Ecosystem Services of Roots – Hydraulic Redistribution, Carbon Sequestration and Soil Fixation – ECOSFIX

Ecosfix is a highly multidisciplinary project uniting practitioners from a socio-economic context with scientists from (agro)forestry, soil science, ecology, mechanical engineering and hydrology. Beginning with a better quantitative description of the structure and function of roots at different depths within the soil profile, we will seek to define spatial and temporal dynamics of root growth in different complex (agro)forest structures. These forest structures are representative of different types of food and fibre production in a range of climates. Root growth in complex communities has found to increase compared to monocultures, thus having major implications for mixed crops and agroforestry. We will measure root traits with soil depth at the individual and community level within each forest structure examined. As fine roots are major conduits for C into the soil, sequestration is a major service that roots provide. We will determine the fate of root-related C into the soil profile using isotopic chemistry. Monitoring of hydraulic redistribution within the soil profile will be carried out using isotopic tracers and results will provide information concerning hydraulic redistribution by plant roots within a community. By carrying out experiments on soil cohesion and aggregate stability, we will determine the role that roots play in modifying soil structure, and hence erosion and mass movement processes.

Through integrated modelling and the analysis of patterns among root system traits and functions, ecosystem services can be assigned to different suites of root traits. The trade-offs between traits and services will be investigated and a set of criteria will be proposed related to site effects.

A major milestone of this project is the production of a decision support tool and guidelines for end users. Our research will be performed within the carefully defined socio-economic context of local end-user requirements. The relations between researchers and managers/stakeholders are at the forefront of the work to be carried out and will be facilitated through the participation of a partnering agroforestry association, a NGO and a training/research centre.

Ecosfix proposes to understand the functional importance of one of the most poorly understood components of the soil-plant-atmosphere continuum: the distal part of root systems. Recent studies based on the use of stable isotopes of water show that the root systems of many species are likely to redistribute water within their rhizosphere. Nevertheless, the quantities of water mobilized by this mechanism and the functional importance remain unclear. We will address this scientific challenge and assess the functional importance of water redistribution (whether vertically or laterally) by deep-rooted species in a multi-specific population and the benefits that associated shallow-rooted species can draw from the process.

Danjon F, Stokes A, Bakker MR 2012. Root systems of woody plants. Chapter in: “Plant Roots – The Hidden Half” 3rd Edition, (Eds A. Eshel; U. Kafkaki). Plenum Publishing, NY

In the current context of climate change and a staggering increase in the world’s population, urgent solutions are required to ensure both ecological integrity and optimal productivity of any agricultural/forested site. The FAO has estimated that more than 10 Mha of the world’s cultivated land suffers from degradation, particularly soil erosion and mass movement on hillslopes; soil loss in turn compromising the quantity of carbon (C) that can be sequestered in the soil. There is also a pressing need to improve non-irrigated agriculture upon which the world's poorest populations depend. Understanding the hydrological interactions between plant roots and the soil profile is thus a priority. Although ecological intensification is currently being studied in many projects worldwide, largely with regard to e.g. production scenarios for increasing yield, the ‘hidden half’ of a plant, i.e. the root system, is still neglected in many studies or is limited to those processes occurring in the upper soil layers. In Ecosfix, we propose to investigate the influence of root structure and function on physical and biological processes, from the soil surface to the deep horizons. This new paradigm will permit us to evaluate the ecosystem services provided by plant root functioning throughout the soil profile, with specific reference to soil erosion, mass movement, C sequestration and hydraulic redistribution.

Ecosfix is a highly multidisciplinary project uniting practitioners from a socio-economic context with scientists from (agro)forestry, soil science, ecology, mechanical engineering and hydrology. Beginning with a better quantitative description of the structure and function of roots at different depths within the soil profile, we will seek to define spatial and temporal dynamics of root growth in different complex (agro)forest structures. These forest structures are representative of different types of food and fibre production in a range of climates. Root growth in complex communities has found to increase compared to monocultures, thus having major implications for mixed crops and agroforestry. We will measure root traits with soil depth at the individual and community level within each forest structure examined. As fine roots are major conduits for C into the soil, sequestration is a major service that roots provide. We will determine the fate of root-related C into the soil profile using isotopic chemistry. Monitoring of hydraulic redistribution within the soil profile will be carried out using isotopic tracers and results will provide information concerning hydraulic redistribution by plant roots within a community. By carrying out experiments on soil cohesion and aggregate stability, we will determine the role that roots play in modifying soil structure, and hence erosion and mass movement processes.

Through integrated modelling and the analysis of patterns among root system traits and functions, ecosystem services can be assigned to different suites of root traits. The trade-offs between traits and services will be investigated and a set of criteria will be proposed related to site effects. A major milestone of this project is the production of a decision support tool and guidelines for end users. Our research will be performed within the carefully defined socio-economic context of local end-user requirements. The relations between researchers and managers/stakeholders are at the forefront of the work to be carried out and will be facilitated through the participation of a partnering agroforestry association, a NGO and a training/research centre.