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TERENO-SOILCan: a lysimeter-network in Germany observing soil processes and plant diversity influenced by climate change

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Thomas Pütz at Forschungszentrum Jülich
Thomas Pütz
Ralf Kiese at Karlsruhe Institute of Technology
Ralf Kiese
Ute Wollschläger at Helmholtz Centre for Environmental Research
Ute Wollschläger
Jannis Groh at University of Bonn
Jannis Groh
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Abstract and Figures

The aim of TERENO (TERrestrial ENvironmental Observatories) is to collect long-term observation data on the hydrosphere, biosphere, pedosphere, lower atmosphere and anthroposphere along multiple spatial and temporal gradients in climate sensitive regions across Germany. The lysimeter-network SOILCan was installed as a part of TERENO between March and December 2010 within the four observatories. It represents a long-term large-scale experiment to study the effects of climate and management changes in terrestrial ecosystems, with particular focus on the impact of these changes on water, energy and matter fluxes into groundwater and atmosphere. SOILCan primarily focuses on soil hydrology, the carbon and nutrient cycle and plant species diversity. Time series measurements of states and fluxes at high spatial and temporal resolution in the soil and biosphere are combined with remote sensing information for the development and calibration of process-based models simulating impacts of climate change in soil processes at field to regional scale. Within the framework of SOILCan, 132 fully automated lysimeter systems were installed at 14 highly equipped experimental field sites across the four TERENO observatories. Relevant state variables of grassland and arable ecosystems are monitored characterizing climate, hydrology and matter fluxes into the atmosphere and within the hydrosphere as well as plant species diversity. Lysimeters are either being operated at or near their original sampling location or were transferred within or between the four TERENO observatories thereby using temperature and rainfall gradients to mimic future climatic conditions (space for time), which allow measuring impacts of climate change on terrestrial ecosystems. The lysimeters are cultivated as grassland (intensive, extensive and non-used) or arable land, the latter with a standardized crop rotation of winter wheat—winter barley—winter rye—oat. This publication describes the general design of the SOILCan experiment including a comprehensive description of the pedological characteristics of the different sites and presents a few exemplary results from the first years of operation.
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THEMATIC ISSUE
TERENO-SOILCan: a lysimeter-network in Germany observing
soil processes and plant diversity influenced by climate change
Th. Pu
¨tz
1
•R. Kiese
2
•U. Wollschla
¨ger
3
•J. Groh
1
•H. Rupp
4
•S. Zacharias
4
•
E. Priesack
5
•H. H. Gerke
6
•R. Gasche
2
•O. Bens
7
•E. Borg
8
•C. Baessler
9
•
K. Kaiser
7
•M. Herbrich
6
•J.-C. Munch
4
•M. Sommer
6
•H.-J. Vogel
3
•
J. Vanderborght
1
•H. Vereecken
1
Received: 21 April 2016 / Accepted: 25 August 2016 / Published online: 12 September 2016
Springer-Verlag Berlin Heidelberg 2016
Abstract The aim of TERENO (TERrestrial ENviron-
mental Observatories) is to collect long-term observation
data on the hydrosphere, biosphere, pedosphere, lower
atmosphere and anthroposphere along multiple spatial and
temporal gradients in climate sensitive regions across
Germany. The lysimeter-network SOILCan was installed
as a part of TERENO between March and December 2010
within the four observatories. It represents a long-term
large-scale experiment to study the effects of climate and
management changes in terrestrial ecosystems, with par-
ticular focus on the impact of these changes on water,
energy and matter fluxes into groundwater and atmosphere.
SOILCan primarily focuses on soil hydrology, the carbon
and nutrient cycle and plant species diversity. Time series
measurements of states and fluxes at high spatial and
temporal resolution in the soil and biosphere are combined
with remote sensing information for the development and
calibration of process-based models simulating impacts of
climate change in soil processes at field to regional scale.
Within the framework of SOILCan, 132 fully automated
lysimeter systems were installed at 14 highly equipped
experimental field sites across the four TERENO obser-
vatories. Relevant state variables of grassland and arable
ecosystems are monitored characterizing climate, hydrol-
ogy and matter fluxes into the atmosphere and within the
hydrosphere as well as plant species diversity. Lysimeters
are either being operated at or near their original sampling
location or were transferred within or between the four
TERENO observatories thereby using temperature and
rainfall gradients to mimic future climatic conditions
(space for time), which allow measuring impacts of climate
change on terrestrial ecosystems. The lysimeters are cul-
tivated as grassland (intensive, extensive and non-used) or
arable land, the latter with a standardized crop rotation of
winter wheat—winter barley—winter rye—oat. This pub-
lication describes the general design of the SOILCan
experiment including a comprehensive description of the
pedological characteristics of the different sites and
This article is part of a Topical Collection in Environmental Earth
Sciences on ‘‘Water in Germany’’, guest edited by Daniel Karthe,
Peter Chifflard, Bernd Cyffka, Lucas Menzel, Heribert Nacken, Uta
Raeder, Mario Sommerha
¨user and Markus Weiler.
&Th. Pu
¨tz
t.puetz@fz-juelich.de
1
Institute of Bio- and Geoscience IBG-3: Agrosphere,
Forschungszentrum Ju
¨lich GmbH, 52425 Ju
¨lich, Germany
2
Atmospheric Environmental Research Division (IMK-IFU),
Karlsruhe Institute of Technology, KIT,
82467 Garmisch-Partenkirchen, Germany
3
Department Soil Physics, Helmholtz Centre for
Environmental Research – UFZ, 06120 Halle, Germany
4
Department Monitoring and Exploration Technologies,
Helmholtz Centre for Environmental Research – UFZ,
04318 Leipzig, Germany
5
Institute of Soil Ecology, German Research Centre
Environment and Health, HMGU, 85764 Neuherberg,
Germany
6
Leibniz-Centre for Agricultural Landscape Research (ZALF)
E.V, 15374 Mu
¨ncheberg, Germany
7
Helmholtz Centre Potsdam, German Research Centre for
Geosciences, Potsdam, GFZ, 14473 Potsdam, Germany
8
DLR Neustrelitz German Aerospace Centre, DLR,
17235 Neustrelitz, Germany
9
Department Community Ecology, Helmholtz Centre for
Environmental Research – UFZ, 06120 Halle, Germany
123
Environ Earth Sci (2016) 75:1242
DOI 10.1007/s12665-016-6031-5
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... The situation can only be created experimentally. Within the TERENO-SOILCan lysimeter-network (TERrestrial ENvironmental Observatories; Pütz et al., 2016), lysimeters extracted (monolithically) from different land use types (natural and managed grassland, arable land), and soil types were transferred according to a modified space-for-time approach to sites with differing climatic conditions. This setup allows us to evaluate the impact of altered climatic conditions on agricultural ecosystems (Pütz et al., 2016) and to quantify changes in the soil water cycle and crop production due to climate variability. ...
... Within the TERENO-SOILCan lysimeter-network (TERrestrial ENvironmental Observatories; Pütz et al., 2016), lysimeters extracted (monolithically) from different land use types (natural and managed grassland, arable land), and soil types were transferred according to a modified space-for-time approach to sites with differing climatic conditions. This setup allows us to evaluate the impact of altered climatic conditions on agricultural ecosystems (Pütz et al., 2016) and to quantify changes in the soil water cycle and crop production due to climate variability. In previous studies, the soil water balance components of the lysimeter at the original location have been compared with those of the transferred lysimeter to define the impact of different climatic and management conditions on nitrogen leaching (Fu et al., 2017), to evaluate precipitation measurement methods (Schnepper et al., 2023), and to improve the modelling of the hydrological processes and ecosystem productivity of the same soil but under different climatic conditions for arableland and grassland ecosystems (Jarvis et al., 2022;. ...
... The experimental set-up is part of the TERENO-SOILCan lysimeter network (Pütz et al., 2016). The lysimeters are 1.5 m deep and have a surface area of 1 m 2 . ...
Effects of different climatic conditions on soil water storage patterns
Article
Full-text available
The soil water storage (SWS) defines the crop productivity of a soil and varies under different climatic conditions. Pattern identification and quantification of these variations in SWS remain difficult due to the non-linear behaviour of SWS changes over time. Wavelet analysis (WA) provides a tool to efficiently visualize and quantify these patterns by transferring the time series from the time domain into the frequency domain. We applied WA to an 8-year time series of SWS, precipitation (P), and actual evapotranspiration (ETa) in similar soils of lysimeters in a colder and drier location and in a warmer and wetter location within Germany. Correlations between SWS, P, and ETa at these sites might reveal the influence of altered climatic conditions but also of subsequent wet and dry years on SWS changes. We found that wet and dry years exerted an influence over SWS changes by leading to faster or slower response times of SWS changes in relation to precipitation with respect to normal years. The observed disruption of annual patterns in the wavelet spectra of both sites was possibly caused by extreme events. Extreme precipitation events were visible in SWS and P wavelet spectra. Time shifts in correlations between ETa and SWS became smaller at the wetter and warmer site over time in comparison to at the cooler and drier site, where they stayed constant. This could be attributed to an earlier onset of the vegetation period over the years and, thus, to an earlier ETa peak every year. This reflects the impact of different climatic conditions on soil water budget parameters.
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... Since the construction of the first weighing lysimeter in Germany in 1902, the technology has improved a lot to assess the changes in the soil water storage of the soil column that fills the lysimeter (Goss & Ehlers, 2009). An example are the lysimeters of the German TERrestrial ENvironmental Observatories (TERENO) SOILCan network which are of high accuracy and high temporal resolution and provide the opportunity for in-depth long-term investigations of the different components of the soil water cycle (Zacharias et al., 2011;Pütz et al., 2016). The ability to successfully quantify small water fluxes such as dew and hoar frost formation as well as nighttime ETa demonstrates the high precision of the lysimeters . ...
... This dynamic bottom boundary control ensures that the soil water dynamics of the lysimeter match field conditions regarding their water flux direction and rate . Further technical specifications of the lysimeter used in this study are found in Pütz et al. (2016). ...
... Location of TERENO observatories over Germany and locations of the four study sites (marked by red circle), as well as distances (in km) between different sites (three different shades of blue are used to indicate different spatial scales; modified fromPütz et al., 2016). RO: Rollesbroich, WU: Wüstebach, SE: Selhausen, GW: Graswang. ...
Analysis of scale-dependent spatial correlations of actual evapotranspiration measured by lysimeters
Article
  • Oct 2024
  • AGR FOREST METEOROL
Accurate determination of actual evapotranspiration (ETa) is important in various research fields like hydrology, meteorology, ecology and agriculture. In situ ETa can be determined using weighing lysimeters and eddy covariance. However, despite being regarded as the most precise in situ method for measuring ETa, the information content of lysimeter measurements remains poorly understood. Here we examined the spatial correlations between ETa measured at different locations by lysimeter (ET-LYS) and at different locations by eddy covariance (ET-EC). This was done for the period 2015 - 2020 and the analysis was made for different spatial (range: 0 to 500 km) and temporal scales (range: 1 day to 1 year) using 23 lysimeters and 4 eddy covariance towers. We found that: (a) Same lysimeters at the plot scale show very high correlations of ET-LYS; (b) The Pearson correlation of daily standardized anomalies of ET-LYS between sites exhibit moderate to high correlations and were similar to that of ET-EC, indicating that lysimeter is generally as representative as EC regarding ETa, and can provide certain information at the landscape and larger regional scale. During winter, the spatial correlations for ET-LYS were smaller; (c) Wavelet analysis indicated that temporal correlations in ETa were strongest for distances in time around 12 months (yearly cycle) and less than three months. Spatial correlations were smaller under drought conditions (in the year 2018). Furthermore, combination of multiple ET-LYS from different sites improved the predictability of ET-LYS for another site, suggesting that ET-LYS can be predicted well using ET-LYS from different neighboring sites. Overall, lysimeter measurements can provide information at much larger scales compared to their small measurement area.
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... Since the construction o the rst weighing lysimeter in Germany in 1902, the technology has improved a lot to assess the changes in the soil water storage o the soil column that lls the lysimeter (Goss & Ehlers, 2009). An example are the lysimeters o the German TERrestrial ENvironmental Observatories (TERENO) SOILCan network which are o high accuracy and high temporal resolution and provide the opportunity or in-depth long-term investigations o the dierent components o the soil water cycle (Zacharias et al., 2011;Pütz et al., 2016). The ability to success-ully quantiy small water fuxes such as dew and hoar rost ormation as well as nighttime ETa demonstrates the high precision o the lysimeters . ...
... This dynamic bottom boundary control ensures that the soil water dynamics o the lysimeter match eld conditions regarding their water fux direction and rate . Further technical specications o the lysimeter used in this study are ound in Pütz et al. (2016). ...
... Location o TERENO observatories over Germany and locations o the our study sites (marked by red circle), as well as distances (in km) between dierent sites (three dierent shades o blue are used to indicate dierent spatial scales; modied romPütz et al., 2016). RO: Rollesbroich, WU: Wüstebach, SE: Selhausen, GW: Graswang. ...
View
... We filled in missing values in the collection process through interpolation, with only a few isolated instances of data points missing over the nearly two-year period. The observations from the SLSs required preprocessing to mitigate the impact of extraneous factors, such as dust storms, on the determination of water variability components in the vaporimeter observations [33,34]. Initially, the data collected during evident non-adsorption events, including rainfall, snowfall, and dust storms, were excluded. ...
... We filled in missing values in the collection process through interpolation, with only a few isolated instances of data points missing over the nearly two-year period. The observations from the SLSs required preprocessing to mitigate the impact of extraneous factors, such as dust storms, on the determination of water variability components in the vaporimeter observations [33,34]. Initially, the data collected during evident nonadsorption events, including rainfall, snowfall, and dust storms, were excluded. ...
Experimental Study of Water Vapor Adsorption on Bare Soil and Gravel Surfaces in an Arid Region of Ningxia, China
Article
Full-text available
  • Mar 2024
Water vapor adsorption on soil, a crucial non-rainfall water resource in arid regions, warrants further experimental investigation, particularly on two typical land surfaces: bare soil and gravel. This study examined the formation characteristics and influencing factors of vapor adsorption in an arid region of Northwestern China. Observations and analyses were conducted on adsorption and evaporation measurements taken by two small weighing lysimeters (SLSs); soil temperature at a depth of 5 cm; surface temperature; relative humidity; and air temperature at a height of 30 cm above the ground from 2019 to 2020. The adsorbed water in this area was more abundant at night and less abundant during the day, with a stable nightly adsorption rate of 0.013 mm/h. Adsorption was more frequent in spring and winter (from January to June and November to December), accounting for about 90% of the total annual adsorption. In 2019 and 2020, the ratio values of adsorption to evaporation were 0.16 and 0.10 for bare soil, and 0.10 and 0.12 for gravel, respectively. Adsorption was more likely to occur when the soil moisture content was less than 13%; the highest adsorption frequency was close to 20% when the RH was between 75 and 95%; low soil temperatures were more conducive to the occurrence of adsorption. The effect of temperature differences (TaTs) on adsorption was stronger than that of relative humidity. The adsorption frequency generally showed a bimodal change with increasing temperature difference, but the effect of temperature differences was less effective for gravel than bare soil. When the relative humidity was high and the temperature difference was weakly positive, the maximum adsorption intensity could reach 0.18 mm/h.
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... The lysimeters (Fig. 1) were manufactured according to Pütz et al. (2016) by UGT (Umwelt Geräte Technik, Müncheberg, Germany). The lysimeters were constructed of stainless-steel cylinders with a surface area of 1 m 2 and a depth of 1.5 m. ...
... To assess the water balance, the lysimeters were positioned on three load cells (Model 3510, Tedea-Huntleigh, Canoga Park, CA, USA) that had a resolution of 1 g (equivalent to 0.001 mm precipitation and a water flux of 0.001 l). The leaching water extracted from 140 cm depth was collected and stored in water tanks that were positioned on a plateau balance with a resolution of 1 g (equivalent to a water flux of 0.001 l (Pütz et al. 2016). Data on load cells and plateau balance were stored every minute on the data logger. ...
Lysimeter-based full fertilizer N balances corroborate direct dinitrogen emission measurements using the N gas flow method
Article
Full-text available
  • Feb 2024
  • BIOL FERT SOILS
The ¹⁵N gas flux (¹⁵NGF) method allows for direct in situ quantification of dinitrogen (N2) emissions from soils, but a successful cross-comparison with another method is missing. The objectives of this study were to quantify N2 emissions of a wheat rotation using the ¹⁵NGF method, to compare these N2 emissions with those obtained from a lysimeter-based ¹⁵N fertilizer mass balance approach, and to contextualize N2 emissions with ¹⁵N enrichment of N2 in soil air. For four sampling periods, fertilizer-derived N2 losses (¹⁵NGF method) were similar to unaccounted fertilizer N fates as obtained from the ¹⁵N mass balance approach. Total N2 emissions (¹⁵NGF method) amounted to 21 ± 3 kg N ha− 1, with 13 ± 2 kg N ha− 1 (7.5% of applied fertilizer N) originating from fertilizer. In comparison, the ¹⁵N mass balance approach overall indicated fertilizer-derived N2 emissions of 11%, equivalent to 18 ± 13 kg N ha− 1. Nitrous oxide (N2O) emissions were small (0.15 ± 0.01 kg N ha− 1 or 0.1% of fertilizer N), resulting in a large mean N2:(N2O + N2) ratio of 0.94 ± 0.06. Due to the applied drip fertigation, ammonia emissions accounted for < 1% of fertilizer-N, while N leaching was negligible. The temporal variability of N2 emissions was well explained by the δ¹⁵N2 in soil air down to 50 cm depth. We conclude the ¹⁵NGF method provides realistic estimates of field N2 emissions and should be more widely used to better understand soil N2 losses. Moreover, combining soil air δ¹⁵N2 measurements with diffusion modeling might be an alternative approach for constraining soil N2 emissions.
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... The increasing use of lysimeters in multidisciplinary studies relates to the role of water and energy fluxes as fundamental ecological frames (Lloyd and Taylor, 1994;Wang and Dickinson, 2012). In fact, lysimeters allow the use of other sensors to further characterize the water and energy fluxes, such as temperature probes, heat flux plates, and water content or potential sensors (Pütz et al., 2016;Kohfahl et al., 2021;Riedl et al., 2022). ...
View
... To parameterize the hydrological model for this study, a comprehensive and detailed dataset was required. Therefore, we used data measured at one MR facility as described by Lärm et al. (2023) at the Selhausen test site (Figure 1a) located within the TERENO (TERrestrial ENvironmen-tal Observatories) Eifel-Lower Rhine observatory in North Rhine-Westphalia, Germany (Bogena et al., 2018;Pütz et al., 2016). At this site, two identically constructed MR facilities were present, situated within different river sediments of the Rur river catchment (Bogena et al., 2018;Brogi et al., 2019;Weihermüller et al., 2007). ...
Spatial variability of hydraulic parameters of a cropped soil using horizontal crosshole ground penetrating radar
Article
Full-text available
Soil hydraulic parameters (SHP) play a crucial role controlling the spatiotemporal distribution of water in the soil–plant continuum and thus affect water availability for crops. To provide reliable information on the SHP at different scales, measurement techniques with a good spatial resolution and low labor costs are required. In this study, we used crosshole ground penetrating radar (GPR)‐derived soil water contents (SWCs) measured along horizontal rhizotubes under a controlled experimental test site cropped with winter wheat to estimate the unimodal and dual‐porosity soil hydraulic characteristics with different soil layer setups. Therefore, sequential inversion of the GPR‐derived SWCs was performed using the hydrological model HYDRUS‐1D, whereby the SWC data were either averaged prior inversion or used in a spatially distributed way. To analyze if the time‐lapse gathered GPR data contain enough information to estimate the SHP, additional synthetic studies were performed increasing the data resolution to daily GPR measurements. The results showed that the time‐lapse data contained enough information to estimate the SHP accurately. Additionally, spatially distributed soil hydraulic characteristics differed from the one estimated based on averaged SWCs derived from spatially distributed GPR data. Finally, we derived spatially resolved SHP, which can be used for 3D process rhizosphere processes and root–soil interaction modeling.
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... In 2010, the TERENO SOILCan lysimeter network was initiated, which installed high precision lysimeters at TERENO sites. The SOILCan lysimeter network is based on the concept of "space for time" substitution, in which intact soils were transferred along temperature and precipitation gradients within and between TERENO observatories to investigate the expected impacts of climate change on grassland or arable soils (Pütz et al., 2016). SOILCan comprises 132 lysimeters at 13 different TERENO sites, each paired with a suite of meteorological measurements. ...
Fifteen Years of Integrated Terrestrial Environmental Observatories (TERENO) in Germany: Functions, Services, and Lessons Learned
Article
Full-text available
  • Jun 2024
The need to develop and provide integrated observation systems to better understand and manage global and regional environmental change is one of the major challenges facing Earth system science today. In 2008, the German Helmholtz Association took up this challenge and launched the German research infrastructure TERrestrial ENvironmental Observatories (TERENO). The aim of TERENO is the establishment and maintenance of a network of observatories as a basis for an interdisciplinary and long‐term research program to investigate the effects of global environmental change on terrestrial ecosystems and their socio‐economic consequences. State‐of‐the‐art methods from the field of environmental monitoring, geophysics, remote sensing, and modeling are used to record and analyze states and fluxes in different environmental disciplines from groundwater through the vadose zone, surface water, and biosphere, up to the lower atmosphere. Over the past 15 years we have collectively gained experience in operating a long‐term observing network, thereby overcoming unexpected operational and institutional challenges, exceeding expectations, and facilitating new research. Today, the TERENO network is a key pillar for environmental modeling and forecasting in Germany, an information hub for practitioners and policy stakeholders in agriculture, forestry, and water management at regional to national levels, a nucleus for international collaboration, academic training and scientific outreach, an important anchor for large‐scale experiments, and a trigger for methodological innovation and technological progress. This article describes TERENO's key services and functions, presents the main lessons learned from this 15‐year effort, and emphasizes the need to continue long‐term integrated environmental monitoring programmes in the future.
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... SWC is measured within each lysimeter at a depth of 0.1 m below the surface with time domain reflectometry probes (CS610, Campbell Scientific, North Logan, UT, USA) at a resolution of 0.1 % SWC, according to the manufacturer. More details on the technical specifications of lysimeter facilities within SOILCan are given in Pütz et al. (2016), on excavation methods in Pütz and Groh (2023), and on the Selhausen facility in Groh et al. (2022). ...
Interpretability of negative latent heat fluxes from eddy covariance measurements in dry conditions
Article
Full-text available
  • Apr 2024
  • BG
It is known from arid and semi-arid ecosystems that atmospheric water vapor can directly be adsorbed by the soil matrix. Soil water vapor adsorption was typically neglected and only recently received attention because of improvements in measurement techniques. One technique rarely explored for the measurement of soil water vapor adsorption is eddy covariance (EC). Soil water vapor adsorption may be detectable as downwardly directed (i.e., negative) EC latent heat (λE) flux measurements under dry conditions, but a systematic assessment of the use of negative λE fluxes from EC flux stations to characterize adsorption is missing. We propose a classification method to characterize soil water vapor adsorption, excluding conditions of dew and fog when λE derived from EC is not trustworthy due to stable atmospheric conditions. We compare downwardly directed λE fluxes from EC with measurements from weighing lysimeters for 4 years in a Mediterranean savanna ecosystem and 3 years in a temperate agricultural site. Our aim is to assess if overnight water inputs from soil water vapor adsorption differ between ecosystems and how well they are detectable by EC. At the Mediterranean site, the lysimeters measured soil water vapor adsorption each summer, whereas at the temperate site, soil water vapor adsorption was much rarer and was measured predominantly under an extreme drought event in 2018. During 30 % of nights in the 4-year measurement period at the Mediterranean site, the EC technique detected downwardly directed λE fluxes of which 88.8 % were confirmed to be soil water vapor adsorption by at least one lysimeter. At the temperate site, downwardly directed λE fluxes were only recorded during 15 % of the nights, with only 36.8 % of half hours matching simultaneous lysimeter measurement of soil water vapor adsorption. This relationship slightly improved to 61 % under bare-soil conditions and extreme droughts. This underlines that soil water vapor adsorption is likely a much more relevant process in arid ecosystems compared to temperate ones and that the EC method was able to capture this difference. The comparisons of the amounts of soil water vapor adsorption between the two methods revealed a substantial underestimation of the EC compared to the lysimeters. This underestimation was, however, comparable with the underestimation in evaporation by the eddy covariance and improved in conditions of higher turbulence. Based on a random-forest-based feature selection, we found the mismatch between the methods being dominantly related to the site's inherent variability in soil conditions, namely soil water status, and soil (surface) temperature. We further demonstrate that although the water flux is very small with mean values of 0.04 or 0.06 mm per night for EC or lysimeter, respectively, it can be a substantial fraction of the diel soil water balance under dry conditions. Although the two instruments substantially differ with regard to the measured ratio of adsorption to evaporation over 24 h with 64 % and 25 % for the lysimeter and EC methods, they are in either case substantial. Given the usefulness of EC for detecting soil water vapor adsorption as demonstrated here, there is potential for investigating adsorption in more climate regions thanks to the greater abundance of EC measurements compared to lysimeter observations.
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Assessing soil fertilization effects using time-lapse electromagnetic induction
Preprint
Full-text available
  • Oct 2024
Adding mineral fertilizers and mineral nutrient is a common practice in conventional farming and fundamental to maintain optimal yield and crop quality, whereby nitrogen is the most applied fertilizer often used excessively, leading to adverse environmental impacts. To assist farmers in optimal fertilization and crop management, non-invasive geophysical methods can provide knowledge about the spatial and temporal distributions of nutrients in the soil. In recent years, electromagnetic induction (EMI) is widely used for field characterization, to delineate soil units and management zones or to estimate soil properties and states. Additionally, ground penetrating radar (GPR) and electrical resistivity tomography (ERT) have been used in local studies to measure changes of soil properties. Unfortunately, the measured geophysical signals are confounded by horizontal and vertical changes of soil states and parameters and the single contributions of those states and parameters are not easy to disentangle. Within fields, and also between fields, fertilization management might vary in space and time, and therefore, the differences in pore fluid conductivity caused directly by fertilization, or indirectly by different crop performance, makes the interpretation of large-scale geophysical survey over field borders complicated. To study the direct effect of mineral fertilization and its effects on the soil electrical conductivity, a field experiment was performed on 21 bare soil plots with seven different fertilization treatments. As fertilizers, calcium ammonium nitrate (CAN) and potassium chloride (KCl) were chosen and applied in three dosages. Soil water content, soil temperature, and bulk electrical conductivity were recorded permanently over 450 days. Additionally, 20 EMI, 7 GPR, and 9 ERT surveys were performed and at days of ERT measurements soil samples for nitrate and reference soil electrical conductivity measurements were taken. The results showed that the commonly used CAN application dosage did not impact the geophysical signals significantly. On the other hand, EMI and ERT were able to trace back the temporal changes in nitrate concentrations in the soil profile over more than one year. On the other hand, the results also showed, that both techniques were not able to trace the nitrate concentrations in the very shallow soil layer of 0–10 cm. Irrespectively of the low impact of fertilization on the geophysical signal, the results indicated that past fertilization practices cannot be neglected in EMI studies, especially if surveys are performed over large areas with different fertilization practices or crop grown with different fertilizer demands or uptake.
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A comprehensive filtering scheme for high-resolution estimation of the water balance components from high-precision lysimeters
Article
Full-text available
  • Aug 2015
Large weighing lysimeters are currently the most precise method to directly measure all components of the terrestrial water balance in parallel via the built-in weighing system. As lysimeters are exposed to several external forces such as management practices or wind influencing the weighing data, the calculated fluxes of precipitation and evapotranspiration can be altered considerably without having applied appropriate corrections to the raw data. Therefore, adequate filtering schemes for obtaining most accurate estimates of the water balance components are required. In this study, we use data from the TERENO (TERrestrial ENvironmental Observatories) SoilCan research site in Bad Lauchstädt to develop a comprehensive filtering procedure for high-precision lysimeter data, which is designed to deal with various kinds of possible errors starting from the elimination of large disturbances in the raw data resulting e.g., from management practices all the way to the reduction of noise caused e.g., by moderate wind. Furthermore, we analyze the influence of averaging times and thresholds required by some of the filtering steps on the calculated water balance and investigate the ability of two adaptive filtering methods (the adaptive window and adaptive threshold filter (AWAT filter; Peters et al., 2014), and a new synchro filter applicable to the data from a set of several lysimeters) to further reduce the filtering error. Finally, we take advantage of the data sets of all 18 lysimeters running in parallel at the Bad Lauchstädt site to evaluate the performance and accuracy of the proposed filtering scheme. For the tested time interval of 2 months, we show that the estimation of the water balance with high temporal resolution and good accuracy is possible. The filtering code can be downloaded from the journal website as Supplement to this publication.
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How to Control the Lysimeter Bottom Boundary to Investigate the Effect of Climate Change on Soil Processes?
Article
Full-text available
Core Ideas The water flux in lysimeters with a tension‐controlled bottom boundary depends strongly on the applied pressure head. The surrounding subsurface conditions have a significant influence on the measured pressure heads that are used to control the bottom boundary of transferred lysimeters. Use of nonappropriate water table depths and soil textural properties which do not correspond to the conditions where the lysimeter originated can lead to large differences in soil water fluxes. The control of the bottom boundary of transferred lysimeters should be managed by measured pressure heads from the site where the lysimeter was taken from in order to enable a direct comparison of changes in soils and to investigate the effect of climate change on soil processes and soil functions. A dynamic tension‐controlled bottom boundary of lysimeters allows observing water and matter fluxes in lysimeters that are close to natural field conditions, as pressure heads at the lysimeter bottom are adjusted to measured pressure heads at the same depth in the surrounding field. However lysimeters are often transferred from their sampling location for practical reasons or to study, for example, the effect of climate change on soil functions. This transfer can be accompanied by a change aboveground but also in subsurface conditions that are used to control the bottom boundary and that may affect the soil water balance of lysimeters. This issue is also relevant for lysimeter stations which use a tension‐controlled bottom boundary and are not directly installed near the site of excavation. The potential impact of different bottom boundary conditions on the water balance of lysimeters that were transferred in a climate impact experiment (SOILCan) was investigated exemplarily by a numerical study. Results showed that by using nonappropriate pressure heads, which were measured in soil profiles with a different texture and water table depth than the profile where the lysimeter was taken from, had partially large impacts on soil water fluxes, especially when the water table was located within a specific critical range. Different climate conditions between sampling and installation site were buffered by the soil and did not show a strong influence on the bottom boundary control of lysimeters when the groundwater table depth was assumed to remain constant. Considering a change in groundwater table depths due to changing climate tempered the effects of climate change on the soil water balance terms. In general, results demonstrate the importance of a proper control of the lysimeters bottom boundary conditions in studies that investigate the influence of climate change on soil functions and ecosystem variables by transferring lysimeter along climate gradients.
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Modeling Soil Processes: Review, Key Challenges, and New Perspectives.
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We reviewed soil modeling and the role of soil processes in quantifying ecosystem services. Key challenges were identified and the establishment of a soil modeling consortium to advance soil modeling activities, provide a data-model platform, perform model intercomparison and foster communication amongst Earth science disciplines is proposed.
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Modeling Soil Processes: Review, Key Challenges, and New Perspectives
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Core Ideas A community effort is needed to move soil modeling forward. Establishing an international soil modeling consortium is key in this respect. There is a need to better integrate existing knowledge in soil models. Integration of data and models is a key challenge in soil modeling. The remarkable complexity of soil and its importance to a wide range of ecosystem services presents major challenges to the modeling of soil processes. Although major progress in soil models has occurred in the last decades, models of soil processes remain disjointed between disciplines or ecosystem services, with considerable uncertainty remaining in the quality of predictions and several challenges that remain yet to be addressed. First, there is a need to improve exchange of knowledge and experience among the different disciplines in soil science and to reach out to other Earth science communities. Second, the community needs to develop a new generation of soil models based on a systemic approach comprising relevant physical, chemical, and biological processes to address critical knowledge gaps in our understanding of soil processes and their interactions. Overcoming these challenges will facilitate exchanges between soil modeling and climate, plant, and social science modeling communities. It will allow us to contribute to preserve and improve our assessment of ecosystem services and advance our understanding of climate‐change feedback mechanisms, among others, thereby facilitating and strengthening communication among scientific disciplines and society. We review the role of modeling soil processes in quantifying key soil processes that shape ecosystem services, with a focus on provisioning and regulating services. We then identify key challenges in modeling soil processes, including the systematic incorporation of heterogeneity and uncertainty, the integration of data and models, and strategies for effective integration of knowledge on physical, chemical, and biological soil processes. We discuss how the soil modeling community could best interface with modern modeling activities in other disciplines, such as climate, ecology, and plant research, and how to weave novel observation and measurement techniques into soil models. We propose the establishment of an international soil modeling consortium to coherently advance soil modeling activities and foster communication with other Earth science disciplines. Such a consortium should promote soil modeling platforms and data repository for model development, calibration and intercomparison essential for addressing contemporary challenges.
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Biodiversity increases the resistance of ecosystem productivity to climate extremes
Article
Full-text available
  • Oct 2015
  • NATURE
It remains unclear whether biodiversity buffers ecosystems against climate extremes, which are becoming increasingly frequent worldwide. Early results suggested that the ecosystem productivity of diverse grassland plant communities was more resistant, changing less during drought, and more resilient, recovering more quickly after drought, than that of depauperate communities. However, subsequent experimental tests produced mixed results. Here we use data from 46 experiments that manipulated grassland plant diversity to test whether biodiversity provides resistance during and resilience after climate events. We show that biodiversity increased ecosystem resistance for a broad range of climate events, including wet or dry, moderate or extreme, and brief or prolonged events. Across all studies and climate events, the productivity of low-diversity communities with one or two species changed by approximately 50% during climate events, whereas that of high-diversity communities with 16-32 species was more resistant, changing by only approximately 25%. By a year after each climate event, ecosystem productivity had often fully recovered, or overshot, normal levels of productivity in both high- and low-diversity communities, leading to no detectable dependence of ecosystem resilience on biodiversity. Our results suggest that biodiversity mainly stabilizes ecosystem productivity, and productivity-dependent ecosystem services, by increasing resistance to climate events. Anthropogenic environmental changes that drive biodiversity loss thus seem likely to decrease ecosystem stability, and restoration of biodiversity to increase it, mainly by changing the resistance of ecosystem productivity to climate events.
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Q-SOS—A Sensor Observation Service for Accessing Quality Descriptions of Environmental Data
Article
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  • Aug 2015
  • ISPRS
The worldwide Sensor Web comprises observation data from diverse sources. Each data provider may process and assess datasets differently before making them available online. This information is often invisible to end users. Therefore, publishing observation data with quality descriptions is vital as it helps users to assess the suitability of data for their applications. It is also important to capture contextual information concerning data quality such as provenance to trace back incorrect data to its origins. In the Open Geospatial Consortium (OGC)'s Sensor Web Enablement (SWE) framework, there is no sufficiently and practically applicable approach how these aspects can be systematically represented and made accessible. This paper presents Q-SOS-an extension of the OGC's Sensor Observation Service (SOS) that supports retrieval of observation data together with quality descriptions. These descriptions are represented in an observation data model covering various aspects of data quality assessment. The service and the data model have been developed based on open standards and open source tools, and are productively being used to share observation data from the TERENO observatory infrastructure. We discuss the advantages of deploying the presented solutions from data provider and consumer viewpoints. Enhancements applied to the related open-source developments are also introduced.
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Water balance and leaching of dissolved organic and inorganic carbon of eroded Luvisols using high precision weighing lysimeters
Article
  • Jan 2017
  • SOIL TILL RES
Erosion can be observed in many arable soil landscapes such as those of the hummocky ground moraine. The topsoil removal by water erosion in combination with tillage operations (e.g., ploughing) is leading to truncated soil profiles along slopes with reduced solum thickness and modified properties of soil horizons. The objectives were to identify and quantify effects of erosion-induced soil modifications on the water balance and the leaching of dissolved organic and inorganic carbon (DOC, DIC), considering complex soil-crop interactions. The idea was to compare lysimeter-based water and solute balances of eroded Luvisols that differed in solum depth. The six high precision weighing lysimeters (1.0 m² surface, 1.5 m high; UMS Science-Lysimeter) had a resolution of 10 g (=0.01 mm). The cylindrical steel rings of the lysimeters were filled with undisturbed soil monoliths from two fields. Lysimeter soils were cultivated with maize, winter rye, Sudangrass, triticale, alfalfa, and Persian clover during the observation period April 2011 to March 2014. Cumulative drainage of the six lysimeter soils ranged from 57 for the least to 104 mm y⁻¹ for the most eroded Luvisols; the differences of about 83% indicated that the erosional profile modifications in combination with differences in crop development affected the water balance components. Soil-crop interactions depending on properties of differently-truncated soil profiles caused varying amounts of precipitation and evapotranspiration for the 3-years. Since lysimeter effluent concentrations of DOC (5 ± 0.5 mg L⁻¹) and DIC (62 ± 5 mg L⁻¹) were relatively constant in time, the DOC and DIC leaching was mainly controlled by the water fluxes. Thus, the leaching rates ranged from 0.3 (Luvisol) to 0.5 g m⁻² yr⁻¹ (eroded Luvisol) for DOC and 3.3 (Luvisol) to 7.1 g m⁻² yr⁻¹ (eroded Luvisol) for DIC. Because of the complex soil crop interactions, a clear relation between erosion-induced soil profile modification and the water balance and DOC and DIC leaching could not be identified. Nevertheless, when transferring lysimeter results to the arable soil landscape the erosion-induced modifications even within the same pedogenetic soil type should be considered.
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Revisiting hydraulic hysteresis based on long term monitoring of hydraulic states in lysimeters
Article
Hysteretic processes have been recognized for decades as an important characteristic of soil hydraulic behavior. Several studies confirmed that wetting and drying periods cannot be described by a simple functional relationship, and that some nonequilibrium of the water retention characteristics has to be taken into account. A large number of models describing the hysteresis of the soil water retention characteristic were successfully tested on soil cores under controlled laboratory conditions. However, its relevance under field conditions under natural forcings has rarely been investigated. In practice, the modeling of field soils usually neglects the hysteretic nature of soil hydraulic properties. In this study, long-term observations of water content and matric potential in lysimeters of the lysimeter network TERENO-SoilCan are presented, clearly demonstrating the hysteretic behavior of field soils. We propose a classification into three categories related to different time scales. Based on synthetic and long-term monitoring data, three different models of hysteresis were applied to data sets showing different degrees of hysteresis. We found no single model to be superior to the others. The model ranking depended on the degree of hysteresis. All models were able to reflect the general structure of hysteresis in most cases but failed to reproduce the detailed trajectories of state variables especially under highly transient conditions. As an important result we found that the temporal dynamics of wetting and drying significantly affects these trajectories which should be accounted for in future model concepts.
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Third-Generation Lysimeters: Scientific Engineered Monitoring Systems
Chapter
  • Jan 2014
Third-generation lysimeters meet the needs of 21st century environmental research and monitoring. High-resolution sensors, field-replicating hydraulic and thermal conditions and an excavation method showing the soil inside the lysimeter cylinder are important features in their quality process chain. Older lysimeter systems are unable to provide such detailed information about the soil water budget and all linked processes. Due to an increasing awareness of climate change, water management, agronomy and soil science issues, it was essential to upgrade lysimeter systems in order to gather more detailed information about processes and fluxes. Different lysimeter station layouts were developed for specific requirements and to increase their fields of application for particular tasks such as fertilisation treatments or irrigation and reproducing identical climatic conditions. Additionally, highly engineered third-generation bespoke lysimeter types are available to support particular projects. As an example, the meteorological lysimeter precisely measures precipitation, evapotranspiration and leachate. For this, the lysimeter weighs to the nearest gramme range a surface of 1 m2 and supplies results to an accuracy of 0.01 mm for water input such as rain, dew, frost or snow and water output by evapotranspiration and leachate as well as reporting the change of soil water content. Combined with additionally measured meteorological data, this enables water balance models to be developed and potential evapotranspiration can be determined.
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