Seeking deeper for future: potential of subsoils management for the storage of organic matter in agricultural fields

Dr Julien Guigue1, Msc Chris Henke1, Pr Ingrid Kögel-Knabner1

1Technical University of Munich, Freising Weihenstephan, Germany

While the demographic pressure for food demand is continuously rising, global environmental changes are threatening the productivity of agroecosystems. Climatic events like floods or droughts, and long-term decrease in soil organic matter stocks due to intensive agriculture are examples pointing to the necessity to find solutions for sustainable performance of agroecosystems.

Significant amounts of water and nutrients are stored in deep soil horizons, and thus subsoil management is being considered as an alternative to sustain high demand in crop productivity. Moreover, despite low concentrations in organic matter, subsoils correspond to larger volume of soil and thus contain a high proportion of SOM. For these reasons, the dynamics of SOM in deep horizons is logically receiving more focus and their potential for the stabilisation of organic carbon need to be determined.

We used samples from a field experiment in Germany where the agricultural management was adapted to investigate the potential benefits of deep ploughing with OM incorporation. We recorded hyperspectral images of soil cores (depth = 1 m) using Vis-NIR spectroscopy and the C distribution within the soil was modelled at a very high spatial resolution (53×53 μm). The SOC mapping revealed an increase in SOC stocks resulting from deep ploughing, and the high resolution images generated allows the observation of OM distribution in the subsoil and the response in SOM stocks to different types of organic matter incorporation (compost vs green manure).

Hyperspectral imaging of soil cores allows the quantification of OM stocks and changes in deeper horizons, and visualisation of heterogeneity in the spatial distribution of soil organic matter is helping to understand and quantify the processes related to changes in soil C stocks in subsoils.


Biography: Julien Guigue is a Post-Doctoral scientist at Technical University of Munich. He is doing research on soil organic matter dynamics in agricultural ecosystems, more specifically on the effect of agricultural management of subsoils on SOM distribution and stocks.

SOIL ORGANIC MATTER

7th International Symposium
Soil Organic Matter

6 – 11 October 2019

Hilton Adelaide

Adelaide, South Australia

Australia

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