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Effect of exposure on the water balance of two identical lysimeters
Abstract
This study looks at the water balance of two identical weighable lysimeters located right next to each other. They contain the same soil and are managed in the same way. Both were planted with maize. The area around them was planted with maize, too, to ensure that the lysimeters were located inside a crop. The only difference between them was that one side of lysimeter 2 was exposed due to a footpath.
... A construção dos lisímetros tem levado em consideração necessidades específicas, que dependem da cultura estudada (ex.: profundidade do sistema radicular e projeção da copa), do tipo de solo e do clima (CAMPECHE et al., 2011;ESCARABAJAL-HENAREJOS et al., 2015). O custo de construção e instalação de um lisímetro pode variar consideravelmente, sendo afetado principalmente pelo seu tamanho, tipo de material e, especialmente, pelo tipo de mecanismo de pesagem (HAGENAU;MEISSNER;BORG, 2015;PAYERO;IRMAK, 2008). ...
... A construção dos lisímetros tem levado em consideração necessidades específicas, que dependem da cultura estudada (ex.: profundidade do sistema radicular e projeção da copa), do tipo de solo e do clima (CAMPECHE et al., 2011;ESCARABAJAL-HENAREJOS et al., 2015). O custo de construção e instalação de um lisímetro pode variar consideravelmente, sendo afetado principalmente pelo seu tamanho, tipo de material e, especialmente, pelo tipo de mecanismo de pesagem (HAGENAU;MEISSNER;BORG, 2015;PAYERO;IRMAK, 2008). ...
... A construção dos lisímetros tem levado em consideração necessidades específicas, que dependem da cultura estudada (ex.: profundidade do sistema radicular e projeção da copa), do tipo de solo e do clima (CAMPECHE et al., 2011;ESCARABAJAL-HENAREJOS et al., 2015). O custo de construção e instalação de um lisímetro pode variar consideravelmente, sendo afetado principalmente pelo seu tamanho, tipo de material e, especialmente, pelo tipo de mecanismo de pesagem (HAGENAU;MEISSNER;BORG, 2015;PAYERO;IRMAK, 2008). ...
Existem muitas metodologias para medição ou estimativa da evapotranspiração de cultura (ETc). Essas metodologias apresentam grandes diferenças entre si, especialmente no que se refere à base de formulação (empíricos, físicos ou a combinação de ambos), ao nível tecnológico (equipamentos, sensores sofisticados, etc.), a necessidade de dados de entrada, a área de aplicação, custo e precisão. Esta diversidade está relacionada à complexidade envolvida na transferência de água do sistema solo-planta para a atmosfera, com as variadas condições climáticas ao redor do planeta e também com os diferentes tipos de vegetação estudados. Nesta revisão, os seguintes métodos foram descritos e revisados: lisimetria (LIS), balanço de água no
solo (BAS), razão de Bowen - balanço de energia (RBBE), covariância de vórtices turbulentos (CVT), modelos de fluxo de seiva (MFS), sistema de câmaras (SC), e métodos baseados no coeficiente de cultura (MBKc). Por fim, os métodos baseados no balanço de energia das superfícies (SRBE) e em índices de vegetação (SRIV), calculados a partir de dados de sensoriamento remoto (SR). Esses métodos foram selecionados por serem considerados, dentro do seu tipo de abordagem (hidrológica, micrometeorológica, fisiológica, empírica e sensoriamento remoto), os mais difundidos entre a comunidade científica internacional, e na agricultura.
... Studies of soil water balance are facilitated by the use of lysimeters (Hillel, 1998;Beeson, 2011;Meissner et al., 2008;Hagenau et al., 2015;Klammler and Fank, 2014). Lysimeters are large containers filled with soil and placed in the field (Lal and Shukla, 2004). ...
... Lysimeters must be deep enough to promote root development (Hagenau et al., 2015;Meissner et al., 2010), with a minimum area of 2 m 2 to account for soil variability (Aboukhaled et al., 1982). Moreover, crop population, height, irrigation and fertilization should be similar between lysimeters and the surrounding area (Gebler et al., 2015). ...
... Higher evapotranspiration rates on potash tailings piles would lead to lower brine injection and salt loading into rivers and streams . On the other hand, one needs to take care in extrapolating these results to larger scales because the artificial lower boundary condition of the gravity lysimeters, where drainage occurs when saturation is reached (Klammler and Fank, 2014), does not correspond with the tension head of the potash tailings, which in turn can lead to different upward or downward water fluxes (Hagenau et al., 2015). ...
Water balance is an important tool to evaluate water deficit or excess in crop systems. However, few studies have evaluated the water balance of vegetation grown on the residues from potash mining because the high sodium chloride levels of the residues hinder agricultural development. Therefore, this study aims to measure the water balance components in eight non-weighing lysimeters installed on a potash tailings pile in Heringen (Werra), Germany. These lysimeters were filled with different mixtures of household waste incineration slags and coal combustion residues, resulting in 4 different substrates with two repetitions. Manual seeding was performed using 65% perennial ryegrass (Lolium perenne L.), 25% red fescue (Festuca rubra L.) and 10% Kentucky bluegrass (Poa pratensis L.). Environmental conditions were monitored using an automatic weather station; ground-level and 1-m-high rain gauges. Precipitation and drainage were recorded weekly following the initial saturation of the lysimeters. Water balance components were determined for two hydrological years based on the expression: ET (mm)?=?P - D, where ET?=?evapotranspiration, P?=?precipitation and D?=?drainage. In addition, evapotranspiration was studied using the standard FAO Penman-Monteith equation and Haude's method. The lysimeter water balance measured in 2014 revealed an actual evapotranspiration rate of 66.4% for substrate 1, 66.9% for substrate 2, 65.1% for substrate 3 and 64.1% for substrate 4. In 2015, evapotranspiration ranged from 65.7% for substrate 4 to 70.2% for substrate 1. We observed that the FAO Penman-Monteith and Haude's evapotranspiration models generally overestimated the water use of the green coverage by 67% and 23%, respectively. Our study suggests that an evapotranspiration cover for potash tailings piles may decrease brine drainage from these piles and reduce soil and water contamination.
... A notable environmental influence is the degree of vegetation surrounding each lysimeter, which has been shown to impact water balance measurements (Allen et al., 2011). Hagenau et al. (2015) found that P measured by two adjacent, identically treated lysimeters varied by 100 mm over a growing season due to a slight increase in exposure of one lysimeter from a nearby pathway. Differences in the amount of vegetation on the lysimeter surface can also cause water balance variations since ET rates and intercepted P are closely tied to vegetation cover (Balykin et al., 2016;Lazarovitch et al., 2006;Wegehenkel and Gerke, 2013). ...
... The total uncertainty of the sum, which included the uncertainty of the AWAT filtering, was 1.5% of the mean P across both soil types. Minor differences in measured P totals were likely due to differences in crops affecting interception, from variations in the degree of sheltering from the surrounding plots (Hagenau et al., 2015), and dew formation as affected by plant numbers (Groh et al., 2018). Spatial variability of summer convective rainstorms could also affect the spatial variability of lysimeter P measurements (Herbrich and Gerke, 2017b). ...
Diversifying annual crop rotations is postulated to promote soil ecosystem services through reduction of greenhouse gas emissions, control of soil evaporation, moderation of soil freeze-thaw cycles, increases in soil organic carbon, and reduced nutrient leaching, all of which are processes that are impacted by the water balance. A newly-installed facility with large monolithic weighing soil lysimeters dedicated to studying changes in soil ecosystem services induced by rotation diversification was installed in June 2016 in Elora, ON, Canada. The high-precision lysimeters, nine for each of two different soils (silt loam, loamy sand) are a closed system to fully evaluate water balance components. In the first year of operation, the lysimeters were not subject to any diversification treatments. This provided an opportunity to study water budget components (precipitation, P; evapotranspiration, ET; change is soil storage, Δ S; drainage, D) measured by the 9 replicate lysimeters for each soil type. The objectives of this study were to 1) determine the total uncertainty of P, ET, Δ S and D induced by data smoothing and gap filling data procedures; and 3) characterize the spatial variability of water budget components for the baseline year. Cumulative sums of water balance variables from data processing procedures found that the adaptive window and adaptive threshold (AWAT) data smoothing method introduced minimal errors (0.2 to 1.9%). Filling missing data gaps using data from replicate lysimeters, i.e., lysimeters of the same soil type and agronomy, introduced errors of only 0.3 to 0.5% for P and ET (120-day sums). There was greater uncertainty for D and Δ S (10.8% and 2.1%, respectively) because of the variability in D. P showed a small degree of spatial variation across all 18 lysimeters, with variations being 1.5% of the mean cumulative sums when using data with no gaps, which demonstrated the high precision of the lysimeter measurements. Spatial variability of evapotranspiration (ET) was higher (6.1% for the silt loam and 5.7% for the loamy sand), but within the range of variability estimated for similar lysimeter facilities. The differences in plant cover on individual lysimeters were the main source of variation for ET and S. Results inform future comparisons of water budget components for other lysimeter sites and demonstrate the suitability of this facility for examining the complex impacts of crop diversification on soil ecosystem services, providing a basis for future evaluations of water balance components.
... Among several methods of experimentally determination of ETc and Kc, the methodology of weighing lysimeters is considered a standard in studies of water consumption of crops (Mariano et al., 2015;Hagenau et al., 2015). This equipment is a small representative plot of a large area, constructed to measure water balance co mponents of a vegetated surface or of bare soil. ...
... Lysimeters are composed of a tank filled with soil or substrate, installed with its surface level to the area around the land, and being desirably, undetectable to the naked eye due to the similarity of its cover in relation to external area. They are supported in a weighing mechanis m that measures the mass variation of the system and transmits it as an electrical signal to a datalogger that registers the values at defined time intervals Hagenau et al., 2015). One of the difficult ies in using lysimeters is the high cost of construction and installation (Nascimento et al., 2016;Silva et al., 2016). ...
Sugarcane pre-sprouted plantlets (PSP) production system is an innovative method to enhance crop multiplication rate. Determination of crop evapotranspiration (ETc) is crucial for water requirement identification throughout the plant cycle for irrigation management. ETc can be satisfactorily measured by weighing lysimeters. The objective of the study was to construct and calibrate three low-cost weighing lysimeters to measure ETc of PSP. The built lysimeters had 0.6909 m2 area (1179 mm × 586 mm), with 400 mm depth supported by 3 load cells. Lysimeters calibration showed excellent precision measurements, due to high linear correlation (R2 = 1.0000) between electric signal and equivalent mass, high accuracy, confirmed by mean absolute error between 0.0272 and 0.0382 mm, mean square error between 0.0011 and 0.0024 mm2 and Willmott's index of agreement (d) equal to unit. Maximum hysteresis (0.1951 mm) and hysteresis at full scale (0.4492%) did not compromise the evaluations. Daily ETc measurements showed variation of 0.27 mm among lysimeters and were coincident with daily course of reference evapotranspiration (ETo). The cost of the equipment was low, except for the data acquisition system. Therefore, lysimeters presented low cost and were adequate to measure ETc of PSP in greenhouse-grown.
... On the one hand, suction controlled devices got emphasized to work better than free draining lysimeters (Vereecken and Dust, 1998;Zhu et al., 2002;Gee et al., 2009;Peters and Durner, 2009;Barkle et al., 2014) and on the other hand studies by Meissner et al. (2010) yielded that there are no significant differences between both types for longer observation periods. Each of these effects or a combination of these problems could lead to deviations between the water regime of the lysimeter and the investigated field (Hagenau et al., 2015). As a result of these studies it could be concluded that the reliability of lysimeter data to describe water flow on field scale could be enhanced when achieving as much information as possible from the investigated lysimeters. ...
... A weighing mechanism and registration of the depth depending matrix potential and soil moisture provided not only the determination of the outflow but also of the actual inflow into the lysimeter system, whereas a controlled lower boundary could mimic field conditions better as compared to gravitation lysimeters. But the installation of lysimeters obtaining a huge surface area and sufficient depth, a weighing mechanism, soil moisture sensors in several depths, and a controlled lower boundary is very expensive (Weihermü ller et al., 2007;Hagenau et al., 2015). In Germany, the first simple constructed non-weighable gravitation lysimeters (NWGL), also used in the presented study, were built in the 1920s and they are still working (Lanthaler and Fank, 2005). ...
The transfer of lysimeter-based water balances to field scale is still a challenge, whereby the reliability of measured data from non-weighable gravitation lysimeters (NWGL) is more questioned than the transferability of data from more modern lysimeter devices. The hypothesis of this study was to predict the water regime of a drained arable field (81 ha) based on measurement results of three neighboring (distance of 20 km northern Altmark region Saxony-Anhalt, Germany) NWGL (surface area of 1 m2, depth of 1.25 m) for three hydrological years (HY) from 11/1/2012 to 10/31/2015. For the first two HY, manually collected monthly outflow rates from the NWGL were comparable to registered (data logger) drain rates of the field. But NWGL outflow was underestimated as compared to field drainage in the third HY. This deficit in the lysimeter water balance was caused by heavy rain events in summer 2014 in combination with wind and interception by the crop canopy (Zea maize). Precipitation did not match the NWGL surface whereas this canopy effect did not play a role at the field site. Thus, further numerical simulations of the soil water flow with the HYDRUS 1D/2D-software package, which were based only on input data determined at the NWGL (stand precipitation, potential evaporation/ transpiration) without taking into account the canopy effect, described registered outflow of the field adequately for the whole observation period. But determining precipitation matching the NWGL surface, which was not registered due to the missing weighing mechanism, is absolutely required to interpret deviating measured outflow rates.
... To ensure a stable environment for the observations, the type of lysimeter filling remains the same during the observation period. The surrounding areas were managed similarly to the lysimeters to prevent an "island effect" that would have affected the determination of precipitation due to exposed vegetation (Hagenau et al., 2015). On the arable lysimeters the crop rotation was winter wheat, winter barley, winter rye, and oat during the observation period (2015)(2016)(2017)(2018). ...
Accurate precipitation data are essential for assessing the water balance of ecosystems. Methods for point precipitation determination are influenced by wind, precipitation type and intensity and/or technical issues. High-precision weighable lysimeters provide precipitation measurements at ground level that are less affected by wind disturbances and are assumed to be relatively close to actual precipitation. The problem in previous studies was that the biases in precipitation data introduced by different precipitation measurement methods were not comprehensively compared with and quantified on the basis of those obtained by lysimeters in different regions in Germany.
The aim was to quantify measurement errors in standard precipitation gauges as compared to the lysimeter reference and to analyze the effect of precipitation correction algorithms on the gauge data quality. Both correction methods rely on empirical constants to account for known external influences on the measurements, following a generic and a site-specific approach. Reference precipitation data were obtained from high-precision weighable lysimeters of the TERrestrial ENvironmental Observatories (TERENO)-SOILCan lysimeter network. Gauge types included tipping bucket gauges (TBs), weighable gauges (WGs), acoustic sensors (ASs) and optical laser disdrometers (LDs). From 2015-2018, data were collected at three locations in Germany, and 1 h aggregated values for precipitation above a threshold of 0.1 mm h-1 were compared.
The results show that all investigated measurement methods underestimated the precipitation amounts relative to the lysimeter references for long-term precipitation totals with catch ratios (CRs) of between 33 %–92 %. Data from ASs had overall biases of -0.25 to -0.07 mm h-1, while data from WGs and LDs showed the lowest measurement bias (-0.14 to -0.06 mm h-1 and -0.01 to -0.02 mm h-1). Two TBs showed systematic deviations with biases of -0.69 to -0.61 mm h-1, while other TBs were in the previously reported range with biases of -0.2 mm h-1. The site-specific and generic correction schemes reduced the hourly measurement bias by 0.13 and 0.08 mm h-1 for the TBs and by 0.09 and 0.07 mm h-1 for the WGs and increased long-term CRs by 14 % and 9 % and by 10 % and 11 %, respectively.
It could be shown that the lysimeter reference operated with minor uncertainties in long-term measurements under different site and weather conditions. The results indicate that considerable precipitation measurement errors can occur even at well-maintained and professionally operated stations equipped with standard precipitation gauges. This generally leads to an underestimation of the actual precipitation amounts. The results suggest that the application of relatively simple correction schemes, manual or automated data quality checks, instrument calibrations, and/or an adequate choice of observation period can help improve the data quality of gauge-based measurements for water balance calculations, ecosystem modeling, water management, assessment of agricultural irrigation needs, or radar-based precipitation analyses.
... To ensure a stable environment for the observations, the type of lysimeter filling remains the same during the observation period. The surrounding areas were similarly managed as the lysimeters to prevent an "isle effect", that would have affected the determination of 160 precipitation due to exposed vegetation (Hagenau et al., 2015). On the arable lysimeters the crop rotation was winter wheat, winter barley, winter rye and oat during the observation period (2015)(2016)(2017)(2018). ...
Accurate precipitation data are essential for assessing the water balance of ecosystems. Methods for point precipitation determination are influenced by wind, precipitation type and intensity and/or technical issues. High-precision weighable lysimeters provide precipitation measurements at ground level that are less affected by wind disturbances and are assumed to be relatively close to “true” precipitation. The problem in previous studies was that the biases on precipitation data introduced by different precipitation measurement methods were not comprehensively compared and quantified with those obtained by lysimeters under different climatic conditions. The aim was to quantify measurement errors of standard precipitation gauges as compared to the lysimeter reference and to analyse the effect of precipitation correction algorithms on the gauge data quality. Both correction methods rely on empirical constants to account for known external influences on the measurements, following a generic and a site-specific approach. Reference precipitation data were obtained from high-precision weighable lysimeters of the TERrestial Environmental Observatories (TERENO)-SOILCan lysimeter network. Gauge types included tipping bucket gauges (TBs), weighable gauges (WGs), acoustical sensors (ASs), and optical laser disdrometers (LDs). The data were collected from 2015–2018 at three sites in Germany and compared with a temporal resolution of 1 hour for precipitation above a threshold of 0.1 mm h-1. The results show that all investigated measurement methods underestimated the precipitation amounts relative to the lysimeter references for long-term precipitation totals with catch ratios (CRs) between 33–92 %. Data from ASs had overall biases of 0.25 to -0.07 mm h-1, while data from WGs and LDs showed the lowest measuring biases (-0.14 to -0.06 mm h-1 and 0.01 to 0.02 mm h-1). Two TBs showed systematic deviations with biases of -0.69 to -0.61 mm h-1, while other TBs were in the previously reported range with biases of -0.2 mm h-1. The site-specific and generic correction schemes reduced the hourly measuring bias by 0.13 and 0.08 mm h-1 for the TBs and by 0.09 and 0.07 mm h-1 for the WGs and increased long-term CRs by 14 and 9 % and by 10 and 11 %, respectively. It could be shown that the lysimeter reference operated with minor uncertainties in long-term measurements under different climatic conditions. The results indicate that even with well-maintained and professionally operated stations, considerable precipitation measurement errors can occur, which generally lead to a loss of recorded precipitation amounts. Data from standard precipitation gauges therefore still represent potentially significant uncertainty factors. The results suggest that the application of relatively simple correction schemes, manual or automated data quality checks, instrument calibrations and/or adequate choice of observation periods can help improve the data quality of gauge-based measurements for water balance calculations, ecosystem modelling, water management, assessment of agricultural irrigation needs or radar-based precipitation analyses.
... The essence of the system in a weighing lysimeter is that it has a mechanism that measures the change in mass. Thus, the methodology of weighing lysimeters is considered a standard in studies of water consumption of crops (Hagenau et al., 2015;Mariano et al., 2015;Libardi et al., 2018). Nevertheless, determining ET c for each region and crop is complex, time-consuming and costly. ...
Accurate calculation of evapotranspiration (ET) for all crops plays an important role. This study was conducted to determine the most accurate reference evapotranspiration (ETr) estimation model for arid climatic conditions using the decision support system (DSS) program for alfalfa plants in south-east Anatolia, Turkey, in 2019 and 2020. The evapotranspiration of 12 mathematical models (ETr-m) and the evapotranspiration of a lysimeter (ETr-l) were used to estimate ETr. In 2 experimental years, 1133 and 1270 mm of irrigation water were applied to alfalfa plants, respectively. The actual total ET was calculated as 1288 and 1294 mm in 2019 and 2020, respectively. The root mean square error (RMSE), mean absolute error (MAE), ETr-m/ETr-l, and index of agreement (d) were calculated separately for each mathematical model. The RMSE, MAE, ETr-m/ETr-l and d values for the mathematical models had a range of 1.25–3.57 mm day 1, 0.91–
1.98 mm day 1, 0.64–1.04 and 0.56–0.94, respectively. According to the results of the regression analysis with the RMSE, MAE, ETr/ETr-m and d values obtained from the models, the Businger–Van Bavel model was the most accurate prediction model. The others were the FAO PPP-17 Penman and the 1982 Kimberly Penman models, respectively.
... All load cell based lysimeters require calibration and frequent calibration may lead to excessive workload although a sensible level of quality control is warranted, and analysis of the costs for the mini-lysimeter system indicates that evapotranspiration can be measured economically at a reasonable accuracy and sufficient resolution with robust method of load cell calibration (Misra et al., 2011). To avoid the exposure effects, a lysimeter must be surrounded by a crop stand wide enough to prevent rain, which falls at an angel towards the lysimeter from reaching it, and it depends on the type of crop the required width may vary from less than one to several meters (Hagenau et al., 2015;Valtanen et al., 2017). Tripler et al. ...
Lysimeter is equipped with mechanisms for weighing by load cells enable automated measurements, and the signals resulting from weight changes in the system due to evaporation that are generally recorded in a data acquisition system. According to methods of measuring water content, lysimeters may be divided into weighing lysimeter and non-weighing lysimeter. The weighing lysimeters provide scientists the basic information for research related to evapotranspiration, and they are commonly divided into two types, continuous weighing and intermittent weighing. Weighing lysimeters have been used to quantify precipitation (P) not only in the form of rain or snow, but also dew, fog and rime, and also to determine actual evapotranspiration (ET). Compared to laboratory experiments, out-door lysimeter studies have advantages, like being closer to field environment conditions, it is possible to grow plants and therefore to study the fate of chemicals in soil/plant systems, transformations and leaching. The limitations are costy, which depend on design, variable experimental conditions, such as environmental/ climatic parameters, which are normally not controlled, the soil spatial variability is normally less, they are not suitable for every plant species and even every soil type. The objective of lysimeter is defining the crop coefficient (Kc), which used to convert ETr into equivalent crop evapotranpiration (ETc) values, and determing agronomical characteristics of crops, which are planted in the field of lysimeter. The duration of a lysimeter study is determined by the objective of the study, but for different crops, it should normally be at least two years. Weighing lysimeters using load cells have the advantage of measuring the water balance in the soil over a short time and with good accuracy. Precipitation should be recorded daily at the lysimeter site. All weather data like air temperature, solar radiation, humidity and potential evporation should be obtained onsite, and the frequency and time of measurements should be at least daily.
... These loads can be particularly important in small lysimeters as their lightweight structure might suffer deformations that affect the weighing system. Hagenau et al. [36] studied the influence of a footpath in two weighing lysimeters showing different evapotranspiration results during harvest period. The data illustrated that the exposure effect can modify the water balance. ...
Featured Application
Small weighing lysimeter for horticultural crops whose root depth is up to 300 mm providing an easy installation and removal, good structural performance and reliable water balances results.
Abstract
Water resources management is a priority issue in agriculture, especially in areas with water supply problems. Recently, one of the most widespread technologies for measuring crop water requirements are weighing lysimeters. Nevertheless, this type of lysimeters are of large dimensions and require a civil work for their installation. In this article, we present a weighing lysimeter prototype (1000 × 600 mm and 350 mm depth) designed to be used in agricultural farming of horticultural crops. We described the design details that includes ease of assembly, carriage and minimum soil alteration. Structural design results and construction process are also provided showing their performance under different tractors scenarios. The measurements accuracy results show the outcomes of the prototype after being tested. Finally, we discuss our design and measurements results by comparing them with other weighing lysimeters. In comparison, the prototype designed is an accurate and reliable device which reduces the surface and depth of the current weighing lysimeters.
... All load cell based lysimeters require calibration and frequent calibration may lead to excessive workload although a sensible level of quality control is warranted, and analysis of the costs for the mini-lysimeter system indicates that evapotranspiration can be measured economically at a reasonable accuracy and sufficient resolution with robust method of load cell calibration (Misra et al., 2011). To avoid the exposure effects, a lysimeter must be surrounded by a crop stand wide enough to prevent rain, which falls at an angel towards the lysimeter from reaching it, and it depends on the type of crop the required width may vary from less than one to several meters (Hagenau et al., 2015;Valtanen et al., 2017). Tripler et al. ...
... From our measurements we found that dew formation accounted for ~4.7 % of the total lysimeter derived P, which is in line with previous studies (Xiao et al. 2009;Heusinger and Weber 2015;Guo et al. 2016), but still explains only a small fraction of the difference in P amounts measured by lysimeters and rain gauges. Weather station exposure or wind effects are another important cause of the underestimation of P by rain gauges (Richter 1995;Hagenau et al. 2015). The measured cumulative ET was 72 % of the calculated reference PET. ...
... The soil water balance equation [37] was employed with a combination of evapotranspiration, irrigation, and precipitation to determine the water storage in soil. This equation can be expressed as ...
Groundwater plays a major role in agro-hydrological processes in the North China Plain (NCP). The NCP is facing a water deficit, due to a rapid decline in the water table because of the double cropping system. A two crop (maize and wheat) rotation is required to balance the food supply and demand, which leads to an imbalance between evapotranspiration (ET) and precipitation. Thus, there has been a decline of about 1.35 m yr⁻¹ of groundwater (Luancheng Agroecosystem Experimental Station (LAES), NCP) during the last 10 years. Lysimeter experiments were conducted under different irrigation treatments (flood, surface drip, and subsurface drip) to account for ET in the selection of a suitable irrigation method. Subsurface drip irrigation reduced ET by 26% compared to flood irrigation, and 15% compared to surface drip irrigation, with significant grain yield and biomass formation due to decreased evaporation losses. Grain yield, yield components, and above ground biomass were similar in subsurface drip and flood irrigation. However, these biomass parameters were lower with surface drip irrigation. Furthermore, subsurface drip irrigation increased the crop water productivity (24.95%) and irrigation water productivity (19.59%) compared to flood irrigation. The subsurface irrigated plants showed an increase in net photosynthesis (~10%), higher intrinsic water use efficiency (~36%), lower transpiration rate (~22%), and saved 80 mm of water compared to flood irrigation. Our findings indicate that subsurface drip irrigation can be adopted in the NCP to increase water use efficiency, optimize grain yield, and minimize water loss in order to address scarcity.
... From our measurements, we found that dew formation accounted for ?4.7% of the total lysimeterderived precipitation, which is in line with previous studies (Xiao et al., 2009;Heusinger and Weber, 2015;Guo et al., 2016) but still explains only a small fraction of the difference in precipitation amounts measured by lysimeters and rain gauges. Weather station exposure or wind effects are another important cause of the underestimation of precipitation by rain gauges (Richter, 1995;Hagenau et al., 2015). The measured cumulative ET was 72% of the calculated reference potential evapotranspiration. ...
Core Ideas
To determine the water retention curve from inverse modeling, θ and ψ need to be monitored.
δ ¹⁸ O ratios contained information to inversely estimate soil hydraulic parameters.
Different observation types should be combined in a single OF to estimate parameters.
Averages of local measurement could be described using effective parameters.
Accurate measurement of fluxes at lysimeter boundaries improved model parameterization.
Accurate estimates of soil hydraulic parameters and dispersivities are crucial to simulate water flow and solute transport in terrestrial systems, particularly in the vadose zone. However, parameters obtained from inverse modeling can be ambiguous when identifying multiple parameters simultaneously and when boundary conditions are not well known. Here, we performed an inverse modeling study in which we estimated soil hydraulic parameters and dispersivities of layered soils from soil water content, matric potential, and stable water isotope (δ ¹⁸ O) measurements in weighable lysimeter systems. We used different optimization strategies to investigate which observation types are necessary for simultaneously estimating soil hydraulic and solute transport parameters. Combining water content, matric potential, and tracer (e.g., δ ¹⁸ O) data in one objective function (OF) was found to be the best strategy for estimating parameters that can simulate all observed water flow and solute transport variables. A sequential optimization, in which first an OF with only water flow variables and subsequently an OF with transport variables was optimized, performed slightly worse indicating that transport variables contained additional information for estimating soil hydraulic parameters. Hydraulic parameters that were obtained from optimizing OFs that used either water contents or matric potential could not predict non‐measured water flow variables. When a bromide (Br ⁻ ) tracer experiment was simulated using the optimized parameters, the arrival time of the bromide pulse was underestimated. This suggested that Br ⁻ sorbed onto clay minerals and amorphous oxides under the prevailing geochemical conditions with low pH values. When accounting for anion adsorption in the simulation, Br ⁻ concentrations were well predicted, which validated the dispersivity parameterization.
... Heterogeneous atmospheric conditions in greenhouses was the motivation for a rotating lysimeter system proposed by Lazarovitch et al. (2006a). Recently, Hagenau et al. (2015) demonstrated how two identical lysimeters were effected significantly by slightly different surrounding conditions in the field. It is well known that soil heterogeneity will affect the results of measurements (Weihermüller et al., 2006). ...
... As the mentioned lysimeters were not embedded in a field canopy, border effects have influenced the apparent P. Furthermore, the spatial variability of measured P between lysimeters was very high during strong wind events. The effect of variability in lysimeter P was also previously observed between two lysimeters within field and at field border, respectively (Hagenau et al., 2015). In conclusion, the AWAT filter can cope with weather-dependent occurrence of high spatial variability of P and with the problem of systematic differences in P amounts on lysimeter compared to rain gauges. ...
Due to climate change, agricultural production in Europe will be challenged by higher temperatures and shifts in precipitation distribution that will give rise to frequent summer droughts. An adaptation of agricultural systems to these changes requires detailed knowledge of crop water use characteristics. This study aimed to evaluate the dynamics of evapotranspiration and water uptake in different crops under the typical edaphoclimatic conditions of Switzerland. Seven years (2009–2015) of high resolution lysimeter mass data including 70 lysimeter-by-year combinations were evaluated. The “adaptive window and adaptive threshold “-filter (AWAT) was used to determine evapotranspiration (ET), precipitation (P), crop coefficient (Kc) and water use efficiency (WUE). Additionally, FDR sensors installed in the lysimeter soil core allowed recording the temporal dynamic of soil water extraction. The evaluation comprised grain maize, silage maize, rapeseed, sugar beets, winter barley, winter wheat and temporary ley. The AWAT filter was successfully used to determine lysimeter P that was inserted in the lysimeter water balance equation to calculate daily ET. It could be shown that the peak of daily crop coefficient coincided with the time of flowering for all flowering arable crops. WUE’s lay in the range given by standard literature, but daily crop coefficients were clearly higher than proposed by the Food and Agriculture Organization of the United Nations (FAO) which is partially due to an oasis and border effect of the lysimeters. Years with limited water availability were characterized by a comparably low Kc. For example, rapeseed in 2011 and maize in 2015 showed substantially lower Kc values. In accordance with the reduced Kc, readily available water was totally removed down to soil depth of at minimum 0.85 m. The limited water availability led to significantly lower yields only in case of silage maize in 2015. These results show overall current water supply to be sufficient under Swiss conditions; however, if drought events like in 2015 become more frequent and even more intense, yield potential of typical Swiss arable crops will be limited by water availability.
... 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. ...
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.
Lysimeters are critical instruments for studying infiltration, runoff and evapotranspiration processes in the hydrological cycle and play a critical role in promoting efficient water‐saving irrigation. This paper provides a systematic review of the development process and research status of lysimeters, progressing from simple to complex designs, from single instruments to clusters, and from manual measurement to intelligent monitoring. The working principles of various types of lysimeter were first described based on Chinese lysimeter patents over the past 20 years. Second, this paper analyses the measurement performance and application scope of different lysimeters and further studies the weighting stability of various weighing lysimeters. Third, by analysing sources of measurement error, the reliability improvement methods of lysimeters are analysed from the aspects of environment control and sensor compensation. Fourth, this paper reviews typical research on the automation and informatization of lysimeters and discusses future intelligent developments and application prospects for lysimeters in complex environments. Finally, the measurement performance of different lysimeters is analysed based on experimental data sets. This paper puts forward some suggestions for developing lysimeters with high performance, high efficiency and high reliability, hoping to promote the development of intelligent agriculture.
The sugarcane pre-sprouted plantlets (PSP) production system is an innovative method to enhance crop multiplication rates. This system is greenhouse-grown, where correct irrigation management is essential to maintain the production quality. The purpose of this study was to determine the water requirement of three cultivars (CTC9005HP, RB966928, and SP87365) of pre-sprouted sugarcane plantlets, in which crop evapotranspiration (ETc) is a function of the product of the crop coefficient (Kc) and reference evapotranspiration (ETo). Three specifically built PSP-weighing lysimeters were used to determine ETc, while ETo was calculated by the FAO-56 method, making it possible to assess Kc values during the PSP cycle production. The ETc ranged from 3 to 6.9 mm d⁻¹ for CTC9005HP, 3.1 to 6.8 mm d⁻¹ for RB966928, and 2.9 to 6.6 mm d⁻¹ for SP87365. Daily Kc values increased from 1.00 to 1.46 for CTC9005HP, 1.02 to 1.53 for RB966928, and 1.02 to 1.49 for SP87365. This research makes evident the importance of assessing appropriate Kc values in order to estimate crop water requirements and irrigation needs. Therefore, these results are appropriate for proper irrigation management in a greenhouse-grown sugarcane PSP.
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 discipline of environmental biophysics relates to the study of energy and mass exchange between living organisms and their environment. The study of environmental biophysics probably began earlier than that of any other science, since knowledge of organism-environment interaction provided a key to survival and progress. Systematic study of the science and recording of experimental results, however, goes back only a few hundred years. Recognition of environmental biophysics as a discipline has occurred just within the past few decades.
Weighing lysimeters are valuable devices for measuring water-balance components with high temporal resolution and high accuracy. However, some older lysimeter facilities still operate with lever-arm-counterbalance weighing systems that are sensitive to disturbances, e.g., forces exerted by wind. Filtering and averaging are commonly used for processing noisy raw data. We studied some data of a lever-arm weighing system and performed additional experiments in order to (1) determine the measurement accuracy of the current weighing scheme (facility, and measuring and averaging procedure) regarding wind effects, (2) describe the oscillation behavior, (3) test the mechanical performance of the system, and (4) adapt the averaging procedure with respect to improved interpretation of the weighing data.
The measurement accuracy for a wind velocity < 5 m s–1, measured in 10 m height, was ≈ ± 0.4 kg (equivalent to ± 0.14 mm); at a higher wind velocity, the accuracy was three times lower, but there was no linear relationship. Additional experiments showed that the weighing system is oscillating with more or less irregular amplitudes. A loading–unloading experiment delivered proper results of the measured loads. The mechanical system reacted immediately, and no directional effects were found. However, small changes of < 1 kg could hardly be determined due to the oscillations. A time series of raw data measured every 2 s served as basis for improving the averaging method. A moving average from 64 values was computed representing the currently used method, and serving as reference. With this procedure an accuracy of ± 0.38 kg could be reached. Averaging 150 values led to an accuracy of ± 0.28 kg (0.1 mm) for a wind velocity < 5 m s–1.
The water balance of a certain soil profile in a certain time interval is subjected to changes of soil water content within the respective profile, and fluxes at its upper and lower boundary. Weighing lysimeters are valuable instruments for water-balance studies. Typically, mass changes—thus, changes of soil profile water content—are detected by a weighing system, while seepage water outflow is measured by a tipping bucket, and precipitation data originate from a rain gauge. Hence, evapotranspiration as unknown component can be determined by solving a simple water-balance equation. However, using separately measured precipitation data may cause implausible (negative) evapotranspiration. In this study, change of soil profile water content, seepage water, precipitation, and evapotranspiration were determined directly from 10-min lysimeter data from 2011. Precipitation measured with the lysimeter was in total 20% greater than rain-gauge values. Even dew formation was measured and considered as water-balance component; however, its total amount was rather low. Evapotranspiration calculated on daily and hourly base indicated a sound correlation with measured data, but measured values were considerably smaller. Both calculated and measured dew amount were of the same magnitude. Comparison of lysimeter evapotranspiration with daily calculations (neglecting dew) and hourly computation (considering dew) delivered similar results. Generally, the utilized lysimeter facility and the specific data management provided sound water-balance components with high accuracy and temporal resolution, respectively.
Quantification of soil water flow is a prerequisite to accurate prediction of solute transfer within the unsaturated zone. The monitoring of these fluxes is challenging because the results are required to answer both scientific and practical questions regarding protection of groundwater, sustainable management of agricultural, forestry, mining or set-aside industrial areas, reducing leachate loss from landfills or explaining the fate of environmentally harmful substances. Both indirect and direct methods exist for estimating water-flux rates and have been used with varying success. In Europe, the use of direct lysimetry methods for measuring water and solute fluxes in soils has increased in recent years. This technique ensures reliable drainage data, but requires relatively large investment and maintenance expenses. Other research groups, especially in the USA, have developed alternative techniques. In this paper we compare the functioning of a passive-wick sampler, especially the deep-drainage meter type (DDM), with two different types of drainage lysimeters (weighing and non-weighing) under field conditions in Germany for the measurement period from May 2004 until April 2009. The study showed that under sandy soil conditions no significant differences occurred between the measurements from DDM and both drainage lysimeter types. Only in periods with increased precipitation was there a tendency of drainage over-estimation by the DDM in comparison with the lysimeters tested. For longer periods, no significant differences in the amount of drainage or the pattern of drainage formation were found between weighing and non-weighing gravitation lysimeters. The practical use of DDMs is restricted because the groundwater level must be >2 m from the soil surface. Suggestions are made for the technical improvement of the DDM as well as the testing of the device with more cohesive soils.
Field lysimeters are often used to assess environmental behavior of agrochemicals. Most lysimeters used to date have a free-draining lower boundary where leaching out of the lysimeter occurs by gravity alone. In this case, the lower boundary of a lysimeter is open to the atmosphere, and consequently, leachate is collected only if the bottom of the lysimeter becomes water saturated. In a field soil, such local water saturation does not occur. The objective of this study was to evaluate the effect of the lower boundary condition on chemical leaching. Numerical simulations were used to compare solute transport in field soils and in lysimeters. Simulations were carried out in homogeneous sandy and loamy soils under steady-state, unsaturated water flow conditions. Water flow was described by the Richards equation and solute transport by the advection-dispersion equation. The effect of linear and nonlinear and instantaneous and kinetic sorption was investigated. The results showed that for a conservative solute the differences between field soil and lysimeter increase as the coarseness of the soil increases. Decreasing water flux increases the difference between field soil and lysimeter. In general, solute transport in the lysimeter is characterized by a slower mean velocity, a larger spreading, and smaller concentration values. For solutes subject to linear equilibrium sorption, the sorption mechanism compensates for the effects of the lower boundary condition. The larger the sorption coefficient, the less the difference between lysimeter and field soil. However, large differences are found in the case of strongly convex nonlinear sorption isotherms.
More and more evapotranspiration models, evapotranspiration crop coefficients and associated measurements of evapotranspiration (ET) are being reported in the literature and used to develop, calibrate and test important ET process models. ET data are derived from a range of measurement systems including lysimeters, eddy covariance, Bowen ratio, water balance (gravimetric, neutron meter, other soil water sensing), sap flow, scintillometry and even satellite-based remote sensing and direct modeling. All of these measurement techniques require substantial experimental care and are prone to substantial biases in reported results. Reporting of data containing measurement biases causes substantial confusion and impedance to the advancement of ET models and in the establishment of irrigation water requirements, and translates into substantial economic losses caused by misinformed water management.
Basic principles of ET measuring systems are reviewed and causes of common error and biases endemic to systems are discussed. Recommendations are given for reducing error in ET retrievals. Upper limits on ET measurements and derived crop coefficients are proposed to serve as guidelines. The descriptions of errors common to measurement systems are intended to help practitioners collect better data as well as to assist reviewers of manuscripts and users of data and derived products in assessing quality, integrity, validity and representativeness of reported information. This paper is the first part of a two-part series, where the second part describes recommendations for documentation to be associated with published ET data.
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.
Lysimeters for Evapotranspiration and Environmental Measurements
- R G Allen
- T A Howell
- W O Pruitt
- I W Walter
- Jensen
Allen, R.G., Howell, T.A., Pruitt, W.O., Walter, I.W., Jensen, M.E. (Eds.), 1991.
Lysimeters for Evapotranspiration and Environmental Measurements. Proc. Int.
Symp. Lysimetry, July 23-25, 1991, Honolulu, Hawaii. ASCE, New York.
Niederschlagsmessung für die Landwirtschaft-Vergleich von Messwerten verschiedener Regenmesser (Hellmann, Kippwaage, Ombrometer und Lysimeter). Masterarbeit, Naturwissenschaftliche Fakultät III
- J Fischer
Fischer, J., 2013. Niederschlagsmessung für die Landwirtschaft-Vergleich von
Messwerten verschiedener Regenmesser (Hellmann, Kippwaage, Ombrometer
und Lysimeter). Masterarbeit, Naturwissenschaftliche Fakultät III, MartinLuther-Universität Halle-Wittenberg, Halle (Saale).
An Introduction to Environmental Physics
- J L Monteith
- M Unsworth
Monteith, J.L., Unsworth, M., 1990. An Introduction to Environmental Physics,
second ed. Arnold, London.
Meteorologische Lysimeteruntersuchungen (Wasserhaushalt des Bodens
- H Schiff
Schiff, H., 1971. Meteorologische Lysimeteruntersuchungen (Wasserhaushalt des
Bodens, Abhängigkeit von meteorologischen Einflußgrößen und Wetterlage).
Niederschlagsmessung für die Landwirtschaft - Vergleich von Messwerten verschiedener Regenmesser (Hellmann, Kippwaage
- J Fischer
Fischer, J., 2013. Niederschlagsmessung für die Landwirtschaft -Vergleich von
Messwerten verschiedener Regenmesser (Hellmann, Kippwaage, Ombrometer
und Lysimeter). Masterarbeit, Naturwissenschaftliche Fakultät III, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale).