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Data and information for the Bio-char working group.


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    Data From: Ammonia volatilization from composting with oxidized biochar
    Hestrin, Rachel; Enders, Akio; Lehmann, Johannes (2020)
    Data in support of the following research: Animal manure, agricultural residues, and other sources of biomass can be diverted from the waste stream and composted into valuable fertilizer. However, composting often results in substantial N loss through NH3 gas volatilization. We investigated biochar’s capacity to improve NH3–N retention during composting of poultry manure and straw. After 7 weeks, total NH3–N loss from composting with unoxidized biochar was twofold and sixfold higher than N loss from composting with oxidized biochar and without biochar (307, 142, and 51 mg N g-1 N in the initial compost feedstocks, respectively). When cumulative NH3–N loss was calculated relative to CO2–C loss to account for differences in microbial activity, NH3–N:CO2–C loss from compost with oxidized biochar was 55% lower than from compost with unoxidized biochar (82% lower based on mass balance). Oxidized biochar particles removed from compost after 7 weeks retained 16.0 mg N g-1 biochar, compared to only 6.1 mg N g-1 retained by unoxidized biochar, suggesting that N retention by biochar particles provides a mechanism for reduced NH3–N loss. These data show that oxidized biochar enhanced microbial activity, doubled composting rate, and reduced NH3–N loss, and that biochar’s physiochemical characteristics modulate its performance in compost. In particular, the presence of oxidized surface functional groups—which can be increased artificially or through environmental weathering—appear to play an important role in key compost processes. This has implications for other natural and managed systems where pyrogenic organic matter may mediate biological activity and nutrient cycles.
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    Data from: Pore-Size and Water Activity Effects on Survival of Rhizobium tropici in Biochar Inoculant Carriers
    Vanek, Steven J; Theis, Janice; Wang, Bing; Hanley, Kelly; Lehmann, Johannes (2016)
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    Biochar solutions for reducinf pollution in the Netherlands
    van Hofwegen, Guido; van den Broek, Joep A.; Becx, Gertjan A.; Hoffland, Ellis; Oenema, Oene (2006-10-04T20:12:22Z)
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    Black Carbon from Rice Residues as Soil Amendment and for Carbon Sequestration
    Haefele, SM; Konboon, Y; Knoblauch, C; Koyama, S; Gummert, M; Ladha, JK (2006-09-14)
    On highly weathered soils in tropical and subtropical climates, maintenance of soil organic matter is essential to sustain system productivity and avoid rapid soil degradation. But climatic conditions as well as soil characteristics favor the rapid decomposition of organic matter. However, several recent studies indicated that black carbon, the product of incomplete combustion of organic material, could combine characteristics highly beneficial for soil nutrient dynamics with high stability against chemical and microbial breakdown. Lasting soil amelioration by incorporation of black carbon from wooden plants was proposed based on the beneficial evidence from ?Terra Preta? soils in Western Amazonia. Theoretically, charred crop residues in rice-based systems could serve the same purpose but this hypothesis has never been tested. Within this context, our objectives were to 1) assess possible options for the use of charred rice residues, to 2) test the effect of charred rice residues on important soil fertility parameters and rice growth, and 3) to evaluate the effect and stability of charred rice residues in a variety of rice growing environments. Initial investigations showed that charred rice husks are already used in several Asian countries, e.g. in Japan for seed bed preparation of rice and vegetable crops, and in the Philippines for soil amelioration in ornamental plant production. Charring of rice husks in Japan is known as ?Kuntan? and simple techniques for its production are even part of agricultural training courses. First experiments showed that charring rice husks slightly increases the relative carbon content but the weight loss from fresh to charred rice husks is about 70%. Similarly to carbon, the relative concentration of other nutrient elements (e.g., N, P, K, Ca, Mg) is maintained or even increased. Greenhouse studies in pot experiments conducted in the Philippines and northeast Thailand in 2005 showed positive effects of charred rice husks on rice biomass, rice yield, and cation exchange capacity. No increased leaching of organic carbon was observed when charred rice husks were added to the soil. Randomized and replicated field trials including control treatments and +/- inorganic fertilizer treatments were established in a variety of rice-growing environments including irrigated lowlands, rainfed uplands (both in the Philippines), rainfed lowlands (northeast Thailand), and the rice-wheat system (India). In these trials, the quantity of carbon applied equaled about 1.4% in the surface soil layer (0.0 - 0.1 m) or about 16 t carbon per hectare. Converted to biomass, this is equivalent to the crop residues of about 10 to 20 seasons, depending on the system's productivity (including straw and assuming the above mentioned efficiency in black carbon production). In the first cropping season, observed agronomic effects of the charred rice husks were variable and depended on the cropping system and the indigenous soil fertility. Contrary to that, the effects on soil characteristics were more consistent and major effects were an increase of the cation exchange capacity, a decrease of soil bulk density, and a stable increase of soil organic carbon. However, preliminary results strongly suggest that a continuation of the field trials is necessary to better evaluate the long-term treatment effects. If the greater part of the applied black carbon proves to be stable in some or all tested cropping systems, this technology could be an interesting option for carbon sequestration. If used at a large scale, considerable research efforts would be needed to evaluate the various and far-reaching consequences of the proposed technology.
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    Exploring Atypical Stabilization Pathways Using Pool-Based Modeling
    Sohi, Saran; Yates, Helen; Lehmann, Johannes; Liang, Biqing; Gaunt, John (2006)
    Simulation models that explicitly account for the impact and interaction of soil and environmental variables can assist in predicting the accumulation of C and its rate of turnover. Relevant, verifiable (i.e. measurable) pools of Soil Organic Matter (SOM) provide the most robust basis for elucidating the underlying mechanisms. We have developed a model based around three measurable pools of SOM which can be measured using a density-based fractionation procedure, and verified by extensive chemical characterization. The model has been optimized against measurements of C and N and isotope-tracers in several soils amended with isotope-labeled organic matter. According to recent estimates black C is a much larger component of Soil Organic Carbon (SOC) in typical agricultural soils than previously assumed. Since black C may also be the most stable form of organic C in the soil, the amount of black C in the soil must impact both on the bulk rate of soil C mineralization (turnover) and the extent to which a particular management intervention can alter SOC. Until now our simulations have not accounted explicitly for the effect of black C on the dynamics of each pool. We are now examining how black C is characterized by physical location within the soil matrix, and in order to account for the influence of black C using this model affects C mineralization, and the distribution of charcoal between each of the measured fractions.
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    Nutrient Bioavailability of Anthropogenic Dark Earth Soils and Surrounding Soils of Central Amazonian
    Falcao, Newton Paolo de Souza; Souza da Silva, Ana Cristina; Franca Borges, Lillian; Comerford, Nicolas (2006-09-13T23:08:42Z)
    A greenhouse experiment was carried out at the National Institute for Amazon Research, Manaus, AM, Brazil, to evaluate the nutrient bioavailability of Anthropogenic Dark Earth Soils and surrounding soils. Maize (Zea maiz L.) was planted in pots with two kg of air-dried soil to determine the relative fertility of the Dark Earth Soil and surrounding soil (Oxisol). Soil samples of surface layer (0-20 cm) was collected of four sites (Laranjal farm, Açutuba farm, Jiquitaia farm, Hatahara farm) and two soils per site (Dark Earth Soil and Oxisols) following a randomized factorial design (4X2) with 8 treatments and eight replication, totals 64 pots. Half the pots were watered with distilled water to field capacity as required. The other half was watered with a minus-P nutrient solution to field capacity as required. The nutrient solution was applied to supply nutrients minus P, giving a bioassay of P bioavailability for the different soil locations and depths. Entire plants were harvested at the end of 2 months and total dry matter of shoots, roots and total nutrients uptake by plant were measured. Additionally soil fertility variability and phosphorus fractionation was done after maize was harvested. The results showed that Dark Earth soils are inherently more fertile by contrasting the growth and nutrient accumulation in the water-only-pots. Dark earth soil phosphorus availability from Açutuba ranged from 236 mg kg-1 (minus nutrient solution treatment) to 227 mg kg-1 (treatment with nutrient solution); dark earth soil phosphorus availability from Rio Preto da Eva ranged from 284 mg kg-1 (minus nutrient solution treatment) to 189 mg kg-1 (treatment with nutrient solution) and dark earth soil phosphorus availability from Laranjal ranged from 367 mg kg-1 (minus nutrient solution treatment) to 305 mg kg-1 (treatment with nutrient solution). The total phosphorus in the shoots showed a slight decrease with all treatments with dark earth soil plus nutrient solution. The treatments with dark earth soil plus nutrient solution showed that the phosphorus amount in the shoots ranged from 3, 11 to 3, 79 g kg-1. On the other hand, the same treatment minus nutrient solution showed that the phosphorus concentration in shoots ranged from 3, 43 to 4, 92 g kg-1. The treatments with surrounding soil plus nutrient solution showed that the phosphorus amount in the shoots ranged from 0, 92 to 3, 01 g kg-1. On the other hand, the same treatment minus nutrient solution showed that shoots phosphorus concentration ranged from 1, 30 to 3, 86 g kg-1. The higher increment of biomass was got to dark earth soil plus nutrient solution ranged from 9,56 g/pot (minus nutrient solution) to 26,13 g/pot (plus nutrient solution), an increment of 273%. All dark earth soil treatment presented low amounts of exchangeable potassium, ranged from 0, 05 Cmolc kg-1 to 0, 14 Cmolc kg-1, after maize was harvested. Based on preliminary results presented above, we propose that the natural fertility of the Dark Earth Soil is relative since low levels of potassium are a restriction to crop growing. Not only the surrounding soils but also the dark earth soils in all sites presented aluminium phosphate plus iron phosphate higher than 65% of the total phosphorus pool, except the dark earth soil from the Hatahara farm that showed calcium phosphate higher then 60% of the total phosphorus pool.
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    Isolating Unique Bacteria from Terra Preta Systems: Using Culturing and Molecular Tools for Characterizing Microbial Life in Terra Preta
    O'Neill, Brendan; Grossman, Julie; Tsai, S.M.; Gomes, Jose Elias; Garcia, Carlos Eduardo; Solomon, Dawit; Liang, Biqing; Lehmann, Johannes; Thies, Janice (2006-08-16T20:11:25Z)
    The greater fertility of Terra Preta (TP) soils is thought to be due to their high black carbon (BC) content, which contributes to increased nutrient and moisture retention, and increased pH. It is likely that the unique chemistry of BC results in distinct microbial communities involved in nutrient cycling and organic matter turnover. TP soils offer an excellent model system for studying soils containing elevated and stable BC fractions in comparison to adjacent soils, because state factors, such as mineralogy, precipitation and climate, are the same between soils at a given site. Given this we compared the microbial communities in background soils adjacent to TP sites at four locations in the Brazilian Amazon. We used a combination of culture-based and molecular techniques to characterize and identify the key members of the bacterial communities in these soils. We found that culturable bacteria were more numerous in TP soils than in adjacent background soils. Bacteria were grown on soil extract agar prepared from TP and adjacent soils and, by cross-cultivation, bacteria uniquely suited to growth on TP soil substrates were isolated. All isolates were screened by use of RFLP fingerprinting and then the 16S rDNA of unique isolates was sequenced. Clustering analysis of RFLP fingerprints indicated that isolates obtained from TP soils were more closely associated with each other than with bacterial isolates from adjacent soils within the same site. We hypothesized that TP would contain microbes that are uniquely associated with soils high in BC as compared to adjacent soils and that these organisms would have more phylogentic simlarity to each other across TP sites than in comparison to their corresponding adjacent soils. Of sequenced organisms most fell within the groupings Firmicutes, High G+C actinimyces, alpha-proteobacteria and gamma-proteobacteria, but only 18% had matches in the database above 97% and only 4% of sequences above 99% similarity. Finally we compared phylogenies of sequences obtained from individual soil isolates with those obtained from cloning and sequencing DNA from PCR-DGGE gels. Results from both approaches show a greater homology between sequences obtained from the four TP sites than between sequences obtained from adjacent and TP soils from the same site. By combining culture-based and culture-independent molecular techniques we obtained a more complete analysis of the suites of organisms unique suited to soils rich in BC. Black carbon is widespread in the environment and, once created, persists over long time scales. Knowledge of the ecology of TP soils may contribute to a broader understanding of the behavior of BC in natural environments and its possible use in agricultural systems to improve soil fertility.