Monitoring Shallow Soil Water Content Under Natural Field Conditions Using the Early-Time GPR Signal Technique

2013 ◽  
Vol 12 (4) ◽  
pp. vzj2012.0202 ◽  
Author(s):  
C. Ferrara ◽  
P.M. Barone ◽  
C. M. Steelman ◽  
E. Pettinelli ◽  
A.L. Endres
2018 ◽  
Vol 17 (1) ◽  
pp. 180001 ◽  
Author(s):  
Jonathan Algeo ◽  
Lee Slater ◽  
Andrew Binley ◽  
Remke L. Van Dam ◽  
Chris Watts

2017 ◽  
Author(s):  
Remke L. Van Dam* ◽  
Jonathan Algeo ◽  
Lee D. Slater ◽  
Andrew M. Binley ◽  
Christopher W. Watts

2016 ◽  
Vol 33 (3) ◽  
Author(s):  
Marcelo Jorge Luz Mesquita ◽  
José Gouvêa Luiz ◽  
José de Paulo Rocha da Costa

ABSTRACT. Electromagnetic methods play an important role in the study of soil water content, mainly because electromagnetic properties in the shallow subsurface area are primarily controlled by the presence of... RESUMO. Os métodos eletromagnéticos são uma importante ferramenta no estudo da umidade do solo, principalmente porque as propriedades eletromagnéticas da subsuperfície rasa são...


2006 ◽  
Vol 16 (1) ◽  
pp. 47-59 ◽  
Author(s):  
Diego Batlla ◽  
Roberto Luis Benech-Arnold

It has been hypothesized that fluctuations in soil water content may affect the dormancy status of weed seed banks under field conditions. In this paper, we present results showing that fluctuations in soil water content affect the dormancy status of buried seeds ofPolygonum aviculareL. stored at dormancy-releasing temperatures. Effects of fluctuations in soil water content on the dormancy status ofP. aviculareseeds were evaluated by comparing changes in the range of temperatures and water potentials permissive for germination, and in the sensitivity to fluctuating temperatures, between seeds subjected to a moist soil regime (MS) or to a fluctuating soil water content regime (FS). In comparison to the dormancy release pattern observed for seeds subjected to MS, seeds subjected to FS generally showed an increase in their dormancy level after periods of storage under dry soil conditions, and a decrease in their dormancy level after periods of storage under moist soil conditions. These effects were more pronounced during early stages of the storage period, producing larger changes in the thermal and water potential range for seed germination than in the sensitivity of seeds to fluctuating temperatures. Seeds subjected to FS generally exhibited a lower mean low-limit temperature, lower mean thermal time and hydrotime requirements for germination, and a higher proportion of the seed population with the capacity to germinatein situ, than seeds subjected to MS. The results obtained suggested that fluctuations in soil water content could be an additional factor affecting dormancy and weed emergence patterns under field conditions.


Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5272 ◽  
Author(s):  
Zemni ◽  
Bouksila ◽  
Persson ◽  
Slama ◽  
Berndtsson ◽  
...  

Capacitance sensors are widely used in agriculture for irrigation and soil management purposes. However, their use under saline conditions is a major challenge, especially for sensors operating with low frequency. Their dielectric readings are often biased by high soil electrical conductivity. New calculation approaches for soil water content (θ) and pore water electrical conductivity (ECp), in which apparent soil electrical conductivity (ECa) is included, have been suggested in recent research. However, these methods have neither been tested with low-cost capacitance probes such as the 5TE (70 MHz, Decagon Devices, Pullman, WA, USA) nor for field conditions. Thus, it is important to determine the performance of these approaches and to test the application range using the 5TE sensor for irrigated soils. For this purpose, sandy soil was collected from the Jemna oasis in southern Tunisia and four 5TE sensors were installed in the field at four soil depths. Measurements of apparent dielectric permittivity (Ka), ECa, and soil temperature were taken under different electrical conductivity of soil moisture solutions. Results show that, under field conditions, 5TE accuracy for θ estimation increased when considering the ECa effect. Field calibrated models gave better θ estimation (root mean square error (RMSE) = 0.03 m3 m−3) as compared to laboratory experiments (RMSE = 0.06 m3 m−3). For ECp prediction, two corrections of the Hilhorst model were investigated. The first approach, which considers the ECa effect on K’ reading, failed to improve the Hilhorst model for ECp > 3 dS m−1 for both laboratory and field conditions. However, the second approach, which considers the effect of ECa on the soil parameter K0, increased the performance of the Hilhorst model and gave accurate measurements of ECp using the 5TE sensor for irrigated soil.


2019 ◽  
Vol 39 (15) ◽  
Author(s):  
李新乐 LI Xinle ◽  
吴波 WU Bo ◽  
张建平 ZHANG Jianping ◽  
辛智鸣 XIN Zhiming ◽  
董雪 DONG Xue ◽  
...  

Irriga ◽  
2004 ◽  
Vol 9 (1) ◽  
pp. 82-88 ◽  
Author(s):  
Rosangela Villwock ◽  
Maria Herminia Ferreira Tavares ◽  
Marcio Antonio Villas Boa

CALIBRAÇÃO DE UM EQUIPAMENTO TDR EM CONDIÇÕES DE CAMPO   Rosangela Villwock; Maria Hermínia Ferreira Tavares; Márcio Antônio Vilas BoasCentro de Ciências Exatas e Tecnológicas, Universidade Estadual do Oeste do Paraná, Cascavel ,  PR,  [email protected]   1 RESUMO  A utilização da Reflectometria no Domínio do Tempo (TDR) tornou-se um método muito bem aceito nas avaliações de teores de água no solo. Todavia, para utilização do equipamento há a necessidade de calibrá-lo para que se obtenha valores acurados de umidade volumétrica, devendo-se sempre respeitar as peculiaridades de cada solo para que o processo de calibração ocorra de forma correta. O objetivo deste trabalho foi calibrar o equipamento TDR em condições de campo, especificamente para um Latossolo Vermelho distroférrico, localizado no Núcleo Experimental de Engenharia Agrícola, Universidade Estadual do Oeste do Paraná, Campus de Cascavel. O modelo polinomial cúbico foi o que melhor se ajustou aos dados para a calibração do equipamento.  UNITERMOS: constante dielétrica aparente, modelo polinomial cúbico, umidade do solo.   VILLWOCK, R.; TAVARES, M. H. F.; VILLAS BOAS, M. A.TDR EQUIPMENT CALIBRATION IN FIELD CONDITIONS   2 ABSTRACT  The use of Time Domain Reflectometry (TDR) has become a very well accepted method to evaluate soil water content. However, for the equipment utilization there is the need to calibrate it to obtain accurate values of volumetric soil water content, always respecting the soil characteristics. The objective of this research was to calibrate the TDR equipment in field conditions, specifically for a Rhodic Hapludox, at the UNIOESTE Experimental Station of Agricultural Engineering, in the campus of Cascavel, State of Parana. The cubic polynomial model was the model that best adjusted the data for the calibration of the equipment.  KEYWORDS: apparent dielectric constant, cubic polynomial model, soil moisture. 


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