EGU21-15676
https://doi.org/10.5194/egusphere-egu21-15676
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Nutrient cycling differs between cropped soils with century-old and recently pyrolyzed biochar

Victor Burgeon1, Julien Fouché2, Sarah Garré1,3, Ramin Heidarian-Dehkordi1, Gilles Colinet1, and Jean-Thomas Cornelis1
Victor Burgeon et al.
  • 1TERRA Teaching and Research Centre, Gembloux Agro-Bio Tech, University of Liège, Gembloux 5030, Belgium
  • 2LISAH, Univ Montpellier, INRAE, IRD, Institut Agro, Montpellier, France
  • 3Flanders Research Institute for Agriculture, Fisheries and Food, Center of Expertise for Agriculture and Climate, P39 - Caritasstraat 39, 9090 Melle Belgium

The amendment of biochar to soils is often considered for its potential as a climate change mitigation and adaptation tool through agriculture. Its presence in tropical agroecosystems has been reported to positively impact soil productivity whilst successfully storing C on the short and long-term. In temperate systems, recent research showed limited to no effect on productivity following recent biochar addition to soils. Its long-term effects on productivity and nutrient cycling have, however, been overlooked yet are essential before the use of biochar can be generalized.

Our study was set up in a conventionally cropped field, containing relict charcoal kiln sites used as a model for century old biochar (CoBC, ~220 years old). These sites were compared to soils amended with recently pyrolyzed biochar (YBC) and biochar free soils (REF) to study nutrient dynamics in the soil-water-plant system. Our research focused on soil chemical properties, crop nutrient uptake and soil solution nutrient concentrations. Crop plant samples were collected over three consecutive land occupations (chicory, winter wheat and a cover crop) and soil solutions gathered through the use of suctions cups inserted in different horizons of the studied Luvisol throughout the field.

Our results showed that YBC mainly influenced the soil solution composition whereas CoBC mainly impacted the total and plant available soil nutrient content. In soils with YBC, our results showed lower nitrate and potassium concentrations in subsoil horizons, suggesting a decreased leaching, and higher phosphate concentrations in topsoil horizons. With time and the oxidation of biochar particles, our results reported higher total soil N, available K and Ca in the topsoil horizon when compared to REF, whereas available P was significantly smaller. Although significant changes occurred in terms of plant available nutrient contents and soil solution nutrient concentrations, this did not transcend in variations in crop productivity between soils for neither of the studied crops. Overall, our study highlights that young or aged biochar behave as two distinct products in terms of nutrient cycling in soils. As such the sustainability of these soils differ and their management must therefore evolve with time.

How to cite: Burgeon, V., Fouché, J., Garré, S., Heidarian-Dehkordi, R., Colinet, G., and Cornelis, J.-T.: Nutrient cycling differs between cropped soils with century-old and recently pyrolyzed biochar, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-15676, https://doi.org/10.5194/egusphere-egu21-15676, 2021.

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