Research

1. Soil fertility

R. Merckx, E. Smolders and J. Diels
 
Our division has a long-standing experience in integrated (tropical) soil fertility management as well as in the environmental issues related to excessive fertilization in regions with intensive animal husbandry. Both seemingly contrasting research domains share one common challenge: how to unequivocally determine biological availability of nutrients to plants or biota in general, be it in the deficiency region or in eutrophication scenarios? While food security is the concern spurring research efforts in tropical areas, a general concern toward designing efficient farming systems with minimal impact on their surroundings is the overarching mission of our division. Specific research efforts encompass both basic process research unraveling the driving variables of bio-availability as well as more applied research targeting the adoption of improved soil fertility management techniques in farming communities.

URL projects: ees.kuleuven.be/bwb/projects

2. Soil physics

J. Diels and J. Vanderborght
 
Many soil functions are related to soil properties. Soil moisture plays a crucial role in natural and agricultural ecosystems and the soil is an important node in the water cycle where the exchange of water between the atmosphere, groundwater and rivers occurs. This exchange is strongly coupled with the exchange of energy and heat between the surface and the atmosphere and therefore is important for weather forecasts and predictions of regional and global climate change. The physical condition of the soil (soil moisture and soil air content, soil temperature and soil structure) largely determines biogeochemical cycles that determine nutrient cycles in soil, biodegradation of organic toxins and emission or absorption of greenhouse gases from or through the soil. Groundwater and soil vapor act as transport pathways by which substances are transported through the soil.

The research group 'soil physics and soil hydrology’ conducts research on soil physical processes. This includes the development of observation methods, techniques and technology for estimation of moisture content, mass and heat fluxes in the soil at different spatial and temporal scales. Another important theme is to develop simulation models that describe physical processes in soil and water, and that predict flows of water, energy and mass in the soil and at the surface. These simulation models are used to predict the impact of control measures and to suggest adjustments to the latter.

URL projects: ees.kuleuven.be/bwb/projects

3. Nutrient and carbon fluxes in terrestrial and aquatic systems

S. Bouillon, R. Merckx, E. Smolders and J. Diels
 
This research line studies the fluxes, origin, and cycling of carbon and nutrients in a wide range of both natural ecosystems and agricultural systems, in both temperate and tropical climates. Current projects focus, amongst others, on:

• Understanding deep soil carbon cycling, mechanisms of carbon preservation in relationship to soil characteristics and possible influence of climate change on soil C dynamics; effects of soil erosion on carbon cycling.
  
  

• Carbon and nutrient cycling in river basins and lakes: origin of aquatic carbon pools in relationship to land-use patterns, the importance of carbon export and in-stream mineralization and CO2 efflux in the overall carbon budget, and associated changes in the quantity, age and composition of organic matter; quantifying aquatic primary production and its regulating factors.

• Quantifying greenhouse gas emissions (CO2, CH4, N2O) from both terrestrial and aquatic ecosystems, and understanding the driving forces and factors influencing greenhouse gas production (e.g. temperature effects, tillage vs. no-tillage, soil structure, organic matter availability, …)

URL projects: ees.kuleuven.be/bwb/projects

4. Water management

D. Raes
 
The agricultural sector currently accounts for 70 % of the fresh water withdrawal in the world. In water scarce regions, where already half of the world population lives today, water availability is the major bottleneck for obtaining good and reliable crop yields. Doubling the global food production, which is needed to meet the population growth and increase in prosperity, can only be achieved by strongly improving the water use efficiency (WUE) of crops, i.e. by producing higher yields with less water (more crop per drop).

Our research group studies crop, field and irrigation management practices with which WUE of major staple food crops of a region can be optimized. This is mainly done through application of the crop water productivity model AquaCrop. In collaboration with the Food and Agriculture Organization of the United Nations (FAO), our group contributes strongly to the development, improvement and validation of the various components of FAO’s water productivity model. In the frame of Master and PhD research, experiments in farmers’ fields are done in various regions of the world and simulations are run to calibrate and validate AquaCrop. The model uses a relatively small number of parameters (explicit and mostly intuitive) and attempts to balance simplicity, accuracy and robustness. AquaCrop simulates the crop yield and WUE that can be expected for a selected crop in a given environment. By considering climate change and farmers’ common practices when running simulations, we are able to develop strategies and guidelines that can be supported by the local community, and this not only for the current but also for future climatic conditions.

URL projects: ees.kuleuven.be/bwb/projects

5. Hydrology

G. Wyseure
 
Hydrologic processes in and around soils
We study the physical processes governing the cycling of water where the soil acts as a major control. Therefore special attention is given to the water pathways and budgets in and around soils. This not only at the micro-scale but also at the scale of landscape elements such as hill-slopes, wetlands, shallow subsurface drainage and interaction between river and groundwater ecosystems. Special attention is given to the connectivity and interaction between different compartments as a control to the flow of water within the catchments. The water carries also dissolved elements like nitrates and dissolved organic matter.

One of the major objectives of a better insight into hydrological processes in and around soils is to create a better holistic understanding of the hydrological cycle. This should lead to a more sustainable management of water resources, land use impact, water quality and water-related natural hazards.

URL projects: ees.kuleuven.be/bwb/projects

6. Land evaluation

S. Deckers
 
Land evaluation assesses the suitability of land for a particular land use. Suitability is deducted from soil characteristics, climatological data, hydrology and socio-economical factors and evaluated according to the requirements of a specific land-use type.
Land evaluation research aims to support sustainable agricultural development in equilibrium with biodiversity:

• Sustainable farming systems in developing countries: scientists and farmers look for the most appropriate farming system, balancing  production with natural carrying capacity.
  

• Reforestation and nature development:  In Europe the abiotic potential for nature conservation is addressed e.g. for converting agricultural land into nature conservation areas. In developing countries, Natural Park authorities and farmers need to handle land-related problems e.g. the management of marginal land.

• Physical and chemical conservation of the soil cover as a valuable natural resource:  soil erosion and sediment fluxes are addressed at river-catchment scale. Likewise important are the behavior of soil carbon and heavy metals.

• Paleo- environmental reconstruction: the soil profile contains valuable historical information that can support archeology, nature conservation and land management.

URL projects: ees.kuleuven.be/bwb/projects

7. Contaminated soils and water: toxicology and environmental microbiology

E. Smolders, D. Springael and J. Vanderborght
 
Soil chemistry, environmental microbiology and soil ecotoxicology are the disciplines with which the environmental quality of soils, ground- and surface water are studied. We study the fate and effects of pesticides, toxic trace metals, polyaromatic hydrocarbons and chlorinated solvents in soil, ground- and surface water and their removal in (bio)systems for treatment of soil and water. We cover the whole scale from a molecular level to the field. We have specific expertise in biodegradation, microbial ecology, interactions in biofilms, microbial adaptation to contaminants, trace metal speciation, isotope techniques, measurements of bioavailability, soil ecotoxicology and risk assessment.

URL projects: ees.kuleuven.be/bwb/projects