Life cycle assessment of wheat straw and corn stover biomass for the production of biochar applied in Saxony's agriculture

Abstract

[ES] Tras la investigación de las consecuencias del cambio climático sobre los suelos de la región de Sajonia en Alemania y la necesidad de su adaptación a través de productos, como el biocarbono, que conservan los nutrientes necesarios para la agricultura; se estudia el ciclo de vida respectivo a la producción de biocarbono con dos tipos de biomasa seleccionadas.

Se realiza, para ambos tipos, una evaluación de impacto ambiental mediante el software de SimaPro y se comparan los resultados de impacto para concluir con la opción de biomasa más conveniente.

[EN] Biochar is a porous carbon-rich material which is produced by the pyrolysis of biomass along with bio-oil and syngas. Applied, e.g., in agricultural soils acts a Negative Emission Technology (NET) creating a long-term carbon sink in which carbon absorbed by plants is retained and stored achieving a long-term carbon sequestration by containing CO2 from the atmosphere. Moreover, it also promotes humus formation by adding nutrients to the soil, increases soil yields, expands the water capacity of soils and improves the resistance of soil to droughts among other factors. Climate change is damaging soils in Germany. In particular, east Germany is affected by summer droughts that reduce water availability, diminish plants photosynthetic output and consequently, plant growth declines. Thus, e.g., applying biochar into the soil of the most affected areas of Germany, such as Saxony region, can contribute to the climate change mitigation and prevent soil damages that affects agriculture. The aim of this study is to carry out an environmental assessment of the production of corn stover and wheat straw biochar through Life Cycle Assessment models following the ISO standards, ISO 14040 and 14044, and then compare the results obtained in both cases to verify the difference they have regarding impact assessment. Crop production is the stage in the life cycle of biochar that constitutes the main environmental damage. Water emissions and raw materials are the main cause of environmental impacts in the ecosystem quality and human health due to the agricultural production and use of grain, seeds and nitrogen fertilisers in the step of harvest of both studied biomasses. Moreover, the results show that the life cycle of WS biochar constitutes a slightly superior environmental damage. However, in either case, biochar diminishes similarly the negatives impacts produced by crop production.