The term "Biochar" is a recent adoption and the definition is emerging based on the usage. The term Terra Preta was a culture, like Agri-culture. The terra preta culture as a major practice as in Amazon itself was lost and being discovered in fragments in several parts of the world where Agriculture practice had been very old. Even in India there are still ongoing practices, where charcoal usage for improving the condition of soils as one of the amendments still exists. The term Biochar, for both micro and macro solutions in the context of soil management, carbon sequestration and + + has come into prominence in the recent past. Biochar is considered by some a an immediate solution, where as Terra Preta is a cultural practice and is long term solution. The common elements like soil microbes, pottery shards, bones, urine, mulch, compost etc are replaced by non-disclosed elements plus charcoal as a commercial product in the form of "Biochar" Products under different names (so more confusion about names). For Biochar to become a culture like Terra Preta is more difficult in the present world, unless we evolve practices adaptable to the present conditions. At GEO the term Biochar is used more liberal with prefix, suffix to define the purpose often.
Biochar - Charcoal produced at a temperature less than 700 degrees centigrade from Biomass and which is used for common good.
Biochar Mulch - When charcoal is used as mulch for plants
Biochar compost - Charcoal + compost, soil microbes, jaggery, green mulch etc, treated for 15 days under moisture conditions.
Biochar urine - Charcoal used for collection of human / cattle / livestock urine
Biochar Bricks - Cement + sand + charcoal used for making bricks used in construction, presently being used at our Research Center
Biochar cleaning - waterless cleaning of the plates after eating
Biochar tooth powder - Traditionally using the wood charcoal / cowdung charcoal for cleaning teeth
Biochar versus Terra Preta
Biomass from exotic and invasive species of plants, crop residue and energy plantations are the various sources. Agriculture biomass available in India is about 800 million tons. Of the total biomass produced from Agriculture at least 20 to 30 % of biomass is wasted. Burning crop residue in the respective fields is a common phenomenon as preparatory measure of fields before monsoon rains and otherwise too. The percentage of crop residue burnt varies from place to place and it is based on the type of crop chosen. From the following major crops in India the quantity of crop residue is as follows (in million tones): Rice (13.1), Wheat (15.4), Sugar(21.6), G.Nut (3.3), Mustard (4.5), Cotton (11.8), Total 69.9 million tones crop residue from the above six major crops. The crop residue is mostly converted into compost or when burnt controlled mostly turns into ash. Ash has its value especially in the acidic soils and for the phosphorous, etc. Considering the value of Biochar especially in the poor, degraded soils, there is a need for designing technologies. The crop residue say cotton plants is hard and could yield good biochar, but handling it and conversion into biochar is a labor intensive / energy consuming process, the energy produced during the process should be used for some practical useful applications too. We see majority of the farmers in our area are just burning in their fields, similarly many other crop residues. One of the emerging areas is agriculture biomass based thermal power plants, this industry only generates ash as a byproduct, majority of such power plants have also accessed CDM funds. The crops being grown recently (improved, HYV, etc.) has less biomass as compared to the traditional crops. The overall biomass percentage from crop residue is diminishing over years. The simplest solutions could be adopted by the farmers, if created awareness on a large scale is
1. Crop residue could be thrown into a trench or a ditch existing near the field or created for the purpose, burn the crop residue, throw more biomass into the burning fire, till the heap reduces in size, through soil or if available water or atleast use fresh leaf bushes to extinguish the fire, (safety of the farmer is important, the farmer should take the necessary measures), within 24 hours some biochar would be available. The time, temperature, air, humidity, etc conditions are important before doing this. Most often farmers also like and would be interested to do this kind of work in the evenings and into the night. This system could be fine tuned through improvements so that least amount of pollution happens through this process.
2. In the gardens and small scale biomass conversion into biochar, I have designed two simple systems based on TLUD and Downdraft principles, using locally available empty tins / drums.
3. The TLUD stoves as described by Paal, would add value in the long run, the biochar yield is not enough to meet the present requirements, especially for carbon sequestration, but energy point of view, a very good efficient technology. Under Magh series, we have designed more than 25 TLUD stove designs including natural draft and forced air, all the declared as Open Knowledge http://goodstove.com
Biochar Applications and crop response
The yield of various crops and biomass growth is positive in majority of cases. If all the soil nutrients are available in plenty and the soil condition is healthy, the variation between biochar and control plot is very less. The difference is high in less fertile and degraded soils. Biochar is good for all types of soils, because the fertility of soils is defined in time and space varies, based on human and natural conditions. The air, water and the nutrients, plus the soil microbes thriving in the space created within the soil through biochar, useful for plants and the environment. 1 kg to 3 kgs of biochar application for every 1 square meter field area is the emerging good application result for our area, the compost and other nutrients should be added to the field, as done regularly to any field as per the crop. Initially the Nitrogen should be added more (1.5 to 2 times) than what is applied regularly, green mulch / composts / farm yard manures etc., are most preferable.
Airborne black carbon from Biochar production and application
Black carbon entering into atmosphere from various sources including during biochar production, application and from wind erosion would have impacts more serious than CO2 itself. In this regard precautions should be taken at the time of production and application, as these are point source controls, it is possible to control to some extent. After application of biochar in the field how it control it from reaching into the atmosphere through wind erosion? There is an argument, whether biochar should be applied in fine powder form or in lumps. If we apply biochar in fine powder form there are some immediate benefits as it would spread on a larger area, but during processing (preparing into fine powder of biochar from lumps), application process and after application the chance of this biochar reaching the atmosphere in the form of Black Carbon is more. Moreover a very small piece of biochar would create an environment within and around it which is more vulnerable as compared to the environment created within and around a large lump of biochar. It is difficult for a lump of biochar to be airborne. The soil can easily hold a lump of biochar and prevent it from erosion by natural forces. In the future over hundreds of years due to human and natural factors the lumps would reduce into small pieces. Rather having desired results immediately considering the impacts of airborne black carbon, on can always choose to apply lumps of biochar rather than fine biochar powder to the soils as an amendment.
Biochar compost Application
Point - eg. Horticulture
Spread - eg. Paddy
Biochar compost preparation practice
Biochar + compost + green mulch + soil microbes + (pottery shards / fish bones / brick pieces / etc.)
Biochar only application
Point - Biochar mulching - eg. Horticulture
Biochar Prepartion methods - Many.
Sustainable Biochar Use for different soils and climatic conditions ?
The biochar has been in use in parts of India, since centuries. Biochar is added along with the farm yard manure / compost every year. As the retention time of biochar in soil is very high, the impact is cumulative. In many villages in India, agriculture is at least a few hundred years old (up to 500 years or more). The existing charcoal in the soil as found in majority of the fields is a cumulative contribution of the farmers - intentional / as a practice / by chance. In all types of soils biochar is found. As this practice has become traditional, it is sustainable. This is irrespective of the climate and soil conditions. The quantity of the biochar that we are suggesting for a field devoid of biochar, where such traditional practices were not there it is in tonnes per hectare. Where as in the fields like India, we need to assess the total biochar existing in each field and suggest the quantity of biochar. Still the quantity of biochar for different climatic conditions and soils should be evolved through standard experiments simultaneously done in different latitudes and longitudes.
Biochar mulching ?
Biochar mulch is application of biochar directly to the plant as we do leaf litter mulching / stone mulching / etc. Biochar mulching is useful to the plants in the following ways:
1. Retention of the soil moisture, reduction of evaporation of water from the soil
2. Reduction in leaching of the bio / chem fertilizers applied
3. Increase in the soil microbes / worms at the biochar and soil interface
4. Regulation of the soil temperture
5. Suppression of weeds if thick biochar mulch is used, by blocking the sunlight the weeds sprouting and growth is suppressed.
6. Repulsion of the termites / ants which might attack the live plants (less dense termites / ants are observed in biochar plots)
7. Over a period of time due to various activities the biochar mixes with the soil, that is good.
8. Prevents soil erosion too.
9. Can increase the ph of the soil towards neutral (mulch very good for acidic soils)
Biochar and food security in urban areas ?
Biochar when added to the soil the density of the soil composition reduces, therefore it is easy to add as a media for the rooftop gardens. The urine collected from toilets could be diluted and added to the plantations for improved fertility. The biodegradable garbage can be easily disposed of in the roofgarden, as the earthworms density increases with about 3% to 5% of the biochar application. The roof will be cooler due to these gardens. With little water the gardens can be easily maintained. All the urban concrete roof tops could be easily converted into beautiful gardens also address the food security. These gardens give lots of space for the mind.
Potential enhancement of C-loss from soils:
This point is of concern as one need to add more compost / mulch. This potential enhancemet may be attributed to more density of soil microbial activity (residing in the charcoal), as they require food and may be they are using this SOM as food ?
Hydrophobicity of fresh biochar:
Short time or long time finally charcoal looses its Hydrophobicity. As we see in the field, the coolness attributed due to the presence of water in charcoal / moisture attracts many small insects / creatures to take shelter near or under charcoal, including scorpions, etc. as observed in the field.
Biochar in Alkaline soils : The experiments were conducted in the alkaline soils, the farmers are happy with the results. The farmers are convinced that the addition of charcoal along with other amendments has benefited them. Please see all the links in http://www.biocharindia.com
Biochar and India : you say that biochar is traditionally used in India. Do you have an idea of the size of biochar-amended areas, their location, the agricultural practices related to biochar and/or other elements that could help to appraise the importance of biochar and the way it is used in India ?
The size of charcoal is being defined by us as we want immediate results. Whereas, the addition of charcoal to the soils is incremental, as small amounts of different sizes of the charcoal from stoves and other activities has found their way into the soil. Over a period of time the large chunks have been converted into small pieces. So we find different grades (sizes) of charcoal in the soil. I always able to easily collect large size pieces of charcoal from the farmers fields. Different size pieces of charcoal serve different purposes in the field. As the benefits of charcoal are related to various aspects, like physical, chemical, biological, etc.
1. whether you think charcoal to be a novel way of binding the carbon to the soil and also increase the fertility of the soil.
Yes it is a novel way, it has many values, improving the fertility of the degraded soils (alkaline / acidic / poor / degraded), preventing wasteful burning of millions of tonnes of biomass in the open fields after harvesting the crop and for carbon sequestration.
2. How can that improve the agricultural quality in India, and its effect on the methods of agriculture in India.
The small and marginal farmers can easily adopt to this method very easily, who are the majority. They could be easily trained on charcoal making from the biomass available in their field and surroundings for treating their soils.
3. I think this technique of producing charcoal from burned leaves and mixing it in the soil has been followed in India from some time. Why has it been that no work has been done here in that respect.
In my terrapreta signatures I posted the information - as part of tradition / culture people had been using charcoal and ash in their fields. Such practice is there all over the world, where civilizations existed in the last 5000 years, there is a need to recognize the values and create awareness.
4. Does this charcoal have the same effect on each variety of soil or does it effect varies with each variety of soil?
The affect is based on the amendments made to soil along with charcoal, charcoal alone has very less value to improve the fertility of the soil. other additions are like soil microbes, FYM, vermicompost, Mulch, micro-nutrients, sand, gypsum, fertilizers, silt, etc.
Percentage of biochar - How to calculate for different types of soils for application. (simple method)
Biochar FAQs is based on the Experiences / observations / learnings of Dr. N. Sai Bhaskar Reddy