Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    Regional soil moisture monitoring network in the Raam catchment in the Netherlands - 2016-04 / 2017-04 (corrected)
    Benninga, H.F. ; Carranza, C.D. ; Pezij, M. ; Ploeg, M.J. van der; Augustijn, D.C.M. ; Velde, R. van der - \ 2018
    University of Twente
    agriculture - hydrology - soil moisture - soil temperature - unsaturated zone - water management
    Regional soil moisture monitoring network in the Raam catchment in the Netherlands - 2016-04 / 2017-04
    Benninga, H.F. ; Carranza, C.D. ; Pezij, M. ; Ploeg, M.J. van der; Augustijn, D.C.M. ; Velde, R. van der - \ 2017
    University of Twente
    agriculture - hydrology - soil moisture - soil temperature - unsaturated zone - water management
    The Raam soil moisture measurement network dataset contains soil moisture and soil temperature measurements for 15 locations in the Raam, which is a 223-km2 river catchment in the southeast of the Netherlands. The network monitors soil moisture in the unsaturated zone for different soil textures and land covers present in the area, and it covers the topographic gradient of the region. At each location we installed Decagon 5TM sensors at depths of 5 cm, 10 cm, 20 cm, 40 cm and 80 cm. The logging time interval is set on 15 minutes. The Raam network is operational since April 2016 and the measurements are on-going.
    Spatial distribution of solute leaching with snowmelt and irrigation: measurements and simulations
    Schotanus, D. ; Ploeg, M.J. van der; Zee, S.E.A.T.M. van der - \ 2013
    Hydrology and Earth System Sciences 17 (2013). - ISSN 1027-5606 - p. 1547 - 1560.
    heterogeneous porous-media - miller-similar medium - modeling water-flow - steady-state flow - unsaturated zone - field soil - transport - nonequilibrium - degradation - lysimeter
    Transport of a tracer and a degradable solute in a heterogeneous soil was measured in the field, and simulated with several transient and steady state infiltration rates. Leaching surfaces were used to investigate the solute leaching in space and time simultaneously. In the simulations, a random field for the scaling factor in the retention curve was used for the heterogeneous soil, which was based on the spatial distribution of drainage in an experiment with a multi-compartment sampler. As a criterion to compare the results from simulations and observations, the sorted and cumulative total drainage in a cell was used. The effect of the ratio of the infiltration rate over the degradation rate on leaching of degradable solutes was investigated. Furthermore, the spatial distribution of the leaching of degradable and non-degradable solutes was compared. The infiltration rate determines the amount of leaching of the degradable solute. This can be partly explained by a decreasing travel time with an increasing infiltration rate. The spatial distribution of the leaching also depends on the infiltration rate. When the infiltration rate is high compared to the degradation rate, the leaching of the degradable solute is similar as for the tracer. The fraction of the pore space of the soil that contributes to solute leaching increases with an increasing infiltration rate. This fraction is similar for a tracer and a degradable solute. With increasing depth, the leaching becomes more homogeneous, as a result of dispersion. The spatial distribution of the solute leaching is different under different transient infiltration rates, therefore, also the amount of leaching is different. With independent stream tube approaches, this effect would be ignored.
    Quantifying heterogeneous transport of a tracer and a degradable contaminant in the field, with snowmelt and irrigation
    Schotanus, D. ; Ploeg, M.J. van der; Zee, S.E.A.T.M. van der - \ 2012
    Hydrology and Earth System Sciences 16 (2012). - ISSN 1027-5606 - p. 2871 - 2882.
    well-structured soil - solute transport - water-flow - preferential flow - spatial variability - propylene-glycol - unsaturated zone - saturated soil - steady-state - nonequilibrium
    To examine the persistence of preferential flow paths in a field soil, and to compare the leaching of a degradable contaminant with the leaching of a tracer, two field experiments were performed using a multi-compartment sampler (MCS). The first experiment was carried out during the snowmelt period in early spring, characterized by high infiltration fluxes from snowmelt. The second experiment was carried out in early summer with irrigation to mimic homogeneous rainfall. During the second experiment, the soil was warmer and degradation of the degradable contaminant was observed. For both experiments, the highest tracer concentrations were found in the same area of the sampler, but the leached tracer masses of the individual locations were not highly correlated. Thus, the preferential flow paths were stable between the two experiments. With a lower infiltration rate, in the second experiment, more isolated peaks in the drainage and the leached masses were found than in the first experiment. Therefore, it is concluded that the soil heterogeneity is mainly caused by local differences in the soil hydraulic properties, and not by macropores. With higher infiltration rates, the high and low leaching cells were more clustered. The leached masses of the degradable contaminant were lower than the leached masses of the tracer, but the masses were highly correlated. The first-order degradation rate and the dispersivity were fitted with CXTFIT; the first-order degradation rate was 0.02 d-1, and the dispersivity varied between 1.9 and 7.1 cm. The persistence of the flow paths during the experiments suggests soil heterogeneity as the driver for heterogeneous flow and solute transport in this soil. At the MCS scale, heterogeneous snowmelt did not seem to have much influence on the flow and solute paths
    Groundwater chemistry of Al under Dutch acid sandy soils: effects of land use and depth.
    Fest, E. ; Temminghoff, E.J.M. ; Griffioen, J. ; Grift, B. ; Riemsdijk, W.H. van - \ 2007
    Applied Geochemistry 22 (2007)7. - ISSN 0883-2927 - p. 1427 - 1438.
    dissolved organic-matter - acid forest soils - aluminum solubility - bs horizons - unsaturated zone - natural-waters - surface waters - heavy-metals - nica-donnan - speciation
    Aluminium has received great attention in the second half of the 20th century, mainly in the context of the acid rain problem mostly in forest soils. In this research the effect of land use and depth of the groundwater on Al, pH and DOC concentration in groundwater under Dutch sandy soils has been studied. Both pH and DOC concentration play a major role in the speciation of Al in solution. Furthermore, the equilibrium with mineral phases like gibbsite, amorphous Al(OH)3 and imogolite, has been considered. Agricultural and natural land use were expected to have different effects on the pH and DOC concentration, which in turn could influence the total Al concentration and the speciation of Al in groundwater at different depths (phreatic, shallow and deep). An extensive dataset (n = 2181) from the national and some provincial monitoring networks on soil and groundwater quality was used. Land use type and groundwater depth did influence the pH, and Al and DOC concentrations in groundwater samples. The Al concentration ranged from 7 to 1941 ¿mol L¿1 at pH <4; highest Al concentrations were found for natural-phreatic groundwater. The DOC concentration decreased and the median pH increased with depth of the groundwater. Natural-phreatic groundwater showed lower pH than the agricultural-phreatic groundwater. Highest DOC concentrations were found for the agricultural-phreatic groundwater, induced by the application of organic fertilizers. Besides inorganic complexation, the NICA-Donnan model was used to calculate Al3+ concentrations for complexation with DOC. Below pH 4.5 groundwater samples were mainly in disequilibrium with a mineral phase. This disequilibrium is considered to be the result of kinetic constraints or equilibrium with organic matter. Log K values were derived by linear regression and were close to theoretical values for Al(OH)3 minerals (e.g. gibbsite or amorphous Al(OH)3), except for natural-phreatic groundwater for which lower log K values were found. Complexation of Al with DOC is shown to be an important factor for the Al concentrations, especially at high DOC concentrations as was found for agricultural-phreatic groundwater.
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