Modelling the relationships and feedbacks between spatial patterns of anecic earthworm populations, related preferential flow pathways and agrochemical transport and degradation in rural catchments
Zusammenfassung der Projektergebnisse
Different earthworm ecological types are responsible for macropores of different size and depth, which results in a varying impact on soil hydrology. Within the BIOPORE‐project we developed a new approach for modelling water and solute transport which is linked to earthworm distribution models. The main advantage of this approach is that it can be parameterized based on observable field parameters (i.e. macropore density and depth distribution) which can on their turn be mapped at catchment scale using models predicting the spatial distribution of earthworms. We showed that BRT models perform well to predict the spatial distributions of the different earthworm ecological types at the catchment scale. We also showed the strong correlation between earthworms of different ecological types with different macropore sizes and depths. The effectivity of these macropores for water transport was shown to depend more on macropore coatings than on the surrounding matrix soil physical characteristics. Also, we successfully tested the hydrological modelling approach by modelling water and bromide transport at a tile drained field site. Based on a Monte Carlo study, we found system‐inherent equifinality, and conclude that even when using physically‐based models this equifinality exists in this kind of models. The integral flow data provides only low dimensional information. Additional information clearly reduced the system‐inherent equifinality. The experiments underpinned that rapid transport of pesticides is an immanent problem of structured soils. The transport was mainly independent of the pesticide’s chemical properties. More interesting is the strong link between hydrological dynamics and pesticide transport. Remobilization of the pesticides was observed during the third of three experiments. Soil water from a depth of 20 ‐ 40 cm seems to be responsible for a large part of the tile drain discharge. This mobilization of soil water leads to a mobilization of stored pesticides and a transport to surface water. Furthermore, we showed that the water that flows in the soil macropores of the Weiherbach catchment is mainly old water and not the irrigated water. This was controlled by the interaction between the macropores and the soil matrix. Large amounts of old water enter the macropore system after a moisture threshold in the soil is exceeded. The combination of our interdisciplinary cross‐scale field studies and modelling efforts provides a much deeper understanding of abiotic and biotic processes and patterns determining earthworms, preferential flow as well as infiltration and travel times distribution of solutes.
Projektbezogene Publikationen (Auswahl)
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(2008). Challenges of species distribution modeling belowground. Journal of Plant Nutrition and Soil Science 171: 325‐337
Schröder B
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(2010). First results in modelling distribution patterns of anecic earthworms on catchment scale: a Boosted Regression Tree model approach. Berichte der DBG, DBGPrints No. 496
Palm J, van Schaik N L M B, Schröder B
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(2010). Mapping spatial distribution of preferential flow using earthworms distribution models in combination with tracer infiltration patterns. Geophys Res Abstr 12, EGU2010‐10978, EGU General Assembly 2010
van Schaik N L M B, Palm J, Klaus J, Schröder B, Zehe E
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(2010). Modelling rapid flow response of a tile drained field site using a 2D‐physically based model: assessment of “equifinal” model setups. Hydrological Processes 24: 1595‐1609
Klaus J, Zehe E
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(2010). Modelling rapid flow response of a tile drained hillslope with explicit representation of preferential flow paths and consideration of equifinal model structures. Geophys Res Abstr 12, EGU2010‐413, 2010, EGU General Assembly 2010
Klaus J, Zehe E
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(2010). Modelling spatiotemporal distribution patterns of earthworms in order to indicate hydrological soil processes. Geophys Res Abstr 12, EGU2010‐10837‐1
Palm J, Klaus J, van Schaik N L M B, Zehe E, Schröder B
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(2010). Use of dye‐tracer infiltration patterns for the macropore parameterization of a physically based model (SWAP). Vadose Zone Journal 9: 95‐106
van Schaik N L M B, Hendriks, R F A, van Dam J C
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Breakthrough of two pesticides into tile drain and shallow groundwater: comparison of tile drain reaction and soil profiles within a field scale irrigation experiment. Geophys Res Abstr 12, EGU2010‐8407, EGU General Assembly 2010
Klaus J, Zehe E, Elsner M, Palm J, Schneider D, Schröder B, Steinbeiss S, West S
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(2011). A novel explicit approach to model bromide and pesticide transport in connected soil structures. Hydrology Earth System Sciences 15(7): 2127‐2144
Klaus J, Zehe E
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(2011). Equifinality and structure control on bromide and pesticide leaching at tile drained hillslopes: a model study based on a comprehensive field data set. Geophys Res Abstr 13, EGU2011‐7475, EGU General Assembly 2011
Zehe E, Klaus J
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(2011). Explicit parameterization of macropore flow based on earthworm species distribution models. Abstracts Soil Science in a changing world, Wageningen, NL
van Schaik N L M B, Palm J, Klaus J, Zehe E, Schröder B
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(2011). Relationships between earthworm abundance and preferential flow paths. Abstracts HydroEco 2011, Vienna, Austria
van Schaik N L M B, Palm J, Klaus J, Zehe E, Schröder B
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(2011). Tile drained hillslopes as natural lysimeters – linking rapid transport and re‐ mobilisation of different pesticides with isotope signatures during controlled irrigation experiments. Geophys Res Abstr 13, EGU2011‐7418, EGU General Assembly 2011
Klaus J, Zehe E, Elsner M, Külls C, Schneider D, Steinbeiss S, West S
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Macropore flow of old water revisited: where does the mixing occur at the hillslope scale? Hydrol. Earth Syst. Sci. Discuss., 9, 4333‐4380
Klaus J, Zehe E, Elsner M, Külls C, McDonnell JJ
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Perspectives in modelling earthworm dynamics and their feedbacks with abiotic soil properties. Applied Soil Ecology
Schneider A‐K, Schröder B
