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Description

Main research question/goal

Life Cycle Assessments or LCAs were originally designed to evaluate the sustainability of the fossil fuel based industry. Since the 1990s, the method has been applied to food products to calculate the ecological footprint of a product and its packaging. Subsequently, entire agricultural production systems were also studied, which revealed the difficulty in evaluating their environmental sustainability, as influences of policy, agricultural practices, weather conditions, innovation and also (longer term) soil quality cause high variability. In this doctoral work, we quantify the long term relationship between land use practices and yield, through the intermediate step of land use practices, translated into changes in soil quality. We aim for useful indicators for soil quality and ecosystem services that can be incorporated into LCA analyses.


Research approach

We translate the term 'impact on soil quality' into soil organic carbon because the build-up of carbon in the soil is strongly related to land use. A model predicts the evolution of soil organic carbon stock as a consequence of farm management and productivity changes. By making simulations with this model, we investigate whether the choice of agricultural practices (e.g. crop rotation, type of manure, whether or not to sow a green manure crop) can actually have an impact on the soil's carbon stock. Finally, we develop a procedure to compare the environmental sustainability of organic and conventionally produced products by taking into account the capacity of a production system to provide ecosystem services (in addition to agricultural products). We are incorporating this complex concept of 'ecosystem services provided' into the LCA methodology.



 
The impact on soil quality in the Boone LCA is ultimately dependent on the following measurements: 1. change in the organic carbon stock, 2. change in biomass productivity, and 3. change in land requirements. The three represent a cause-effect chain, which correctly exposes the impact of land use on soil quality.
 
The simulations via the model confirm that the choice of agricultural practices (for example a certain crop rotation, the type of manure, whether or not to sow green covers) can have a major influence on the carbon stock of the soil.
 
The complex fact of the "delivered ecosystem services" has now also been incorporated into the LCA method. In this study, a procedure has been developed to compare the environmental sustainability of biologically and conventionally produced products by taking into account the capacity of a production system to deliver ecosystem services (in addition to agricultural products).


Relevance/Valorisation

The research project has now been completed. Data from our modified LCA analysis prove to be very useful to determine the costs and benefits of a measure in favour of soil remediation, and to weigh several measures against each other. The new calculation method makes an economic estimate of the soil remediation measures in terms of the use of raw materials. This is done using the balance calculation between the consumption of natural raw materials related to production on the one hand (including the raw materials needed to carry out remediation measures) and the output of crop production systems on the other hand (the harvested crops). In a test case, the newly developed indicator was applied to several possible rotation systems in Flanders, each time comparing recovery measures. It shows that the benefits of restoring soil organic carbon levels outweigh the efforts, but that the results strongly depend on the nature of the restorative measures applied. For example, green cover crops have a clear positive effect on soil quality as well as yield.

AcronymSUSBODEM
StatusFinished
Effective start/end date1/01/1530/06/19

ID: 4339057