Using Unmanned Aerial Vehicle to Obtain Digital Images and Estimating In-Situ Soil Water Content

2020 ◽  
Author(s):  
Ching-Hsiung Wang ◽  
Hong-Ru Lin ◽  
Jyun-Lin Chen ◽  
Shao-Yang Huang ◽  
Jet-Chau Wen
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Digital Images ◽  
Color Space ◽  
Gravimetric Method ◽  
Time Domain Reflectometry ◽  
Soil Samples ◽  
Cost Efficient ◽  
Space Data

<p>Soil water content (SWC) is a vital factor for soil sciences. Nowadays, there are many methods for estimating SWC, including the Time-domain reflectometry (TDR) and the Gravimetric method. Nevertheless, most of them may cause damages to soil structure and require a large workforce and resources. The optical method is a non-destructive and cost-efficient; therefore, recommended for SWC estimations.</p><p>This study analyses soil samples at the field site, as well as it uses aerial photo-shooting to obtain the digital image distribution of surface soil. Both soil samples and digital images were categorized into groups; 9 in total, depending on time parameters (one group equals one day). More specifically, the gravimetric method was selected for the SWC measurements in the laboratory, while the images were modified in such a way so to match the CIE 1931 XYZ color space resolution for further calculations. Then, comparing the CIE 1931 XYZ color space data with the Soil Water Content correlation of 9 groups by validation.</p><p>According to the findings, the sensitivity of CIE 1931 XYZ color space in SWC alternations is high. Additionally, it can be observed that the SWC result data of the model are similar to the SWC measurements; therefore, the CIE 1931 XYZ color space can be applied to agriculture and disaster prevention, and it is a cost-efficient method for SMC estimations, and it can provide several benefits.</p>

scholarly journals Sampling and TDR probe insertion in the determination of the volumetric soil water content

2003 ◽  
Vol 27 (4) ◽  
pp. 575-582 ◽  
Author(s):  
W. G. Teixeira ◽  
G. Schroth ◽  
J. D. Marques ◽  
Bernd Huwe
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Gravimetric Method ◽  
Time Domain Reflectometry ◽  
Volumetric Soil Water Content ◽  
Undisturbed Samples ◽  
Similar Accuracy ◽  
Volumetric Soil Water

Volumetric soil water content (theta) can be evaluated in the field by direct or indirect methods. Among the direct, the gravimetric method is regarded as highly reliable and thus often preferred. Its main disadvantages are that sampling and laboratory procedures are labor intensive, and that the method is destructive, which makes resampling of a same point impossible. Recently, the time domain reflectometry (TDR) technique has become a widely used indirect, non-destructive method to evaluate theta. In this study, evaluations of the apparent dielectric number of soils (epsilon) and samplings for the gravimetrical determination of the volumetric soil water content (thetaGrav) were carried out at four sites of a Xanthic Ferralsol in Manaus - Brazil. With the obtained epsilon values, theta was estimated using empirical equations (thetaTDR), and compared with thetaGrav derived from disturbed and undisturbed samples. The main objective of this study was the comparison of thetaTDR estimates of horizontally as well as vertically inserted probes with the thetaGrav values determined by disturbed and undisturbed samples. Results showed that thetaTDR estimates of vertically inserted probes and the average of horizontally measured layers were only slightly and insignificantly different. However, significant differences were found between the thetaTDR estimates of different equations and between disturbed and undisturbed samples in the thetaGrav determinations. The use of the theoretical Knight et al. model, which permits an evaluation of the soil volume assessed by TDR probes, is also discussed. It was concluded that the TDR technique, when properly calibrated, permits in situ, nondestructive measurements of q in Xanthic Ferralsols of similar accuracy as the gravimetric method.

Measuring Soil Water Content With Time Domain Reflectometry

Soil Science ◽  
2010 ◽  
Vol 175 (10) ◽  
pp. 469-473 ◽  
Author(s):  
Zhaoqiang Ju ◽  
Xiaona Liu ◽  
Tusheng Ren ◽  
Chunsheng Hu
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Time Domain ◽  
Time Domain Reflectometry

scholarly journals An empirical model for describing the influence of water content and concentration of sulfamethoxazole (antibiotic) in soil on the total net CO2 efflux

2020 ◽  
Vol 68 (4) ◽  
pp. 351-358
Author(s):  
Miroslav Fér ◽  
Radka Kodešová ◽  
Barbora Kalkušová ◽  
Aleš Klement ◽  
Antonín Nikodem
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Solution Treatment ◽  
Soil Microbial Activity ◽  
Soil Samples ◽  
Co2 Efflux ◽  
The Impact ◽  
Water Contents ◽  
Soil Water Contents

AbstractThe aim of the study was to describe the impact of the soil water content and sulfamethoxazole, SUL, (antibiotic) concentration in soil on the net CO2 efflux. Soil samples were taken from topsoils of a Haplic Fluvisol and Haplic Chernozem. Soil samples were packed into the steel cylinders. The net CO2 efflux was measured from these soil columns after application of fresh water or SUL solution at different soil water contents. The experiments were carried out in dark at 20°C. The trends in the net CO2 efflux varied for different treatments. While initially high values for water treatment exponentially decreased in time, values for solution treatment increased during the first 250–650 minutes and then decreased. The total net CO2 effluxes measured for 20 hours related to the soil water content followed the second order polynomial functions. The maximal values were measured for the soil water content of 0.15 cm3 cm−3 (Haplic Fluvisol with water or solution, Haplic Chernozem with solution) and 0.11 cm3 cm−3 (Haplic Chernozem with water). The ratios between values measured for solution and water at the same soil water contents exponentially increased with increasing SUL concentration in soils. This proved the increasing stimulative influence of SUL on soil microbial activity.

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