Lehmann (Cornell University) also claims Bio-Char or Agri-Char in the soil also sequesters atmospheric CO2.
Over the years I have noticed that flood irrigation of farmland produces higher crop yields than non-aerated well water, implying that soil CO2 made available to the plant root system aids plant growth. Given the large surface area of a good carbon char (more than hundreds of square meters per gram along with soil moisture retention, I can buy that. Fred http://www.css.cornell.edu/faculty/lehmann/biochar/Biochar_home.htm Bio-char or Agri-char: the new frontier Inspired by the fascinating properties of Terra Preta de Indio, bio-char is a soil amendment that has the potential to revolutionize concepts of soil management. While "discovered" may not be the right word, as bio-char (also called charcoal or biomass-derived black carbon, recently in context of agricultural application also named agri-char) has been used in traditional agricultural practices as well as in modern horticulture, never before has evidence been accumulating that demonstrates so convincingly that bio-char has very specific and unique properties that make it stand out among the opportunities for sustainable soil management. The benefits of bio-char rest on two pillars: 1- The extremely high affinity of nutrients to bio-char 2- The extremely high persistence of bio-char These two properties (which are truly extraordinary - see details below) can be used effectively to address some of the most urgent environmental problems of our time: 1- Soil degradation and food insecurity 2- Water pollution from agro-chemicals 3- Climate change "Soils with bio-char additions are typically more fertile, produce more and better crops for a longer period of time." THE TWO PILLARS OF BIO-CHAR PROPERTIES Nutrient Affinity All organic matter added to soil significantly improves various soil functions, not the least the retention of several nutrients that are essential to plant growth. What is special about bio-char is that it is much more effective in retaining most nutrients and keeping them available to plants than other organic matter for example common leaf litter, compost or manures. Interestingly, this is also true for phosphorus which is not at all retained by 'normal' soil organic matter. Reading: Sombroek, W., Nachtergaele, F.O. and Hebel, A.: 1993, ?Amounts, dynamics and sequestering of carbon in tropical and subtropical soils', Ambio 22, 417-426. Mikan, C.J. and Abrams, M.D.: 1995, 'Altered forest composition and soil properties of historic charcoal hearths in southeastern Pennsylvania', Canadian Journal of Forestry ! Research 25, 687-696. Lehmann, J., da Silva Jr., J.P., Steiner, C., Nehls, T., Zech, W. and Glaser, B.: 2003a, ?Nutrient availability and leaching in an archaeological Anthrosol and a Ferralsol of the Central Amazon basin: fertilizer, manure and charcoal amendments', Plant and Soil 249 , 343-357. Lehmann, J., Kern, D.C., German, L.A., McCann, J., Martins, G.C. and Moreira, A.: 2003b, ?Soil Fertility and Production Potential', in J. Lehmann, D.C. Kern, B. Glaser and W.I. Woods (eds.), Amazonian Dark Earths: Origin, Properties, Management , Dordrecht, Kluwer Academic Publishers, pp. 105-1! 24. Liang, B. , Lehmann, J., Solomon, D., Kinyangi, J., Gr! ossman, J., O'Neill, B., Skjemstad, J.O., Thies, J., Luizão, F.J., Petersen, J. and Neves, E.G.: 2006, 'Black carbon increases cation exchange capacity in soils', Soil Science Society of America Journal 70: 1719-1730. Persistence It is undisputed that bio-char is much more persistent in soil than any other form of organic matter that is commonly applied to soil. Therefore, all associated benefits with respect to nutrient retention and soil fertility are longer lasting than with alternative management. The long persistence of bio-char in soil also make it a prime candidate for the mitigation of climate change as a potential sink for atmospheric carbon dioxide. The success of effective reduction of greenhouse gases depends on the associated net emission reductions through bio-char sequestration. However, a net emission reduction can only be achieved in conjunction with sustainable management of biomass production. During the conversion of biomass to bio-char about 50% of the original carbon is retained in the bio-char, which offers a significant opportunity for creating such a carbon sink. Reading: Pessenda, L.C.R., Gouveia, S.E.M. and Aravena, R.: 2001, ?Radiocarbon dating of total soil organic matter and humin fraction and its comparison with 14 C ages of fossil charcoal', Radiocarbon 43 , 595-601. Seifritz, W.: 1993, ?Should we store carbon in charcoal?', International Journal of Hydrogen Energy 18 , 405-407. Schmidt, M.W.I. and Noack, A.G.: 2000, ?Black carbon in soils and sediments: analysis, distribution, implications, and current challenges', Global Biogeochemical Cycles 14 , 777-794. Shindo, H.: 1991, ?Elementary composition, humus composition, and decomposition in soil of charred grassland plants', Soil Science and Plant Nutrition 37 , 651-657. MEETING ENVIRONMENTAL CHALLENGES -(in preparation)- LAND-USE SYSTEMS AND BIO-CHAR USE Bio-fuel production through low-temperature pyrolysis "Combining bio-energy production with bio-char application to soil offers one of the most exciting perspectives of future land-based production technologies." (read more about Bio-char and Bio-energy) Reading: Okimori, Y., Ogawa, M. and Takahashi, F.: 2003, ?Potential of CO2 emission reductions by carbonizing biomass waste from industrial tree plantation in south Sumatra , Indonesia ', Mitigation and Adaptation Straegies for Global Change 8 , 261-280. http://www.css.cornell.edu/faculty/lehmann/biochar/Biochar_energy.htm Bio-Energy and Bio-char This research explores the opportunities and constraints to combining a bio-char soil management with energy production using novel low-temperature pyrolysis. Three real-world issues justify this approach: (1) The ever increasing pressure on rural land users to generate sufficient income from their land with decreasing market prices for food; (2) the necessity to provide sustainable production systems that minimize on- and off-site pollution and soil degradation; and (3) the demand for solutions to global warming. While food prices do not increase sufficiently enough to ensure healthy farm economies without subsidies in many industrialized countries, energy prices increase at unprecedented rates. Within the past two years, gas and diesel prices increased by 150% (DOE, 2005). In contrast, the proportion of a household income spent for food decreased from 21% in 1950 to 10% in 2000 (ERS, 2005). One strategy to resolve this dilemma for farmers is to engage in energy production over the long term in addition to food production in order to diversify income. Several different strategies for land-based bio-energy production exist that build on modern biomass technology (in contrast to traditional biomass, UNDP 2004). The underlying principle is usually the sustainable land-based production of an energy crop or the use of waste biomass (also animal manures!) and the conversion into bio-fuels by various mechanisms. Possible avenues for producing bio-fuels from bio! mass are ethanol production ! through microbial fermentation, extraction of oils from crops, pyrolysis and gasification of biomass (Caputo et al., 2005). Farmers have begun to understand the economic opportunities associated with bio-energy. This proposal introduces an emergent strategy of combining energy production using modern biomass with land application of bio-char which is a residue from the energy production that has multiple environmental benefits. The proposed technology is low-temperature pyrolysis that yields bio-oil, hydrogen or directly electricity as the energy carrier (including valuable co-products), with bio-oil being the more advanced and more wide-spread technology (Meier and Faix 1999; Bridgwater et al. 2002). The biomass feedstock may include a wide variety of biomass (Yaman 2004) such as wood chips or pellets, bark, crop residues such as nut shells or rice husks, and grass residues such as bagasse from the sugarcane industry. More importantly, however, planted energy crops can be used with the sole purpose of producing bio-fuels, such as short-rotation woody plants (e.g. willow), grasses (e.g. Miscanthus spp.), or herbaceous plants. The key for securing environmental benefits is the production of a bio-char by-product during pyrolysis which can be applied to soil. Reading: Day, D., Evans, R.J., Lee, J.W. and Reicosky, D.: 2005, Economical CO2 , SOx , and NOx capture from fossil-fuel utilization with combined renewable hydrogen production and large-scale carbon sequestration', Energy 30 , 2558-2579. Lehmann, J., Gaunt, J. and Rondon, M.: 2006, 'Bio-char sequestration in terrestrial ecosystems a review', Mitigation and Adaptation Strategies for Global Change 11, 403-427 Li, X., Hagaman, E., Tsouris, C. and Lee, J.W.: 2003, Removal of carbon dioxide from flue gas by ammonia carbonization in the gas phase', Energy & Fuels 17 , 69-74. Yaman, S.: 2004, Pyrolysis of biomass to produce fuels and chemical feedstocks', Energy Conversion and Management 45 , 651-671. News Feature article in NATURE: Marris E 2006 Black is the new green. Nature 442: 624-626.
