scholarly journals Laboratory and Physical Prototype Tests for the Investigation of Hydraulic Hysteresis of Pyroclastic Soils

Geosciences ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 320
Author(s):  
Marianna Pirone ◽  
Alfredo Reder ◽  
Guido Rianna ◽  
Luca Pagano ◽  
Marco Valerio Nicotera ◽  
...  
Keyword(s):  
Soil Water ◽  
Field Measurements ◽  
Experimental Tests ◽  
Theoretical Interpretation ◽  
Small Scale ◽  
Hysteretic Model ◽  
Soil Water Retention ◽  
Air Entrapment ◽  
Pyroclastic Soils ◽  
Physical Prototype

Proper soil water retention curves (SWRCs) are necessary for a fair analysis of groundwater flow in unsaturated slopes. The question is whether hydraulic parameters operating in situ can be reliably determined from laboratory tests or physical prototype models in order to interpret and predict soil water distributions in the field. In this paper, some results obtained by tests at different scales (testing on laboratory specimens and a physical prototype) are presented to explore the hydraulic behavior of pyroclastic soils. A theoretical interpretation of the observed behavior in the laboratory and using a physical prototype is proposed by adopting the hysteretic model of Lenhard and Parker. For each tested soil, the main hysteretic loop determined by interpreting experimental tests (at laboratory and prototype scales) overlaps with paths detected by coupling the field measurements of matric suction and water content collected at the site at the same depth. From these results, the physical prototype (medium scale) and the soil specimen (small scale) seem to be acceptable for determinations of SWRC, provided that the air entrapment value is well known.

Newly-amended biochar particles decrease erodibility and improve hydraulic soil properties

2021 ◽  
Author(s):  
Steffen Seitz ◽  
Sandra Teuber ◽  
Christian Geissler ◽  
Philipp Goebes ◽  
Thomas Scholten
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Erosion ◽  
Soil Water ◽  
Water Retention ◽  
Early Stage ◽  
Substrate Surface ◽  
Hydrothermal Carbonization ◽  
Future Research ◽  
Small Scale ◽  
Soil Water Retention

<p>Biochar is charcoal obtained by thermal decomposition of biomass through pyrolysis. The amendment of biochar changes chemical, but also physical properties of soils such as aggregation and texture. Thus, it is assumed that it can also affect soil erosion and erosion-related processes like the movement of water within the soil. In this study, we investigated how biochar particles change erodibility by rain splash instantly after application, as well as the initial movement of soil water.</p><p>Therefore, we conducted a small-scale laboratory experiment with two sieved substrates and using hydrothermal carbonization (HTC)-char and Pyrochar. Soil erodibility was determined with Tübingen splash cups under simulated rainfall, soil hydraulic conductivity was calculated from texture and bulk soil density, and soil water retention was measured using the negative and the excess pressure methods.</p><p>Results showed that the addition of biochar significantly reduced initial soil erosion in coarse sand and silt loam immediately after biochar application. Furthermore, biochar particles were not preferentially removed from the substrate surface. Increasing biochar particle sizes partly showed decreasing erodibility of substrates. Moreover, biochar amendment led to improved hydraulic conductivity and soil water retention regarding soil erosion control, with increasing application rates. It became clear that these effects are already detectable in a very early stage, and without long-term incorporation of biochar into soils. We could further show that different biochar types have varying impacts on investigated parameters due to their chemical properties and sizes, and future research should include varying biochars produced with different production methods.</p><p>In conclusion, this study showed that biochar amendments have the potential to reduce soil erosion by water from a very early stage. This mechanism adds a further ecosystem service to the list of useful impacts of biochar application on agriculture.</p>

Small scale CO2 fluxes in a rainfed maize field under N fertilization

2020 ◽  
Author(s):  
Györgyi Gelybó ◽  
Réka Deli ◽  
Márton Dencső ◽  
Bernadett Kósa ◽  
Viktória Mateika ◽  
...  
Keyword(s):  
Soil Respiration ◽  
Soil Water ◽  
Field Measurements ◽  
Vegetation Period ◽  
N Fertilization ◽  
Small Scale ◽  
Material Transport ◽  
Sowing Time ◽  
Area Index ◽  
Maize Field

<p>Carbon-dioxide (CO<sub>2</sub>) fluxes in the soil-plant-atmosphere system contain bidirectional material transport with organic and inorganic sources and sinks, and various pathways. Proportion of irrigated fields in the total area of Hungarian arable lands is low, and incase of a rainfed field water and CO<sub>2</sub> fluxes are only driven by meteorological factors. In this study we focused on maize under different fertilization treatments to see the plot scale variability of CO<sub>2</sub> fluxes and connected parameters.</p><p>The site is a multifactorial sowing time-fertilizer-maize variety field experiment near Martonvásár. Two treatment plots were selected for the measurements with contrasting 60 kg N ha<sup>-1</sup> and 180 kg N ha<sup>-1</sup> fertilizer treatments and no other factors were considered in the present study. We performed synchronized observations of (i) CO<sub>2</sub> fluxes: soil respiration (Rs; EGM-5 gas analyser + SRC-1 chamber, PPSystems); leaf scale photosynthesis (A; CIRAS-3 portable photosynthesis system, PPSystems)), (ii) soil temperature and soil water content, (iii) plant parameters: root growth (CI-600, CID-Bioscience), plant height, leaf area index (Accupar LP-80 ceptometer, Li-Cor). Data on the above parameters comprise several spatial replicates to explore spatial heterogeneity in case of a maize field managed in accordance with the typical Hungarian practice. The average applied N amount in the country is around 100-105 kg ha<sup>-1</sup>.</p><p>Field measurements for CO<sub>2</sub> fluxes and biotic and abiotic drivers were performed six times in the vegetation period to establish relationship among them. Data were analyzed to optimize the labour intensive protocol for this experimental setup. Photosynthesis varied within the vertical canopy as reflected by measurements on five leaves per plant. Soil respiration was more dependent temporally on soil water availability than on temperature.</p>

scholarly journals How Do Newly-Amended Biochar Particles Affect Erodibility and Soil Water Movement?—A Small-Scale Experimental Approach

Soil Systems ◽  
2020 ◽  
Vol 4 (4) ◽  
pp. 60 ◽  
Author(s):  
Steffen Seitz ◽  
Sandra Teuber ◽  
Christian Geißler ◽  
Philipp Goebes ◽  
Thomas Scholten
Keyword(s):  
Hydraulic Conductivity ◽  
Soil Erosion ◽  
Soil Water ◽  
Water Retention ◽  
Water Movement ◽  
Early Stage ◽  
Substrate Surface ◽  
Small Scale ◽  
Soil Water Retention ◽  
Biochar Amendment

Biochar amendment changes chemical and physical properties of soils and influences soil biota. It is, thus, assumed that it can also affect soil erosion and erosion-related processes. In this study, we investigated how biochar particles instantly change erodibility by rain splash and the initial movement of soil water in a small-scale experiment. Hydrothermal carbonization (HTC)-char and Pyrochar were admixed to two soil substrates. Soil erodibility was determined with Tübingen splash cups under simulated rainfall, soil hydraulic conductivity was calculated from texture and bulk soil density, and soil water retention was measured using the negative and the excess pressure methods. Results showed that the addition of biochar significantly reduced initial soil erosion in coarse sand and silt loam immediately after biochar application. Furthermore, biochar particles were not preferentially removed from the substrate surface, but increasing biochar particle sizes partly showed decreasing erodibility of substrates. Moreover, biochar amendment led to improved hydraulic conductivity and soil water retention, regarding soil erosion control. In conclusion, this study provided evidence that biochar amendments reduce soil degradation by water erosion. Furthermore, this effect is detectable in a very early stage, and without long-term incorporation of biochar into soils.

INFLUENCE OF SOIL MATRIX ON SOIL-WATER RETENTION CURVE AND HYDRAULIC CHARACTERISTICS

2017 ◽  
Vol 16 (4) ◽  
pp. 869-877
Author(s):  
Vasile Lucian Pavel ◽  
Florian Statescu ◽  
Dorin Cotiu.ca-Zauca ◽  
Gabriela Biali ◽  
Paula Cojocaru
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Water Retention Curve ◽  
Hydraulic Characteristics ◽  
Soil Water Retention Curve ◽  
Soil Water Retention ◽  
Soil Matrix ◽  
Retention Curve

scholarly journals Carboxylated nanocellulose superabsorbent: Biodegradation and soil water retention properties

2021 ◽  
pp. 51495
Author(s):  
Ruth M. Barajas‐Ledesma ◽  
Vanessa N. L. Wong ◽  
Karen Little ◽  
Antonio F. Patti ◽  
Gil Garnier
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Soil Water Retention ◽  
Water Retention Properties

scholarly journals The Mechanical Impact of Water Affected the Soil Physical Quality of a Loam Soil under Minimum Tillage and No-Tillage: An Assessment Using Beerkan Multi-Height Runs and BEST-Procedure

Land ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 195 ◽  
Author(s):  
Mirko Castellini ◽  
Anna Maria Stellacci ◽  
Danilo Sisto ◽  
Massimo Iovino
Keyword(s):  
Soil Water ◽  
Water Retention ◽  
Management Practices ◽  
Soil Management ◽  
Soil Water Retention ◽  
Physical Quality ◽  
Soil Physical Quality ◽  
Loam Soil ◽  
The Impact

The multi-height (low, L = 3 cm; intermediate, M = 100 cm; high, H = 200 cm) Beerkan run methodology was applied on both a minimum tilled (MT) (i.e., up to a depth of 30 cm) and a no-tilled (NT) bare loam soil, and the soil water retention curve was estimated by the BEST-steady algorithm. Three indicators of soil physical quality (SPQ), i.e., macroporosity (Pmac), air capacity (AC) and relative field capacity (RFC) were calculated to assess the impact of water pouring height under alternative soil management practices. Results showed that, compared to the reference low run, M and H runs affected both the estimated soil water retention curves and derived SPQ indicators. Generally, M–H runs significantly reduced the mean values of Pmac and AC and increased RFC for both MT and NT soil management practices. According to the guidelines for assessment of SPQ, the M and H runs: (i) worsened Pmac classification of both MT and NT soils; (ii) did not worsen AC classification, regardless of soil management parameters; (iii) worsened RFC classification of only NT soil, as a consequence of insufficient soil aeration. For both soil management techniques, a strong negative correlation was found between the Pmac and AC values and the gravitational potential energy, Ep, of the water used for the infiltration runs. A positive correlation was detected between RFC and Ep. The relationships were plausible from a soil physics point of view. NT soil has proven to be more resilient than MT. This study contributes toward testing simple and robust methods capable of quantifying soil degradation effects, due to intense rainfall events, under different soil management practices in the Mediterranean environment.

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