scholarly journals A Novel Sensor for In Situ Detection of Freeze-Thaw Characteristics in Plants from Stem Temperature and Water Content Measurements

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Chao Gao ◽  
Hao Tian ◽  
Yandong Zhao
Keyword(s):  
Water Content ◽  
Volumetric Water Content ◽  
Measuring Circuit ◽  
Constant Current ◽  
Freeze Thaw ◽  
Stem Temperature ◽  
Plant Stem ◽  
Stem Water ◽  
In Situ Detection

Freezing is a typical abiotic stress on plants, which can induce physiological damages of plants. A better understanding of plant freeze-thaw characteristics contributes to solving some hot issues in plant physiology, such as cold resistance and cold acclimation. This article presents a novel sensor for in situ detection of freeze-thaw characteristics in plants based on stem temperature and water content. The measuring circuit of stem temperature was designed based on constant current source and platinum resistance. The measuring circuit of stem water content was designed based on standing wave ratio and the dielectric properties of stem tissue. The temperature resolution of the compound sensor is less than 0.1°C. The MAE and RMSE of temperature measurement are approximately 0.57°C and 0.65°C, respectively. The volumetric water content resolution of the compound sensor is less than 0.05%. The MAE and RMSE of volumetric water content measurement are approximately 1.59% and 1.81%, respectively. Moreover, a mathematical model for describing the freeze-thaw characteristics of plant stem was established and solved based on the compound sensor. Then, some freeze-thaw indicators including stem water content, ice content, freezing depth, freezing velocity, thawing depth, and thawing velocity were solved and used to interpret the freeze-thaw rules of plant stem. It can be concluded that the freeze-thaw velocity is closely related to the physicochemical properties of plant stem which also change dynamically in the freeze-thaw cycle.

In-situ and non-invasive measurement of stem water content of trees using an innovative interdigitated-electrodes dielectric sensor less susceptible to stem diameter variation

2021 ◽  
Vol 307 ◽  
pp. 108473
Author(s):  
Xianglin Cheng ◽  
Xiaofei Yan ◽  
David A. Grantz ◽  
Yang Xiang ◽  
Ricardo F. de Oliveira ◽  
...  
Keyword(s):  
Water Content ◽  
Stem Diameter ◽  
Interdigitated Electrodes ◽  
Non Invasive ◽  
Diameter Variation ◽  
Dielectric Sensor ◽  
Stem Water ◽  
Invasive Measurement

In situ measurement of stem water content and diurnal storage of an apricot tree with a high frequency inner fringing dielectric sensor

2018 ◽  
Vol 250-251 ◽  
pp. 35-46 ◽  
Author(s):  
H. Zhou ◽  
Y. Sun ◽  
G. Shan ◽  
D.A. Grantz ◽  
Q. Cheng ◽  
...  
Keyword(s):  
Water Content ◽  
High Frequency ◽  
In Situ Measurement ◽  
Dielectric Sensor ◽  
Stem Water ◽  
Apricot Tree

scholarly journals In-Situ Monitoring and Characteristic Analysis of Freezing-Thawing Cycles in a Deep Vadose Zone

Water ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1261
Author(s):  
Ce Zheng ◽  
Yudong Lu ◽  
Xiuhua Liu ◽  
Jiří Šimůnek ◽  
Yijian Zeng ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Water Content ◽  
Vadose Zone ◽  
In Situ Monitoring ◽  
Characteristic Analysis ◽  
Soil Layers ◽  
Vapor Flux ◽  
Freeze Thaw ◽  
Soil Temperature And Moisture

Freeze-thaw cycles play a critical role in affecting ecosystem services in arid regions. Monitoring studies of soil temperature and moisture during a freeze-thaw process can generate data for research on the coupled movement of water, vapor, and heat during the freezing-thawing period which can, in turn, provide theoretical guidance for rational irrigation practices and ecological protection. In this study, the soil temperature and moisture changes in the deep vadose zone were observed by in-situ monitoring from November 2017 to March 2018 in the Mu Us Desert. The results showed that changes in soil temperatures and temperature gradients were largest in soil layers above the 100-cm depth, and variations decreased with soil depth. The relationship between soil temperature and unfrozen water content can be depicted well by both theoretical and empirical models. Due to gradients of the matric potential and temperature, soil water flowed from deeper soil layers towards the frozen soil, increasing the total water content at the freezing front. The vapor flux, which was affected mainly by temperature, showed diurnal variations in the shallow 20-cm soil layer, and its rate and variations decreased gradually with increasing soil depths. The freeze-thaw process can be divided into three stages: the initial freezing stage, the downward freezing stage, and the thawing stage. The upward vapor flux contributed to the formation of the frozen layer during the freezing process.

Determining Moisture Content of Soil Layers with Time Domain Reflectometry and Micromechanics

2008 ◽  
Vol 2053 (1) ◽  
pp. 30-38 ◽  
Author(s):  
Sang Ick Lee ◽  
Dan G. Zollinger ◽  
Robert L. Lytton
Keyword(s):  
Dielectric Constant ◽  
Soil Moisture ◽  
Moisture Content ◽  
Water Content ◽  
Time Domain ◽  
Soil Moisture Content ◽  
Time Domain Reflectometry ◽  
Volumetric Water Content ◽  
Dry Density

Although the moisture condition of pavement sublayers can significantly affect pavement performance, accurate interpretation of in situ soil moisture measurements has been difficult to achieve because of the limitations of existing methods. Time domain reflectometry (TDR), originally developed to detect breaks or shorts in electrical conductors, has been used for measuring parameters related to the in situ soil moisture content. However, the apparent length method currently used to determine dielectric constant ignores other electrical properties of the conducting medium that may affect the interpretation of TDR trace to determine soil moisture. Furthermore, the existing methods for computing volumetric water content ignore the variations of dry density and determine the model parameters with assumption or regression analysis. These deficiencies can, in many cases, create a significant systematic error in the final determination of volumetric water content. To minimize these errors and improve the accuracy of moisture content estimate, a new three-step approach was proposed. The approach uses the transmission line equation to calculate the dielectric constant, conductivity, and reflectivity of a soil mixture. A micromechanics and self-consistent scheme was used to determine the volumetric moisture content and dry density on the basis of calibrated values of the solid and water dielectric constants. The system identification method was used iteratively to solve for dielectric parameters, soil moisture content, and dry density values. The validation of the new approach with ground-truth data indicated that the calculated errors were significantly less than those of existing method.

scholarly journals A Novel Sensor for Noninvasive Detection of In Situ Stem Water Content Based on Standing Wave Ratio

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Chao Gao ◽  
Yue Zhao ◽  
Yandong Zhao
Keyword(s):  
Water Content ◽  
Standing Wave ◽  
Noninvasive Detection ◽  
Water Volume ◽  
Average Error ◽  
Physiological Parameter ◽  
Measuring Range ◽  
Measuring Accuracy ◽  
Stem Water

Stem water content (StWC = volume of water : volume of stem) is an important physiological parameter for vascular plants. And a better understanding of StWC contributes to solving some research hotspots in forestry, such as drought resistance, cold resistance, precise irrigation, and health assessment. However, there are few noninvasive, in situ, real-time, safe, and low-cost methods for detecting StWC of woody plants. This article presents a novel sensor for noninvasive detection of in situ StWC based on standing wave ratio. Moreover, extensive experiments were conducted to analyze the performance of this sensor including sensitive distance, measuring range, influence factors, and measuring accuracy. The experimental results show that the sensitive distance of StWC sensor is approximately 53 mm in axial direction and 20 mm in radial direction with the measuring range from 0.01 to 1.00 cm3 cm-3. The combined effects of stem EC and temperature on sensor output are significant and it is necessary to correct the error caused by the two factors. Compared with the oven-drying method, StWC sensor has higher measuring accuracy than Testo 606-2 which is a sensor for measuring wood water content and its average error is less than 0.01 cm3 cm-3. In addition, StWC sensor performed very well on the crape myrtle with high sensitivity equal to 1022.1 mV (cm3 cm-3)-1 and measuring results also accorded with the diurnal dynamics of stem water content.

scholarly journals An improved sensor for precision detection of in situ stem water content using a frequency domain fringing capacitor

2014 ◽  
Vol 206 (1) ◽  
pp. 471-481 ◽  
Author(s):  
Haiyang Zhou ◽  
Yurui Sun ◽  
Melvin T. Tyree ◽  
Wenyi Sheng ◽  
Qiang Cheng ◽  
...  
Keyword(s):  
Water Content ◽  
Frequency Domain ◽  
Stem Water

scholarly journals The use of in situ volumetric water content at field capacity to improve the prediction of soil water retention properties

2008 ◽  
Vol 88 (4) ◽  
pp. 533-541 ◽  
Author(s):  
Hassan Al Majou ◽  
Ary Bruand ◽  
Odile Duval
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Water Content ◽  
Bulk Density ◽  
Water Retention ◽  
Field Capacity ◽  
Volumetric Water Content ◽  
Organic Carbon Content ◽  
Water Retention Properties

Most pedotransfer functions (PTF) developed over the past three decades to generate water retention characteristics use soil texture, bulk density and organic carbon content as predictors. Despite the high number of PTFs published, most being class- or continuous-PTFs, the accuracy of prediction remains limited. In this study, we compared the performance of different class- and continuous-PTFs developed with a regional database. Results showed that the use of in situ volumetric water content at field capacity as a predictor led to much better estimation of water retention properties compared with using predictors derived from the texture, or the organic carbon content and bulk density. This was true regardless of the complexity of the PTFs developed. Results also showed that the best prediction quality was achieved by using the in situ volumetric water content at field capacity after stratification by texture. Comparison of in situ volumetric water content at field capacity, with the water retained at different matric potentials as measured in the laboratory, showed field capacity to approximate 100 hPa, whatever the soil texture. Finally, the lack accuracy of PTFs that do not use the in situ volumetric water content at field capacity as predictor did not appear due to the test soils being unrepresentative of the soils used to develop the PTFs, but were instead related to poor correlations between the predictors used and the water retention properties. Key words: Pedotransfer functions, root mean square error, mean error of prediction, standard deviation of prediction, texture, bulk density, organic carbon content

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