Cross-validation on saplings of High-Capacity Tensiometer and Thermocouple Psychrometer for continuous monitoring of xylem water potential

Abstract The Pressure Chamber, the most popular method used to measure xylem water potential, is a discontinuous and destructive technique and therefore not suitable for automated monitoring. Continuous non-destructive monitoring could only be achieved until very recently via the Thermocouple Psychrometer (TP). We here present the High-Capacity Tensiometer (HCT) as alternative method for continuous non-destructive monitoring. This provided us with a unique chance to cross-validate the two instruments by installing them simultaneously on the same sapling stem. The HCT and the TP showed excellent agreement for xylem water potential < -0.5 MPa. Response to day/night cycles and watering was remarkably in phase, indicating excellent response time of both instruments despite substantially different working principles. For xylem water potential > -0.5 MPa, the discrepancies sometimes observed between the HCT and TP were mainly attributed to the kaolin paste used to establish contact between the xylem and the HCT, which becomes hydraulically poorly conductive in this range of water potential once dried beyond its air-entry value and subsequently re-wetted. Notwithstanding this limitation, which can be overcome by selecting a clay paste with higher air-entry value, the HCT has been shown to represent a valid alternative to the TP.

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MEASUREMENT OF INTERNAL WATER STRESS IN WHEAT PLANTS

Canadian Journal of Plant Science ◽

10.4141/cjps68-012 ◽

1968 ◽

Vol 48 (1) ◽

pp. 89-95 ◽

Cited By ~ 8

Author(s):

S. J. Yang ◽

E. de Jong

Keyword(s):

Water Potential ◽

Soil Water ◽

Great Promise ◽

Plant Water ◽

Thermocouple Psychrometer ◽

Water Potentials ◽

Plant Water Potential ◽

Highly Correlated ◽

The Many ◽

Non Destructive

The thermocouple psychrometer technique was used to measure plant water stresses of wheat. The usefulness of this technique is limited due to the many precautions that must be taken. The β-ray absorption and relative turgidity were highly correlated (P = 0.01) with plant water potential, but the correlation changed with age. Relative turgidity gave a slightly better estimate of leaf water potential than β-ray absorption (r2 of 0.88 to 0.99 and 0.81 to 0.96 respectively). The β-ray technique has great promise because of its non-destructive nature.At soil water potentials higher than −10 atm, plant water potentials remained nearly constant, indicating that soil water was equally available. Temporary wilting occurred at soil water potentials of −35 to −40 atm.

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Remote diagnostics of vibrations of dynamic objects by Doppler microwave sensors

Metrologiya ◽

10.32446/0132-4713.2020-3-25-42 ◽

2020 ◽

pp. 25-42

Author(s):

Dmitrii V. Khablov

Keyword(s):

Intelligent Systems ◽

Electromagnetic Waves ◽

Continuous Monitoring ◽

Phase Changes ◽

Vibration Diagnostics ◽

Remote Diagnostics ◽

Active Vibration ◽

Dynamic Objects ◽

Microwave Sensors ◽

Non Destructive

This paper describes a promising method for non-contact vibration diagnostics based on the use of Doppler microwave sensors. In this case, active irradiation of the object with electromagnetic waves and the allocation of phase changes using two-channel quadrature processing of the received reflected signal are used. The modes of further fine analysis of the resulting signal using spectral or wavelet transformations depending on the nature of the active vibration are considered. The advantages of this non-contact and remote vibration analysis method for the study of complex dynamic objects are described. The convenience of the method for machine learning and use in intelligent systems of non-destructive continuous monitoring of the state of these objects by vibration is noted.

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Improved Protocol for the in Situ Measurement of Water Potential of Plants with a Thermocouple Psychrometer

CHINESE BULLETIN OF BOTANY ◽

10.3724/sp.j.1259.2013.00531 ◽

2014 ◽

Vol 48 (5) ◽

pp. 531-539

Author(s):

Zhu Jianjun ◽

Bai Xinfu ◽

Liu Linde

Keyword(s):

Water Potential ◽

In Situ Measurement ◽

Thermocouple Psychrometer

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Feasibility of Using VIS/NIR Spectroscopy and Multivariate Analysis for Pesticide Residue Detection in Tomatoes

Processes ◽

10.3390/pr9020196 ◽

2021 ◽

Vol 9 (2) ◽

pp. 196

Author(s):

Araz Soltani Nazarloo ◽

Vali Rasooli Sharabiani ◽

Yousef Abbaspour Gilandeh ◽

Ebrahim Taghinezhad ◽

Mariusz Szymanek ◽

...

Keyword(s):

Near Infrared ◽

Cross Validation ◽

Low Cost ◽

Moving Average ◽

Nir Spectroscopy ◽

Control Treatment ◽

Residue Detection ◽

Non Destructive ◽

Reflective Spectroscopy

The purpose of this work was to investigate the detection of the pesticide residual (profenofos) in tomatoes by using visible/near-infrared spectroscopy. Therefore, the experiments were performed on 180 tomato samples with different percentages of profenofos pesticide (higher and lower values than the maximum residual limit (MRL)) as compared to the control (no pesticide). VIS/near infrared (NIR) spectral data from pesticide solution and non-pesticide tomato samples (used as control treatment) impregnated with different concentrations of pesticide in the range of 400 to 1050 nm were recorded by a spectrometer. For classification of tomatoes with pesticide content at lower and higher levels of MRL as healthy and unhealthy samples, we used different spectral pre-processing methods with partial least squares discriminant analysis (PLS-DA) models. The Smoothing Moving Average pre-processing method with the standard error of cross validation (SECV) = 4.2767 was selected as the best model for this study. In addition, in the calibration and prediction sets, the percentages of total correctly classified samples were 90 and 91.66%, respectively. Therefore, it can be concluded that reflective spectroscopy (VIS/NIR) can be used as a non-destructive, low-cost, and rapid technique to control the health of tomatoes impregnated with profenofos pesticide.

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Mist Irrigation Reduces Post-transplant Desiccation of Bare-root Trees

Journal of Environmental Horticulture ◽

10.24266/0738-2898-12.1.1 ◽

1994 ◽

Vol 12 (1) ◽

pp. 1-3 ◽

Cited By ~ 1

Author(s):

Rick M. Bates ◽

Alex X. Niemiera

Keyword(s):

Water Stress ◽

Water Potential ◽

Acer Platanoides ◽

Sensitive Species ◽

Xylem Water Potential ◽

Post Transplant ◽

Norway Maple ◽

Relative Water ◽

Bare Root ◽

Cherry Trees

Abstract Desiccation during storage and reestablishment is a major factor contributing to poor regrowth of transplanted bare-root trees. The effect of overhead mist irrigation on reducing post transplant water stress in Norway maple (Acer platanoides L. ‘Emerald Lustre’) and Yoshino cherry (Prunus x yedoensis) was examined. Bare-root Norway maple (desiccation tolerant) and Yoshino cherry (desiccation sensitive) trees were transplanted into pine bark-filled containers and subjected to mist or non-mist treatments. Stem xylem water potential, relative water content, and survivability were determined. Xylem water potential increased (became less negative) for misted maple and cherry trees. Water potential increased for non-misted maple and decreased for non-misted cherry trees. Twenty-seven percent of non-misted cherries were evaluated as nonmarketable due to stem dieback compared to 0% for misted trees. Results of this study indicate that mist irrigation effectively reduces desiccation damage for desiccation sensitive species such as cherries and hawthorns.

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Measurement of xylem water pressure using High-Capacity Tensiometer and benchmarking against Pressure Chamber and Thermocouple Psychrometer

E3S Web of Conferences ◽

10.1051/e3sconf/202019503014 ◽

2020 ◽

Vol 195 ◽

pp. 03014

Author(s):

Roberta Dainese ◽

Giuseppe Tedeschi ◽

Thierry Fourcaud ◽

Alessandro Tarantino

Keyword(s):

Water Flow ◽

Water Pressure ◽

High Capacity ◽

Ground Surface ◽

Pressure Chamber ◽

Rainwater Infiltration ◽

Thermocouple Psychrometer ◽

Earth Structures ◽

Pressure Water ◽

The Stability

The response of the shallow portion of the ground (vadose zone) and of earth structures is affected by the interaction with the atmosphere. Rainwater infiltration and evapotranspiration affect the stability of man-made and natural slopes and cause shallow foundations and embankments to settle and heave. Very frequently, the ground surface is covered by vegetation and, as a result, transpiration plays a major role in ground-atmosphere interaction. The soil, the plant, and the atmosphere form a continuous hydraulic system, which is referred to as Soil-Plant-Atmosphere Continuum (SPAC). The SPAC actually represents the ‘boundary condition’ of the geotechnical water flow problem. Water flow in soil and plant takes place because of gradients in hydraulic head triggered by the negative water pressure (water tension) generated in the leaf stomata. To study the response of the SPAC, (negative) water pressure needs to be measured not only in the soil but also in the plant. The paper presents a novel technique to measure the xylem water pressure based on the use of the High-Capacity Tensiometer (HCT), which is benchmarked against conventional techniques for xylem water pressure measurements, i.e. the Pressure Chamber (PC) and the Thermocouple Psychrometer (TP).

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