ET Values Research Articles

Determination of drought resistance of miniature rose varieties

ABSTRACT The researchers aimed to determine the effects of different irrigation levels on plant water consumption (ET), physiological, morphological and biomass traits of four different miniature rose varieties (Rosa Spp, cv. Mandarin, Orange Juwel, Zwergen Fee 09 and Zwergkönig 78). Four different irrigation levels (100% (control), 75%, 50%, 25%) were created in the experiment. The research was carried out at Çanakkale Onsekiz Mart University, Crop Stress Monitoring and Thermography Laboratory in 2020–2021. Water stress negatively affected the physiological and morphological traits measured in all four varieties. The six-month ET values of Mandarin, Orange Juwel, Zwergen Fee 09 and Zwerkönig 78 miniature rose varieties were 255.7–642.3 mm, 293.6–796.3 mm, 277.3–736.2 mm and 261.8–675.9 mm, respectively. Mandarin is more resistant to drought because its ET values are lower than other varieties.

Unveiling Eco-Friendly Reverse Micelle Systems: Dimethyl Carbonate as a Novel Biocompatible Solvent.

In this study, we systematically explored the characteristics of dimethyl carbonate (DMC)/sodium 1,4-bis-2-ethylhexylsulfosuccinate (AOT) reverse micelles (RMs) in the presence of water using dynamic light scattering (DLS), proton nuclear magnetic resonance (1H NMR), and molecular probes. DMC, a biocompatible solvent, enables the formulation of AOT RMs without the need for a co-surfactant. DLS revealed that as the water content increased, the droplet sizes grew larger. 1H NMR studies indicated that at low water content, water molecules interacted with DMC via hydrogen bonding. This interaction promoted the penetration of DMC toward the interface, affecting the solvation of AOT's sulfonate group. At higher water content, a competition for hydrogen bonding emerged between water-water and water-surfactant molecules, leading to distinct interfacial properties, as evidenced by molecular probes. The critical micellar concentration for DMC/AOT/water RMs was 7x10-3 M, similar to RMs formed with other biocompatible solvents. The presence of water facilitated the solvation of the surfactant's polar regions, promoting the RMs formation. The polarity of this system was measured using the ET(30) value. This novel micellar system holds significant potential in various fields, including catalysis, nanomaterials, and green chemistry.

Modeling the Effect of Climate Change on Evapotranspiration in the Thrace Region

The aim of this study is to determine the effect of climate change on reference evapotranspiration (ETo) and sunflower and wheat evapotranspiration (ETs and ETw, respectively) in the Trakya Region of Türkiye. ETo Calculator (version 3.2) and CROPWAT 8.0 were used to compute ETo and ET in the reference period (1970–1990), short- (2016–2025), mid- (2046–2055), and long- (2076–2085) terms. Additionally, ETo was tested in 2012 and ETo was simulated for every 1 °C temperature increase up to 5 °C in the reference period. Calculated ETo and ET values for the future were compared with the reference period. For the future, climate data estimated by RegCM3 Regional Climate Model, A2 scenario were used. While the average ETo value of the reference period was 3.3 mm day−1, it was 3.0 mm day−1 in 2012. Compared to the reference period, ETo values change by −3% (3.2 mm day−1), 9% (3.6 mm day−1), and 21% (4.0 mm day−1) in the short-, mid-, and long-term, respectively. The 575 mm ET deficit calculated during the vegetation period of sunflower in the model reference period was forecasted to change by −11% (514 mm), +15% (660 mm), and +25% (721 mm) in the short-, mid-, and long-term, respectively. For wheat, while 59 mm of excess water was calculated in the reference period, it became 193 mm (+227%) in the short-term and a water deficit of 8 mm (−113%) and 6 mm (−110%) in the mid- and long-term, respectively. In addition, it is estimated that there will be an increase of 0.1 mm day−1 (4%) in ETo values for each 1 °C temperature increase compared to the reference period (1970–1990). It was concluded that climate change in the Trakya Region will not significantly affect wheat farming; however, it will cause a serious water deficit in sunflower production.

Spatiotemporal Variabilities in Evapotranspiration of Alfalfa: A Case Study Using Remote Sensing METRIC and SSEBop Models and Eddy Covariance

Prolonged drought exacerbated by climate change in the Mesilla Valley, one of the major agricultural areas of New Mexico, USA, is causing a shortage of surface water from the Rio Grande for irrigation. Farmers in the Valley are using groundwater for irrigation and complementing it with limited surface water from the river (Rio Grande). Managing irrigation water better is vital to sustaining agriculture in the Valley. Remote sensing (RS)-based crop evapotranspiration (ETa) models offer significant advantages over traditional methods. The ET maps generated by these RS models provide valuable information that can be used to manage irrigation water and crops in water-scarce areas. This study used METRIC and SSEBop RS models to map the ET of alfalfa on a private farm that is managed as commonly practiced in the Valley. The integrated ET values of the two models are compared to those of the ETa measured using the eddy covariance method. The comparison showed that 91.55% of the variability in SSEBop ETa estimates can be explained by the variability in the METRIC ETa estimates, and the variability in eddy covariance ETa can explain 93.07% of the variability in METRIC ETa and 86.01% in the SSEBop Eta estimates. Both METRIC and SSEBop reflected the ETa of alfalfa during full growth and harvesting periods. However, the absolute percent mean relative difference (MRD) of ET was higher for two out of three cuttings by SSEBop (>32%) compared to those for METRIC and eddy covariance. The spatiotemporal variabilities in crop ET estimates using METRIC and SSEBop showed a need to improve on-farm irrigation conveyance and on-the-field irrigation efficiency. Overall, RS models can provide spatiotemporal maps of ET that can be used for decision-making to manage irrigation water better and improve crop yield on a field, farm, and regional scale.

Intelligent monitoring of surface evapotranspiration in the Heihe River Basin based on SEBS modelling

[Objective] The Heihe River Basin, located in northwestern China, is the second largest inland basin in China, and its water resources play a crucial role in the ecology, agriculture and human life of the region. The aim of this study is to investigate the spatial and temporal variations of surface evapotranspiration in the Heihe River Basin and the potential impacts of these variations on water resource management. [Methods] To achieve this goal, we applied the PM-based dual-source model, a meteorological model for estimating global surface ET, which takes into account a variety of factors such as temperature, humidity, wind speed and downward solar shortwave radiation. By analysing the meteorological data and remote sensing data of the Black River Basin, we first investigated the spatial and temporal distribution of surface evapotranspiration. [Conclusion] The results show that surface evapotranspiration shows obvious seasonal and regional variations and is significantly affected by meteorological conditions. The inversion of surface ET in the Heihe River Basin by this dual-source model needs to be improved, and the trend of ET values calculated by the model is relatively small compared with the actual values.

Mechanism analysis on manipulation of long afterglow luminescence properties of Y3Al5-xGaxO12:Ce3+, Cr3+ phosphors

Blue-light activated long afterglow luminescence phosphors have attracted much attention because of their potential application in many fields. Herein, the influence of trap depth and the quantity of electrons captured by the traps on the long afterglow luminescence properties were systematically revealed through a comparative analysis of the long afterglow luminescence performance of the series of Y3Al5-xGaxO12(YAGG):Ce3+, Cr3+ (x = 0, 1, 2, 3, 4, 5) phosphors. To achieve long afterglow luminescence, it requires that the traps can effectively capture electrons, and possess an appropriate trap depth. Additionally, it is discovered that the quantity of electrons captured by the traps is the main factor affecting the duration of long afterglow luminescence. The more electrons are captured, the longer the afterglow lasts. The quantity of trapped electrons is inversely proportional to the energy differences between CBM-Ce5d and trap depth. The sample exhibits the high quantity of trapped electrons attributable to its small energy differences which allows electrons to be directly captured by traps through the tunneling effect. On this basis, the effects of crystal field splitting (εcfs), centroid shift (εc), and the degree of dodecahedral distortion (D (YO)) on trap depth (ET) were discussed to manipulate the trap depth, demonstrating there is a significant positive correlation between εc-εcfs(2(1-10D(YO))) and ET values for the garnet structure A3B2C3O12, when the ion doped at the A-position remains constant and the ions at the B and C positions vary. Notably, A larger D (YO) value corresponds to a deeper trap depth. This study provides a new perspective toward the development and design of long afterglow materials with superior afterglow emission.

Polarity of Organic Solvent/Water Mixtures Measured with Reichardt’s B30 and Related Solvatochromic Probes—A Critical Review

The UV/Vis absorption energies (νmax) of different solvatochromic probes measured in co-solvent/water mixtures are re-analyzed as a function of the average molar concentration (Nav) of the solvent composition compared to the use of the mole fraction. The empirical ET(30) parameter of Reichardt’s dye B30 is the focus of the analysis. The Marcus classification of aqueous solvent mixtures is a useful guide for co-solvent selection. Methanol, ethanol, 1,2-ethanediol, 2-propanol, 2-methyl-2-propanol, 2-butoxyethanol, formamide, N-methylformamide (NMF), N,N-dimethylformamide (DMF), N-formylmorpholine (NFM), 1,4-dioxane and DMSO were considered as co-solvents. The ET(30) values of the binary solvent mixtures are discussed in relation to the physical properties of the co-solvent/water mixtures in terms of quantitative composition, refractive index, thermodynamics of the mixture and the non-uniformity of the mixture. Significant linear dependencies of ET(30) as a function of Nav can be demonstrated for formamide/water, 1,2-ethanediol/water, NMF/water and DMSO/water mixtures over the entire compositional range. These mixtures belong to the group of solvents that do not enhance the water structure according to the Marcus classification. The influence of the solvent microstructure on the non-linearity ET(30) as a function of Nav is particularly clear for alcohol/water mixtures with an enhanced water structure.

Prediction of Paracetamol Solubility in Binary Solvents Using Reichardt’s Polarity Parameter Combined Model

The objective of this research is to propose a general model utilizing the solvatochromic polarity of electronic transition energy (ET) of the Reichardt indicator to predict paracetamol solubility in the solvent mixtures. In order to model validation, the available ET (30) values of nine aqueous mixtures obtained from existing literature sources were utilized. The trained model yielded a relatively accurate estimation of paracetamol solubility in the investigated systems.

Sensitivity of runoff due to changes in the characteristics of the water balance in the Danube River region

Abstract Climate change is presently a widely discussed subject in relation to alterations in water storage capacity and the components of the hydrological balance within catchment areas. This research study was directed at two main objectives: 1. The indirect estimation of long-term mean annual runoff using an empirical model; 2. The determination of changes in the annual runoff regime of fifty Danube sub-basins. Monthly areal precipitation, discharges, and air temperature data from 1961 to 1990 were collected for selected headwater sub-basins of the Danube River. In the first part, Turc-type empirical equations for the estimation of the long-term average annual runoff R in the Danube basin were employed. The parameters of the empirical equations were determined through nonlinear regression. Given the underestimation of the actual (territorial, balance) evapotranspiration ET values determined from the balance equation, the precipitation totals were corrected by +10%. With a 10% increase in precipitation, the values of balance ET reached the values ET determined by the Budyko–Zubenok–Konstantinov method. In the second part, fifty equations for the estimation of changes in the average annual runoff, depending on increases in the air temperature and changes in the annual precipitation separately for each of the 50 sub-basins, were established. In conclusion, the results suggest that, on average, a 100 mm increase in the average annual rainfall in the Danube River headwater sub-basins, will cause a 50 mm increase in outflow, and a 1 °C increase in the average annual air temperature will lead to a 12 mm decrease in runoff.

Investigating hydrophobic environment in alkyl-group-functionalized silica particle with various chain lengths using absorption microspectroscopy.

A well-known solvatochromic dye, Reichardt's dye (R-dye), was used to evaluate the hydrophobicity of alkyl-group-functionalized silica particles (ASPs) with different chain lengths. The absorption spectra of R-dye were measured in a single ASP in a mixed solution of water and an organic solvent (methanol (MeOH), ethanol (EtOH), acetonitrile (ACN), tetrahydrofuran (THF), or N,N-dimethylformamide (DMF)) using absorption microspectroscopy. The polarity parameter in the ASPs (ET), determined by the absorption maximum, was observed to be smaller than those in bulk solutions, indicating that R-dye was present in a more hydrophobic environment. In EtOH, THF, and DMF, R-dye was distributed within the alkyl chain layer including the organic solvent. An increase in the organic solvent content of the bulk solution led to a higher organic solvent concentration in the alkyl chain layer, resulting in a decrease in ET. In MeOH and ACN, the R-dye was distributed within the alkyl chain layer and concentrated phase. Moreover, with the increase in the organic molecule content, the distribution of R-dye in the concentrated phase became dominant in MeOH and ACN system, leading to an increase in the ET value. The findings presented in this paper are expected to attract the attention of a wide range of researchers in chromatography.

Characterization of Triplet State of Cyanine Dyes with Two Chromophores Effect of Molecule Structure

Quantum yields (φT) and energies (ET) of the first triplet state T1 for four molecules of cyanine dyes with two chromophores (BCDs), promising photoactive compounds for various applications, for example, as photosensitizers in photodynamic therapy (PDT) and fluorescence diagnostics (FD), were studied in 1-propanol solutions by steady-state and time-resolved optical absorption techniques. BCDs differ by the structure of the central heterocycle, connecting the chromophores. The heterocycle structure is responsible for electron tunneling between chromophores, for which efficiency can be characterized by splitting of the BCD triplet energy levels. It was shown that the increase in the tunneling efficiency reduces ET values and increases φT values. This aspect is very promising for the synthesis of new effective photosensitizers based on cyanine dyes with two interacting chromophores for various applications, including photodynamic therapy.

Possibility of Using Ferrocene as the Cyclic Voltammetry Probe to Investigate the Polarities of Ionic Liquids.

Polarity has been considered as one of the important properties of an ionic liquid, which influences its design and industrial application. Though many empirical polarity scales of molecular solvents have been used to predict the polarities of ionic liquids, they always have their certain limitations. In the present work, ferrocene was selected as the cyclic voltammetry probe to investigate the polarities of ionic liquids. The experimental results suggested that the half-wave potential values of ferrocene/ferrocenium measured by cyclic voltammetry had a linear relationship with the ET(30) values of aprotic ionic liquids. Meanwhile, some polarity rules obtained here were in line with those summarized by other research studies. In addition, it was concluded that the polarity of a protic ionic liquid was slightly weaker than that of its corresponding Brønsted base. This work could provide a new and simple method to research the polarities of ionic liquids.

Predicting the ET(30) parameter of organic solvents via machine learning

Polarity of organic solvents is an important parameter which needs to be considered during a reaction design as it can drastically impact the rate and dynamics of a chemical reaction. Till now ET(30) scale is the only comprehensive scale which can accurately quantify various solute–solvent and solvent–solvent interactions, the experimental determination of which is an expensive and resource-intensive approach. Therefore, we have resorted to machine learning techniques for predicting the empirical polarity of organic solvents which would provide ET(30) values for new solvents in a fast and efficient manner without having to rely on experimental and computational setup.

Interpreting water demands of forests and grasslands within a new Budyko formulation of evapotranspiration using percolation theory

The relationship between carbon cycle and water demand is key to understanding global climate change, vegetation productivity, and predicting the future of water resources. The water balance, which enumerates the relative fractions of precipitation P that run off, Q, or are returned to the atmosphere through evapotranspiration, ET, links drawdown of atmospheric carbon with the water cycle through plant transpiration. Our theoretical description based on percolation theory proposes that dominant ecosystems tend to maximize drawdown of atmospheric carbon in the process of growth and reproduction, thus providing a link between carbon and water cycles. In this framework, the only parameter is the fractal dimensionality df of the root system. Values of df appear to relate to the relative roles of nutrient and water accessibility. Larger values of df lead to higher ET values. Known ranges of grassland root fractal dimensions predict reasonably the range of ET(P) in such ecosystems as a function of aridity index. Forests with shallower root systems, should be characterized by a smaller df and, therefore, ET that is a smaller fraction of P. The prediction of ET/P using the 3D percolation value of df matches rather closely results deemed typical for forests based on a phenomenology already in common use. We test predictions of Q with P against data and data summaries for sclerophyll forests in southeastern Australia and the southeastern USA. Applying PET data from a nearby site constrains the data from the USA to lie between our ET predictions for 2D and 3D root systems. For the Australian site, equating cited “losses” with PET underpredicts ET. This discrepancy is mostly removed by referring to mapped values of PET in that region. Missing in both cases is local PET variability, more important for reducing data scatter in southeastern Australia, due to the greater relief.

Detailed Understanding of Solvent Effects for the Cationic Ring-Opening Polymerization of 2-Ethyl-2-oxazoline

Polymerization of 2-ethyl-2-oxazoline (EtOx) has often been in the spotlight for fundamental studies of poly(2-alkyl/aryl-2-oxazoline)s (PAOx) polymerization, especially initiator screening, solvent screening, and copolymerization trends. In this work, we build on previous observations of solvent effects on the cationic ring-opening polymerization (CROP) of EtOx, with additional experimental observations of previously unreported solvents to expand the explored parameter space. Our objective is to find solvents with the lowest activation energy (Ea) and higher Arrhenius preexponential factor (A), which will allow us to produce narrow molar mass distributions at higher molecular weights, in the least time. To achieve this, we examined the various single factors like Dimroth ET(30) values, the Kamlet–Abraham–Taft (KAT) linear free-energy relationship (LFER) equation(s), and the Catalan LFER equations. Only one of Catalan’s equations sufficiently disentangled dipolarity and polarizability to give a good fit due to contradictory effects. It was found that solvent nucleophilicity, electrophilicity, and polarizability affected the Ea, but not dipolarity. All four factors affected the A. This indicates that the Ea is minimized in solvents that do not solvate ions well (i.e. force ion-pairing), and A was minimized in more dipolar solvents that solvate the polymer chains well. A strongly negative activation entropy (ΔS‡) shows that the propagation reaction is associative. The Catalan LFER allows for the prediction of Ea, A, ΔH‡, and ΔS‡, and the derived kp, across a broad range of solvents.

Field evaluation of selected autochthonous herbaceous species for cover crops in Mediterranean woody crops

This study evaluated under two contrasting field conditions, and during two seasons, four autochthonous species, Bromus rubens (Br), Brachypodium distachyon (Bd), Medicago truncatula (Mt) and Anthemis arvensis (Aa), as single species and in mixtures of Br + Mt, Br + Aa and Br + Mt + Aa, to determine their suitability as temporary cover crops (CCs) for Mediterranean woody crops. Br, Bd and Mt reached above 90 % ground cover (GC) in spring, while Aa reached a maximum of 80 %; in early winter GC varied from 0 % to 40 %, approximately, depending on the sowing date in the fall. The thermal time required to reach 30 % GC and seed maturity appeared as two key traits to evaluate the suitability of autochthonous species as temporary CCs for Mediterranean woody crops. Our experiment showed that early seeding (no later than mid-October) is critical to exploit these traits into effective CCs under Mediterranean conditions. Phenologic models developed for the tested species, based on temperature, are capable of predicting their development properly under field conditions, and they might be used to predict the evolution of GC when calibrated from field experiments. Aboveground biomass was affected by edaphic conditions, with higher values being observed in the most fertile soil, in Córdoba, in the range of 300–700 g m−2, compared to Adamuz with 150–350 g m−2. When used as monospecific CCs, Br, Bd and Mt had a higher aboveground biomass than Aa. We observed no differences in aboveground biomass among mixtures within each of the two locations. Differences in fine root biomass (RB) and fine root length density (RLd) resembled those of aboveground biomass, albeit with a higher variability. When used as monospecific CCs, fine RB and fine RLd were higher for Br and Bd, followed by Mt, with Aa having the lower values. Fine RB, or fine RL, in the top 0–30 cm of soil is also a relevant trait for selecting temporary CCs for Mediterranean woody crops. Our results show that they are also greatly affected by edaphic-climatic conditions and that they have a moderate correlation with aboveground biomass. The analysis of soil water uptake in the Córdoba plot showed no significant differences among the monospecific species and the mixtures, with ET values during the 2014/15 and 2015/16 growing seasons in the range of 325–300 mm.

Machine learning prediction of empirical polarity using SMILES encoding of organic solvents.

Machine learning based statistical models have played a significant role in increasing the speed and accuracy with which the chemical and physical properties of chemical compounds can be predicted as compared to the experimental, and traditional ab initio and quantum mechanical approaches. The transformative impact that these techniques have, in the field of chemical sciences has completely changed the way experiments are designed. The last decade has seen the prominence of computer-aided molecular design based on machine learning algorithms. The major challenge has been the generation of machine-readable data in the form of descriptors and observations for training the model, which can again be time-consuming and computationally expensive if atomic coordinates based molecular encoding approach is used. In this study, we have tried to solve this problem using SMILES representation of molecules for generating various topological, physicochemical, electronic and steric descriptors using open-source cheminformatics packages. With the aid of the data generated using these packages, we have been able to develop a simple and explainable quantitative structure property relationship model using artificial neural network based on 7 numerical descriptors and 1 categorical descriptor for predicting the empirical polarity of a wide diversity of organic solvents. Since polarity is the representation of various solute-solvent and solvent-solvent interactions taking place in an organic transformation, its intuition beforehand will definitely help a chemist in a better experimental design. An ANN algorithm based on 8 descriptors was successfully employed to predict the ET(30) values of organic solvents.

Application of Reichardt’s Solvent Polarity Scale (ET(30)) in the Selection of Bonding Agents for Composite Solid Rocket Propellants

Bonding agents (BA) are key compounding ingredients for the correct formulation of composite solid rocket propellants (CSRP). In particular, the addition of BA is essential to achieve suitable mechanical properties of CSRP in terms of adequate tensile strength and elongation at the break. It is shown that the polarity of each conventional BA as well as new potential BA can be measured through the Reichardt’s ET(30) polarity scale. Using this methodology, it was possible to propose a substitute for MAPO (tris-(methylaziridinyl)-phosphine oxide), a conventional BA with the drawback of high toxicity and high reactivity, with TTPT (tris-(pyrrolidine)-phosphine oxide), a completely safe and effective BA. In this work, several other potential BA were evaluated through the Reichardt’s ET(30) polarity scale but only a selection of the potential BA were effectively tested in a standard CSRP. The evaluation of TTPT vs. MAPO showing the ability of the former BA to match the mechanical properties of the latter BA was particularly interesting. A reasonable correlation between the elongation at break of the CSRP and the ET(30) value of the BA used in the compound was found.

Effects of Farmland Landscape Fragmentation on Agricultural Irrigation in Hotan Oasis

Farmland landscape fragmentation is an important problem affecting the agricultural modernization process in China. However, farmland landscape fragmentation leads to land being wasted and increases management costs, particularly in the dryland’s oasis regions. Therefore, investigating the impact of farmland landscape fragmentation on agricultural irrigation is of great significance in developing oasis agriculture. This paper used the landscape quantitative index (DIVISION), the moving window method, and gradient analysis methods to study the temporal and spatial pattern changes in farmland fragmentation in the Hotan Oasis. Additionally, the impact of fragmentation on irrigation in the oasis was elaborated upon by exploring the relationship between evapotranspiration and its components in farmland fragmentation. The results showed that the farmland area of the Hotan Oasis increased from 1546.19 km2 in 2000 to 2068.23 km2 in 2020, and farmland landscape fragmentation increased with the expansion of the Hotan Oasis. In addition, a significant relationship between farmland fragmentation and evapotranspiration and its components was evident. A lower DIVISION value corresponded to a higher ET value, a lower ETs/ETc ratio, and a higher water use efficiency. When the total farmland area is assumed to remain unchanged, the irrigation water consumption is reduced by 4.82 × 108 m3 according to the size and proportion of arable land with the lowest degree of fragmentation (L1, division value of 0.46). In addition, with the increase in the proportion of farmland, the scale of oasis decreases by 2431.56 km2 for the reduction in field roads, shelterbelt, and bare land. These findings suggest that solving the problem of farmland fragmentation can effectively reduce irrigation water consumption, realize the internal expansion of the oasis through intensive land use, and relieve the pressure of the external expansion of the oasis.

Evapotranspiration in a subtropical wetland savanna using low‐cost lysimeter, eddy covariance and modelling approaches

AbstractEvapotranspiration (ET) constitutes the largest loss of water from subtropical grassland and wetland ecosystems, yet data in much of the world have high uncertainty at the landscape scale as there is little information on plant water use. Additionally, anthropogenic alterations to grasslands are a major threat globally and alter ecosystem water use, but the impact of these changes is often unquantified. A major reason for this is the complexity and expense of field‐based ET quantification methods such as agricultural lysimeters and eddy covariance systems. Accurate measurements of ET are critical for sustainable water management. This study developed two different low‐cost lysimeters—weighing‐type and water level‐based, to measure ET under partly controlled conditions for single species as well as mixed grassland and wetland communities. Lysimeters were placed in an open‐sided, transparent‐roofed shadehouse and watered periodically. ET values were then compared with (i) actual ET from an eddy covariance tower onsite, (ii) vapour transport‐based reference ET models (FAO Penman–Monteith, modified Turc and Abtew simple radiation models), and (iii) reference ET data customized for vegetation types from the Florida Automated Weather Network (FAWN). Both weighing‐type and water level lysimeters yielded seasonal patterns and annual magnitudes similar to other ET methods. Annual ET measurements from single‐species weighing‐type lysimeters (ranging from 881 to 1278 mm for four plant species, n = 5 per species, 20 in total) and water level lysimeters (1085 ± 306 mm, plant community average, n = 31) were about 10–20% lower than reference ET models (~1300 mm) and similar to FAWN data (1050 mm). Actual ET from eddy covariance was 722 mm for 10 months (missing data for February and March), while weighing lysimeter measurements for the dominant grass Paspalum notatum was 885 mm for the same 10 months. While rainfall exclusion and watering can result in ET differing from actual field conditions, low‐cost lysimeters can provide an independent measure of ET for comparison with regional ET models/remote sensing data lacking field validation. Thereby, low‐cost lysimeters are potentially useful for water resources and ecosystem management in data‐poor regions of the world.