The soil biota can be regarded as the ‘biological engine’ of the Earth, driving many of the key ecosystem services which soils deliver. Besides carbon and nutrients, the soil biota require energy to function. “By including energy properties of organic inputs, we can increase our understanding of soil carbon dynamics in diversified cropping systems”, says Louis J. P. Dufour.
In a new doctoral thesis by Louis J.P. Dufour, a PhD student in the soil nutrient cycling research group at the department of soil and environment at SLU, the effects of diversified organic inputs on below-ground carbon dynamics have been investigated using a bioenergetics approach, i.e. how the soil biota acquires and transforms energy.
Crop diversification is a potentially attractive agricultural practice to improve organic carbon storage in soils. Although it is promoted by the EU Common Agricultural Policy (CAP), we still lack a mechanistic understanding of how diversified cropping systems affect organic carbon storage in soils. Deepening our understanding of the relationship between crop diversity and microbial processing of organic inputs may improve our mechanistic understanding of carbon dynamics in diversified cropping systems.
It is not easy to answer the question of whether the diversity of organic inputs plays an important role in soil carbon dynamics. However, Louis' work has shown that it is not sufficient to consider only the chemical composition of diversified organic inputs, but that including energetic properties will further our understanding of carbon dynamics in diversified cropping systems.
In his work, Louis used soils from cereal dominated agriculture, grasslands to woodland ecosystems, including a long-term field trial with Salix, and their chemical and biological characteristics were evaluated. Soils are one of the most complex systems on Earth and organic matter models are therefore often used to predict potential carbon sequestration in soils. Reliable model predictions require information from empirical studies.
For example, a recent model developed in the Soil and Environmental Physics group, another research group based in the same department as Louis, focuses on microbial energetic limitation and physical protection of organic matter. Empirical data provided by Louis’ work has the potential to inform models of organic matter dynamics. In a wider perspective, these research outcomes will provide policy-relevant data that can underpin future CAP instruments and contribute to the development of sustainable agriculture.
Link to the dissertation: https://publications.slu.se/?file=publ/show&id=132976&lang=se
Louis J.P. Dufour defends his dissertation on the 26th of may at 13.000 in Sal L Undervisningshuset Ultuna. To register to the dissertation online, please contact Anke.Herrmann@slu.se