Here you will find current studies on biochar
The extent and intensity of the pre-Columbian influences on the lowland Amazon remained uncertain and controversial. The presence of nutrient-enriched Terra Preta soils is widely regarded as an indication of long-term colonization and site fidelity of the first settlers. mehr
The extent and intensity of pre-Columbian impacts on lowland Amazonia have remained uncertain and controversial. Various indicators can be used to gauge the impact of pre-Columbian societies, but the formation of nutrient-enriched terra preta soils has been widely accepted as an indication of long-term settlement and site fidelity. Using known and newly discovered terra preta sites and maximum entropy algorithms (Maxent), we determined the influence of regional environmental conditions on the likelihood that terra pretas would have been formed at any given location in lowland Amazonia. Terra pretas were most frequently found in central and eastern Amazonia along the lower courses of the major Amazonian rivers. Terrain, hydrologic and soil characteristics were more important predictors of terra preta distributions than climatic conditions. Our modelling efforts indicated that terra pretas are likely to be found throughout ca 154 063 km2 or 3.2% of the forest. We also predict that terra preta formation was limited in most of western Amazonia. Model results suggested that the distribution of terra preta was highly predictable based on environmental parameters. We provided targets for future archaeological surveys under the vast forest canopy and also highlighted how few of the long-term forest inventory sites in Amazonia are able to capture the effects of historical disturbance.
Soil mineral degradation is a major problem mainly due to soil erosion and nutrient leaching. The addition of biochar is a solution, as it has been shown that biochar improves soil fertility. mehr
Soil mineral depletion is a major issue due mainly to soil erosion and nutrient leaching. The addition of biochar is a solution because biochar has been shown to improve soil fertility, to promote plant growth, to increase crop yield, and to reduce contaminations. We review here biochar potential to improve soil fertility. The main properties of biochar are the following: high surface area with many functional groups, high nutrient content, and slow-release fertilizer. We discuss the influence of feedstock, pyrolysis temperature, pH, application rates, and soil types. We review the mechanisms ruling the adsorption of nutrients by biochar.
The production of biochar (the carbonaceous solid formed by pyrolysis of biomass) and its storage in soils may potentially help to mitigate climate change by binding carbon, while providing energy and crop yields. mehr
Production of biochar (the carbon (C)-rich solid formed by pyrolysis of biomass) and its storage in soils have been suggested as a means of abating climate change by sequestering carbon, while simultaneously providing energy and increasing crop yields. Substantial uncertainties exist, however, regarding the impact, capacity and sustainability of biochar at the global level. In this paper we estimate the maximum sustainable technical potential of biochar to mitigate climate change. Annual net emissions of carbon dioxide (CO2), methane and nitrous oxide could be reduced by a maximum of 1.8 Pg CO2-C equivalent (CO2-Ce) per year (12% of current anthropogenic CO2-Ce emissions; 1 Pg=1 Gt), and total net emissions over the course of a century by 130 Pg CO2-Ce, without endangering food security, habitat or soil conservation. Biochar has a larger climate-change mitigation potential than combustion of the same sustainably procured biomass for bioenergy, except when fertile soils are amended while coal is the fuel being offset.
In this study, the effects of biochar changes during the composting of pig manure were examined to investigate the correlation between N2O emission and the amount of denitrifying bacteria. mehr
Although nitrous oxide (N2O) emissions from composting contribute to the accelerated greenhouse effect, it is difficult to implement practical methods to mitigate these emissions. In this study, the effects of biochar amendment during pig manure composting were investigated to evaluate the inter-relationships between N2O emission and the abundance of denitrifying bacteria. Analytical results from two pilot composting treatments with (PWSB, pig manure + wood chips + sawdust + biochar) or without (PWS, pig manure + wood chips + sawdust) biochar (3% w/w) demonstrated that biochar amendment not only lowered NO2–-N concentrations but also lowered the total N2O emissions from pig manure composting, especially during the later stages. Quantification of functional genes involved in denitrification and Spearman rank correlations matrix revealed that the N2O emission rates correlated with the abundance of nosZ, nirK, and nirS genes. Biochar-amended pig manure had a higher pH and a lower moisture content. Biochar amendment altered the abundance of denitrifying bacteria significantly; less N2O-producing and more N2O-consuming bacteria were present in the PWSB, and this significantly lowered N2O emissions in the maturation phase. Together, the results demonstrate that biochar amendment could be a novel greenhouse gas mitigation strategy during pig manure composting.
Energy production from bioenergy plants can significantly reduce greenhouse gas emissions by substituting fossil fuels. Biochar incorporation into the soil can further reduce the net climate gas production of bioenergy crop cultivation. mehr
Energy production from bioenergy crops may significantly reduce greenhouse gas (GHG) emissions through substitution of fossil fuels. Biochar amendment to soil may further decrease the net climate forcing of bioenergy crop production, however, this has not yet been assessed under field conditions. Significant suppression of soil nitrous oxide (N2O) and carbon dioxide (CO2) emissions following biochar amendment has been demonstrated in short-term laboratory incubations by a number of authors, yet evidence from long-term field trials has been contradictory. This study investigated whether biochar amendment could suppress soil GHG emissions under field and controlled conditions in a Miscanthus × Giganteus crop and whether suppression would be sustained during the first 2 years following amendment. In the field, biochar amendment suppressed soil CO2 emissions by 33% and annual net soil CO2 equivalent (eq.) emissions (CO2, N2O and methane, CH4) by 37% over 2 years. In the laboratory, under controlled temperature and equalised gravimetric water content, biochar amendment suppressed soil CO2 emissions by 53% and net soil CO2 eq. emissions by 55%. Soil N2O emissions were not significantly suppressed with biochar amendment, although they were generally low. Soil CH4 fluxes were below minimum detectable limits in both experiments. These findings demonstrate that biochar amendment has the potential to suppress net soil CO2 eq. emissions in bioenergy crop systems for up to 2 years after addition, primarily through reduced CO2 emissions. Suppression of soil CO2 emissions may be due to a combined effect of reduced enzymatic activity, the increased carbon-use efficiency from the co-location of soil microbes, soil organic matter and nutrients and the precipitation of CO2 onto the biochar surface. We conclude that hardwood biochar has the potential to improve the GHG balance of bioenergy crops through reductions in net soil CO2 eq. emissions.
The application of biochar (charcoal or biomass-derived carbon) to soils is proposed as a novel approach to establish a significant, long-term atmospheric carbon dioxide sink in terrestrial ecosystems. mehr
The application of bio-char (charcoal or biomass-derived black carbon (C)) to soil is proposed as a novel approach to establish a significant, long-term, sink for atmospheric carbon dioxide in terrestrial ecosystems. Apart from positive effects in both reducing emissions and increasing the sequestration of greenhouse gases, the production of bio-char and its application to soil will deliver immediate benefits through improved soil fertility and increased crop production. Conversion of biomass C to bio-char C leads to sequestration of about 50% of the initial C compared to the low amounts retained after burning (3%) and biological decomposition (< 10–20% after 5–10 years), therefore yielding more stable soil C than burning or direct land application of biomass. This efficiency of C conversion of biomass to bio-char is highly dependent on the type of feedstock, but is not significantly affected by the pyrolysis temperature (within 350–500 ∘C common for pyrolysis). Existing slash-and-burn systems cause significant degradation of soil and release of greenhouse gases and opportunies may exist to enhance this system by conversion to slash-and-char systems. Our global analysis revealed that up to 12% of the total anthropogenic C emissions by land use change (0.21 Pg C) can be off-set annually in soil, if slash-and-burn is replaced by slash-and-char. Agricultural and forestry wastes such as forest residues, mill residues, field crop residues, or urban wastes add a conservatively estimated 0.16 Pg C yr−1. Biofuel production using modern biomass can produce a bio-char by-product through pyrolysis which results in 30.6 kg C sequestration for each GJ of energy produced. Using published projections of the use of renewable fuels in the year 2100, bio-char sequestration could amount to 5.5–9.5 Pg C yr−1 if this demand for energy was met through pyrolysis, which would exceed current emissions from fossil fuels (5.4 Pg C yr−1). Bio-char soil management systems can deliver tradable C emissions reduction, and C sequestered is easily accountable, and verifiable.
This paper presents a novel attempt to investigate the impact of biochar (applied at 0.1, 0.5 and 2.5%) on the physical properties of the soil in relation to quantified soil variables. mehr
Evidence suggests that biochar influences soil physical properties, especially soil hydrology, yet relatively little data exists on this topic, especially in relation to soil type or characteristics. This paper presents a novel attempt at analysing the influence of biochar (applied at 0.1, 0.5 and 2.5%) on the physical properties of soil with respect to quantified soil variables. Pot experiments were used to establish the effect of biochar on: bulk density, soil moisture content at field capacity and available water capacity. The aggregate effect of biochar across all soils was significant (P < 0.01) for all of the properties. With increasing amount of biochar, changes to bulk density, field capacity and available water were more pronounced. In the 2.5% treatments these changes ranged from − 4.2% to − 19.2%, 1.3% to 42.2% and 0.3% to 48.4%, respectively. Regression revealed that soil silt content negatively moderated the influence of biochar on field capacity and available water capacity. The results suggested that medium (20 t ha− 1) and high (100 t ha− 1) biochar applications could improve water-holding capacity (by up to 22%) and ameliorate compaction (by up to 15%) and that soils low in silt are likely to be more hydrologically responsive to biochar application.
This study shows for the first time that low-dose root zone application of urea-reinforced biochar resulted in a significant increase in yield in a fertile silt loam soil. mehr
A widely abundant and invasive forest shrub, Eupatorium adenophorum, was pyrolyzed in a cost-efficient flame curtain kiln to produce biochar. The resulting biochar fulfilled all the requirements for premium quality, according to the European Biochar Certificate. The biochar was either applied alone or mixed with fresh cow urine (1:1 volume) to test its capacity to serve as slow release fertilizer in a pumpkin field trial in Nepal. Treatments included cow-manure compost combined with (i) urine-only; (ii) biochar-only or (iii) urine-loaded biochar. All materials were applied directly to the root zone at a biochar dry matter content of 750 kg·ha −1 before seeding. The urine-biochar treatment led to a pumpkin yield of 82.6 t·ha −1 , an increase of more than 300% compared OPEN ACCESS Agriculture 2015, 5 724 with the treatment where only urine was applied, and an 85% increase compared with the biochar-only treatment. This study showed for the first time that a low-dosage root zone application of urine-enhanced biochar led to substantial yield increases in a fertile silt loam soil. This was tentatively explained by the formation of organic coating of inner pore biochar surfaces by the urine impregnation, which improved the capacity of the biochar to capture and exchange plant nutrients.
The properties and application of biochar from conventionally slow pyrolysis have been much studied, but biochar by-product in bio-oil production, produced by rapid pyrolysis, has rarely been studied. mehr
The characteristics and application of biochar from conventionally slow pyrolysis have been studied a lot, but biochar, as a byproduct in the bio-oil production process, produced by fast pyrolysis was rarely studied. This work assessed the characterization and utilization of biochars derived from rice husk (RH) and elm sawdust (ES) by fast pyrolysis. Incubation experiment of rice husk biochar (RHB) and acid soil in a controlled cabinet was carried out to test the effect of biochar on soil available elements. The volatile and fixed carbon was 2.2 and 1.7-fold respectively higher in elm sawdust biochar (ESB) than those in RHB, but the ash content was 4.2-fold higher in RHB than that in ESB. Although the C, H, N, and O contents were significantly varied in two biochars, the ratio H/C and O/C were nearly the same. The Fourier Transform Infrared Spectroscopy (FTIR) results revealed that RHB had more functional groups than ESB. More surface area was found in RHB (78.15 m2 g−1) than ESB (0.22 m2 g−1) by BET test. Incorporation of the biochar improved the quality of acid soil properties. The levels of soil pH, K, Ca, Mg, Na and total C and N increased while the Al and Pb contents decreased. Total carbon and potassium increased by 72% and by 6.7-fold respectively over the control at 4% of rice husk biochar adding level.
Here, nutrient release from a variety of new and aged biochar, pure and mixed with soil, is investigated using batch extraction and column leaching. mehr
Biochar has shown promise as a soil amendment that increases carbon sequestration and fertility, but its effects on dissolved organic carbon (DOC), nitrogen (N) and phosphorus (P) cycling and loss is not well understood. Here, nutrient release from a variety of new and aged biochars, pure and mixed with soils, is examined using batch extraction and column leaching. In successive batch extractions of biochar, cumulative losses were about 0.1–2, 0.5–8 and 5–100% of the total C, N and P initially present, respectively, with greater releases from biochars made at lower temperature and from grass. Ammonium was usually the most abundant N form in leachates but nitrate was also abundant in some biochars, while organic N and P represented as much as 61% and 93% of the total N and P lost, respectively. Release of DOC, N and P into water was correlated with biochar volatile matter content and acid functional group density. However, P release via Mehlich-1 extraction was more strongly related to ash content, suggesting a mineral-associated P fraction. Columns with soil/biochar mixtures showed evidence of both soil nutrient sorption by biochar and biochar nutrient sorption by soil, depending upon biochar and soil type. This study demonstrates that biochars contain a range of nutrient forms with different release rates, explaining biochar's variable effect on soil fertility with soil and crop type and over time.
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