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Lysimeter application for measuring the water and solute fluxes with high precision
Abstract
Different methods exist for measuring water and solute flux in and below the root zone. Besides indirect methods (e.g. water balance, tensiometer, time domain reflectometry, frequency domain reflectometry and environmental tracer), direct methods (e.g. drainagetype lysimeter, water flux meter) have a long tradition and have been successfully used in seepage research. However, lysimeters are most reliable and accurate for in situ water and solute assessment. A large weighable outdoor lysimeter is the best method for obtaining reliable data about seepage water quantity and quality, but it involves significant investment and additional expenses for maintenance. To tackle this problem new methods for the vertical collection of large volume soil monoliths and for the placement of the lysimeter in a container lysimeter unit have been developed. The design of lysimeters typically used in Europe - a weighable gravitation lysimeter and a weighable groundwater lysimeter are explained. An example is given for the high precision of the new lysimeter weighing technique. Besides recording rainfall and seepage, its weighing precision makes it possible to register mass input by dew, fog or rime. It also permits accurate calculation of actual evapotranspiration. The newly developed lysimeter types will be an essential tool for scaling up results obtained in small-scale experiments to larger geographical units. Furthermore, the newly developed experimental set-up allows a scenario simulation of topical climatic and hydrologic questions, e.g. global warming and its impact on the water and solute balance, the influence of dew and fog on the establishment of a vegetation cover in arid areas or the transport of contaminants during heavy rainfall following a severe drying-up of the soil profile.
... To separate external sources of errors from the weighing series, data smoothing was frequently used to remove the noise in high I General Introduction weighing system have been proposed to quantify the overall water balance ( ) including water fluxes at the upper and bottom lysimeter boundaries. Today, several weighing lysimeter systems including additional sensors and are in use for a variety of purposes (Meißner et al., 2010 s, solute and water balance modeling or analysis of precision weighing lysimeters (Unold and Fank, 2008) as introduced in this study are designed to determine even small amounts of precipitation manifested as rime, fog or dew by measuring small changes in water storage in a temporal resolution of one hour ...
... Optimal conditions for P-measurements would require rain collection at the soil surface with micro topographic structure that is identical with that of the surrounding area (Mekonnen et al., 2015). In this context, lysimeters are able to match surrounding field conditions (Unold and Fank, 2008;Meißner et al., 2010) like the crop sequence or the micro topographic surface structures. Lysimeters with a high-precision weighing system (Unold and Fank, 2008) have been proposed to quantify precipitation in a high temporal resolution (Peters et al., 2014;Schrader et al., 2013). ...
... Time-series of mass changes from high precision lysimeter could be used to estimate P, if deep drainage rates are determined independently, on assuming that positive values of ∆M represent P and negative values ET, respectively (e.g., Young et al., 1996). In this way lysimeter technology developed at a quality level to investigate hydrological aspects exceeding old-fashioned outdoor leaching tests (Meißner et al., 2010). ...
In the arable soil landscape of hummocky ground moraines, an erosion-affected spatial differentiation of soils can be observed. Man-made erosion leads to soil profile modifications along slopes with changed solum thickness and modified properties of soil horizons due to water erosion in combination with tillage operations. Soil erosion creates, thereby, spatial patterns of soil properties (e.g., texture and organic matter content) and differences in crop development. However, little is known about the manner in which water fluxes are affected by soil-crop interactions depending on contrasting properties of differently-developed soil horizons and how water fluxes influence the carbon transport in an eroded landscape. To identify such feedbacks between erosion-induced soil profile modifications and the 1D-water and solute balance, high-precision weighing lysimeters equipped with a wide range of sensor technique were filled with undisturbed soil monoliths that differed in the degree of past soil erosion. Furthermore, lysimeter effluent concentrations were analyzed for dissolved carbon fractions in bi-weekly intervals. The water balance components measured by high precision lysimeters varied from the most eroded to the less eroded monolith up to 83 % (deep drainage) primarily caused due to varying amounts of precipitation and evapotranspiration for a 3-years period. Here, interactions between crop development and contrasting rainfall interception by above ground biomass could explain differences in water balance components. Concentrations of dissolved carbon in soil water samples were relatively constant in time, suggesting carbon leaching was mainly affected by water fluxes in this observation period. For the lysimeter-based water balance analysis, a filtering scheme was developed considering temporal autocorrelation. The minute-based autocorrelation analysis of mass changes from lysimeter time series revealed characteristic autocorrelation lengths ranging from 23 to 76 minutes. Thereby, temporal autocorrelation provided an optimal approximation of precipitation quantities. However, the high temporal resolution in lysimeter time series is restricted by the lengths of autocorrelation. Erosion-induced but also gradual changes in soil properties were reflected by dynamics of soil water retention properties in the lysimeter soils. Short-term and long-term hysteretic water retention data suggested seasonal wettability problems of soils increasingly limited rewetting of previously dried pore regions. Differences in water retention were assigned to soil tillage operations and the erosion history at different slope positions. The threedimensional spatial pattern of soil types that result from erosional soil profile modifications were also reflected in differences of crop root development at different landscape positions. Contrasting root densities revealed positive relations of root and aboveground plant characteristics. Differences in the spatially-distributed root growth between different eroded soil types provided indications that root development was affected by the erosion-induced soil evolution processes. Overall, the current thesis corroborated the hypothesis that erosion-induced soil profile modifications affect the soil water balance, carbon leaching and soil hydraulic properties, but also the crop root system is influenced by erosion-induced spatial patterns of soil properties in the arable hummocky post glacial soil landscape. The results will help to improve model predictions of water and solute movement in arable soils and to understand interactions between soil erosion and carbon pathways regarding sink-or-source terms in landscapes.
... Lysimetry is originally a method for the investigation of soil hydrology and soil chemistry. In the last few years, however, lysimeters will be increasingly used for precipitation measurements due to the high precision weighing system (von Unold and Fank, 2008;Meissner et al., 2010;Schrader et al., 2013;Peters et al., 2014;Gebler et al., 2015;Herbrich and Gerke, 2016;Hoffmann et al., 2016). The advantage of lysimeters in rainfall recording lies in the recognition that they do not exhibit the commonly occurring errors associated with the standard rain gauges. ...
... 2.5. Calculating precipitation from lysimeter data Meissner et al. (2000Meissner et al. ( , 2007Meissner et al. ( , 2010 have shown that weighable lysimeters were able to measure water fluxes with high precision. The total mass of the system (M) was the sum of the mass of lysimeter (M lys ) and of drainage (M drain ). ...
Current precipitation measurements are conducted largely by simple automatic rain gauges. Despite being error-prone and sometimes of questionable accuracy, the procedure is still widely used. In recent years new possibilities have emerged, which are based on different measuring principles. Although the application of alternative devices is increasing, its use in research is limited. In this study, precipitation measurements by different devices were compared, and systematic errors caused by individual characteristics were corrected. Data were collected by means of a monitoring network, which included a piezoelectric precipitation sensor mounted at 2.3 m, a standard tipping bucket at 1 m, and a weighable gravitation lysimeter at ground level. As measurements at ground level are considered as optimum, the records of the lysimeter were thereby determined as a reference. The results showed that precipitation measured by elevated rain gauges differed in total between −6.8% and +35% compared to rainfall measured by the lysimeter. The records correlated well, but the analyses indicated a strong influence of the precipitation intensity on the recorded amount of precipitation. The deviations between values of the rain gauges and those of the lysimeter increased with rainfall intensity. In general, the tipping bucket demonstrated negative error values and indicated an underestimation of precipitation compared to records at ground level, whereas the piezoelectric precipitation sensor showed an overestimation by highly positive error values. A subsequent precipitation correction through the linear scaling method improved significantly the raw data of the rain gauges.
... Prolonged water saturation in the capillary fringe may lead to anoxic conditions that, among other chemical artifacts ascribed to lysimeter studies, are particularly crucial in NO 3 -NO 2 biochemistry. For instance, Hagenau et al. (2015) detected differences between water regimes determined in lysimeters and nearby soils, whereas Meissner et al. (2010) found no significant differences in the water regimes and effluent quality between a free-draining lysimeter and the adjacent soil. However, the unconfined soil of Meissner et al. (2010) was sitting on groundwater whose level temporarily varied around the 1-m depth. ...
... For instance, Hagenau et al. (2015) detected differences between water regimes determined in lysimeters and nearby soils, whereas Meissner et al. (2010) found no significant differences in the water regimes and effluent quality between a free-draining lysimeter and the adjacent soil. However, the unconfined soil of Meissner et al. (2010) was sitting on groundwater whose level temporarily varied around the 1-m depth. They adjusted level variations in the unhampered neighboring soil experimentally to the confined lysimeter soil. ...
Core Ideas
Preferential flow in a free‐draining lysimeter is approached by viscous flow theory.
Water perching at the lysimeter bottom is assessed with viscous flow theory.
Viscous flow theory is applied to rewetting after exceptional drought.
Rapid infiltration and drainage in a free‐draining weighing lysimeter are assessed with a viscous flow approach that is based on the concept of moving water films. The two parameters film thickness and specific contact area of the film per unit volume of the permeable medium together with the rate and duration of water input suffice to quantify viscous flow at the Darcy scale. The two parameters are deducible from wetting front velocities and water content variations during the passing of the film. Temporarily perching water tables at lysimeter bottoms are considered artifacts of the lysimeter method that may severely alter the biogeochemistry of the effluent. The viscous flow approach assesses the duration of water perching from drainage flow interpretation. Perching in the sense of viscous flow occurred at most 10% of the time during drainage flow. Drainage ceased completely during a 6‐mo period that yielded only 46% of rainfall compared with the 30‐yr average. During rewetting of the lysimeter soil, viscous flow applied to infiltrations of nine precipitation episodes, showing successive penetrations of wetting fronts shortly before the onset of drainage.
... Lysimetry is a well-established technique to measure evapotranspiration (e.g., Maidment, 1992;Rana and Katerji, 2000;Goss and Ehlers, 2009;Meissner et al., 2010; see also Seneviratne et al., 2012, for a recent overview). Lysimeters are vessels containing a soil column in near-natural condition. ...
... Surface soil heat flux G is determined following Fuchs and Tanner (1968) by calculating the change in heat storage above the sensors. This estimation is performed using the average of three soil temperature sensors (107T, Campbell Scientific Inc., USA) installed at the same locations as the heat-flux plates, as well as soil moisture (TRIME-IT, IMKO GmbH, D) and soil density measurements (Mittelbach et al., 2012). The ensemble of the three different locations for soil heat flux and soil temperature is used to account for the spatial heterogeneity of the soil matrix and thus to obtain surface soil heat-flux data, which are spatially represen- tative for the footprint domain of all other measured components of the energy balance. ...
Accurate measurements of evapotranspiration are required for many meteorological, climatological, ecological, and hydrological research applications and developments. Here we examine and compare two well-established methods to determine evapotranspiration at the site level: lysimeter-based measurements (EL) and eddy covariance (EC) flux measurements (EEC). The analyses are based on parallel measurements carried out with these two methods at the research catchment Rietholzbach in northeastern Switzerland, and cover the time period of June 2009 to December 2015. The measurements are compared on various timescales, and with respect to a 40-year lysimeter-based evapotranspiration time series. Overall, the lysimeter and EC measurements agree well, especially on the annual timescale. On that timescale, the long-term lysimeter measurements also correspond well with catchment water-balance estimates of evapotranspiration. This highlights the representativeness of the site-level lysimeter and EC measurements for the entire catchment despite their comparatively small source areas and the heterogeneous land use and topography within the catchment. Furthermore, we identify that lack of reliable EC measurements using open-path gas analyzers during and following precipitation events (due to limitations of the measurement technique under these conditions) significantly contributes to an underestimation of EEC and to the overall energy balance gap at the site.
... Many modifications to drainage lysimeters or soil columns have been proposed, described, and tested (Fuhr et al., 1998;Van Wesenbeeck et al., 1998;Meissner et al., 2000;Schroll and Kühn, 2004;Wolters et al., 2004;Meissner et al., 2008;Meißner et al., 2010). von Unold and Fank (2008) described four standardized lysimeter configurations, which includes hydro-lysimeter, meteorological, scientific field and agro-lysimeters. ...
... These lysimeters still have limitations in monitoring lateral flow of water. Drainage lysimeters or soil columns have been used for developing evapotranspiration and leaching models (Payero and Irmak, 2008;Meißner et al., 2010) and for monitoring pesticides (Fuhr et al., 1998) and other purposes already discussed above. Temporal resolution for monitoring soil solution largely depends on precipitation or irrigation received in study area. ...
Core Ideas
Soil solution sampling is essential to better understand water and solute movement in soils.
A review of different types of soil solution samplers is provided in this paper, including: drainage lysimeter or soil column, pan lysimeter, resin bags or membranes, wick lysimeters, suction cup, and suction plate.
Recent developments, modifications, and recommendation criteria are provided for selecting appropriate soil solution extraction samplers.
A number of contaminants including agrochemicals (fertilizers, pesticides), heavy metals, trace elements, and pathogenic microbes along with pharmaceuticals and hormones used in animal production move through the soil and are responsible for degradation of groundwater quality. Therefore, it is essential to sample soil solution for better understanding of movement and environmental fate of various contaminants in soils. We review different soil solution extraction samplers. The soil solution samplers discussed here are: drainage lysimeter or soil column, pan lysimeter, resin bags or membranes, wick lysimeters, suction cup, and suction plate. We have reviewed 304 journal articles representing a wide array of scientific disciplines. A brief history of soil solution monitoring and terminology used for describing various soil solution samplers is also provided. This review classifies literature on the basis of type of soil solution extraction samplers, soil type, land use–land cover (LULC), and analytes measured. Recommendation criteria are provided for selecting appropriate soil solution extraction samplers based on spatial and temporal variation, cost, soil type, amount of disturbance caused during installation of soil solution samplers, and monitoring of leachates involving different cations, anions, carbon, pH, EC, colloids, pesticides, and microbes. Use of advanced techniques with lysimeters for monitoring soil moisture content, soil water potential and flux is also discussed in this review.
... Thus, lysimeters not only function as in situ water and solute quality assessing tools, but are of significant importance in a variety of fields such as agricultural management, including meteorology, agronomy, agriculture, ecosystems and environment, applied geochemistry, environmental pollution, environmental radioactivity, forest ecology and management, forest meteorology, hydrology, soil and tillage research, biochemistry waste management and water quality management [4]. ...
... Another research approach is the study of dissolved substances in soil water, their space and time distribution in ecosystem. They can be the important plant nutrients but the contaminants as well [4]. ...
Modern lysimeter facilities in connection with meteorological stations allow monitoring and evaluation of mutual basic components of the environment, such as water, air, soil and vegetation. Water is the most important component of the ecosystem and the component which connects all the other components. Therefore, we need to know the basic distribution and water balance in the different components of the environment to be able to interpret some processes in nature. Rainfall, which is the primary source of vital processes in the soil, is formed in the air. The amount of precipitation that gets into the soil and into the groundwater is affected by weather conditions. Primary distribution of rainwater is divided between infiltration, surface runoff, transpiration and evapotranspiration. The amount of water infiltrated into the soil and then evaporated by solar activity or activities of plants can be identified primarily by monitoring changes in weight. For this monitoring we use weighable lysimeter. This equipment with the monolith size of surface area 1 m 2 and the depth of 1.5 m is able to follow online updates of weight of the 2 ton body with an accuracy of 100 g. When we add to quantification of leakages through the bottom layer, we obtain a comprehensive record of rainfall at the time in the natural environment of the individual components. The obtained data can be further interpreted in terms of the needs of hydrology, agriculture, and environmental studies, and according to the purpose and objectives for which we want to use them.
... Lysimeters have been used for a variety of purposes in recent decades (Basso et al., 1995;Howell et al., 1985;Martin et al., 1994;Owens, 1987;Rasse et al., 2000;Reeder, 1986;Ritchie and Burnett, 1968;Yang et al., 2014) and specifically for the measurement of percolation of water beneath the vegetation root zone and water use through evapotranspiration processes (Meißner et al., 2010). The ability to monitor drainage over the entire year with large lysimeters contributes to useful insights into the temporal variation in NO À 3 -N leaching (Basso and Ritchie, 2005). ...
... Lysimeters have been demonstrated to be more reliable and accurate for in situ water and solute assessment (Meißner et al., 2010). As the most accurate measurement, they have been used to simulate soil water balances (Soldevilla-Martinez et al., 2013), water movement and nitrate dynamics (Phogat et al., 2013). ...
Excessive application of N fertilizer contributes substantially to high levels of nitrate (NO3--N) in surface and groundwater on Northern China. A trial was set up to quantify the fate of N within intensive wheat maize rotation system with a view to improve N and water use efficiencies. This paper describes the construction and testing of a lysimeter facility used for this trial. A 44 lysimeter/rain shelter facility was constructed at Shandong Agricultural University (SDAU). Each lysimeter was equipped with a neutron access tube for soil water monitoring and ceramic solution samplers for soil solutions collection. In order to precisely quantify water input, two rain shelters were used to exclude rainwater. The water balance showed that water outputs and inputs agree within 10% for all lysimeters, and that the average water used being 5% less than the total irrigation water supplied was considered as an acceptable error for such large lysimeters. Wheat grown in these devices was consistently higher than those grown with similar fertilizer management in a field located in Ling Xian due to enhanced soil fertility and irrigation in the devices. The facility was shown to be suitable for investigating water and nutrient balances of the root zone.
... [18] A specificity of the Rietholzbach catchment site is its large weighing lysimeter, which provides continuous evapotranspiration measurements since 1976 (Figure 2e). Weighing lysimeters are well-established instruments to measure evapotranspiration [e.g., Maidment, 1992;Rana and Katerji, 2000;Goss et al., 2010;Meissner et al., 2010], whereby the measurements consist of weight and seepage measurements, and the evapotranspiration is derived from water-balance computations. The term ''lysimeter'' itself is used for a wide range of devices and/or structures that allow the measurement of water flow through a given soil volume. ...
... [20] Despite the relatively high number of publications citing lysimeters for hydrological applications [e.g., Meissner et al., 2010], it is difficult to assess how many longterm and continuous measurements of evapotranspiration with large weighing (undisturbed) lysimeters are actually available. Possibly the longest available evapotranspiration records fulfilling these criteria are from the Coshocton site in Ohio, which pioneered the use of high-quality weighing lysimeters in the mid-1930s, and is still active nowadays [e.g., Harmel et al., 2007]. ...
The prealpine Rietholzbach research catchment provides long-term continuous hydroclimatological measurements in northeastern Switzerland, including lysimeter evapotranspiration measurements since 1976, and soil moisture measurements since 1994. We analyze here the monthly data record over 32 years (1976-2007), with a focus on the extreme 2003 European drought. In particular, we assess whether the well-established hypothesis that the 2003 event was due to spring precipitation deficits is valid at the site. The Rietholzbach measurements are found to be internally consistent and representative for a larger region in Switzerland. Despite the scale discrepancy (3.14 m(2) versus 3.31 km(2)), the lysimeter seepage and catchment-wide streamflow show similar monthly dynamics. High correlations are further found with other streamflow measurements within the Thur river basin (1750 km2) and-for interannual anomalies-also in most of northern Switzerland. Analyses for 2003 confirm the occurrence of extreme heat and drought conditions at Rietholzbach. However, unlike findings from regional-scale modeling studies, they reveal a late onset of the soil moisture deficit (from June onward), despite large precipitation deficits from mid-February to mid-April. These early spring deficits were mostly compensated for by decreased runoff during this period and excess precipitation in the preceding weeks to months (including in the 2002 fall). Our results show that evapotranspiration excess in June 2003 was the main driver initiating the 2003 summer drought conditions in Rietholzbach, contributing 60% of the June 2003 water storage deficit. Finally, long-lasting drought effects on the lysimeter water storage due to rewetting inhibition were recorded until spring 2004.
... We placed activated resin bags at both the top and bottom of the soil core to intercept and deionize water entering the core. We also placed a second inner resin bag at the bottom of each core to capture drainage and dissolved solutes leaching out of the soil core (Meißner et al. 2010). A subsample of soil was collected adjacent each core at the start of the incubation to measure the initial inorganic soil N. ...
Increased atmospheric nitrogen (N) deposition and climate warming are both anticipated to influence the N dynamics of northern temperate ecosystems substantially over the next century. In field experiments with N addition and warming treatments, cumulative treatment effects can be important for explaining variation in treatment effects on N dynamics over time; however, comparisons between data collected in the early vs. later years potentially can be confounded with interactions between treatment effects and inter-annual variation in environmental conditions or other factors. We compared the short-term versus long-term effects of N addition and warming on net N mineralization and N leaching in a grass-dominated old field using in situ soil cores. We added new N addition and warming plots (3 years old) to an existing field experiment (16 years old), which enabled comparison of the treatment effects at both time scales while controlling for potential inter-annual variation in other factors. For net N mineralization, there was a significant interaction between plot age and N addition over the growing season, and for extractable inorganic N there was a significant interaction between plot age and warming over winter. In both cases, the directions of the treatment effects differed among old and new plots. Moreover, the responses in the new plots differed from the responses observed previously when the 16-year-old plots had been new. These results demonstrate how inter-annual variation in responses, independent from cumulative treatment effects, can play an important role in interpreting long-term effects on soil N cycling in global change field experiments.
... High precision weighing lysimeters are ideal instruments to determine soil water balance components, as all input and output variables can be accurately determined for a known soil volume. Its soil moisture dynamics are directly responsive, and it can capture synergistic changes in water balance components (Fank & Unold, 2007;Meißner et al., 2010). These lysimeters are able to observe non-rainfall precipitation, such as dew and water vapour adsorption . ...
In high‐altitude cold areas, how precipitation and freeze–thaw processes affect soil water dynamics is not well understood due to a lack of high real‐time resolution measurements. This study measured soil water balance components with a high‐precision lysimeter in an alpine meadow ecosystem in the Qinghai Lake watershed from June 30, 2020, to June 30, 2021. The results showed that the total precipitation (TP), evapotranspiration (ET), soil water storage change (ΔS) and the vertical water flow (WF) of this ecosystem were 705.18, 633.21, 72.58 and −0.60 mm, respectively, during the study period. Continuous wet days with precipitation events larger than 10.00 mm led to percolation, while continuous dry days with strong ET caused an upward WF. Pearson correlation analysis suggests that a larger instantaneous precipitation intensity may be more conducive to an increase in shallow soil moisture (R ² > 0.72, p < 0.05). Furthermore, the TP thresholds in the complete thawing period inducing the soil water response in the mattic epipedon layer (0–20 cm) and organic layer (20–40 cm) were 3.24 mm and 16.61 mm, respectively. The difference in the average response time of soil water to a single precipitation event between the mattic epipedon layer and organic layer was 5.52 ± 3.65 h. These results deepen the understanding of the temporal pattern of water flux in alpine meadow ecosystems on the Tibetan Plateau.
... The lysimetric method allows for comparison of the precipitation recharge parameters in different regions. It also allows the comparison of precipitation recharge data, which can be obtained by other observational methods to further improve forecast models for the development of groundwater resources [39][40][41]. ...
The aim of this paper is to identify the trends of changes in atmospheric precipitation percolation under the changing climate conditions of Lithuania (the East Baltic region) based on long-term lysimeter studies. Data from 1987–2022 research (n = 1296) was used to determine trends in precipitation infiltration changes. Two 10-year periods, 1989–1998 and 2011–2020, were selected from the whole observation period (1987–2022) to assess changes in precipitation infiltration due to climate change. The air temperature has increased significantly in November (+3.4 °C) and December (+3.3 °C), with a +2.2 °C increase in the standard climate normal. The distribution of yearly precipitation has changed, with the annual amount decreasing from 686 to 652 mm. Precipitation increased the most in July and August (10.9 and 22.9 mm). In autumn, the amount of precipitation decreased by 7.9–31.1 mm. The number of rainy days did not change during the year, but the frequency of heavy precipitation increased significantly in August. The annual percolation increased by 14.2% over 2011–2020 compared to 1989–1998. Percolation increased by 19.0, 22.3, and 20.1% during the spring, autumn, and winter, respectively, and decreased by 35.0% in summer. The increase in annual percolation is mostly related to the increase in temperature during the cold season: November and December. During these months, the likelihood of early freeze formation, which interrupts gravitational water percolation in soil, is significantly reduced. In the spring, the increase in average air temperatures in March leads to faster melting of the winter snow in a shorter period, which significantly increases percolation processes. In Lithuania, higher percolation in autumn and winter, when part of the agricultural land is not covered by vegetation, may lead to higher leaching of chemical elements.
... Irrigation water for rice was sampled during irrigating. Leachates were collected by one lysimeter (Fig. S1), modified from the gravitation lysimeter (Meissner et al., 2010;Sołtysiak and Rakoczy, 2019) and buried at 60 cm soil depth, since more than 90% of the roots of rice, wheat and maize are above this depth (Yamaguchi and Tanaka, 1990;Fan et al., 2016), for three treatments with three replicates. The lysimeter includes a 50-cm stainless steel square collection box, a 10 L glass leachate-store bottle inside a PVC cylinder, and a sampling device including a collection bottle, a buffer bottle and a vacuum pump (see Hao et al., 2019 for lysimeter structure in detail). ...
Many Chinese croplands are suffering from soil acidification, defined as a decrease in soil acid neutralizing capacity (ANC), due to over-application of nitrogen (N) fertilizer and removal of base cations (BCs) in crop harvest. The contribution of fertilization and harvesting on soil acidification rates for different cropping systems is, however, seldom quantified under field conditions. Here, field experiments were conducted on a moderately acid silty clay soil in southwest China to quantify proton (H +) production rates under three fertilization management regimes, including control (non-N), optimized fertilization and farmers' practices (i.e. over fertilization), by measuring the inputs and outputs of major element in three cropping systems, i.e. rice-fallow, rice-wheat and maize-wheat. The maize-wheat cropping system had the highest proton production rates (2.3-10.2 kmol c H + ha − 1 yr − 1), followed by rice-fallow (3.2-4.6 kmol c H + ha − 1 yr − 1) and rice-wheat (2.2-4.5 kmol c H + ha − 1 yr − 1) systems. Crop removal, dominated by straw removal, was the main driver of proton production in all three cropping systems, contributing over 50% of the total H + production. Compared to the control, N fertilizer application enhanced soil acidification rates among three cropping systems, but had no significant effects on H + production per kg grain in the rice-fallow and rice-wheat systems. The same was true for the maize-wheat system in case of optimized fertilization, but over fertilization increased both soil acidification rate and H + production per kg grain, while grain yield was comparable to that with optimized fertilization. The change in soil ANC was dominated by accumulation of SO 4 2− (leading to potential soil acidification) that was mainly added to the soil with superphosphate containing high concentrations of both Ca 2+ and SO 4 2− sometimes even causing an increase in the base cation pool, despite BC crop removal. The low contribution of N transformation processes to the total H + production (3-47%) was due to high denitrification in this specific soil. The soil pH and base saturation did not change significantly among the three fertilization management regimes, largely due to the large BCs pools in the soil. Although the common farmers' practice does not strongly increase proton production in rice-fallow and rice-wheat systems, it still implies a waste of N fertilizer as the excess N input is either enhancing straw production or lost to air in this silty clay soil. Hence, optimized fertilization and localized BCs-rich straw return are suggested to reduce costs of N fertilizer without yield losses and mitigate soil acidification in those systems.
... Precision lysimeters are expensive, they need intensive maintenance, careful data processing and noise filtering techniques but compared to traditional rain gauges, they significantly improve the accuracy of precipitation and non-rainfall precipitation such as rime, dew and vapour adsorption, beside all the other soil water budget parameters. A general overview of different lysimeter designs is given by von Unold and Fank (2008), Meissner et al. (2010) and Schrader et al. (2013). Peters et al. (2014) present the program AWAT, optimized for precision lysimeter data https://doi.org/10.1016/j.jhydrol.2020.125580 ...
Precipitation measurements are performed mostly by simple automatic rain gauges installed at a certain level above the ground surface, but these methods are often affected by significant measurement errors due to the deformation of the wind field above the rain gauge orifice. In recent years precision lysimeters have emerged, providing an efficient means to improve rainfall measurements and to check the reliability of the standard devices. This article reports comparative rainfall measurements by different devices including a precision lysi-meter, two tipping bucket rain gauges and one weighing rain gauge. Rainfall and meteorological data were collected within 3-4.5 years of operation using intervals of 1, 10 and 30 min for registration providing a large data set of exclusively rainfall precipitation without snow and without the effect of freezing. Results show very good agreement of lysimeter, tipping bucket 1 and the weighing pluviometer measurements without any need of precipitation correction, whereas tipping bucket 2 rain gauge underestimated precipitation.
... In the past often weighable lysimeter were used as tools to measure all relevant water balance components in an entire soil profile and provided observations from an intermediate scale (Abdou and Flury 2004;Singh et al. 2017). The popularity of using lysimeter experiments to monitor and model water and solute transport processes across the soil-plantatmosphere continuum has increased substantially since the beginning of the nineties ( Figure I. 1), especially because lysimeters are the only device allowing directly to determine the quantity and quality of percolating water through the vadose zone (Meissner et al. 2010). ...
... The accurate quantification of soil water flow is a prerequisite to accurate prediction of solute transfer within the unsaturated zone of the soil. Measuring these fluxes is a challenge because the results are required not only for scientific but also practical questions regarding the impact of climate change on water resources, the sustainable management of agricultural, forestry, mining or set aside industrials areas, the reduction of leachate loss from landfills, and for explaining the fate of environmental harmful substances (Meissner et al., 2010a). A suite of methods for measuring water and solute flux in and below the root zone have been developed and critically reviewed (Meissner et al., 2010b;Fuehr et al., 1998;Gee and Hillel, 1988). ...
A lysimeter is a device to collect drainage water for mass and solute balances and fills the gap between laboratory and field-scale studies. There is a tendency in the international literature that this measuring technique is increasingly used to investigate the effects of climate change on land and water resources. These studies include simple nonweighable lysimeters as well as highly sophisticated weighable lysimeters. The objective of the paper is to demonstrate different lysimeter types and how they can be used to investigate the effects of climate change. On the basis of case studies, the determination of soil water balance parameters such as precipitation, actual evapotranspiration, soil moisture, and the leaching behavior of the environmental relevant nutrient phosphorus will be explained and evaluated regarding sustainable soil management strategies under the conditions of climate change.
... The common feature of all lysimetric designs is that the root-soil zone of the experimental vegetation is completely cut off from the ambient soil with regard to any water or nutrient flux. At the same time, the atmospheric conditions and soil surface are almost comparable with natural conditions (Unlu et al., 2010, Meissner et al., 2010. Recently several workers have used lysimeters for biodrainage and related physiological issues involving tree species (Chhabra and Thakur 1998, Boman et al., 2007, Gafni and Zohar 2008. ...
... Keywords: seepage volume, triticale, wheat, yield Einleitung Die Sickerwassermenge und die Auswaschung von im Sickerwasser gelösten Stoffen kann mit Lysimetern am zuverlässigsten quantifiziert werden (Goulding und Webster 1992, Meissner et al. 2010, Bohner & Eder 2011. Wägbare Lysimeter sind zudem die genauste Methode zur direkten Messung aller Komponenten der Wasserbilanz (Meissner et al. 2007, Hannes et al. 2015. ...
... Meissner et al. (2010a) consider lysimetry to be the most important direct method for assessing soil water drainage. Lysimetry is certainly the most accurate tool to measure water and solute fluxes (Meissner et al. 2010b). ...
This study aimed to quantify the water balance components at a grassland and a forest site representative of the Atlantic Forest biome in southern Brazil using drainage lysimeters. Since it was not possible to place mature trees on the forest lysimeter, it was planted with young trees and understory vegetation. Data from this lysimeter and computations with the water balance and the Penman-Monteith equation were then used to assess the values of the water balance components for the mature forest.
Total precipitation during the study period was 2308 mm. In the forest environment, 46% thereof was intercepted by the canopy from where it later evaporated. Hence, much less rain reached the ground than under grassland. Runoff from both sites was <1% of precipitation and therefore not a significant factor in the water balance. Cumulative drainage amounted to 1136 mm from grassland: from the mature forest, it was estimated to be 389 mm. There were two reasons for this low value under forest: Interception prevented a lot of water from reaching the ground, and the actual evapotranspiration from the mature forest was much higher than from grassland (1231 mm compared to 1964 mm).
... However, from the ecological point of view, the impact of the strength of anthropogenic load with nitrogen fertilizers can be assessed based on the established conditions for migration of chemi-cal elements under one-meter soil layer. Many studies have documented that the chemical composition of lysimetric water depends on the natural conditions -geology and hydrology of the land, soil type and climatic conditions, the form and amount of fertilizer used, and the processes of weathering (Atanassov et al., 1985;Meissner et al., 2010;Stoichev, 1997;Stoichev et al., 1996;Zhao, 2010). It is estimated that the rate of weathering of various minerals is a function of export of dissolved chemical elements draining the soil profile and are determined by the mineral and chemical composition of soil forming rocks (Chadwick and Chorover, 2001;Taylor and Velbel, 1991;Yakubu and Ojanuga, 2013). ...
The study characterized the regime of nutrient leaching under different nitrogen and phosphorus supply of irrigated maize grown as monoculture on Fluvisol for the period 1999-2008 and additionally studied in the years 2009, 2010, and 2011. The aim of the study was to estimate the effect of longterm fertilizer application on the leaching of nutrients from the soil under maize grown as monoculture. The experiment design included four nitrogen fertilizer rates (B1-control, B5, B4, B3, B2) calculated to compensate 50, 75, 100, and 125% from the plant N uptake, respectively. The field plots were equipped with lysimeters (at 50 and 100 cm depth) for studying the relationship between the applied fertilizer rates and the nutrient concentrations in the lysimetric water. The greatest nitrogen concentration in lysimetric water was observed under variant (B3-N200 P150) throughout the study period and the highest N losses were registered (36 kg ha⁻¹) in 2010 under the same treatment (B3). A very good correlation was found between the N rates, calcium, and magnesium losses. Lysimetric water component compensation shows that agricultural activities have only influenced the speed of weathering and had no significant effect on the rates.
... Lysimetry is a well-established technique to measure evapotranspiration (e.g., Maidment, 1992;Rana and Katerji, 2000;Goss and Ehlers, 2009;Meissner et al., 2010; see also Seneviratne et al., 2012 for a recent overview). Lysimeters are vessels containing a soil column in near-natural condition. ...
Accurate measurements of evapotranspiration are required for many meteorological, climatological, ecological, and hydrological research applications and developments. Here we examine and compare two well-established methods to determine evapotranspiration at the site level: lysimeter-based measurements (EL) and eddy-covariance (EC) flux measurements (EEC). The analyses are based on parallel measurements carried out with these two methods at the research catchment Rietholzbach in northeastern Switzerland, and cover the time period June 2009 to December 2015. The measurements are compared on various time scales, and with respect to a 40-year lysimeter-based evapotranspiration time series. Overall, the lysimeter and EC measurements agree well, especially on the annual time scale. On that time scale, the long-term lysimeter measurements also correspond well with catchment water-balance estimates of evapotranspiration. This highlights the representativeness of the site-level lysimeter and EC measurements for the entire catchment despite their comparatively small source areas and the heterogeneous land use and topography within the catchment. Furthermore, we identify that lack of reliable EC measurements during and following rainfall events (due to limitations of the measurement technique under these conditions) significantly contributes to an underestimation of EEC and to the overall energy balance gap at the site.
... On the other hand, comparing water productivity data with those from other regions can be biased, and results of gross water and solute balancing may be an improper measure of water productivity. The latest developments in lysimetry (Meißner et al. 2010) may lead to better data and a better understanding of the processes. ...
Central Asia is the global hotspot of a nexus of resources. Land, water and food are key issues in this nexus. We analysed the status of land and water resources and their potential and limitations for agriculture in the five Central Asian Transition States. Agricultural productivity and its impacts on land and water quality were also studied. The ecological status of open waters and soils as dependent on the kind of water and land use was shown. The main sources were information and data from the scientific literature, recent research reports, the statistical databases of the FAO and UNECE, and the results of our own field work. Agriculture is crucial for the economy of all Central Asian countries and responsible for about 90 % of their water use. We found that land and water resources may provide their function of food supply, but the agricultural productivity of grassland and cropland is relatively low. Irrigation agriculture is sometimes inefficient and may cause serious detrimental side effects involving soil and water salinisation. Dryland farming, as currently practiced, includes a high risk of wind and water erosion. Water bodies and aquatic, arable and grassland ecosystems are in a critical state with tendencies to accelerated degradation and landscape desertification. Despite all these limitations, agricultural landscapes in Central Asia have great potential for multi-functional use as a source of income for the rural population, tourism and eco-tourism included. The precondition for this is a peaceful environment in which they can be developed. All major rivers and their reservoirs cross borders and involve potential conflict between upstream and downstream riparians. The nexus of resources requires more detailed research, both in the extent of individual elements and processes, and their interactions and cycles. Processes in nature and societies are autocorrelated and intercorrelated, but external disturbances or inputs may also trigger future developments. We emphasise the role of knowledge and technology transfer in recognising and controlling processes. There has been a lot of progress in science and technology over the past ten years, but agri-environmental research and education in Central Asia are still in a crisis. Overcoming this crisis and applying advanced methods in science and technology are key issues for further development. Science and technology may provide an overall knowledge shift when it comes to recognising processes and initiating sustainable development. The following chapters introduce the results of further, more detailed and regional analyses of the status of soil and water. Novel measurement and assessment tools for researching into, monitoring and managing land and water resources will be presented. We will inform future elites, scientists and decision makers on how to deal with them and encourage them to take action.
... Many methods to estimate deep seepage such as direct measurements with drainage lysimeters (Meissner et al., 2010a) and passive wick-samplers ( Gee et al., 2009;Meissner et al., 2010b), conceptual ( Bethune et al., 2008), mechanistic (Jimenez Martinez et al., 2009;Lu et al., 2011) and empirical ( Selle et al., 2008;Wessolek et al., 2008) modeling approaches and tracer balance calculations ( Fragala and Parkin, 2010;Perkins et al., 2011) have been developed and applied at different scales. However, in many cases it is still a challenge to quantify deep seepage with adequate time and effort (cf. ...
Deep seepage estimation is important for water balance investigations of groundwater and the vadose zone. A simplified Buckingham-Darcy method to assess time series of deep seepage fluxes was proposed by Schindler and Müller (1998). In the method dynamics of water fluxes are calculated by a soil hydraulic conductivity function. Measured soil moistures and matric heads are used as input data. Resulting time series of flux dynamics are scaled to realistic absolute levels by calibrating the method with the areal water balance. An assumption of the method is that water fluxes at different positions exhibit identical dynamics although their absolute values can differ. The aim of this study was to investigate uncertainties of that method depending on the particle size distribution and textural heterogeneity in non-layered soils. We performed a numerical experiment using the two-dimensional Richards Equation. A basic model of transient water fluxes beneath the root and capillary zone was setup and used to simulate time series of soil moisture, matric head, and seepage fluxes for 4221 different cases of particle size distribution and intensities of textural heterogeneity. Soil hydraulic parameters were predicted by the pedotransfer function Rosetta. Textural heterogeneity was modeled with Miller and Miller scaling factors arranged in spatial random fields. Seepage fluxes were calculated with the Buckingham-Darcy method from simulated soil moisture and matric head time series and compared with simulated reference fluxes. The median of Root Mean Square Error was about 0.026 cm d−1 and the median of maximum cross correlation was 0.96 when the method was calibrated adequately. The method’s performance was mainly influenced by (i) the soil textural class and (ii) the time period used for flux calibration. It performed best in sandy loam while hotspots of errors occurred in sand and silty texture. Calibrating the method with time periods that exhibit high variance of seepage fluxes yielded the best performance. The geostatistical properties of the Miller and Miller scaling field influenced the performance only slightly. However, the Miller and Miller scaling procedure generated heterogeneous flow fields that were addressed as main reason for mismatches of simulated reference fluxes and fluxes obtained with the Buckingham-Darcy method.
... The pan, or drainage, lysimeter, is a method that allows direct measurements and provides more precise and consistent evaluations of water fluxes through an integrated approach in time and space (Webster et al., 1993;Zotarelli et al., 2007). Lysimeters have been demonstrated to be more reliable and accurate for in situ water and solute assessment (Meissner et al., 2010) as long as the lysimeter pan is located close to the water table depth or, in cases where the water table is absent, when a tension corresponding to conditions of the nearby soil is applied (Webster et al., 1993). Lysimeters have also been used in peat soils comparing to laboratory methods estimating unsaturated hydraulic conductivity and gave reliable results (Schwärzel et al., 2006). ...
The evaluation of downward water fluxes in Histosols is critical for water budget and irrigation studies in natural and cultivated wetlands. By analyzing water fluxes in cultivated organic soils, our study aimed to (i) compare drainage water fluxes measured using in situ lysimeters to fluxes estimated by three indirect methods, specifically, a simplified water balance, a water balance including soil water storage changes, and a method based on the Buckingham–Darcy law; and (ii) investigate water flux mechanisms using a bromide tracer in the same lysimeters. In 2008–2009, three sites were each set up with four drainage lysimeters equipped with water content probes and tensiometers. Bromide was applied over each lysimeter at the beginning of the lettuce growing cycle. Daily outflow water volumes were measured and solute samples were collected. The results showed that measured cumulative drainage was very low (0–40.2 mm) compared to water input (30–128 mm). A rupture point in the unsaturated hydraulic conductivity at matric potentials around −4.5 to −6 kPa, combined with the stratified profile of the organic layers, may in part explain these observations. The measured water fluxes were also significantly lower (by 1.2 to 1255.3 times) than the estimations made with the three indirect methods. Finally, the analyses of soil and outflow bromide concentrations confirmed the low fluxes through the lysimeters and revealed an accumulation at the surface layer interface (at a depth of about 0.3 m), indicating that water perched in the profile and suggesting that preferential flow occurred, leading to episodic solute leaching. Direct evaluation of water and solute fluxes are needed in such soils, as all three methods presented important biases.
Irrigation is one of the most important sustainable applications in agriculture. Nutrient-rich soil and adequate soil moisture are the most essential requirements for agricultural productivity. Some areas are rain fed while others have the provision of irrigation either through canals or ground water. Innovation for reducing the freshwater footprint in agriculture such as the adoption of low-cost and energy-saving suitable irrigation techniques like solar, drip, sprinkler, controlled tube irrigation, and fertigation will reduce the water wastage in agriculture. Constructed ponds will facilitate groundwater recharge by rainwater harvesting. Soils represent an important part of the ecosystem. They control the water flow, the recharge of ground water, the nutrient supply of the plants, and can reduce the number of pollutants or protect the ground and drinking water from them. Pesticides from agricultural industry, greenhouse gases from the atmosphere, and wastewater from contaminated sites are reflected with many other parameters in the chemical and microbiological situation of soils which is of primary importance for the plant quality. Therefore, the knowledge of the situation below the soil surface is an important task for the agricultural and industrial researches. Lysimeters represent a practical tool to get a view in the deeper soils. The level of the lysimeter vessel surface flushes with the surface of the surrounding area. They simulate the natural relation between soil, atmosphere, and plants. The dimension of the soil monoliths can vary from small (less than 0,5 m2 surface and not deeper than 1 m) to big types (2 m2 surface and up to 3.5 m depth). An overview of the various requirements for sustainable water uses in agriculture that contributes to cross-discipline discussions and understanding are reviewed in this chapter. Irrigation water use trends for sustainable agriculture in selected parts of the globe are cited as examples.KeywordsAgricultural water managementBest management practiceCroplandDrip systemsIntegrated water managementIrrigationLysimeterSprinklersSustainable developmentWater use efficiency
Soil degradation is an exceedance of the capacity and resiliency of soil for providing functions and ecosystem services. It is a complex ongoing phenomenon threatening humans’ livelihoods and our future on earth. Knowledge gain can help to find solutions for monitoring, preventing and combating soil degradation. In this chapter we address the essence, causes, extent, features and implications of various types of chemical and biological soil degradation. The aspects of chemical degradation, such as pollution, acidification, salinization, nutrient depletion and eutrophication are characterized shortly; for biological degradation, harm to soil microbiota and biodiversity, and soil organic matter depletion are considered. Progress in monitoring and modelling or forecasting these types of degradation is also shown. Soils of drylands, the Arctic and all man-made soils are hotspots of chemical and biological degradation. As chemical and biological degradation processes in the microscale are lingering and interacting, they need better awareness and monitoring approaches. Highly developed laboratory methods of soil chemical and biological analyses are existing, but screening methods that work under field conditions are comparatively rare. Biological soil degradation needs further evidence-based research and high-precision data for understanding and combating processes. Crucial questions such as calculation of carbon sequestration potential of agricultural soils and assessment of desertification processes should be better explored to bridge science-policy gaps.
This study aims to analyze the influences of applications of two different evapotranspiration (ET) estimation methods on the irrigation water requirements (IWR) for paddy rice and water supply reliability of agricultural reservoirs. The modified Penman (MP), traditional method, and the Penman-Monteith (PM), the new adopted method, were applied on 149 reservoirs located in Honam province for this study. The weather date was used from 1987 to 2016, and analysed the trends of temperature and rainfall during rice growing season between past and current 10 years respectively. The increased average temperature and rainfall were observed from the current 10 years compared to the past years. This phenomena impacts on the results of ET and IWR estimations with decreased IWR obtained from high rainfall regions and increased ET obtained high temperature regions. For the comparisons of application results of two ET approaches, the PM method showed lower ET and IWR, and hence more reliable storage capacity of the reservoirs respect to water supply to paddy fields. The results also showed that the influences of different ET methods applications on the water supply reliability of reservoirs are negligible for the cases of over 3.7 watershed ratio and 670 mm unit reservoir storage, while significant variations of the results obtain from the applications between two ET approaches for the opposite cases. Further studies are necessary to consider various field conditions for practical applications of the PM method estimating ET in the fields of paddy farming.
Citrus latifolia is increasingly being cultivated in Mediterranean areas, where the need for precise irrigation implies a sound knowledge of the crop's water requirements, which is carried out by monitoring the tree water status in the plant-soil-atmosphere system. Two year-old lime trees (Citrus latifolia Tan. cv. Bearss) were cultivated in 45 L weighing pot-lysimeters filled with a clay-loam soil and equipped with soil water sensors for recording the real-time soil water status. Irrigation, drainage, pot weight, and agro-meteorological variables were also recorded in real-time. Plant water relations - stem (Ψstem) and leaf (Ψleaf) water potentials, and leaf gas exchange - were periodically measured throughout the experiment. The automated irrigation protocol based on the volumetric soil water content was set to prevent tree water stress (with mean seasonal values of Ψstem above -0.8 MPa and 7 μmol m⁻² s⁻¹ and 80 mmol m⁻² s⁻¹, for net phtosynthesis and stomatal conductance, respectively). From the soil water pot balance, the computed fortnightly ET mean values throughout the growing season varied from 0.25 to 2.56 L plant⁻¹ day⁻¹ in winter and summer months, respectively. Maximum ET values occurred in July when evaporative demand was highest and lime fruits were in their most active growing phase. For day length, lime tree biomass changes were negligible, and the pot tree weight variations served for ET water balance validation (r²=0.92***). The contribution of this work is that it establishes a scalable weighing lysimeter prototype for determining the ET of lime trees grown in Mediterranean semi-arid conditions, using real-time soil water balance monitoring managed by an irrigation automation protocol. This approach could be replicated for precise ET measurements in other crops.
p>Ljubljana field aquifer is an important source of drinking water for the Ljubljana city and surrounding areas. Knowledge of the water balance and of the water flow dynamics through the unsaturated zone and recharge of Ljubljana field aquifer is crucial. The water balance assessment of the upper unsaturated zone provides an insight into groundwater recharge and renewal. With the help of build-in monolith weighing lysimeter in Kleče in Ljubljana we have assessed the water balance for hydrological year from March 2014 to February 2015. Water balance parameters, precipitation and evapotranspiration were determined from the changes in the mass of lysimeter and outflow tank. Precipitation events were evaluated based on their duration, intensity and the amount of precipitation. Evapotranspiration and the duration of precipitation were estimated based on the changes of the lysimeter mass. Results show that the chosen period was extremely wet. In the selected hydrological year, precipitation contributed to positive water balance of the upper unsaturated zone, as well as to the recharge of the aquifer. </p
Mining is one of the most essential economic activities. However, mining produces large volumes of waste. A prominent example is the potash industry, which generates millions of tons of tailings, approximately 90 % of which are comprised of sodium chloride. Precipitation events dissolve this sodium chloride and generate saline drainage. To minimize the amount of brine, the University of Kassel, in partnership with the Schmeisky environmental consultancy, is attempting to develop an evapotranspiration cover for potash tailings piles based on technosol application. To further the research in this field and to assess the drainage quality of technosols used for the evapotranspiration cover of mining tailings, one experiment with 8 nonweighing lysimeters was conducted above a potash tailings pile in Heringen, Germany. Lysimeters were filled with four different technosols composed of municipal solid waste incineration bottom ash and coal combustion residues. During three hydrological years, the drainage amount, pH and electrical conductivity were evaluated on a weekly basis. Monthly analyses included the concentrations of chloride, sodium, sulfate, calcium, potassium, nitrate, magnesium and ammonium, as well as chromium, nickel, zinc, copper, lead, cadmium, mercury and arsenic. Overall, it was observed that the pH of the drainage increased, whereas its electrical conductivity decreased due to the leaching of ions. Chemical elements generally decreased to lower limits for waste use. Moreover, higher ionic loads were verified in winter, and technosols with larger proportions of municipal solid waste incineration bottom ash presented higher total ionic loads during the evaluation time of the experiment.
The lysimeter is most often defined as a box filled with soil with an intact structure for measuring the amount of infiltration and evapotranspiration in natural conditions. At the bottom of the device there is an outflow for atmospheric precipitation water infiltrating to a measuring container. Lysimeter studies are included in the group of dynamic leaching tests in which the leaching solution is added in a specified volume over a specific period of time. Lysimeter studies find applications in, amongst others, agrotechnics, hydrogeology and geochemistry. Lysimeter tests may vary in terms of the type of soil used (anthropogenic soil, natural soil), sample size, leaching solution, duration of the research and the purpose for conducting it. Lysimeter experiments provide more accurate results for leaching tests compared with static leaching tests. Unlike several-day tests, they should last for at least a year. There are about 2,500 lysimeters installed in nearly 200 stations around Europe. The vast majority of these (84%) are non-weighing lysimeters. There are a few challenges for lysimeter research mostly connected with the construction of the lysimeter, estimating leaching results and calibrating numerical transport models with data obtained from lysimeters. This review is devoted to the analysis of the principal types of lysimeters described in the literature within the context of their application. The aim of this study is to highlight the role of lysimeters in leaching studies.
Understanding the actual evapotranspiration (ET) variation of the sparsely distributed xerophytic shrubs is crucial to accurately upscale community ET to ecosystem scale. Here we quantified the actual ET of two dominant xerophytic shrubs of the Tengger Desert in northwestern China, i.e. Salsola passerina and Reaumuria soongorica, by using four large weighing lysimeters. The results showed that with the increase in precipitation from 140 to 171 mm in the year 2015/2016, the daily mean evaporation (E) of the bare area, and ET of the single shrub communities of S. passerina, R. soongorica, and the associated shrub community (S. passerina þ R. soongorica) increased 50, 60, 44, and 47%, respectively; correspondingly, the total E and ET increased 49, 61, 44, and 47%, respectively. The variation of soil moisture within 0–40 cm depth plays a vital role in regulating the E and ET. The new shoot length, as one of important parameters of the xerophytic shrub, was significantly exponentially related to the cumulative ET. From the long- and short-term perspective, event-based precipitation and wind speed are the dominant driving factors behind changes in E and ET, respectively. Relative humidity is the main influencing factor for E and ET after a large rainfall event within 8 days.
The determination of precipitation (P) is still a challenge, but central for quantifying soil water and element balances. Time series of mass changes (ΔM) from high precision weighing lysimeter may be used to estimate P if deep drainage rates are determined independently. High temporal resolution, however, is accompanied by problems such as correlated data and noise. The objective was to analyze the temporal autocorrelation (AC) in ΔM time series and to identify temporal resolutions for determining uncorrelated P rates. Minute-based time series of ΔM are analyzed; the data have been recorded at the UMS Science Lysimeters that are located in Dedelow (northeast Germany) as part of the TERENO SoilCan lysimeter network. Periods in 2012 and 2013 were selected in which the wind speed was below 6 ms−1. Data noise-correction was carried out by using a moving average before the ΔM values cumulated over 60, 30, and 10 min intervals were compared. On a monthly basis, the temporal AC lengths for ΔM were larger in spring (68 min), autumn (62 min), and winter (76 min) than in the summer (23 min). These AC lengths reflected mainly the effect of differences in P-rates and -duration between lower-intensity rainfall and shorter summer storms. The monthly sums of P based on the 60-min interval were up to 20% lower than those obtained by using the 10-min intervals. For P-values obtained by summing up the ΔM over periods shorter than the autocorrelation length, oscillated fluctuations in ΔM did not cancel out within an interval. The temporal autocorrelation in the highly-resolved lysimeter data limited the evaluation of ΔM time series. Compared to rain gauge data, the P-rates obtained from the weighing lysimeters were generally higher. However, this difference decreased when increasing the time interval for cumulating mass changes. Cumulated positive ΔM values based on time intervals larger than the AC length (e.g., 60 min) provided an optimal approximation of the quantity of P, but on the expense of a loss in temporal resolution limited by the AC lengths. Smoothing could reduce noise in the original lysimeter data; however, not the validity problems that are related to the temporal AC.
The monolithic weighing lysimeter is a useful facility that could directly measure water movement via layers, drainage, and evapotranspiration (ET) with precise sensors. We evaluated water movement through layers and water balance using the lysimeter with undisturbed paddy sandy loam soil, Gangseo soil series (mesic family of Anthraquic Eutrudepts classified by Soil Taxonomy) during winter season from Dec. 2014 to Feb. 2015. Daily ET indicated up to 1.5 mm in December and January and 2 mm in February. The abrupt increase of soil water tension at the depth of 0.1 m, when soil temperature at the same depth was below 2^{\circ}C, was observed due to temporary frost heaving. The surface evaporation was less than reference ET below -15 kPa of soil water potential at the depth of 0.1 m. The maximum drainage rate was similar to the saturated hydraulic conductivity of a plow pan layer. Both upward and downward water movement, related to ET and drainage, were retarded by a plow pan layer. This study demonstrated that the lysimeter study could well quantify water balance components even under frost heaving during winter season and that a plow pan with low permeability could act as a boundary that affects drainage and evapotranspiration.
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.
In India the estimated mineral deposits are about 20,000 representing about 60 different kinds. At most of these reserves mining activity is in progress. Abandoned mine sites and smelting areas have often been neglected for restoration. Ecorestoration is a necessary step failing which the detrimental effects would be loss of forest cover, leaching of toxic substances, contamination of cultivated land and ultimately posing threat to biodiversity. Establishment of phyto-cover for containment of hazardous waste, and municipal solid waste; phyto-treatment technologies for environmental remediation and possibilities for energy generation are presented in this paper.
Austräge von gelöstem organischem Kohlenstoff (DOC) aus Mooren sind aus Gründen des Klima- und Trinkwasserschutzes unerwünscht. Einflüsse von Landnutzung auf die Höhe der DOC-Konzentrationen werden teilweise inkonsistent beschrieben und überdies sind wenige Angaben zu den stark anthropogen überprägten Niedermooren Nordostdeutschlands verfügbar. Daher sind in der vorliegenden Arbeit Zusammenhänge von Management und Standorteigenschaften zu DOC-Konzentrationen auf Lysimeter- und Freilandebene untersucht worden. Es zeigte sich, dass die DOC-Gehalte des wiedervernässten Niedermoores deutlich und die DOC-Austräge tendenziell geringer waren als am landwirtschaftlich genutzten Standort, und dass die DOC-Konzentrationen im Grabenwasser seit der Wiedervernässung gesunken sind. Die unmittelbar durch Landnutzung beeinflussten Parameter Wasserstand und Vegetation waren in Lysimeterversuchen von untergeordneter Bedeutung. Niedermoore scheinen bedingt durch ihre individuelle Genese ein spezifisches DOC-Potential bzw. einen „Fingerabdruck“ zu haben, weshalb bei Wiedervernässung zwar sinkende, aber nicht unbedingt geringe, naturnahen DOC-Konzentrationen erreicht werden können.
The release of dissolved organic carbon (DOC) from peatlands implies a loss of sequestered carbon. During the last two decades, an increase of DOC exports in Europe and North America has been reported. The influence of land use on DOC has been contradictorily discussed and a lack of knowledge exists particularly for fens in Northeastern Germany. Therefore, we aimed to investigate DOC release from fen soils with differing land use intensity. To exclude climatic influences and water level fluctuations, a lysimeter study was performed. The lysimeter vessels contained three histosols from Northeastern Germany and varied in peat quantity, substrate quality, water table depth, pH and vegetation, as these factors are strongly influenced by land use intensity. Water for DOC analysis was sampled biweekly over a two year period. DOC release ranged from 4 to 123 mg/L− 1 with a median of 32 ± 22 mg/L− 1. Lowest DOC concentrations were found at deeply drained gleysols and at relatively slightly decomposed, acidic histosols. Highest concentrations were measured in the most degraded histosols. Degree of decomposition and pH were found to be the major driving factors for DOC release. Long-lasting rewetted lysimeters were not observed to release a lower amount of DOC than drained ones, which may be of importance when restoration of degraded peatlands is intended. As lysimeters from the same site released relatively similar amounts of DOC despite their varying management during the last 50 years, it appears that peatlands have an individual potential for DOC release.
The detailed representation of hydrological processes involved in soil water balance
and the little knowledge about the influences of tropical forests has acquired great importance
for the efficient management of water resources and a better understanding of the
hydrological cycle. Therefore, is necessary to use of techniques that allow monitoring and the
representation of involved variables, represent in a possible closer way the natural
environment. This work aimed to investigate the dynamics of soil hydrological processes and
the determination of the most adequate time scale for determining the water balance, utilizing
drainage lysimeters containing undisturbed soil, installed in native grassland compared with
the native forest, representative of the Atlantic Forest biome under the climatic conditions of
the southern Brazil. The monitoring of the variables rainfall, runoff and drainage was
performed through electronic rain gauges and the soil water content was monitored by
electronic tensiometers installed at different depths of 10, 30 and 70 cm inside the lysimeters.
The results showed that due to interception of solar radiation, the native forest provides the
formation of an internal microclimate differentiated in relation to the external environment of
native grassland, resulting in a lower input energy and exerting significant influences on the
processes involved in the water balance. This difference in climatic conditions combined with
soil characteristics, allows the lysimeter installed in native forest presents highest soil water
storage capacity of water, being observed higher water contents in the soil, at all depths,
compared the condition of native grassland. Consequently, the lysimeter installed in the native
forest maintains the drainage flows for longer time than the lysimeter installed in the native
field, being the drainage process influenced by the season and the antecedent soil moisture.
Regarding the runoff, it is observed that the volumes per event are greater in native grassland
than in native forest. The water balance calculation based on data monitored in the lysimeters
shows that average daily actual evapotranspiration was 36.93% higher than in the native
grassland lysimeter compared to lysimeter installed inside the native forest, having significant
difference between the two environments. The lysimeters used in this study as well as the
methodologies adopted for monitoring hydrological variables involved in water balance, did
not show satisfactory results for the determination of evapotranspiration in daily periods since
they are not able to represent the observed lags in speed that different processes occur in the
interior of the soil profile. The timescale for events showed to be the most appropriate in
determining the water balance in relation to the daily period and decendial period.
This work presents a gravity lysimeter construction with an undisturbed soil sampling in order to study the surface runoff and groundwater recharge generation in the laboratory.
In general, small soil sampling is not able to represent the soil macropores and does not characterize the shallow lithologic profile continuously. On the other hand, watershed approaches lead to a lumped soil approach which does not allow one to characterize the
water flowing components as a function of the soil profile itself. This lysimeter was constructed with a 3.10mm thickness stainless steel, in a 0,6m-dyameter 1,8m-height cylinder. The lysimeter represents approximately the soil boundary conditions to water infiltration, percolation and direct runoff as in a shallow soil profile in field scale. The sample was obtained and installed in the laboratory integrally observing a compaction degree of 10,5%. Synthetic rainfall events are being led upon this lysimeter and its flow components monitored in order to assess possible disturbances in the hydraulic behavior of the lysimeter due to soil compaction and then validate the laboratory lysimeter as a hydrologic soil test method.
A simple model to predict soil water components and the CO2 release for peat soils is presented. It can be used to determine plant water uptake and the CO2 release as a result of peat mineralization for different types of peat soils, various climate conditions, and groundwater levels. The model considers the thickness of the root zone, its hydraulic characteristics (pF, Ku), the groundwater depth and a soil-specific function to predict the CO2 release as a result of peat mineralization. The latter is a mathematical function considering soil temperature and soil matric potential. It is based on measurements from soil cores at varying temperatures and soil water contents using a respiricond equipment. Data was analyzed using nonlinear multiple regression analysis. As a result, CO2 release equations were gained and incorporated into a soil water simulation model. Groundwater lysimeter measurements were used for model calibration of soil water components, CO2 release was adapted according long-term lysimeter data of Mundel (1976). Peat soils have a negative water balance for groundwater depth conditions up to 80—100 cm below surface. Results demonstrate the necessity of a high soil water content i.e. shallow groundwater to avoid peat mineralization and soil degradation. CO2 losses increase with the thickness of the rooted soil zone and decreases with the degree of soil degradation. Especially the combination of deep groundwater level and high water balance deficits during the vegetation period leads to tremendous CO2 losses.
Optimization of water use in agriculture and quantification of percolation from landfills and watersheds require reliable estimates of vadose zone water fluxes. Current technology is limited primarily to lysimeters, which directly measure water flux but are expensive and may in some way disrupt flow, causing errors in the measured drainage. We report on design considerations and field tests of an alternative approach, passive wick fluxmeters, which use a control tube to minimize convergent or divergent flow. Design calculations with a quasi-three-dimensional model illustrate how convergence and divergence can be minimized for a range of soil and climatic conditions under steady state and transient fluxes using control tubes of varying heights. There exists a critical recharge rate for a given wick length, where the fluxmeter collection efficiency is 100% regardless of the height of the control tube. Otherwise, convergent or divergent flow will occur, especially when the control tube height is small. While divergence is eliminated in coarse soils using control tubes, it is reduced but not eliminated in finer soils, particularly for fluxes 60% annual precipitation) from gravel surfaces and least (no drainage) from silt loam soils. In Oregon and New Mexico, United States, and in New Zealand, drainage showed substantial spatial variability. The New Mexico tests were located in semiarid canyon bottom terraces, with flash flood prone locations having extremely high drainage/precipitation ratios. In the wettest environments, drainage was found to be closely linked to the rate and duration of precipitation events.
Solute transport experiments using a non-reactive tracer were conducted on short, undisturbed, saturated columns of a sandy loam soil. All columns, 20 cm in diameter and 20 cm long, were collected along a transect of 35 m. Most of the soil columns had pre-existing macropores. The columns were leached at a steady flow-rate under ponding conditions. The resulting breakthrough curves (BTCs) showed a large heterogeneity. Several of the BTCs displayed early breakthrough and long tailing. All the data were interpreted in terms of dimensional time moments, the classical convection-dispersion equation (CDE) and the mobile-immobile transport model (MIM). Experimental time moments were found to vary significantly among the different BTCs. Analysis of the time moments also revealed that the variance of the field-scale BTC was several times larger than the average of the local-scale variance. The pore water velocity v and dispersion coefficient D were obtained by fitting the CDE to the local-scale BTCs, resulting in an average dispersivity of 7·4 cm. Frequency distributions for the CDE parameters v and D were equally well described by a normal or log-normal probability density function (pdf). When a log-normal pdf for D is considered, the variance of the loge transformed D values (ln D2) was found to be 2·1. For the MIM model, two additional parameters were fitted: the fraction of mobile water, m/, and the first-order mass transfer coefficient, . The MIM was more successful in describing the data than the CDE transport model. For the MIM model, the average dispersivity was about 2 cm. The MIM parameters v, D and
Unsaturated water flux densities are needed to quantify water and contaminant transfer within the vadose zone. However, water flux densities are seldom measured directly and often are predicted with uncertainties of an order or magnitude or more. A water fluxmeter was designed, constructed, and tested to directly measure drainage fluxes in field soils. The fluxmeter was designed to minimize divergence. It concentrates flow into a narrow sensing region filled with a fiberglass wick. The wick applies suction, proportional to its length, and passively drains the meter. The meter can be installed in an augured borehole at almost any depth below the root zone. Water flux through the meter is measured with a self-calibrating tipping bucket, with a sensitivity of ∼4 mL tip−1. For our meter this is equivalent to detection limit of ∼0.1 mm. Passive-wick devices previously have not properly corrected for flow divergence. Laboratory measurements supported predictions of a two-dimensional (2-D) numerical model, which showed that control of the collector height H and knowledge of soil hydraulic properties are required for improving divergence control, particularly at fluxes below 1000 mm yr−1. The water fluxmeter is simple in concept, is inexpensive, and has the capability of providing continuous and reliable monitoring of unsaturated water fluxes ranging from less than 1 mm yr−1 to more than 1000 mm yr−1.
Two weighing lysimeters were installed at the University of Arizona's Karsten Center for Turfgrass Research. The goals of the facility are to measure evapotranspiration (ET) and to perform water use and deep percolation experiments in a deep soil profile under both natural precipitation and irrigation conditions. Each lysimeter is 4.0 m deep, 2.5 m in diameter, and equipped with 96 sampling ports for soil solution samplers, tensiometers, time domain reflectometry (TDR) probes, and thermocouples. The weighing scales have a capacity of 45 Mg and can detect a 200-g mass change, equivalent to ± 0.04 mm of water on the surface. The lysimeters were filled with Vinton fine sand (sandy, mixed thermic Typic Torrifluvent). Monitoring the unvegetated lysimeters for 18 weeks indicated that about 66% of all precipitation percolated into the soil profile. In June 1994, the lysimeter surfaces and surrounding area were planted with `Tifway' bermudagrass (Cynodon dactylon x transvaalensis var. Tifway), and irrigation began. Three phases of turf water use were identified during the first 155 days after planting-establishment, full cover and overseeding. The percentage of water that percolated into the soil profile deeper than the root zone was 35.6%, 10.1%, and 48.3%, respectively, showing the effectiveness of active root water uptake in reducing deep percolation. The TDR, neutron probe and tensiometer methods provided very similar indications of the depth of the wetting front. Differences in depth estimates could be caused by differences in sampling volume among the three methods. The TDR and neutron probe provided estimates of soil water storage that usually were within 10% of one another, and consistent with changes in lysimeter mass.
Tests were carried out to determine the weighing precision of a 2 m deep lysimeter with a 1 m² cross-sectional area and a total mass of 3500 to 3850 kg, depending on the soil water content. The weighing mechanism consists on three shear-stress cells laid out for a load capacity of 1320 kg each. Mass changes as small as 20 g, which is equivalent here to a water gain or loss of 0.02 mm, can be measured with good accuracy and stability under favorable environmental conditions (low wind speed, relatively constant temperature). This precision does not depend on the position on the lysimeter where the mass change occurs and is as good as the best values reported in the literature for other lysimeters. To prevent water and debris from entering the cleavage between lysimeter vessel and pit casing, a rubber collar can be placed across the cleavage. It is attached to the casing and extends about 1–2 cm into the vessel. Although the collar is not supposed to touch the vessel, it does at a few points. This seriously lowers weighing precision, because this contact exerts forces on the vessel, which distort the true weight. Hence, one should refrain from using this type of collar and develop another one. Weighing precision decreases with increasing wind speed, because wind exerts forces on the lysimeter vessel and can thus alter its apparent weight. It is temperature-dependent, too.
The surface renewal method was used to estimate evapotranspiration (ET) for a restored marsh on Twitchell Island in the Sacramento–San Joaquin Delta, California, USA. ET estimates for the marsh, together with reference ET measurements from a nearby climate station, were used to determine crop coefficients over a 3-year period during the growing season. The mean ET rate for the study period was 6 mm day−1, which is high compared with other marshes with similar vegetation. High ET rates at the marsh may be due to the windy, semi-arid Mediterranean climate of the region, and the permanently flooded nature of the marsh, which results in very low surface resistance of the vegetation. Crop coefficient (Kc) values for the marsh ranged from 0·73 to 1·18. The mean Kc value over the entire study period was 0·95. The daily Kc values for any given month varied from year to year, and the standard deviation of daily Kc values varied between months. Although several climate variables were undoubtedly responsible for this variation, our analysis revealed that wind direction and the temperature of standing water in the wetland were of particular importance in determining ET rates and Kc values. Published in 2007 by John Wiley & Sons, Ltd.
Modeling analyses suggest that an increase in growth rate of atmospheric CO2 concentrations during an anomalously warm year may be caused by a decrease in net ecosystem production (NEP) in response to increased heterotrophic respiration (Rh). To test this hypothesis, 12 intact soil monoliths were excavated from a tallgrass prairie site near Purcell, Oklahoma, USA and divided among four large dynamic flux chambers (Ecologically Controlled Enclosed Lysimeter Laboratories (EcoCELLs)). During the first year, all four EcoCELLs were subjected to Oklahoma air temperatures. During the second year, air temperature in two EcoCELLs was increased by 4°C throughout the year to simulate anomalously warm conditions. This paper reports on the effect of warming on soil CO2 efflux, representing the sum of autotrophic respiration (Ra) and Rh.
During the pretreatment year, weekly average soil CO2 efflux was similar in all EcoCELLs. During the late spring, summer and early fall of the treatment year, however, soil CO2 efflux was significantly lower in the warmed EcoCELLs. In general, soil CO2 efflux was correlated with soil temperature and to a lesser extent with moisture. A combined temperature and moisture regression explained 64% of the observed variation in soil CO2 efflux. Soil CO2 efflux correlated well with a net primary production (NPP) weighted greenness index derived from digital photographs. Although separate relationships for control and warmed EcoCELLs showed better correlations, one single relationship explained close to 70% of the variation in soil CO2 efflux across treatments and years. A strong correlation between soil CO2 efflux and canopy development and the lack of initial response to warming indicate that soil CO2 efflux is dominated by Ra. This study showed that a decrease in soil CO2 efflux in response to a warm year was most likely dominated by a decrease in Ra instead of an increase in Rh.
Lysimeter experiments were conducted with sandy-clay-loam soil to study the efficiency of two amendments in reclaiming saline-sodic soil using moderately saline and SAR (sodium-adsorption ratio) irrigation water. Gypsum obtained from industrial phosphate by-products and reagent grade Ca chloride were applied to packed soil columns and irrigated with moderately saline (ECe = 2.16 dS m–1), moderate-SAR water (SAR = 4.8). Gypsum was mixed with soil prior to irrigation at application rates of 5, 10, 15, 20, 25, and 32 Mg ha–1, and Ca chloride was dissolved directly in leaching water at application rates of 4.25, 8.5, 12.75, 17.0, and 21.25 Mg ha–1, respectively. The highest application rate in both amendments resulted in 96% reduction of total Na in soil.
The hydraulic conductivity (HC) of soils receiving gypsum increased in all treatments. The highest HC value of 6.8 mm h–1 was obtained in the highest application rate (32 Mg ha–1), whereas the lowest value of 5.2 mm h–1 was observed with the control treatment. Both amendments were efficient in reducing soil salinity and sodicity (exchangeable-sodium percentage, ESP); however, Ca chloride was more effective than gypsum as a reclaiming material. Exchangeable Na and soluble salts were reduced with gypsum application by 82% and 96%, and by 86% and 93% with Ca chloride application, respectively. Exchangeable Ca increased with increasing amendment rate. Results of this study revealed that sodium was removed during cation-exchange reactions mostly when the SAR of effluent water was at maximum with subsequent passage of 3 to 4 pore volumes. Gypsum efficiently reduced soil ESP, soil EC, leaching water, and costs, therefore, an application rate of 20 Mg ha–1 of gypsum with 3 to 4 pore volumes of leaching water is recommended for reclaiming the studied soil.
A simple model to predict soil water components and the CO2 release for peat soils is presented. It can be used to determine plant water uptake and the CO2 release as a result of peat mineralization for different types of peat soils, various climate conditions, and groundwater levels. The model considers the thickness of the root zone, its hydraulic characteristics (pF, Ku), the groundwater depth and a soil-specific function to predict the CO2 release as a result of peat mineralization. The latter is a mathematical function considering soil temperature and soil matric potential. It is based on measurements from soil cores at varying temperatures and soil water contents using a respiricond equipment. Data was analyzed using nonlinear multiple regression analysis. As a result, CO2 release equations were gained and incorporated into a soil water simulation model. Groundwater lysimeter measurements were used for model calibration of soil water components, CO2 release was adapted according long-term lysimeter data of Mundel (1976). Peat soils have a negative water balance for groundwater depth conditions up to 80-100 cm below surface. Results demonstrate the necessity of a high soil water content i.e. shallow groundwater to avoid peat mineralization and soil degradation. CO2 losses increase with the thickness of the rooted soil zone and decreases with the degree of soil degradation. Especially the combination of deep groundwater level and high water balance deficits during the vegetation period leads to tremendous CO 2 losses.
Lysimeters and neighbouring fields were used from 1998 to 2000 to assess parameters of N use efficiency of three Swiss spring wheat (Triticum aestivum L.) genotypes. An old (Albis), a new (Toronit) and an experimental genotype (L94491) were compared with no and ample (250 kg N ha−1) N fertilizer supply. N fertilization increased biomass, grain yield and grain N concentration of all genotypes in all years and in both testing systems (field, lysimeters) but only a few genotype × N interactions were observed. Generally, Toronit was superior in producing biomass and grain yield and L94491 in accumulating N in the grain resulting in identical N biomass yields. Albis showed the lowest and Toronit the highest fertilizer recovery, irrespective of the method of calculation (15N or difference method). The medium yielding L94491 recovered similar amounts of fertilizer N as Toronit, mainly due to the high N concentration in the biomass. The ranking of the genotypes for the investigated traits was similar in both testing systems and results comparable with those reported in the literature, indicating that the lysimeter facility is suitable for investigations of agronomic traits on soil–plant relationships, where a constant recording of the soil properties is required.
Urea fertilizer-induced N2O emissions from soils might be reduced by the addition of urease and nitrification inhibitors. Here, we investigated the effect of urea granule (2–3 mm) added with a new urease inhibitor, a nitrification inhibitor, and with a combined urease inhibitor and nitrification inhibitor on N2O emissions. For comparison, the urea granules supplied with or without inhibitors were also used to prepare corresponding supergranules. The pot experiments without vegetation were conducted with a loess soil at (20 ± 2)°C and 67% water-filled pore space. Urea was added at a dose of 86 kg N ha–1 by surface application, by soil mixing of prills (<1 mm) and granules, and by point-placement of supergranules (10 mm) at 5 cm soil depth. A second experiment was conducted with spring wheat grown for 70 d in a greenhouse. The second experiment included the application of urea prills and granules mixed with soil, the point-placement of supergranules and the addition of the urease inhibitor, and the combined urease plus nitrification inhibitors at 88 kg N ha–1. In both experiments, maximum emissions of N2O appeared within 2 weeks after fertilization. In the pot experiments, N2O emissions after surface application of urea were less (0.45% to 0.48% of total fertilization) than from the application followed by mixing of the soil (0.54% to 1.14%). The N2O emissions from the point-placed-supergranule treatment amounted to 0.64% of total fertilization. In the pot experiment, the addition of the combined urease plus nitrification inhibitors, nitrification inhibitor, and urease inhibitor reduced N2O emissions by 79% to 87%, 81% to 83%, and 15% to 46%, respectively, at any size of urea application. Also, the N2O emissions from the surface application of the urease-inhibitor treatment exceeded those of the granules mixed with soil and the point-placed-supergranule treatments receiving no inhibitors by 32% to 40%. In the wheat growth experiment, the N2O losses were generally smaller, ranging from 0.16% to 0.27% of the total fertilization, than in the pot experiment, and the application of the urease inhibitor and the combined urease plus nitrification inhibitors decreased N2O emissions by 23% to 59%. The point-placed urea supergranule without inhibitors delayed N2O emissions up to 7 weeks but resulted in slightly higher emissions than application of the urease inhibitor and the urease plus nitrification inhibitors under cropped conditions. Our results imply that the application of urea fertilizer added with the combined urease and nitrification inhibitors can substantially reduce N2O emissions.
A laboratory experiment was designed to assess the impact of surface seal development on the hydrological response of a clay soil. The influence of surface sealing on vertical macropore flow and lateral throughflow was of particular interest. The extent and development of the surface seal in repacked lysimeters was designed to match that recorded over two growing seasons at a clay field site in Essex, and was not extensive enough to reduce significantly the infiltration capacity of the soil. Consequently, the hydrological response of the lysimeters was similar under sealed and unsealed conditions, with a more rapid wetting response under sealed conditions being attributed to the higher soil moisture content required to create the surface seal. Macropore flow was initiated at the A/B soil boundary of the lysimeters, in response to the development of a saturated layer. The rate of macropore and throughflow in the soil was dictated by rainfall intensity at the soil surface as this controlled the depth of water in the perched water table. Simulation of the tensiometer response in the lysimeters demonstrated that it was possible to attribute the rapid movement of water through the A horizon to water displacement processes alone, without recourse to preferential flow processes.
In order to investigate the transferability of lysimeter results to the actual field situation, a leaching study with [14C]benazolin and bromide was carried out in a sandy soil. A suction base system, where soil water and solute fluxes through a lateral cross-sectional sampling area could be measured in an undisturbed field environment, was developed as reference system. Using that measuring instrument, possible artefacts of the lysimeter system could be excluded. The outflow of soil water and leaching of benazolin and bromide showed no system-related differences between the lysimeters and the undisturbed field represented by the suction base station. Higher outflow of leachate and bromide in the lysimeters could be attributable to different meteorological conditions at the lysimeter and the field station.© 1999 Society of Chemical Industry
Keywords:in situ;undisturbed sampling;soil structure;lysimeter vessel;soil processes;soil monolith
Lysimeter experiments were carried out to study pesticide transport through macroporous soils. In order to differentiate between the effects of soil structure and chemical behaviour, the leaching experiments were conducted using disturbed and undisturbed soil samples. Two herbicides with different sorption behaviours, and bromide as tracer were applied. The results were used to validate a dynamic simulation model which considers bypass flow in macropores. The simulation results show that the model is able to reproduce the soil suction within the soil as well as the spatial distribution of bromide and the herbicides. The continuity of the macropores is most important for the efficiency of bypass flow. The results indicate that cultivation practices like ploughing significantly influence the temporal and spatial distribution of the macropores. (C) 1998 SCI
A 2600 m 3 free-draining lysimeter constructed in a Pinus sylvestris plantation forest in Colbitz, Germany, has been monitored daily since 1974, with the intent of improving the understanding the effect of afforestation upon groundwater recharge (drainage). The objective of this research was to employ a downward approach in the development of a conceptual water balance model applicable to the site. Observed annual and inter-annual trends were successfully replicated by a simple capacitance model using a simplified representation of vegetation growth. An important limitation of the capacitance approach in simulating the timing of drainage at sub-annual time scales was identified, which could not be overcome by adding complexity to the model basis. Given the a priori use of capacitance approaches for simulating drainage in many hydrological models, the findings of this study suggest that (a) these approaches are sufficient where the prediction of annual and inter-annual drainage behaviour is the primary objective, and that (b) an alternative basis accounting for the time delay between precipitation inputs and drainage generation is required for modelling if the prediction of drainage at sub-annual time scales is a priority.
For many years lysimeters have been proven to be effective tools in assessing and predicting the effects of current land use and future land use changes in catchment areas on both water and solute balances. Although due to the diverse aspects of mass transport modelling, many different types of lysimeters exist, water and solute balances are by no means fully understood, especially in post-mining areas. To tackle this problem, a new piece of equipment has been developed which enables the actual weight of a lysimeter to be precisely measured. The newly designed device, which has been used for one of the experiments described in this paper, permits the weighing of for example a 2 m3 lysimeter vessel with an accuracy down to 30 g. The second newly developed appliance presented here is the GAMS (Gas-Migration-Simulator). Basically comparable to a lysimeter, the difference is that the GAMS allows the detailed investigation of soil-gas migration processes and their dependence on parameters like the diffusion coefficient and the gas permeability of the soil, alterations of the groundwater level and on various external influences such as changes of the actual meteorological conditions. These two newly developed techniques are described in this paper, and their respective suitability is demonstrated on the basis of data sets recorded during initial experiments.
Losses or nitrogen (N) by leaching were estimated in three experiments using bromide (Br) as a tracer. An estimate or denitrification was also made, by difference, by combining the estimate of leaching with a measure of total loss of applied N using 15N. This was compared with a direct measure of denitrification made using acetylene inhibition. Bromide proved to be a poor tracer for nitrate (NO3) leaching at two of the three sites, Brimstone and Hoosfield. Performance was rather better at the Broad Mead site. Problems in using Br were associated with (a) difficulties in measuring small concentrations of Br close to background in soil, and (b) reactions involving N such as immobilisation and mineralisation that rapidly change NO3 pools but do not affect Br. Use of Br in field experiments is unlikely to provide reliable estimates of NO3 leaching over timescales of several weeks as used here unless much more frequent sampling is done. Simultaneous measurements of total losses of N using a 15N tracer were combined with estimates of NO3 leaching using Br to calculate denitrification; these estimates were compared with measurements of denitrification using acetylene inhibition. Agreement was poor because of (i) the lack of reliability of the acetylene inhibition technique, and (ii) the very large errors associated with calculating denitrification as the difference between an estimate of NO3 leaching and total N losses.
A three-year long lysimeter experiment with a fine-grained aluminum (Al) recycling by-product and a mixture of this by-product and a coal combustion waste was conducted. The wastes were proposed as possible soil substitutes in an engineered surface barrier covering a potash mining residue mount. To evaluate the suitability of the wastes as surface barrier material, their hydrological behavior under field conditions must be known. Lysimeter experiments provide one means to study the hydrological behavior of soils or soil-like materials. However, it is difficult to estimate the long-term hydrological behavior from short-term lysimeter studies. The present study was conducted therefore to derive from short-term lysimeter observations the long-term hydrological behavior of the two waste materials. The lysimeter data were used to calibrate the one-dimensional soil water flow model HYDRUS-1D. With the calibrated model, hydrological simulations for the site of the residue mount were carried out for a period of 31 yr. Calculated long-term annual seepage from the lysimeters was 237 mm for the pure Al waste and 186 mm for the mixture, or 39% and 24% of the average annual precipitation (764 mm). The average discharge of the bare mount is 482 mm or 63%. We conclude that a soil cover could considerably reduce the discharge and that the mixture is better suited as surface barrier than the pure Al waste.
A lysimeter experiment on mineral fertilizer use and soil type was begun in 1985 to study the interrelationships between the level of mineral fertilization and the leaching of nutrients. Increased application of mineral fertilizers brought about not only a significant reduction in effluence build-up, but also a significant increase in yield. The lowest levels of nitrogen leaching were found in clay-sand soil in use as grassland, and the highest in sandy soil used as arable land. Unexpectedly, the study was unable to prove statistically that a reduction in N, P and K leaching follows automatically from a reduction in mineral fertilization. Hence, suboptimal fertilization cannot be the only corrective measure if a noticeable or marked reduction in the adverse impact on water quality due to nutrient leaching is to be achieved. Interim plantings should be integrated in crop rotations. Agricultural crops must be siteadapted and suited to the fertilization regime.
Fuor years after 15N labelled fertiliser nitrogen (as Ca(NO3)2 and equivalent to 400 kg N ha−1) was applied to permanent grass swards growing in lysimeter monoliths, approximately one-quarter remained immobilised in soil organic matter. In the intervening years similar but non-labelled applications were made. Although differing rainfall regimes applied during the experiment had significantly affected nitrogen uptake by plants and nitrate loss in drainage, they caused no significant effect on the tracer nitrogen remaining in the soil, the ranges were 85–97 kg N ha−1 and 79–94 kg N ha−1 respectively for the 135 cm deep clay and silt loam soil monoliths. Labelled nitrogen unaccounted for in crop, drainage or soil was presumed to have been denitrified. These losses averaged 62 and 49 kg N ha−1 on the clay and silt loam soils respectively; again the differing rainfall regimes caused no significant differences. The ratio between estimates of labelled nitrogen denitrified and of annual nitroux oxide loss was approximately 9:1 for both soils. The conversion from permanent grass to winter wheat in autumn 1981, involving killing and then burying the sward, resulted in no pronounced increase in net mineralisation of labelled nitrogen. However, the balance between crop uptake and the quantity leached did change. Labelled nitrogen assimilated was less for the wheat (growing without addition of fertiliser nitrogen) than for the grass in its last year, and the quantity leached was considerably greater than under grass swards that were supplied with an average rainfall distribution. Following the first wheat harvest total nitrogen leached averaged 51 and 44 kg N ha−1 on the clay and silt loam soils respectively. Rates of nitrous oxide emissions during the autumn following sward destruction were greater than in earlier years, but this enhanced loss was of short duration. The crop clearly benefited from the succession of nitrogen applications made to grass, as grain yield and total nitrogen uptake exceeded 7 t ha−1 and 120 kg N ha−1 respectively on both soils. These quantities exceed the national averages for winter wheat and are also considerably greater than for crops from lysimeters which received no nitrogen fertiliser throughout the experiment.
The effect of drought and irrigation on the yield and fertiliser nitrogen uptake by cut permanent grass swards was investigated using lysimeters containing monoliths (80 cm diam., 135 cm deep) of two soil types (Salop series, clay loam and Bromyard series, silt loam). Over the five summers 1977–81 swards were treated with four dressings of calcium nitrate at rates of 0 and 100 kg N ha−1 after each cut; in the first year, the nitrogen was labelled with 15N. Rainfall equivalent to the long-term average gave mean yields of 12.9 t dry matter ha−1 for Salop and 14.3 t dry matter ha−1 for Bromyard. Irrigation (to 120% of average summer rainfall) gave a non-significant increase of 8–9% in herbage yield on both soils. When the average rainfall distribution was modified to create periods of drought for 4 weeks duration immediately before each cut and fertiliser application, yields were significantly depressed, by 12% on Salop soil and 20% on Bromyard soil. Adjustment of the drought so that cutting and nitrogen application fell mid-way in the dry period resulted in only a small non-significant depression of yield on both soils (yield 95–96% of average rainfall treatment). The recovery of applied 15N labelled fertiliser in herbage during the first year of the experiment was in the range 45–47% for the Salop soil and 39–52% for the Bromyard soil. In the Salop soil the recovery of the labelled nitrogen was not significantly affected by imposition of drought conditions or by irrigation. However, in the Bromyard soil the drought treatment resulted in a significant reduction in the recovery of fertiliser nitrogen to 79% of that of the average rainfall treatment and irrigation increased the recovery to 106%. The contrasting results from the two soils was due to the imposed drought treatments which were more effective in creating differing soil water status in the Bromyard soil. This was due to its good drainage and lower water holding capacity. On both soils, fertiliser nitrogen constituted 53–60% of the total nitrogen content of the herbage. This experiment indicates that on clay soils with poor drainage status, the pattern of rainfall distribution has relatively little impact on the productivity of the sward and its utilisation of fertiliser nitrogen. On freely-draining soils, however, heavy rainfall after drought following cutting and nitrogen application can substantially depress yield and fertiliser use.
With the harmonisation of data requirements for pesticide registration under EC Directive 91/414 there is need for progress on the techniques used to analyse such data and so help make consistent the judgements applied by national regulatory authorities. This paper proposes a Bayesian technique for combining data from environmental fate and behaviour studies of pesticides in soil. The method uses expert knowledge, based on degradation and adsorption data, and logistic regression methods to form a prior probability distribution for the probability that a given compound leaches. Results from lysimeter experiments are used update the prior knowledge. Data for the compounds bentazone and triclopyr are used to illustrate the techniques. The advantages of the methodology and its implications for the pesticide registration procedure are discussed in the light of possible advances using modern Bayesian statistical techniques and mathematical models. © 1998 Society of Chemical Industry
Fertilizers and liming agents are generally used to achieve optimal economic yields. However, several negative effects of long-term annual fertilization of nitrogen (N) in particular have been observed, such as reduced cation exchange capacity and decreased base saturation, which may stimulate accelerated leaching loss of other nutrients. Equilibrium-tension lysimeters installed at a depth of 1.4 m were used to evaluate leaching of soil-solution ionic constituents from a tallgrass prairie restoration and optimally and deficiently N-fertilized, no-tillage (NT) and chisel-plowed (CP) maize (Zea mays L.) agroecosystems on Plano silt loam soil (fine-silty, mixed, superactive, mesic Typic Argiudoll). This study was conducted in south-central Wisconsin, USA during a 1-year period of above-normal precipitation between January 2000 and January 2001. The loss of soluble constituents added to agroecosystems to maintain adequate soil fertility and pH, such as N, phosphorus, potassium, calcium, and magnesium, was generally numerically smaller from the natural prairie 25 years after conversion from cultivated agriculture than from optimally and deficiently N-fertilized, NT and CP maize agroecosystems, though the differences were not significant. Tillage and fertilizer N-rate generally did not significantly affect drainage, ionic concentrations, or their leaching losses in the maize agroecosystems, though all parameters evaluated tended to be numerically smaller in the deficiently than optimally N-fertilized maize agroecosystems. Nitrate-N leaching losses were generally significantly positively correlated with leaching losses of K, Ca, Mg, and Na in the maize agroecosystems, but not for the prairie, indicating that nitrate-N leaching plays a significant role in the concomitant loss of cations to maintain soil-solution charge balance in N-fertilized maize agroecosystems in a temperate environment.
Fulvic acids (FAs) from topsoil and ground water solutions were investigated to discover effects of land use and peat degradation on their molecular chemical composition and thermal properties. The FAs were extracted from three Gleysols under arable land, intensive and extensive grassland, and from three Histosols under alder forest, extensive grassland, and a natural succession in a long-term (> 200 years) cultivated fen area. Functional groups and molecular subunits of the FAs were investigated by 13C Nuclear Magnetic Resonance (13C NMR) spectroscopy. Thermal properties and structural molecular subunits were investigated by off-line pyrolysis, and Pyrolysis-Field Ionization Mass Spectrometry (Py-FIMS). The 13C NMR spectra showed that the FAs from topsoil solutions had smaller proportions of alkyl C (mean: —8 %) and more aromatic C (mean: + 6 %) than FAs from ground water. This clear differentiation of dissolved FAs in the soil profiles is consistent with Py-FIMS data which have shown enrichments of lipids in ground water FAs. Furthermore, Py-FIMS revealed that the FAs from topsoils were richer in phenols + lignin monomers, carbohydrates, as well as mostly aromatic N-containing compounds. These molecular subunits of FAs, relatively enriched in topsoil, were also the main indicators of land use and peat degradation. For topsoil solutions, the proportions of phenols + lignin monomers and carbohydrates increased stepwise with peat degradation in Gleysols and Histosols. Correspondingly, the thermal properties indicated the incorporation of these compounds into FAs by chemical bonds of larger thermal stability. Statistical evaluation by principal component analysis of Py-FIMS clearly supported the differentiation of FAs according to the origin from topsoils and ground water, different soil types, and land use and peat degradation. Hence, it is concluded that water soluble FAs can be utilized as objective ecological indicators for soil effects on adjacent ground and surface waters.Molekulare Zusammensetzung von Fulvosäuren in unterschiedlich genutzten Gleyen und NiedermoorenFulvosäuren (FAs) aus Bodenlösung und Grundwasser wurden untersucht, um Veränderungen von Zusammensetzung und thermischen Eigenschaften infolge unterschiedlicher Landnutzung und Torfdegradierung zu erforschen. Dazu wurden die FAs aus drei Gleyen unter Acker, extensivem und intensivem Grasland sowie aus drei Niedermooren unter Erlenbruchwald, Dauergrasland und natürlicher Sukzession in einem bereits seit langer Zeit kultivierten Niedermoorgebiet extrahiert. Funktionelle Gruppen und molekulare Untereinheiten der FAs wurden mit 13C-Kernresonanz-Spektroskopie (13C-NMR), off-line-Pyrolyse und on-line-Pyrolyse-Feldionisation-Massenspektrometrie (Py-FIMS) analysiert. Die 13C-NMR-Spektren <?tw=99%>zeigten niedrigere Anteile an Alkyl-C (Mittelwert: —8 %) <?tw>und höhere Anteile an aromatischem C (Mittelwert: + 6 %) der FAs aus Lösungen aus Oberböden im Vergleich zu den FAs aus Grundwasser. In Übereinstimmung damit ergab die Py-FIMS relative Anreicherungen an Lipiden in den FAs aus Grundwasser. Die FAs aus Oberböden waren dagegen reicher an monomeren Ligninbausteinen, Kohlenhydraten und N-Verbindungen. Diese in den FAs aus Oberböden angereicherten, molekularen Untereinheiten waren auch die Hauptindikatoren für Effekte der Landnutzung und Torfdegradierung. In beiden Gruppen von Böden führte eine erhöhte Intensität der Bodennutzung und damit verbundene Belüftung zu größeren Anteilen an Phenolen + Ligninmonomeren und Kohlenhydraten. Die aus den Py-FI-Massenspektren berechneten Thermogramme zeigen, dass diese Verbindungen nicht nur relativ angereichert, sondern auch durch chemische Bindungen mit größerer thermischer Stabilität charakterisiert sind. Die Ergebnisse belegen, dass gelöste FAs als schnell wirksame und objektive Indikatoren für mögliche Auswirkungen von Landnutzungsänderungen auf benachbarte Oberflächengewässer genutzt werden können.
A study of partitioning of rainfall into throughfall, stemflow, and interception was conducted in a dry sclerophyll eucalypt forest and an adjacent pine plantation over a period of seven years, on a rainfall event basis. The following three issues are discussed: (1) the relationship between canopy storage capacity and interception of continuous events, (2) interception, throughfall, and stemflow, and (3) the effect on interception of thinning the pine plantation.
Species composition and tree type are considered when comparing these results with published studies from similar forest types in southeastern Australia. The periodic (annual) variations of interception in this and the other studies makes comparison difficult.
Lysimeter trials carried out over several years showed that cutting mineral fertilizer by 50% does not immediately result in a reduction of the leaching losses of relevant macronutrients (N, P, K). Land usage changes in the form of 1-year rotating set-asides entail greater N-leaching compared to best management practices (BMP). By contrast, after set-aside lasting 3–5 years, reductions in N-leaching of 25–45% must be expected. Lysimeter trials of reintegrating land set-aside for a number of years into intensive agriculture without increasing N-leaching losses are presented. Ways of scaling up lysimeter results to fields and small catchments are described, as well as areas where research still needs to be carried out are discussed. Copyright © 2002 John Wiley & Sons, Ltd.RÉSUMÉDes essais lysimétriques sur plusieurs années ont démontré qu'une réduction de 50% de l'utilisation d'engrais minéraux n'entraînait pas immédiatement une réduction de l'exportation des macro-substances nutritives importantes (N, P, K). Des modifications au niveau de l'aménagement des sols sous forme de jachères tournantes annuelles sont, comparées à une exploitation se conformant aux principes de “best management practices”, liées à de forts lessivages des substances azotées. Par contre, en cas de mise en jachère sur 3, voire 5 années, on peut compter sur des réductions du lessivage des substances azotées comprises entre 25 et 45%. Des alternatives permettant la réintégration en agriculture intensive des surfaces jachérisées pendant plusieurs années sans augmentation des exportations des substances azotées sont proposées. Des méthodes d'extension des résultats lysimétriques à des unités plus grandes (champs, bassins d'alimentation restreints) sont présentées et les perspectives de recherche sont évoquées. Copyright © 2002 John Wiley & Sons, Ltd.
A 36 tonne monolithic weighing lysimeter (3.7 m diameter and 1.5 m deep) was installed in Kioloa State Forest near Batemans Bay, New South Wales, Australia, to provide a continuous record of water use from a regenerating natural eucaplyt community, five years old at installation. The resolution is equivalent to 0.05 mm of evaporation and provides hourly information for diurnal variation of forest evaporation. The sensitivity of 14 ppm compares favourably with those reported for other lysimeters, similar in magnitude, in the U.S.A.
Design criteria for selecting, isolating and suspending a sample community ‘in situ’ with an electro-mechanical balance are outlined. Procedures adopted during installation are described with emphasis placed on precautions taken to minimize disturbance and to avert possible changes in character of the isolated natural community. Lysimeter performance was assessed both in terms of its accuracy and its operation as a remote facility with infrequent attention.
The bio-drainage–commercial forestry strategy was applied in five plots in the Yizre'el Valley, northern Israel, to evaluate the hydrological and salinity impacts of eucalypt plantations. Each plot contained a mix of 11 selected eucalyptus species/ecotypes. Two plots (Nahalal and Genigar), representing the two extreme waterlogging/salinity conditions in the valley, were selected for in-depth monitoring over a 10-year period to assess the likely environmental improvement through bio-drainage. Despite impressive growth rates of genetically improved Eucalyptus camaldulensis in the year-round waterlogged, slightly saline Nahalal site (650 mm annual rainfall), the water uptake by the trees was insufficient to control the rising water table caused by excessive water inputs, both natural and human. In the more saline, alkaline and drier Genigar plot (450 mm annual rainfall), where rainfall is the only water input, the ground water dropped to below 3 m from soil surface in the fourth year after planting, i.e. deeper than the adjacent ground water levels. Both sites showed appreciable rise in wells that penetrated the 3- to 4-m confining layer. The 10-year salinity (EC) trend of the top layer in Nahalal varied because the drainage was limited by the positive water balance and the above-average spells of dry winters. In and below the 4 m deep layer the EC remained below 1·5 dS m−1 throughout the entire 10-year study. The last EC measurement, taken in 2003, showed values not higher than 4 dS m−1 throughout the 6 m soil profile. In Genigar, there was significant leaching of salts from the top layer (1 m) during the 9-year monitoring period, but recently a salts ‘bulge’ was gradually developed in the 1–5 m strata indicating that the expected downward movement of leached salts was impeded by the 3–4 m deep low-permeability clayey layer that lies over a coarser, far more conductive and notably confined layer, which leads to a perched water body. The last EC measurement at the end of 2003 showed a maximum value of 5·5 dS m−1 at 3 m depth. No signs of tree stress were observed in either site, at any soil depth during the 10 years of monitoring. Theoretical considerations do not support the hypothesis that there would be a fatal long-term accumulation of salts in the root zone. The Israeli experience has shown that the bio-drainage technique can effectively lower a shallow water table and reverse salinity trends, provided that the overall water balance is negative, i.e. that the water inputs match the water use by the tree plantation and local drainage characteristics. However, the rate of improvement of the hydraulic, salinity, sodicity and soil physical properties is site specific. Excess fresh water inputs into the plantation, although they create waterlogging conditions, supply unlimited water to the trees, which, in turn, show exceptional growth rates, with usable commercial value. Copyright © 2007 John Wiley & Sons, Ltd.
More than 40 years of revegetation using mainly Caragana korshinskii at Shapotou Desert Experimental Research Station in China has established a dwarf-shrub and herbaceous cover on the stabilized sand dunes. The evapotranspiration (ET) of the dwarf-shrub C. korshinskii community and the evaporation (E) of the bare soil were measured by the auto-weighing lysimeter method during the growing seasons from 1990 to 1995. The average ET rate was 0·83 mm d−1, which varied from 0·71 to 1·06 mm d−1 during the 6-year period. Monthly ET ranged from 0·14 to 2·35 mm d−1, with a monthly precipitation (P) range of 0 to 3·12 mm d−1. Monthly ET/P ratios varied from 0·94 to 1·28 and averaged 97·4% overall. Most of the precipitation in this area usually falls between June and September. The lowest precipitation was recorded in 1991, with most of it falling during April and May. This temporal anomaly in the precipitation resulted in the highest ET/P ratio (by 0·33) and soil moisture depletion (ΔS = −31·5 mm) for the 6-year period. ET from the revegetated sand dunes around Shapotou under natural precipitation may account for 12·2% of the potential evaporation. Cumulative P and cumulative ET and E were highly correlated, with a well-defined linear relationship of ET = 0·80P + 10·0 and E = 0·55P + 5·89, with regression R2 ranging from 0·953 to 0·985. In 1991, however, the regression equations for both ET and E were considerably different than the other years, with a steeper slope and a negative intercept resulting from the anomaly in the precipitation pattern. Copyright © 2004 John Wiley & Sons, Ltd.
Large land areas in Sweden are planned to be planted with high producing, short rotation forest stands of willow in the beginning of the 1990s. Since willow is a highly hydrophilic species, this new land use may have strong implications on water resources. To assess these implications, evaporation of Salix viminalis and Salix viminalis x caprea stands in lysimeters was analysed with the simple, yet physically realistic KAUSHA model. Parameter values for the Lohammar equation were deduced (b = 100 m3 kg−1, kmax = 0.01 m s−1), believed to be applicable to other sites. Simulated evaporation during the 1980 growth season for a normal stand with a production of 12 tonnes of dry matter per hectare per season was 526 mm, of which 375 mm was transpiration, 56 mm interception evaporation, and 95 mm soil evaporation. For an optimally irrigated 20-tonnes stand, the total evaporation was 584 mm, of which 430 mm was transpiration. As a comparison, Penman open water evaporation was 430 mm. To avoid soil water stress in the 20-tonnes stand, 140 mm was needed as irrigation, equivalent to 25 per cent of the mean annual precipitation. Since intensively cultivated willow plantations seemed to be using much water, it was concluded that introduction of this agri-forestry practice must be carefully planned to make use of this property, e.g. in biological filters or in reclaiming water-logged land.
The spatial distribution of source areas and associated residence times of water in the catchment are significant factors controlling the annual cycles of dissolved organic carbon (DOC) concentration in Deer Creek (Summit County, Colorado). During spring snowmelt (April–August 1992), stream DOC concentrations increased with the rising limb of the hydrograph, peaked before maximum discharge, then declined rapidly as melting continued. We investigated catchment sources of DOC to streamflow, measuring DOC in tension lysimeters, groundwater wells, snow and streamflow. Lysimeter data indicate that near-surface soil horizons are a primary contributor of DOC to streamflow during spring snowmelt. Concentrations of DOC in the lysimeters decrease rapidly during the melt period, supporting the hypothesis that hydrological flushing of catchment soils is the primary mechanism affecting the temporal variation of DOC in Deer Creek. Time constants of DOC flushing, characterizing the exponential decay of DOC concentration in the upper soil horizon, ranged from 10 to 30 days for the 10 lysimeter sites. Differences in the rate of flushing are influenced by topographical position, with near-stream riparian soils flushed more quickly than soils located further upslope. Variation in the amount of distribution of accumulated snow, and asynchronous melting of the snowpack across the landscape, staggered the onset of the spring flush throughout the catchment, prolonging the period of increased concentrations of DOC in the stream. Streamflow integrates the catchment-scale flushing responses, yielding a time constant associated with the recession of DOC in the stream channel (84 days) that is significantly longer than the time constants observed for particular locations in the upper soil. © 1997 John Wiley & Sons, Ltd.
Time sequences of tracer release from an alpine snowpack were investigated at Mammoth Mountain, California in 1989. Lysimeter discharge and conductivity were recorded at 30 minute intervals. Three separate applications of chemical tracers were added to the snow surface to provide an ionic signal with known origins in the snowpack. Grab samples of meltwater and snow from snow pits were analysed for chemical composition. There were three distinct discharge periods, each characterized by diurnal fluctuations in discharge and conductivity. An inverse relation between discharge and conductivity was interpreted as the combination of a concentrated signal from regions in the pack less subject to leaching and a relatively dilute signal from near the snow surface where the snow was actively melting Conductivity peaks were highest and diurnal changes greatest immediately following periods of freezing. Grab samples showed little correlation with either 30 minute or daily average conductivity. Relative concentrations of individual ions in meltwater were similar between samples. Non-systematic grab sampling of snowpack meltwater is shown to be potentially misleading because of multiple ionic pulses over the ablation season and strong diurnal fluctuations in chemical concentrations. Continuous measurements of discharge conductivity are a good indicator of diurnal and seasonal changes in the rate of ion release from the snowpack, and should be used to guide sampling. Composite, or time-integrated samples rather than grab samples may be required to estimate daily and weekly rates of ion release in melting snow.
Arid-site recharge, while generally low, can be highly variable. Recharge under similar climate and soil conditions but with different plant cover and topography can vary from zero to more than the annual precipitation. Simple estimates of recharge based on fixed fractions of annual precipitation are misleading because they do not reflect the plant and soil factors controlling recharge. Detailed water balance models, successful for irrigated agriculture, fail to predict evapotranspiration accurately under conditions where plants suffer seasonal water stress and cover is sparse. Recharge, when estimated as a residual in water balance models, may be in error by as much as an order of magnitude. Similar errors can occur when soil water flow models are used with measured or estimated soil hydraulic conductivities and tension gradients. Lysimetry and tracer tests offer the best hope for evaluating recharge at arid sites, particularly in siting waste disposal facilities, where reliable recharge estimates are needed. Quantification of drainage using lysimetry over several years under a given set of soil, plant, and climate conditions for a specific site can provide a basis for calibrating models for recharge prediction. Tracer tests using such long-lived tracers as 36Cl or perhaps stable isotopes (180, deuterium) can provide qualitative estimates of recent recharge at a given site.
Two soil–water balance models were tested by a comparison of simulated with measured daily rates of actual evapotranspiration, soil water storage, groundwater recharge, and capillary rise. These rates were obtained from twelve weighable lysimeters with three different soils and two different lower boundary conditions for the time period from January 1, 1996 to December 31, 1998. In that period, grass vegetation was grown on all lysimeters. These lysimeters are located in Berlin-Dahlem, Germany. One model calculated the soil water balance using the Richards equation. The other one used a capacitance approach. Both models used the same modified Penman formula for the estimation of potential evapotranspiration and the same simple empirical vegetation model for the calculation of transpiration, interception, and evaporation. The comparisons of simulated with measured model outputs were analyzed using the modeling-efficiency index IA and the root mean squared error RMSE. At some lysimeters, the uncalibrated application of both models led to an underestimation of cumulative and annual rates of groundwater recharge and capillary rise, despite a good simulation quality in terms of IA and RMSE. A calibration of soil-hydraulic and vegetation parameters such as maximum rooting depth resulted in a better fit between simulated and observed cumulative and annual rates of groundwater recharge and capillary rise, but in some cases also decreased the simulation quality of both models in terms of IA and RMSE. The results of this calibration indicated that, in addition to a precise determination of the soil water-retention functions, vegetation parameters such as rooting depth should also be observed. Without such information, the rooting depth is a calibration parameter. However, in some cases, the uncalibrated application of both models also led to an acceptable fit between measured and simulated model outputs.
Humus horizons of dystric cambisols were sampled six times during 1990–1992 at 66 points along a beech forest transect in Scania, s. Sweden. Cation concentrations of soil solutions obtained by centrifugation of sifted samples at field moisture were related to pH, DOC, exchangeable pools of the cations and soil moisture. Soil solution Al was speciated in free ionic (easily reacting) Alr and organically complexed Alorg. Two or three variables accounted for a large share (70–90 %) of the cation variability between sampling points. Exchangeable soil pools were the most important variables for K, Mg. Ca, and Mn and contributed more when calculated on C. E. C. than on soil dry weight. Some function of pH was also of importance to most cation concentrations. Alr correlated well with both Alorg(+) and pH(-). Soil moisture was positively related to DOC and K, negatively to H-ion concentration. pH measured by different methods were closely correlated (r = 0.93–0.97), pHkcl and pH being ca. 0.5 unit lower, pH ca. 0.3 unit higher than soil solution pH, which varied between 3.5 and 5.6.
Presently, the soil water balance of flood-influenced soils in fluvial plains is insufficiently described. The new development of a weighable groundwater lysimeter is the basis for recording the water-balance components precipitation, evapotranspiration, groundwater recharge, capillary rise, and interaction with the water course. Soil-hydrologic measuring setups at two floodplain sites of the Elbe river serve for direct comparability of lysimeter measurements with data obtained on site. A groundwater control was designed for lysimeters that automatically adjusts the current groundwater level at the floodplain measuring setups and quantifies inflow into or outflow from the lysimeter. It turned out that the lysimeter developed is capable of identifying the individual water-balance quantities at high accuracy. Contrary to previous assumptions, it was possible to prove groundwater recharge for the floodplain sites.
Analyses of the response by a weighing lysimeter in Kioloa State Forest during and after rainfall provided values of interception loss rate. The derived rates for time scales between 0.1 and 1.0mm h ⁻¹ were generally similar throughout storm events to losses determined from throughfall and stemflow observations. During post‐rainfall periods of canopy drying, enhanced rates of lysimeter evaporation were consistent with micrometeorological determinations of the partitioning of available radiant energy, based on atmospheric gradients of humidity and temperature.
Interception losses from the eucalypt forest, deduced from the lysimeter response, varied between 10 and 15 per cent of gross rainfall in three consecutive 12 month periods whereas the corresponding rainfall ranged between 590 and 1530 mm yr ⁻¹ . Daytime losses accounted for about two‐thirds of total interception loss with a similar fraction occurring during rain periods.
Storage capacity of the evergreen forest canopy was inferred to be 0.35 mm. Hourly loss rates during rainfall ranged up to 0.8 mm h ⁻¹ but with decreasing mean values and variability with increasing time scale resulting in a monthly mean value computed for the total number of hours of rain of approximately 0.1 mm h ⁻¹ . A preliminary analysis of loss rate in terms of storm windspeed and rainfall intensity explained about half of its variation in statistically derived relationships. Improved time resolution of the order of seconds was considered a prerequisite to the physical understanding of turbulent transport from saturated canopies.
The small value of interception storage capacity was considered in relation to that for pine forest as a basis for explaining observed differences in interception behaviour between eucalypt forest and coniferous plantations in the same area. Large differences in interception losses between the Kioloa site and evergreen forest in the South Island of New Zealand and also eucalypt forest in Western Australia were attributed to dissimilar meteorological conditions at the various sites.
Imbalanced nutrient management has caused soil phosphorus (P) to become an environmental rather an agronomic problem in more economically developed countries. This subject has been the topic of numerous journal special issues, conferences, and reviews but we consider yet another review of this subject is necessary with the main target of providing a point of view on nonpoint transfer from soils and control strategies for an improved environmental management of P. This review considers the causes of the excessive P transfer from soil to surface water in Europe and the scientific knowledge necessary to develop control strategies.
Exact information about soil water flow is needed to quantify solute transfer within the unsaturated zone. Water flux densities are often measured indirectly, e.g., with water-balance, water content–change, or tracer methods, and, therefore, often predicted with notable uncertainties. Over the last years, direct lysimetry methods have been increasingly used to study water and solute migration in soil profiles. A large weighable lysimeter is the best method to obtain reliable drainage data, but it requires relatively high investment and maintenance expenses. To reduce cost and improve comparability with undisturbed sites, a new technology to collect large monolithic soil columns with a surface area of 0.5–2 m2 and a depth of 1–3 m as well as a containerized polyethylene (PE-HD) lysimeter station were developed. In addition, the station was fitted with a new high-precision weighing technique. In this paper, the latter is demonstrated with data from a newly constructed gravitation lysimeter. Besides recording rainfall and seepage, its weighing precision makes it possible to register mass input by dew, fog, or rime. It also permits a very accurate calculation of actual evapotranspiration. Because this new type of lysimeter allows a very high temporal resolution, it is ideally suited to develop and test models for soil hydrologic processes.
Experiments were conducted on an intact soil column to test the suitability of several transport codes in describing the movement of reactive organic compounds through soil containing preferred flow pathways (macropores). The equilibrium-based advection-dispersion model and the nonequilibrium two-region/two-site model were used to describe the elution of a nonretarded tracer ([14C]methanol) and two retarded tracers (trichlorobenzene and tetrachlorobenzene). The advection-dispersion model proved adequate in describing the movement of the nonreactive tracer but it failed to describe the elution of the hydrophobic organics. The organic tracers required the nonequilibrium model to account for their apparent rapid movement. The two-site model, when calibrated to the trichlorobenzene breakthrough data, successfully predicted the elution of tetrachlorobenzene.
Future catchment planning requires a good understanding of the impacts of land use and management, especially with regard to nutrient pollution. A range of readily usable tools, including models, can play a critical role in underpinning robust decision-making. Modelling tools must articulate our process understanding, make links to a range of catchment characteristics and scales and have the capability to reflect future land-use management changes. Hence, the model application can play an important part in giving confidence to policy makers that positive outcomes will arise from any proposed land-use changes. Here, a minimum information requirement (MIR) modelling approach is presented that creates simple, parsimonious models based on more complex physically based models, which makes the model more appropriate to catchment-scale applications. This paper shows three separate MIR models that represent flow, nitrate losses and phosphorus losses. These models are integrated into a single catchment model (TOPCAT-NP), which has the advantage that certain model components (such as soil type and flow paths) are shared by all three MIR models. The integrated model can simulate a number of land-use activities that relate to typical land-use management practices. The modelling process also gives insight into the seasonal and event nature of nutrient losses exhibited at a range of catchment scales. Three case studies are presented to reflect the range of applicability of the model. The three studies show how different runoff and nutrient loss regimes in different soil/geological and global locations can be simulated using the same model. The first case study models intense agricultural land uses in Denmark (Gjern, 114 km2), the second is an intense agricultural area dominated by high superphosphate applications in Australia (Ellen Brook, 66 km2) and the third is a small research-scale catchment in the UK (Bollington Hall, 2 km2). Copyright © 2007 John Wiley & Sons, Ltd.
Hexagenia are an important component of fish and waterfowl diets, provide an ecological link in the conversion of detritus to usable nutrients and are useful test organisms for monitoring trends in aquatic contaminants. Consequently, Hexagenia bilineata were used in toxicity tests to determine their sensitivity to leachate from spent shale oil and to evaluate the influence of including artificial glass burrows in exposure chambers. Gill beat frequency and mortality were significantly higher (p = 0.01) in nymphs that were not afforded an opportunity to burrow than in those exposed to the toxicant but that had access to artificial burrows. Molting frequency was depressed in Hexagenia lacking burrows, and it was further decreased as the amount of toxicant increased. Thus, thigmotactic stress accentuated by the presence of shale oil leachate was relieved by including artificial burrows in the exposure chambers. The resulting toxicity data are more ecologically meaningful because the burrowing life history characteristic of the Hexagenia was addressed and incorporated into the test protocol.
Sampling of soil pore moisture in the vadose zone underneath land disposal facilities (landfills and surface impoundments) for hazardous waste has been suggested as an “early warning system” to detect leakage from these facilities. Some states require vadose zone moisture sampling at such sites. Given a leak of a particular size, mathematical models can estimate the necessary moisture sample volume collection times and lysimeter spacings to guarantee detection of the leak in a homogeneous medium. Examination of 47 hazardous waste sites existing in 1984 indicated the most were located in areas with water tables too shallow to permit vadose zone detection monitoring. Several of the 47 sites had soils that could be described as loamy sand, silt loam or silty clay. Using these three soils as examples, the process of lysimeter leak-detector network design has been illustrated. For a particular loamy sand with a saturates hydraulic conductivity of 10-6 cm/ sec, the maximum ceramic lysimeter spacing is 15.5 feet at a depth of 30 feet to collec a moisture sample of 10 mL in one week from a 1 ft2 leak. For a silt loam, maximum lysimeter spacing would be 17 feet at depth of 15 feet. For silty clays, the maximum lysimeter spacing is 7 feet at a depth of 2 feet; maximum emplacement depth is about 9 feet. Calculations show that in some soils, suction lysimeters will not be able to collect usable moisture samples. Since soil properties vary widely and lysimeter spacing is strongly dependent on soil-moisture characteristics appropriate soil measurements and modeling must be performed at each disposal facility to estimate lysimete performance and to select locations for emplacement.
Different methods exist for measuring soil water and solute fluxes in and below the root zone and have been critically reviewed.
Besides indirect methods (e.g. water balance, tensiometer, time domain reflectometry – TDR, frequency domain reflectometry
– FDR, environmental tracer) direct methods (e.g. drainage-type lysimeter, water fluxmeter) have a long tradition and have
been successfully used in seepage research. A large weighable out door lysimeter is the best method for obtaining reliable
data about seepage water quantity and quality, but it involves significant investment and additional expenses for maintenance.
To tackle this problem new methods for the vertical collection of large volume soil monoliths (up to 6m3) as well as for the horizontal collection (up to 6m3) have been developed. For the placement of the lysimeter a container lysimeter unit was constructed, which is cheaper than
a conventional steel or concrete cellar. Furthermore, the technical design of the newly developed lysimeter types as a weighable
gravitation lysimeter, a weighable groundwater lysimeter and a lateral flow lysimeter are presented.