scholarly journals The sensitivity of cosmogenic radionuclide analysis to soil bulk density: Implications for soil formation rates

2020 ◽  
Vol 72 (1) ◽  
pp. 174-182
Author(s):  
Daniel Evans ◽  
Ángel Rodés ◽  
Andrew Tye
Keyword(s):  
Bulk Density ◽  
Soil Formation ◽  
Soil Bulk Density ◽  
Radionuclide Analysis ◽  
Cosmogenic Radionuclide

Lithological controls on soil formation rates and the implications for soil sustainability

2020 ◽  
Author(s):  
Daniel Evans ◽  
John Quinton ◽  
Andrew Tye ◽  
Angel Rodes ◽  
Jessica Davies ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Soil Formation ◽  
Case Scenario ◽  
Worst Case ◽  
Radionuclide Analysis ◽  
Rock Types ◽  
Soil Sustainability ◽  
The Uk ◽  
The Impact ◽  
Cosmogenic Radionuclide

<p>Soils deliver multiple ecosystem services and their long-term sustainability is fundamentally determined by the rates at which they form and erode. Our knowledge and understanding of soil formation is not commensurate with that of soil erosion, but developments in cosmogenic radionuclide analysis have enabled soil scientists to more accurately constrain the rates at which soils form from bedrock. To date, all three major rock types – igneous, sedimentary and metamorphic lithologies – have been examined in such work. Soil formation rates have been measured and compared between these rock types but the impact of rock characteristics such as mineralogy or porosity on soil formation rates has seldom been explored. In this UK-based study, we addressed this knowledge gap by using cosmogenic radionuclide analysis to investigate whether the lithological variability of sandstone governs pedogenesis. Soil formation rates from two arable hillslopes underlain by different types of arenite sandstone were calculated. Rates ranged from 0.090 to 0.193 mm yr<sup>-1</sup> and although the sandstones differed in porosity, no significant differences in soil formation rates were found between them. On the contrary, these rates significantly differed from those measured at two other sandstone-based sites in the UK, and with the rates compiled in global inventory of cosmogenic studies on sandstone-based soils. We suggest that this is due to the absence of matrix and the greater porosities exhibited at our UK sites in comparison to the matrix-abundant, less porous wackes that have been studied previously. We then used soil formation rates to calculate first-order soil lifespans for both of our hillslopes. In a worst case scenario, the lifespan of the A horizon at one of our sites could be eroded in less than 40 years, with bedrock exposure occurring in less than 190 years.  This underlines the urgency required in ameliorating rates of soil erosion. However, we also demonstrate the importance of measuring soil erosion and formation in parallel, at the site of interest, rather than calculating a mean rate from the literature, as we demonstrate soil formation rates can vary significantly among variants of the same rock type.</p><p> </p>

scholarly journals A photogrammetry-based approach for soil bulk density measurements with an emphasis on applications to cosmogenic nuclide analysis

2020 ◽  
Vol 8 (4) ◽  
pp. 995-1020
Author(s):  
Joel Mohren ◽  
Steven A. Binnie ◽  
Gregor M. Rink ◽  
Katharina Knödgen ◽  
Carlos Miranda ◽  
...  
Keyword(s):  
Bulk Density ◽  
Soil Formation ◽  
Soil Condition ◽  
Soil Bulk Density ◽  
Small Scale ◽  
Soil Density ◽  
Cosmogenic Nuclide ◽  
Sampling Campaign ◽  
Accuracy And Precision

Abstract. The quantification of soil bulk density (ρB) is a cumbersome and time-consuming task when traditional soil density sampling techniques are applied. However, it can be important for terrestrial cosmogenic nuclide (TCN) production rate scaling when deriving ages or surface process rates from buried samples, in particular when short-lived TCNs such as in situ 14C are applied. Here, we show that soil density determinations can be made using structure-from-motion multi-view stereo (SfM-MVS) photogrammetry-based volume reconstructions of sampling pits. Accuracy and precision tests as found in the literature and as conducted in this study clearly indicate that photographs taken from both a consumer-grade digital single-lens mirrorless (DSLM) and a smartphone camera are of sufficient quality to produce accurate and precise modelling results, i.e. to regularly reproduce the “true” volume and/or density by >95 %. This finding holds also if a freeware-based computing workflow is applied. The technique has been used to measure ρB along three small-scale (<1 km) N–S transects located in the semi-arid to arid Altos de Talinay, northern central Chile (∼30.5∘ S, ∼71.7∘ W), during a TCN sampling campaign. Here, long-term differences in microclimatic conditions between south-facing and north-facing slopes (SFSs and NFSs, respectively) explain a sharp contrast in vegetation cover, slope gradient and general soil condition patterns. These contrasts are also reflected by the soil density data, generally coinciding with lower densities on SFSs. The largest differences between NFSs and SFSs are evident in the lower portion of the respective slopes, close to the thalwegs. In general, field-state soil bulk densities were found to vary by about 0.6 g cm−3 over a few tens of metres along the same slope. As such, the dataset that was mainly generated to derive more accurate TCN-based process rates and ages can be used to characterise the present-day condition of soils in the study area, which in turn can give insight into the long-term soil formation and prevailing environmental conditions. This implies that the method tested in this study may also being applied in other fields of research and work, such as soil science, agriculture or the construction sector.

MEASUREMENT AND PALEOCLIMATIC SIGNIFICANCE OF SOIL BULK DENSITY FOR LOESS IN EXTREME ARID REGION

2010 ◽  
Vol 30 (2) ◽  
pp. 127-132
Author(s):  
Jinbo ZAN ◽  
Shengli YANG ◽  
Xiaomin FANG ◽  
Xiangyu LI ◽  
Yibo YANG ◽  
...  
Keyword(s):  
Bulk Density ◽  
Arid Region ◽  
Soil Bulk Density ◽  
Paleoclimatic Significance

scholarly journals Machine-Learning Classification of Soil Bulk Density in Salt Marsh Environments

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4408
Author(s):  
Iman Salehi Hikouei ◽  
S. Sonny Kim ◽  
Deepak R. Mishra
Keyword(s):  
Machine Learning ◽  
Remote Sensing ◽  
Salt Marsh ◽  
Bulk Density ◽  
Remote Sensing Data ◽  
Soil Bulk Density ◽  
Soil Samples ◽  
Marsh Soil ◽  
Landsat 7 ◽  
Salt Marsh Soil

Remotely sensed data from both in situ and satellite platforms in visible, near-infrared, and shortwave infrared (VNIR–SWIR, 400–2500 nm) regions have been widely used to characterize and model soil properties in a direct, cost-effective, and rapid manner at different scales. In this study, we assess the performance of machine-learning algorithms including random forest (RF), extreme gradient boosting machines (XGBoost), and support vector machines (SVM) to model salt marsh soil bulk density using multispectral remote-sensing data from the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) platform. To our knowledge, use of remote-sensing data for estimating salt marsh soil bulk density at the vegetation rooting zone has not been investigated before. Our study reveals that blue (band 1; 450–520 nm) and NIR (band 4; 770–900 nm) bands of Landsat-7 ETM+ ranked as the most important spectral features for bulk density prediction by XGBoost and RF, respectively. According to XGBoost, band 1 and band 4 had relative importance of around 41% and 39%, respectively. We tested two soil bulk density classes in order to differentiate salt marshes in terms of their capability to support vegetation that grows in either low (0.032 to 0.752 g/cm3) or high (0.752 g/cm3 to 1.893 g/cm3) bulk density areas. XGBoost produced a higher classification accuracy (88%) compared to RF (87%) and SVM (86%), although discrepancies in accuracy between these models were small (<2%). XGBoost correctly classified 178 out of 186 soil samples labeled as low bulk density and 37 out of 62 soil samples labeled as high bulk density. We conclude that remote-sensing-based machine-learning models can be a valuable tool for ecologists and engineers to map the soil bulk density in wetlands to select suitable sites for effective restoration and successful re-establishment practices.

Measurement of Soil Bulk Density and Water Content with Time Domain Reflectometry: Algorithm Implementation and Method Analysis

2021 ◽  
pp. 126389
Author(s):  
Marco Bittelli ◽  
Fausto Tomei ◽  
Anbazhagan P. ◽  
Raghuveer Rao Pallapati ◽  
Puskar Mahajan ◽  
...  
Keyword(s):  
Water Content ◽  
Bulk Density ◽  
Time Domain ◽  
Soil Bulk Density ◽  
Time Domain Reflectometry ◽  
Algorithm Implementation ◽  
Method Analysis
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