Final Report Summary - BASE (Biochar Application in a Natural Ecosystem)
Biochar is a charcoal like substance that is produced through the heating of organic materials, such as wood or green wastes, to temperatures in excess of 350°C in low to zero oxygen environments. This process, known as pyrolysis, changes the chemical structure of the start material, reducing the biodegradability of the material and so increasing the amount of time the material remains in soil (i.e. before being decomposed into CO2 and returned to the atmosphere).
The project BASE (Biochar Application to Soil in a natural Ecosystem) was funded by a Marie Curie Career Integration Grant for a two year period, hosted at Wageningen UR, Netherlands. It aimed to combined interdisciplinary techniques from soil physics, chemistry and biology to investigate the ecological consequences of biochar application in a north European grassland.
The main results of the project include the provision of evidence that not all biochars are the same, physical and chemical characteristics can vary widely with implication for how a biochar acts after application to soil. For example, one of the most widely posited benefits of biochar is increased water holding capacity after application to soil, in particular to sandy soil. However, in this project we showed that the biochar used in for our experiments, produced from cuttings from a grassland and produced at either 400°C or 600°C did not significantly affect soil hydrological properties of a sandy loam soil. Through analysis with cutting edge microtomography and three phase contact angle measurements we were able to show that the structure of the biochar was such that it should significantly increase the soil water retention of the soil; the biochar contained sufficient interconnected pores. However, the material was highly hydrophobic as demonstrated by three phase contact angles in excess of 110°. This hydrophobicity prevented the water from entering the pore space of the biochar particles in soil. This work was published in the journal Geoderma.
Further to this we found evidence that biochar’s effects on crop productivity likely result from fertilisation effects of nutrients within the biochar. This can be in the form in potassium (K) from the ash constituent of biochar which lead to increase legume biomass on biochar plots in a field experiment. Alternatively, through the application of stable isotopes were were able to show that nitrogen (N) from biochar is available for plant uptake and so is capable of causing a fertilisation effect in N limited systems. However, this fertilisation effect was less than was observed in the presence of the material that the biochar was produced from in unpyrolysed form. This sheds doubt on the oft quoted benefits of biochar on crop productivity and highlights the need to rigorously applied controls for experiments investigating the effects of biochar application to soil.
Having returned to academia after three years working in scientific policy support for the European Commission, the fellow’s main goal in recent years has been to increase the strength of my publishing record, including publishing in high impact journals. This grant has enabled me to do this by providing the financial means to apply cutting edge techniques such as x-ray tomography, stable isotope probing techniques and DNA analysis in the form of DNA micro-arrays. The fellow has also been able to raise my international profile by presenting my work at several national and international conferences.
The results from this project are of interest to a wide range of target groups and stakeholders ranging from land managers and policy makers, through to the general public who may be considering using biochar in their own gardens. For this reason, among others, we aimed to publish some of the work in open source journals (1 published, and another in the final stages of preparation aimed for Scientific Reports (Nature Publishing Group).
To further aid disemination of the project results we ran a project website include a blog section. The website address is base-project.org.
The project BASE (Biochar Application to Soil in a natural Ecosystem) was funded by a Marie Curie Career Integration Grant for a two year period, hosted at Wageningen UR, Netherlands. It aimed to combined interdisciplinary techniques from soil physics, chemistry and biology to investigate the ecological consequences of biochar application in a north European grassland.
The main results of the project include the provision of evidence that not all biochars are the same, physical and chemical characteristics can vary widely with implication for how a biochar acts after application to soil. For example, one of the most widely posited benefits of biochar is increased water holding capacity after application to soil, in particular to sandy soil. However, in this project we showed that the biochar used in for our experiments, produced from cuttings from a grassland and produced at either 400°C or 600°C did not significantly affect soil hydrological properties of a sandy loam soil. Through analysis with cutting edge microtomography and three phase contact angle measurements we were able to show that the structure of the biochar was such that it should significantly increase the soil water retention of the soil; the biochar contained sufficient interconnected pores. However, the material was highly hydrophobic as demonstrated by three phase contact angles in excess of 110°. This hydrophobicity prevented the water from entering the pore space of the biochar particles in soil. This work was published in the journal Geoderma.
Further to this we found evidence that biochar’s effects on crop productivity likely result from fertilisation effects of nutrients within the biochar. This can be in the form in potassium (K) from the ash constituent of biochar which lead to increase legume biomass on biochar plots in a field experiment. Alternatively, through the application of stable isotopes were were able to show that nitrogen (N) from biochar is available for plant uptake and so is capable of causing a fertilisation effect in N limited systems. However, this fertilisation effect was less than was observed in the presence of the material that the biochar was produced from in unpyrolysed form. This sheds doubt on the oft quoted benefits of biochar on crop productivity and highlights the need to rigorously applied controls for experiments investigating the effects of biochar application to soil.
Having returned to academia after three years working in scientific policy support for the European Commission, the fellow’s main goal in recent years has been to increase the strength of my publishing record, including publishing in high impact journals. This grant has enabled me to do this by providing the financial means to apply cutting edge techniques such as x-ray tomography, stable isotope probing techniques and DNA analysis in the form of DNA micro-arrays. The fellow has also been able to raise my international profile by presenting my work at several national and international conferences.
The results from this project are of interest to a wide range of target groups and stakeholders ranging from land managers and policy makers, through to the general public who may be considering using biochar in their own gardens. For this reason, among others, we aimed to publish some of the work in open source journals (1 published, and another in the final stages of preparation aimed for Scientific Reports (Nature Publishing Group).
To further aid disemination of the project results we ran a project website include a blog section. The website address is base-project.org.