Chemical Properties of Biochar Materials Manufactured from Agricultural Products Common to the Southeast United States

Abstract

<jats:p>The use of biochar as a soil amendment has fostered much attention in recent years due to its potential of improving the chemical, physical, and biological properties of agricultural soils and/or soilless substrates. The objective of this study was to evaluate the chemical properties of feedstocks, common in the southeast United States, and their resulting biochar products (after being torrefied) and determine if the chemical properties were within suitable ranges for growers to use the biochar products as root substrate components. Poultry litter biochar produced at 400 °C for 2 hours had a higher total phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), chloride (Cl), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), sodium (Na), and zinc (Zn) concentration than biochar made using the same process with mixed hard wood species, miscanthus (<jats:italic>Miscanthus capensis</jats:italic>), cotton (<jats:italic>Gossypium hirsutum</jats:italic>) gin trash, switchgrass (<jats:italic>Panicum virgatum</jats:italic>), rice (<jats:italic>Oryza sativa</jats:italic>) hull, and pine (<jats:italic>Pinus</jats:italic> sp.) shavings feedstocks. The pH of the biochar products ranged from 4.6 for pine shaving biochar to 9.3 for miscanthus biochar. The electrical conductivity (EC) ranged from 0.1 dS·m<jats:sup>−1</jats:sup> for mixed hardwood biochar to 30.3 dS·m<jats:sup>−1</jats:sup> for poultry litter biochar. The cation exchange capacity (CEC) of the biochar products ranged from a low of 0.09 meq/g for mixed hardwood biochar to a high of 19.0 meq/g for poultry litter biochar. The water-extractable nitrate, P, K, Ca, Mg, sulfate, boron, Cl, Cu, Fe, Mo, Na, and Zn were higher in poultry litter biochar than in all of the other types of biochar. The high EC and mineral element concentration of the poultry litter biochar would prevent its use in root substrates except in very small amounts. In addition, the high degree of variability in chemical properties among all of the biochar products would require users to know the specific properties of any biochar product they used in a soil or soilless substrate. Modifications to traditional limestone additions and fertility programs may also need to be tested and monitored to compensate for the biochar pH and mineral nutrient availability. Users should be aware that biochar products made from different feedstocks can have very different chemical properties even if the same process was used to manufacture them.</jats:p>

Biochar production from poultry litter as management approach and effects on plant growth

“…This result indicates that the P content in PLB was increased after producing biochar from PL. This result was in accordance with the results of Singh et al (2010) at 300 °C and 500 °C temperature; Cantrell et al (2012); and Evans et al (2017). But Cely et al (2015) revealed a different result that P concentration decreases after producing biochar, as different factors such as type of organic material, pyrolysis conditions, etc.…”

“…Results revealed that available N content was 40% higher in PLB than PL. Experiments conducted by Chan et al (2008); Novak et al (2009a) at 350 °C and Evans et al (2017) at 400 °C temperature reported that the N content increased in PLB after pyrolysis, whereas the total N content of PLB (2.04 ± 0.08) % was a little bit lower than that of PL (2.23 ± 0.14) % that means after pyrolysis at 300 °C the total N content was slightly decreased in PLB (8.52%). In this experiment, the total N content of PLB was similar to the result of Chan et al (2008), who reported 2% total N in PLB.…”

Evaluating On-demand Irrigation Systems for Container-grown Woody Plants Grown in Biochar-amended Pine Bark

“…Because the effect of biochar depends on the type of feedstock, the pyrolysis conditions, and the ecosystem or cropping systems to which biochar is applied (Altland and Boldt, 2018;Sohi et al, 2009), different nutrient concentration can be reported after biochar application. Biochar chemical properties may vary with source material even with the same production techniques (Evans et al, 2017). Thus, biochar amendments could be produced and prescribed based on meeting the nutrient needs of a specific crop.…”

“…The reason may be a result of the biochar being produced from a wide range of biomass material that may affect the final product characteristics. Biochar products produced from different feedstocks can have different chemical properties even when using the same manufacturing process (Evans et al, 2017).…”

Consequential Life Cycle Assessment of Swine Manure Management within a Thermal Gasification Scenario

“…The environmental emissions associated with biochar transport to the field were considered with a transportation distance assumed to be 10 km (6.2 miles), which is slightly more than the upper bound on average manure hauling distances, i.e., between 1.6 and 6.4 km (1 and 4 miles). Biochar land application is beneficial both as a fertilizer/soil conditioner and as a carbon sequestration option [36]. In this study, the benefits of biochar application to the soil were determined as the avoided synthetic fertilizers due to the presence of P and K in the biochar.…”