolysis process. Is there any parameter used to decide the end point of pyrolysis something like compost maturity?

Thank you Sikha! As you know there are traditional and improved or automated biochar production methods, For example, using earth kiln,  the kiln is fired and the biomass is heated up to allow pyrolysis for several days or weeks depending on the feedstock and size of the earth kiln. While in containerized automated batch pyrolysis plant (Charmaker MPP20), pyrolysis of whole logs at up to 5 ton per load may take 5-7 hours with the heating temperature of 550oC. Therefore, the time required to accomplish one load of pyrolyis depends on the type and size of the pyrolysis plant. There are also small-size prototype pyrolysis equipment that may char a biomass from half to an hour. 

The question now is the type and size of affordable equipment that can be used at farm scale for subsistence farmers. For example a stove type that can be used both for cooking and at the same time production of biochar with restricted oxygen would be preferable. Hopefully, this will be realized. In fact,  research is going on in this regard.  

Manures provide benefits to soils beyond those attributable to the nutrients they contain because the manures provide food (energy) to the soil organisms. Because biochar is resistant to degradation in the soil environment, and therefore does not provide a source of energy to the soil food web, I do not think it is a promising alternative.

Many experiments where biochar is applied alone have demonstrated a negative impact on plant growth while the combination of biochar with organic or inorganic fertilisers seems to result in a positive effect. This is probably due to the greater nutrient retention rather then a greater nutrient supply.

Yes, biochar alone is not an alternative option to increase and sustain crop yield, but its integration with inorganic organic fertilizers may enhance soil biophysical and chemical properties, and crop yield while mitigating climate change through carbon sequestration in soils. 

 Thanks so much Getachew  for excellent feedbacks , so appreciative of you . you have surely steered the discussion to some logical conclusions. The whole discussion  has to be viewed , what Tom has suggested , improve the biochar efficiency along with some organic manures ,   so that such source is utilized by the microbes to release the assimilable nutrients available to crops .  This is enable the whole dynamics of cabon/nutrient release on different kinetics , thereby , keeping microbes active for much extended period. This is how , we will be able to expand the horizon of effectiveness of biochar on both short term and long terms basis , the other day what Johannes was talking . In this  context , let us not forget the points raised by Dr Hepperly to include legume  crops along side AMF -centric microbes. If there are any other way to improve the efficacy of biochar , please suggest   .

What is your opinion friends, if biochar is applied along with chemical fertilizers, what kind of it holds under any cropping sequence ?

manures are quite Carbon labile, compost much less and biochar is a long term decomposition. These can be blended. I use a 20 to 80 vermi manure, leaf compost mixture to get season long result. Vermicompost which is worm manure can be effectively used as an organic starter amendment compost for peak season into maturity and biochar for year to year build up. 20 70 10 vermimanure, leaf compost and biochar might optimum all these results in an appropriate rate. It has the advantage of being able to be strategically applied directed to where it is needed without phytotoxicity concern.

Dr Getachew and other colleagues, I am yet to get the answer about the biochar maturity indices to be used to identify the process of completion of pyrolysis.

Thats a very good point Dr Hepperly to use the combination of vermicopost plus leaf manure in combination with biochar to not only improve the efficiency of biochar , but to ensure the short term crop response of organic manures. Such combination will take care of engineering rhizosphere soil with non-labile ( Passive carbon pool) stock of carbon . I invite the comments from Getachew , Johannes, Hani  and other colleagues in this regard.

prof, biochar is very helpful in elevating yield of crops. I went through one of my friend publications which i want to share it here. He also worked on biochar in his doctorate studies.

Dr Srivastava et al,

first my response re CSIRO work on degradation / stability of organic soil amendments. It seems, it has not yet been published, but I do have the final project report, and I can send that to your email address Dr Sirvastava. The main investigator was Dr Mark Farrell, CSIRO, if you want to see when the results will be published.

 As I said before, the previous Australian Government invested heavily into research to reduce and mitigate agricultural GHG emissions. National programs focused for example on soil carbon (http://www.agriculture.gov.au/ag-farm-food/climatechange/carbonfarmingfutures/ftrg/soil-carbon-research-theme-projects) and another on N2O emissions (http://www.n2o.net.au/). A presentation by Mark Farrell (http://www.awri.com.au/wp-content/uploads/2014/08/CSIRO-Farrell.pdf) provides a glimpse of the soil carbon work and some results of the work they did with organic soil amendments. Their incubations showed that biochar is very stable (we also agree on that). However, surprisingly, they found that composts (and there are of course also many different types) are not necessarily more stable than manures. In fact, their results suggest that stability of manures (CO2 evolution) is much more predictable than that of composts.

Of course there are many ways of increasing soil carbon levels, one of which is use of organic soil amendments such as biochar, manure, biosolids, etc., but there are also other ones such as mulching, green manure crops, different soil cultivation,  etc. As indicated by Dr Hepperly, it is clear that, when considering ways of improving soil fertility, soil properties, crop yields and soil carbon levels, we need to consider the entire farming system, including the available resources and constraints. I think the sole focus on 'using biochar for increasing stable soil carbon levels' is not necessarily resulting in the best outcomes. In this context I also think that, rather than focusing on recalcitrant carbon, we need to think more in terms of soil organic matter or humus and indeed the whole soil system, as this incorporates everything we have been discussing: stable organic compounds, labile organics compounds, energy for soil microbial processes, mineralisation and nutrient release, soil physical, chemical and biological properties.  

http://www.agriculture.gov.au/ag-farm-food/climatechange/carbonfarmingfutures/ftrg/soil-carbon-research-theme-projects

http://www.n2o.net.au/

http://www.awri.com.au/wp-content/uploads/2014/08/CSIRO-Farrell.pdf

Excellent feedbacks Dr  Biala , worth appreciating. You have provided the whole discussion , the necessary feedbacks on various issues , with the result , all of us are benefitted with current state of affairs on the subject. I do agree   with Dr Happerly  , Getachew as well , concentatrting the entire issue,  more at the production system level than exclusively concentarting on building up labile/non-labile carbon through uni-directional flow of carbon vis-a-vis  nutrients to crops.on a given soil type. Unfortunately , this is what , we have been exactly doing in a farming system mode , but utterly failing at times , in not only sustainain the desired productivity level , off-site movement of nutrients/energy also became the  major point of concern , in addition to  , contentment of GHG emissions.So the production sytem weakened with each crop cycle , and a time came where the given good agricultural practices under an established cropping sequence  failed to produce the same spatial and temporal stability in productivit, besides serving ecologically in terms of either checking  loss on non-labile fraction of soil carbon stock or exploiting the active/labile carbon fraction of soil ,much to the benefit  of the crop. How does exactly , long term evaluation  of any production system function and evaluation criteria used for their effectiveness/sustainability ?

Some of the crops have failed  to respond to biochar application. What could be the reasons?

The main function of biochar is to prevent nutrients being lost in soils unable to do it because of lack of clay and/or organic matter, more generally tropical soils in rainy mossoon or equatorial climates. Biochar application must be complemented with a source of nutrients, for instance nutrient-rich waste organic products. Manioc peels (rich in phosphorus) have been successfully used in complement to charcoal addition. See https://www.researchgate.net/publication/44922021

Article Manioc peel and charcoal: a potential organic amendment for ...

Jean-Francois , you very right , such failures of biochars on tropical soils is very common  . soils because of lower CEC , multiple soil fertility constraints and lower organic matter content , act as triggering factor for lower input -use -efficiency  . And , biochar application if sustained for few years , will bring such favorable changes where  the magnitude of crop response could be easily expanded. This is where ,biochar along with some microbes , manures/compost as starter assimilable form of carbon for indigenous soil microbes ,  could come very handy , in addition to crop residues.

I fully agree with you, biochar may start a process of soil melioration...

Dr. Anoop, both positive and negative results have been reported on biochar. However, most of the research works carried out under field condition in tropical soils had positive effects on soil biophysical and chemical properties and crop performance. Because the origin as Tera Preta and success story of biochar is in tropical soils. However, it should be clear that biochar can increase the efficiency of fertilizer through its physical and chemical properties, but can not totally replace fertilizer.  But in the long-term with the build of soil organic carbon the amount of fertilizer applied can be reduced.  In contrast, the effects of biochar in temperate soils were little or negligible. The problem with biochar is that despite several researches have been conducted most are, peace meal, short-term and greenhouse trials. So, researches that cover multi-locations covering different soil types for  three to five years  is required before final conclusions.

It is obvious that application of composts and manures have positive effects on soil fertility, agronomic use efficiency of nutrients and crop productivity. But  accelerated mineralization is a limitation to the practical application of organic fertilizers under tropical conditions, and only a small portion of them are stabilized in the soil in the long term, with most released back to the atmosphere as CO2.  Repeated application organic materials at high dose is also required. So, these limitations make biochar preferable both as soil amendment and mitigating climate change through the reduction of greenhouse gases emissions.

Jean-Francois , Johannes, Paul , Getachew and my other learned colleagues  . while using biochar ( off course , initially used as soil conditioner , but gradually , it starts its multiple effects on soil nutrient and microbial pool with time lapse) ,  what kind of soil fertility evaluation is to be carried while evaluating the soil fertility benefits in a soil treated with biochar? . Or it is just the conventional  parameters?

That's very much true Dr Getachew . Other day , same thing , Dr Biala was stressing , our major concern is , how to obtain short term benefits to crop ?. What could be the viable strategies to ensure sustained response on soil and crop health coupled with productivity ? Dr Hepperly added very good response in this regard . But , with regard to role biochar in mitigating the emission of GHG is  so much pronounced , besides providing an  effective alternative of efficient farm residue management .

Is there any effect of type of fertilization history on the responsiveness of biochar in addition to effect of soil type and climate ?

My background is very much applied R&D, and as you all know, if, whatever the innovation or new technology might be, if it does not provide adequate economic or other benefits to the decision maker, in our case the farmer, the innovation will not be adopted and become mainstream technology or common practice. And that is precisely where the use of biochar fails, at least here in Australia. I do not know what the current or anticipated price for biochar is in tropical areas, but here in Australia current prices are $150 to $1,100 per tonne for lower grade / naked products and between $900 and $2,200 per tonne for high grade or activated biochar. The high price combined with uncertain benefits is the main reason why biochar use did not achieve broader uptake. If farmers do not see a short or longer-term benefit, or if they can't afford to wait for the long-term benefits, there is no way use of biochar will be taken up by farmers (the lack of short-term economic viability for many environmentally sensible changes in farming (and other industrial production systems) is a major concern all round). While I agree with the general notion about the concern of GHG emissions and climate change, it is certainly unwarranted to expect farmers to 'pay for GHG mitigation' by using economically unviable biochar to sequester soil carbon, while the majority of society and industry is unwilling to pay for any of that, and is allowed to 'pollute' in business as usual (this refers to the situation in Australia, it might be different elsewhere).

Sorry to broaden the issue and to digress somewhat from the original question, but I think we as researchers really have to take a broad perspective, and come up with solutions that are viable for farmers to implement, i.e. if we advocate the use of biochar, or any other changes to existing farming systems, we have to demonstrate to farmers that it provides tangible benefits to them. This has yet to be demonstrated for using biochar. Nothing much will change on the ground until this happens.

Surely. Bt there is a need to search economic profit before conclude definitively!

Increase in amount amount of biochar suppresses the growth of crops due to increasing carbon, But up to 4.5 tons per Hector may be ok. I will send you some information later. 

Hi Annop, I understood your worries the adoption of biochar by farmers will increase if it has immediate benefit to farmers. That is true in subsistence oriented farmers. But  the fertilizer-seed system has been effective since the green revolution for the last half a century with the current climate change scenario meeting the food and industrial needs of the growing population appears challenging with the status quo. 

Biochar research is being diversified: A lot has been done soils and crops responses to biochar.  Now in addition to biochar alone research has been going on biochar plus compost mixture and co-composted biochar-compost to compare with biochar and compost. And results are promising in impoverished soils of tropical agricultural soils. So using biochar as a bulking agent during composting or mixing with compost on site during field application biochar could be profitable in terms of crop yield and climate change mitigation. 

My concern is a bit different from yours. Biochar can be produced from crop residues, wood or wood byproducts, manures, digestate and organic sources. But  although significant quantities of manures and crop residues are produced in the world as potential feedstock for biochar and compost production, they are not returned to soil due to competing utilization in many developing countries. For instance, crop residues are major sources of livestock feed and source of cash income. Manures are used as a source of fuel. If the limitations in this regard are solved the adoption of biochar by smallholder farmers may be increased.

Kindomihou , I agree with you , there is a need to have economics of response before response of biochar is to conclusively propagated. I feel very strongly , enough field studies, pot studies , column studies have been conducted  with regard to magnitude of crop response on yield , changes in  soil properties , reduction of GHG gases . Shamim , there is a huge variation in dose of recommendation of biochar application . It ranges from 0.45 t/ha  on Entisols to as high as 40t/ha on Alfisols/Ultisols ( highly ac idic soils ) , irrespective of pot , or field studies, with  varying  yield responses, maximum  yield increase upto 40% and maximum reduction in GHG emission  upto 61% . I am enclosing one excellent PDF , a review on biochar which has  so explicitly portrayed information globally , worth reading .

Dr Srivastava, do you feel biochar could play an additional role in improving use efficiency of applied nutrients.

Yes very much Dr Deka , this is what we have been stressing so heavily , instead of expecting biochar to a nutrient source , lets consider it more like a soil conditioner , let it impact soil physical properties to influence later the soil chemical properties including soil fertility and microbial load as well  , in  addition to contentment on emission of GHG .

Dr Biala , I do agree with your comments that  some kind inconsistencies associated  with  varied responses accrued from biochar  application across different soil sites and crops as well. And , above all , farmers are not willing to add any additional price for securing carbon credits of their farm . Probably , our agriculture  has to look into these issues sooner or later through some kind act enforcement , something like act for land uses , act for nursery plant production etc... 

Let me respond to comments of Dr Getachew , which is so informative . I agree with your comments , but this si the exact scenario of small holding farmers , he has to meet both ends. but , my major point of concern is , how make biochar responsive as early as possible , so that crop responses   are visible within shortest possible time , instead of long gestation period . We could use some starter manure rich in microbial count , legume crops to leave their residues on filed , starter chemical fertilizers , thereby ,, active pool of nutrient and microbes both get energised   , and side by side let the soils  sequester carbon in passive pool. I agree with you ely about the  necessity of  expanding the objectives  of biochar research .  

Thank you Mr Srivastava for this link.

Now, I clarified the ambiguity that I had at the begining

Thank you so much

Why the dose of biochar in most of the studies is so high compared alkaline soils?

Biochar acts as a sponge to soak up nutrients like nitrogen and potassium, so if you are not applying manures or some other concentrated form of nutrients at the same time as the biochar, it will soak up the nutrients already in the soil to the detriment of the crops you are growing and store it and release it over a long period of time.  So every time you apply  biochar, you must always add N-P-K that will be soaked up by the biochar, instead of the biochar robbing it from your already existing soil nutrient-bank.

Biochar is actually interesting alternative fuel.

It's performance values (factors) are still analyzing with research challenges..

I just share good UK studies and link.

http://etheses.whiterose.ac.uk/8439/1/Assessing%20the%20potential%20of%20biochar%20from%20crop%20residues%20to%20sequester%20CO2_Scenarios%20to%202100.pdf

http://www.srdg.co.uk/homes/sshackle/CostsBiochar.pdf

http://www.biochar-interreg4b.eu/images/file/WP31%20-%20Biochar%20deployment%20scenario.pdf

http://permaculturenews.org/2010/11/18/beware-the-biochar-initiative/

I would like to share you our greenhouse and field studies on biochar, compost, biochar plus compost and co-composted biochar-compost, and their interaction with nitrogen fertilizer under field condition. As Dr. Annop said we need more field studies in different agro-ecologies and soil types.

To estimate the economic benefits of biochar we have to consider the carbon offset from the atmosphere through carbon sequestration.

Thanks  so much Aung  for some scintillating information on biochar , both so informative as well as so analytical about the application of biocahar . I am picking up some excerpts from article of Prof Mae-Wan Ho(http://Permaculturenews.org/2010/11/18/beware-the-biochar-initiative/

Beware the Biochar Initiative - The Permaculture Research Institute) who interpretes ,  It is clear that biochar has not lived up to its promises as a stable C repository or enhancer of crop yields. On the other hand, the risk of oxygen depletion is real . Biochar itself is an oxygen sink in the course of degrading in the soil ; adding to the depletion of oxygen that cannot be regenerated because trees have been turned into biochar for burial. And worse, as in the biofuels boom that has already apparently speeded up deforestation and oxygen depletion since 2003  if biochar is promoted under the Clean Development Mechanism, it will almost certainly further accelerate deforestation and destruction of other natural ecosystems (identified as ‘spare land’) for planting biochar feedstock, and swing the oxygen downtrend that much closer towards mass extinction.

This is how , the debate goes on and on .... friends submitted for your further comments. Thanks once again Aung ....

Thanks Dr Getachew for enclosing some interesting piece of work as PDFs . I have gone through all of them .They very classical publications.These publications also offer us the clues about the further value addition of biochar in the persuit of shortening the time lag to get the crop response at farmers levels. these work s , for sure , will go a long way in understanding the interaction between f biochar-compost -chemical fertilizers vis-à-vis crop response in variety of soils having variety of  fertility constraints .This is another  brighter view of biochar  application , friends . 

What is microbial load of biochars obtained from different feeds, especially the thermophilic microbs.

I do not think Dr Deka  , biochar would ever act as carrier of microbes , much unlike composts having some indigenous microbial load , since temperature of pyrolysis will leave hardly any microorganisms to survive  live?

 Dr Getachew and other colleagues. Instead of converting bioenergy rich plant feedstocks, why not to concentrate more on the production of biochars from sewage sludge and biosolids as one promising option for disposal of sewage as a part of Biochar Production and Utilization Systems.

Dear Sikha Deka

You suggestion of using sewage sludge and biosolids for biochar has an Achilles heal.

Since our residential and industrial sewage systems are interconnected and increasing people are using residential toilets for discarding pharmaceuticals and in appropriate substances of various and sudry types the biosolids are heavily contaminated with heavy metals.

Milorganite is a biosolid material from Milwaukee Wisconsin the product as a label not to be used on food crops based on the high heavy metals from the mixed waste stream.

Biochar will not reduce heavy metal content and it the pH is inappropriate toxicity issues can result.

It is painful to see so many issues related to synthetic pollutants but this is our lamentable current reality.

This type of situation gives me support of chains of responsibility and custody to avoid contaminants proliferating in the environment.

Green wastes and wood by products are good potential biochar candidates which avoid the sanitary mixture issues.

Thank you for your contributions and keen insights. I enjoy your participations.

Well said Dr Hepperly , pollutants in terms of heavy metals toxicity is the major cause of concern with regard to developing biochar from sewage waste /sludge. Is there any possibility of scavenging these heavy metals through use of plant  bio-accumulators or filtering these un-wanted metals through microbial inoculation involving AM-centric microbes coupled with green manure crops providing ample quantity of decomposable carbon ?   Let me acknowledge your logical power   power of  scientific  arguments , so informative and provocative as well.

Dear friends : I was searching some  worth reading material about the environmental risk management  using biochar  as a policy paper, besides one thesis on similar issue by Adriana ( I find it very informative ) . Here  are they   enclosed as a PDFs  for your further reading . Hope , you find them  useful.

Dear friends, kindly let us debate on the possibility of developing biochar from solid wate including sewage sludge since huge quality of bio-solid is annually produced provided the issue of pollutants is addressed. 

Friends , I do agree , biosolids do offer a vast potential scope for biochar production , provided we are able to ward off the increase in concentration of heavy metals ( Hg, Pb, As, Cr, etc) , as pointed out by Dr  Hepperly , Getachew , Joahannes and othe r colleagues. There is an increase in concentration of metals like Fe, Mn, Cu , Zn with increasing temperature of pyrolysis , fine , since these nutrients are considered essential nutrients for most of the crops. Is there any data generated about the leaching test of biosolids-based biochar compared to green waste -based biochar  to have first hand information on such an important issue.

Let me cite a study by Evita eta l ( DOI: 10.10.1016/j.jaap.2013.02.010).  Sewage sludge was pyrolyzed in order to assess the effect of pyrolysis temperature, residence time and biomass chemical impregnation on the yield of biochar production. The pyrolysis temperature was a key factor affecting biochar yield, while the highest yield was obtained at a temperature of 300 °C. Biochar surface area increased with increasing pyrolysis temperature and was maximized (90 m2/g) by impregnating biochar with K2CO3. Raw sewage sludge, as well as biochar samples, were subjected to leaching tests in order to investigate the potential release of heavy metals. Pyrolysis suppressed heavy metal release for the non-impregnated biochars, indicating that there is no environmental risk using sludge-derived biochars as soil amendments. Although K2CO3 and H3PO4 impregnation enhanced the solubility of specific heavy metals, the concentrations in the leachates were low. Biochar impregnated with K2CO3 released 85.7% of its potassium content, whereas orthophosphates were bound strongly in the biochar matrix impregnated with H3PO4. The non impregnated biochar was subjected to batch kinetic experiments in order to examine its ability to adsorb As(V) and Cr(III). Biochar removed approximately 70% of Cr(III) at equilibrium time, whereas only 30% of As(V) was adsorbed onto biochar surface, implying that biochar is more efficient in removing cations than anions from aqueous solutions.

Don't you feel , the efforts such as this ( though many more are available ) would really break a way for scavenging the environment  through benign solid waste management .

Very good explanations and information have been added by Dr. Anoop Kumar, I agree.

Hello Colleagues,

I do appreciate for sharing the valuable of experience of Prof. Dr. Anoop Kumar.

Regards,

Thanks so much Dr Nazir and Dr Aung for nice words and appreciating the kind of discussion , we are currently engaged in .

The very purpose of floating some discussion on sewage sludge ( since we discussed at length about the possibility of biochar preparation , its effect on short as well as long term  was  discussed and many other related  issues) was to explore any possibility of developing a value added product from a shear waste  adding to deterioration in soil and water bodies as a major concern for disposal. and , interestingly , irrespective of feedstock source , recovery nutrients like Al, Fe, K, Na, Mg is hardly affected with increasing temperature of pyrolysis, with an exception Si and N which usually reduce as result of pyrolysis. But , there is no doubt , about the presence of  pollutants , which also increase in their concentration upon pyrolysis . We are , therefore , inviting more discussion on this very important issue . Thanks friends for keeping the discussion so live and so educative for so long ....

Very interesting discussion Dr Srivastava. Do you feel that temperature of pyrolysis will influence the specific area of biochar particles obtained from plant origin feed stock verses sewage sludge.

Dr Shirgure , thanks for your response. Let me respond to your querry, which is good one : 

 An excellent study carried out by Zielinska eta l (2015) who studied , how the initial sewage sludge properties affect the characteristics and composition of sewage sludge-based biochars. Sewage sludges of varying organic matter content were pyrolyzed at temperatures of 500, 600 and 700 °C. The obtained materials were characterized in terms of their composition and physico-chemical as well as their surface and thermal properties. With increasing treatment temperature, the pH, ash content and macro- and micronutrient content increased. The biochar aromaticity also increased. On the other hand, the pyrolysis yield, percentages of H, N and O, molar ratios, polarity of biochars, and crystallite size decreased. The direction of the changes in the content of elemental carbon (C) and in surface area was dependent on the type of sewage sludge. It was found that for some properties of biochars produced could be determined on the basis of an analysis of the properties of the initial sewage sludge (doi: 10.1016/j.jaap.2015.01.025).

Excerpts of another study ( Liu at al. 2014, Pol.J.Environ.Stud. 23:271-275) :The pyrolytic conversion of sewage sludge to biochar and then applied to the land is a sustainable management potion. Therefore, the aim of this work is to evaluate the characteristics of nutrients and heavy metals in biochar from sewage sludge pyrolysis, and pot experiments were carried out with different treatments consisting of infertile and contaminated soils. The results showed that the content of major plant nutrients (N, P, K) in sewage sludge biochar meets agricultural requirements. The concentrations of heavy metals (Cu, Pb, Zn, Cd, and Cr) were evidently increased in biochar, but those of available heavy metals were decreased. The sewage sludge biochar can improve soil fertility and enhance plant growth while not increasing plant uptake of heavy metals, and remedied contaminated soil by

reducing the plant availability of heavy metals ( PDF enclosed ).

Hope , these responses give you some precious clues about the physic-chemical composition of biochars obtained from sewage sludge.

Hello Prof. Dr. Anoop Kumar,

Thank you so much for your valuable share regarding the precious clues about the physic-chemical composition of Biochars obtained from sewage sludge.

Regards,

Prof, Dr. Anoop Kumar,

the recent studies you mentioned are very valuable and worth sharing. Thank you for sharing. The discussions are specially very helpful for me as i have gain much knowledge from it.

Yes Husain, I agree with you. The current discussion on biochar is worth reading. Thanks Dr Srivastava for raising such issue of so huge importance.

Thanks so much friends  for appreciating . Its all , because you all participated and exchanged your valuable experiences , eventually such a discussion helped each and everyone of us , I guess.

If any one of you ,  still feel , something is still missing from the discussion , you can float your quarry. I still feel , there are certain other issues remain to be touched upon .

No Bichar cannot be alternative for farmyard manure

That's good Dr Patil . Can you supplement your response further with some statements for the benefit of all of us. Hope , your response will  set the whole discussion on a fresh note.

Yes, Dr. Pati, if you compare biochar with farmyard manure it cannot be viable alternative in the short-term, you are right. However, if you look at the benefits of biochar in terms of soil quality improvement, resilience and sustainable crop production while mitigating climate change through carbon sequestration the merits of biochar are enormous.

For example, look the limitations of manures and other organic sources under the current rising temperature and hot tropical climates - their decomposition is faster and loss of the major nutrient source (nitrogen) is very high. According to previous works the carryover effect of manures may not be more than one season after the first application in such climates. I think as we have thoroughly discussed in this forum, there are a number of issues that need to be solved through research and policy issues that should be considered in the current face of climate change to make biochar and biochar + compost mixtures viable to farmers and to our planet - the earth.

Dr  Agegenehu, I agree with you. We need to find some short term as well as long term alternative to organic manures  since organic manures effect hardly lasts for than one season. In this context, we should not see role of organic manures only as a nutrient source. It has to be seen much beyond it.

If you compare biochar with organic manure like FYM, on a short term basis, FYM will outsmart biochar and reverse will be common when you evaluate on long term basis.

I agree with Dr Getachew , with the kind of analytical overview of the issue  , he has provided. Time has come to look into the such issue with a short term gain , but keep a vigilant eye on long term basis. The issue of climate change  , which  we are now debating every now and then , do you feel , is the outcome of few years ?   . Every problem relating agriculture eventually comes on the climate change ?.  Please give a thoughtful  look at our agricultural practices, to what an extent , they are  responsible for  emission of GHGs ? . This is where , the concept like biochar has to intervene.  

Friends , in the light on on-going discussion ,  I thought , let me share with you a document , which analyses the state of biochar industry . I am taking out the key findings from the same document(PDF enclosed ) to let you know an overview of expending horizons of biochars with an view on filed studies.

• In 2013, the biochar industry is in a fledgling state, comprised largely of

enterprises selling relatively small volumes of biochar products locally for end uses such as gardening and tree care. Biochar has yet to make a substantial entry into large-scale agricultural operations.

• Unblended biochar and biochar products blended with other materials are being

sold in many countries at a wide range of retail prices ranging from $0.08 to $13.48 per kilogram. The average price reported was $2.48 per kilogram.

• Companies reported volumes of biochar sales totaling 827 metric tons. 90% of

those transactions were made by businesses in North America and Europe with the remainder made in Asia and Africa.

• Woody biomass is by far the largest source of feedstock for the biochar industry.

Globally, the forestry and wood products sector offers a widely accessible source of woody residues that are often centrally located for ease of collection and

transportation.

• The scales and types of biochar production technologies being developed and

marketed range widely—from micro-scale cookstoves to large-scale industrial

facilities. This diversity in technologies, and other characteristics like feedstocks and end uses, may be characteristic of an industry at an early stage of development and experimentation.

• The main barriers to industry expansion are a lack of consumer awareness,

technological constraints, and access to financing. It is not yet possible to predict

the yield gains from biochar in a way that would allow proposed applications to be

valued. Education of stakeholders—from farmers to regulators to lenders—is key to expanding the industry.

• Scientific research into the various facets of biochar continues to expand rapidly.

The number of peer-reviewed biochar-related publications increased nearly

five-fold over the last five years with over 380 papers published in 2013.

Hope , you will like this information to motivate you better on biochars.

That's right, Prof. Dr. Anoop Kumar, I have same opinion with you.

Actually, Biochars is very interesting fuel with the barriers regarding awareness, financial and technical constraints.

I think it will be proven technology in the near future.

Dear all,

I think the original question, i.e whether biochar can be an alternative to organic manures, has lead us astray. The question we should rather try to answer is: What is the best way for biochar and organic manures to complement each other.

The State of Biochar report  states that woody biomass is the main feedstock for biochar - and so it should be if we primarily want high stable C products. So, there is little or no competition between manures and biochar.

The State of Biochar report does not fully acknowledge teh barrier price plays. At an average price of $2.48 / kg for biochar, a farmer has to pay almost $2,500 per tonne and say $12,500 if he applies 5 t/ha. This is a huge expense if the benefit is unclear. How much manure could the farmer buy for that amount of money?

Dr Biala , whichever you try to respond , we have debated this issue also at length. How can we improve the efficacy of biochar ?.  Dr Hepperly , Dr Getachew  , and others have discussed the isssue through their work by combining the biochar with some compost or alternatively with freen manure crops,  in order to build up two different  tiers of  crop  response , one at short term and another at long term. And accrued data have ably established this fact.

On the other hand , escalating cost  of biochar in terms of  its  quantum  that is usually applied annually  in a field , has always discouraged  farmers to experiment biochar on a large scale . But , the kind of analysis, Dr Getachew  and others have provided , seems quite encouraging futuristically. Off course , there are dictinct barriers , they need to be addressed. And , how it is to be addressed, lets discuss here , so that our colleagues get the full package on biochar.