Using dye tracer for visualizing roots impact on soil structure and soil porous system

Biologia ◽  
2015 ◽  
Vol 70 (11) ◽  
Author(s):  
Radka Kodešová ◽  
Karel Němeček ◽  
Anna Žigová ◽  
Antonín Nikodem ◽  
Miroslav Fér
Keyword(s):  
Water Uptake ◽  
Soil Structure ◽  
Preferential Flow ◽  
Soil Surface ◽  
Water Infiltration ◽  
Porous System ◽  
Field Scale ◽  
Thin Sections ◽  
Dye Tracer ◽  
The Impact

AbstractPlants influence the water regime in soil by both water uptake and an uneven distribution of water infiltration at the soil surface. The latter process is more poorly studied, but it is well known that roots modify soil structure by enhancing aggregation and biopore production. This study used a dye tracer to visualize the impact of plants on water flow in the topsoil of a Greyic Phaeozem. Brilliant blue was ponded to 10 cm height in a 1 m × 1 m frame in the field immediately after harvest of winter wheat (Triticum aestivum L.). After complete infiltration, the staining patterns within the vertical and horizontal field-scale sections were studied. In addition, soil thin sections were made and micromorphological images were used to study soil structure and dye distribution at the microscale. The field-scale sections clearly documented uneven dye penetration into the soil surface, which was influenced by plant presence and in some cases by mechanical compaction of the soil surface. The micromorphological images showed that root activities compress soil and increases the bulk density near the roots (which could be also result of root water uptake and consequent soil adhesion). On the other hand in few cases a preferential flow along the roots was observed.

Coupling large and small ring infiltration experiments for investigating preferential flow

2021 ◽  
Author(s):  
Laurent Lassabatere ◽  
Simone Di Prima ◽  
Paola Concialdi ◽  
Majdi Abou Najm ◽  
Ryan D. Stewart ◽  
...  
Keyword(s):  
Preferential Flow ◽  
Soil Surface ◽  
Water Infiltration ◽  
Small Ring ◽  
Hydraulic Parameters ◽  
Ring Size ◽  
Large Rings ◽  
Cumulative Infiltration ◽  
The Impact ◽  
Lithological Heterogeneity

<p>Preferential flow is more the rule than the exception. Water infiltration is often led by preferential flow due to macropores, specific soil structures (e.g., aggregates, macropore networks), or lithological heterogeneity (occurrence of materials with contrasting hydraulic properties). Water infiltration in soils prone to preferential flow strongly depends on soil features below the soil surface, but also the initiation of water infiltration at the surface. When the macropore networks are not dense, with only a few macropores intercepting the soil surface, water infiltration experiments with ring size in the order of 10-15 cm diameter may overlook sampling macropore networks during some infiltration runs, minimizing the effect of macropore flow on the bulk water infiltration at the plot scale.</p><p>In this study, we investigated the effect of ring size on water infiltration into soils prone to preferential flow. We used two ring sizes: small (15 cm in diameter) and large (50 cm in diameter). By doing so, we hypothesized that the large rings, sampling a more representative soil volume, will maximize the probability to intercept and activate a macropore network. In contrast, the small rings may activate the macropore network only occasionally, with other infiltration runs mainly sampling the soil matrix. Thus, the small rings are expected to provide more variable results. On the other hand, the large rings are expected to provide more homogeneous results in line with the soil's bulk infiltration capability, including all pore networks at the plot scale.</p><p>Three different sites were sampled with varying types of preferential flow (macropore-induced versus lithological heterogeneity induced). The experimental plan included inserting large rings at several places in the experimental sites with a dozen small rings nearby to sample the same soil. All the rings were submitted to a similar positive constant water pressure head at the soil surface. The cumulative infiltrations were then monitored and treated with BEST algorithms to get the efficient hydraulic parameters. Note that the cumulative infiltration could not be compared directly since lateral water fluxes varied in extent and geometry between the different ring sizes. The impacts of the ring size on the magnitude of cumulative infiltration and related estimated hydraulic parameters were discussed. Our results demonstrated the impact of ring size but also the dependency of such effect on the site and the type of flow.</p><p>Our results contribute to understanding preferential flow in heterogeneous soils and the complexity of its measure using regular water infiltration devices and protocols.</p>

scholarly journals Water repellency of clay, sand and organic soils in Finland

2008 ◽  
Vol 16 (3) ◽  
pp. 267 ◽  
Author(s):  
K. RASA ◽  
R. HORN ◽  
M. RÄTY
Keyword(s):  
Preferential Flow ◽  
Management Practice ◽  
Soil Surface ◽  
Water Repellency ◽  
Organic Soil ◽  
Water Infiltration ◽  
Organic Soils ◽  
Water Repellent ◽  
Moisture Regime ◽  
Wetting Process

Water repellency (WR) delays soil wetting process, increases preferential flow and may give rise to surface runoff and consequent erosion. WR is commonly recognized in the soils of warm and temperate climates. To explore the occurrence of WR in soils in Finland, soil R index was studied on 12 sites of different soil types. The effects of soil management practice, vegetation age, soil moisture and drying temperature on WR were studied by a mini-infiltrometer with samples from depths of 0-5 and 5-10 cm. All studied sites exhibited WR (R index >1.95) at the time of sampling. WR increased as follows: sand (R = 1.8-5.0) < clay (R = 2.4-10.3) < organic (R = 7.9-undefined). At clay and sand, WR was generally higher at the soil surface and at the older sites (14 yr.), where organic matter is accumulated. Below 41 vol. % water content these mineral soils were water repellent whereas organic soil exhibited WR even at saturation. These results show that soil WR also reduces water infiltration at the prevalent field moisture regime in the soils of boreal climate. The ageing of vegetation increases WR and on the other hand, cultivation reduces or hinders the development of WR.;

Estimation of vineyard soil structure and preferential flow using dye tracer, X-ray tomography, and numerical simulations

Geoderma ◽  
2020 ◽  
Vol 380 ◽  
pp. 114699
Author(s):  
Vilim Filipović ◽  
Jasmina Defterdarović ◽  
Jiří Šimůnek ◽  
Lana Filipović ◽  
Gabrijel Ondrašek ◽  
...  
Keyword(s):  
Numerical Simulations ◽  
Soil Structure ◽  
Preferential Flow ◽  
X Ray ◽  
Dye Tracer ◽  
Vineyard Soil

scholarly journals Effects of large macropores on soil evaporation in salt marshes

2020 ◽  
Author(s):  
Tingzhang Zhou ◽  
Pei Xin ◽  
Jirka Jirka Šimůnek
Keyword(s):  
Water Flow ◽  
Salt Marshes ◽  
Evaporation Rate ◽  
Preferential Flow ◽  
Soil Surface ◽  
Soil Evaporation ◽  
Infrared Light ◽  
Soil Conditions ◽  
Set Up ◽  
The Impact

&lt;p&gt;The occurrence of macropores in salt marsh sediments is a natural and ubiquitous phenomenon. Although they are widely assumed to significantly affect water flow in salt marshes, the effects are not well understood. We conducted physical laboratory experiments and numerical simulations to examine the impact of macropores on soil evaporation. Soil columns packed with either sand or clay and with or without macropores were set up with water tables in the columns set at different levels. A high potential evaporation rate was induced by infrared light and a fan. The results showed that in the soil with a low saturated hydraulic conductivity (and thus a low transport capacity), macropores behaved as preferential flow paths, delivering water from the groundwater towards the soil surface and maintaining a high evaporation rate in comparison with the soil without macropores. This effect was more pronounced for sediments with lower hydraulic conductivities and shallower groundwater tables. These results not only improve our understanding of water flow and soil conditions in salt marshes but also shed light on soil evaporation in other hydrological systems.&lt;/p&gt;

scholarly journals Numerical Simulation of Unstable Preferential Flow during Water Infiltration into Heterogeneous Dry Soil

Water ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 909
Author(s):  
Luis Cueto-Felgueroso ◽  
María José Suarez-Navarro ◽  
Xiaojing Fu ◽  
Ruben Juanes
Keyword(s):  
Numerical Simulation ◽  
Correlation Length ◽  
Soil Structure ◽  
Preferential Flow ◽  
Soil Heterogeneity ◽  
Water Infiltration ◽  
Intrinsic Permeability ◽  
Relative Permeabilities ◽  
Flow Through ◽  
Dry Soil

Water infiltration and unsaturated flow through heterogeneous soil control the distribution of soil moisture in the vadose zone and the dynamics of groundwater recharge, providing the link between climate, biogeochemical soil processes and vegetation dynamics. Infiltration into dry soil is hydrodynamically unstable, leading to preferential flow through narrow wet regions (fingers). In this paper we use numerical simulation to study the interplay between fingering instabilities and soil heterogeneity during water infiltration. We consider soil with heterogeneous intrinsic permeability. Permeabilities are random, with point Gaussian statistics, and vary smoothly in space due to spatial correlation. The key research question is whether the presence of moderate or strong heterogeneity overwhelms the fingering instability, recovering the simple stable displacement patterns predicted by most simplified model of infiltration currently used in hydrological models from the Darcy to the basin scales. We perform detailed simulations of constant-rate infiltration into soils with isotropic and anisotropic intrinsic permeability fields. Our results demonstrate that soil heterogeneity does not suppress fingering instabilities, but it rather enhances its effect of preferential flow and channeling. Fingering patterns strongly depend on soil structure, in particular the correlation length and anisotropy of the permeability field. While the finger size and flow dynamics are only slightly controlled by correlation length in isotropic fields, layering leads to significant finger meandering and bulging, changing arrival times and wetting efficiencies. Fingering and soil heterogeneity need to be considered when upscaling the constitutive relationships of multiphase flow in porous media (relative permeability and water retention curve) from the finger to field and basin scales. While relative permeabilities remain unchanged upon upscaling for stable displacements, the inefficient wetting due to fingering leads to relative permeabilities at the field scale that are significantly different from those at the Darcy scale. These effective relative permeability functions also depend, although less strongly, on heterogeneity and soil structure.

scholarly journals The Impact of Rhizosphere Soil Structure and Mucilage on Root Water Uptake – A Simulation Study

2020 ◽  
Author(s):  
Magdalena Landl ◽  
Maxime Phalempin ◽  
Doris Vetterlein ◽  
Steffen Schlueter ◽  
Mathieu Javaux ◽  
...  
Keyword(s):  
Water Uptake ◽  
Simulation Study ◽  
Soil Structure ◽  
Rhizosphere Soil ◽  
Root Water Uptake ◽  
The Impact

scholarly journals Estimating hydraulic conductivity of a crusted loamy soil from beerkan experiments in a Mediterranean vineyard

2017 ◽  
Author(s):  
Vincenzo Alagna ◽  
Vincenzo Bagarello ◽  
Simone Di Prima ◽  
Fabio Guaitoli ◽  
Massimo Iovino ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Vegetation Cover ◽  
Soil Surface ◽  
Rainfall Event ◽  
Water Infiltration ◽  
Insertion Depth ◽  
Soil Hydraulic Conductivity ◽  
Soil Hydraulic ◽  
The Impact

Abstract. In bare soils of semi-arid areas, surface crusting is a rather common phenomenon due to the impact of raindrops. Water infiltration measurements under ponding conditions constitute a common way for an approximate characterization of crusted soils. In this study, the impact of crusting on soil hydraulic conductivity was assessed in a Mediterranean vineyard (western Sicily, Italy) under conventional tillage. The BEST (Beerkan Estimation of Soil Transfer parameters) algorithm was applied to the infiltration data to obtain the hydraulic conductivity of crusted and uncrusted soils. Soil hydraulic conductivity was found to vary during the year and also spatially (i.e., rows vs. inter-rows) due to crusting, tillage and vegetation cover. A 55 mm rainfall event resulted in a decrease of the saturated soil hydraulic conductivity, Ks, by a factor close to two in the inter-row areas, due to the formation of a crusted layer at the surface. The same rainfall event did not determine a Ks reduction in the row areas (i.e., Ks reduced by a non-significant factor of 1.05) because the vegetation cover intercepted the raindrops and therefore prevented alteration of the soil surface. The developed ring insertion methodology on crusted soil, implying pre-moistening through the periphery of the sampled surface, together with the very small insertion depth of the ring (0.01 m) prevented visible fractures. Consequently, beerkan tests carried out along and between the vine-rows and data analysis by the BEST algorithm allowed to assess crusting-dependent reductions in hydraulic conductivity with extemporaneous measurements alone. Testing the beerkan infiltration run in other crusted soils and establishing comparisons with other experimental methodologies appear advisable to increase confidence on the reliability of the method, that seems suitable to allow simple characterization of crusted soils.

Soil fauna and soil structure

Soil Research ◽  
1991 ◽  
Vol 29 (6) ◽  
pp. 745 ◽  
Author(s):  
KE Lee ◽  
RC Foster
Keyword(s):  
Gas Exchange ◽  
Soil Structure ◽  
Soil Fauna ◽  
Water Movement ◽  
Mineral Soil ◽  
Soil Surface ◽  
Water Infiltration ◽  
Soil Horizons ◽  
Large Numbers ◽  
Capillary Uptake

Significant effects of soil fauna on soil structure are achieved mainly by a few groups among the larger soil invertebrates that are widely distributed and generally present in large numbers. Of these groups the most important are earthworms, termites and ants. The review deals mainly with earthworms, which are distributed throughout all but the coldest and the driest regions of the world. The effects of termites and ants on soil structure are also discussed. These groups of soil animals are also widely distributed, but are most common and most effective in influencing soil structure in tropical and warm temperate regions. A brief section deals with the influence of microarthropods, which are commonly found in large numbers, but because of their small size are unable to make large burrows in the mineral soil horizons, and are largely confined to pre-existing voids in litter and surface soil horizons. Their faecal pellets are granular and largely organic, with little included mineral soil material, and they sometimes make up the major proportion of forest litter layers. Quantitative assessment of the influence of earthworms on soil structure is available, but information on other groups is largely qualitative. The burrows of earthworms contribute to macroporosity and so influence water infiltration and aeration. Anecic species, that live in semi-permanent burrows opening to the soil surface and feed at the surface, provide more or less vertical channels for water infiltration and gas exchange. Endogeic species, that burrow continuously in search of food within the soil, provide more horizontally oriented, frequently extensive and intersecting networks of macropores that promote water movement and gas diffusion. Burrows that penetrate soil surface crusts are particularly important for water entry to the soil. Water movement through pores of the dimensions of earthworm burrows is important only when rainfall or irrigation supplies water at rates that exceed the capacity of the soil surface for capillary uptake. The combination of increase in surface area available for capillary uptake through the burrow walls and of hydraulic pressure resulting from the column of water in a water-filled burrow increases infiltration. Occupied burrows of anecic species may be sealed with soil or plant litter by the resident earthworm when water is ponded on the soil surface, or blocked by the earthworm's body, so as to be ineffective for water infiltration. When burrows are air-filled they provide surfaces that penetrate below ground and facilitate gas exchange.

scholarly journals A modified Green–Ampt model for water infiltration and preferential flow

2016 ◽  
Vol 47 (6) ◽  
pp. 1172-1181 ◽  
Author(s):  
Dedi Liu ◽  
Yao Xu ◽  
Shenglian Guo ◽  
Pan Liu ◽  
David E. Rheinheimer
Keyword(s):  
Water Content ◽  
Preferential Flow ◽  
Soil Surface ◽  
Water Infiltration ◽  
Ratio Test ◽  
Catchment Scale ◽  
Runoff Simulation ◽  
New Model ◽  
Flow Equations ◽  
Flood Peak

Preferential flow is significant for its contribution to rapid response to hydrologic inputs at the soil surface and unsaturated zone flow, which is critical for flow generation in rainfall–runoff (RR) models. In combination with the diffuse and source-responsive flow equations, a new model for water infiltration that incorporates preferential flow is proposed in this paper. Its performance in estimating soil moisture at the catchment scale was tested with observed water content data from the Elder sub-basin of the South Fork Eel River, located in northern California, USA. The case study shows that the new model can improve the accuracy of soil water content simulation even at the catchment scale. The impacts of preferential flow on RR simulation were tested by the Modello Idrologico Semi-Distributio in continuo lumped hydrological model for the Elder River basin. Eleven significant floods events, which were defined as having flood peak magnitudes greater than ten times average discharge during the study period, were employed to assess runoff simulation improvement. The accuracy of the runoff simulation incorporating the preferential flow at the catchment scale improved significantly according to the likelihood ratio test.

scholarly journals Functional attributes: Compacting vs decompacting earthworms and influence on soil structure

2012 ◽  
Vol 58 (4) ◽  
pp. 556-565 ◽  
Author(s):  
Arnauth Martinez Guéi ◽  
Yannick Baidai ◽  
Jérôme Ebagnerin Tondoh ◽  
Jeroen Huising
Keyword(s):  
Soil Structure ◽  
Deciduous Forest ◽  
Positive Impact ◽  
Infiltration Rate ◽  
Water Infiltration ◽  
Earthworm Species ◽  
Insurance Hypothesis ◽  
Hyperiodrilus Africanus ◽  
Structure Regulation ◽  
The Impact

Abstract A short term field mesocosm experiment was performed in semi-deciduous forest areas of Ivory Coast to assess the impact of a decompacting (Hyperiodrilus africanus, Eudrilidae) and two compacting (Millsonia omodeoi and Dichogaster terraenigrae, Acanthodrilidae) earthworm species on soil properties. These species have been selected for their predominance in the region and their contrasting impact on soil structure. The experimental design consisted of a treatment without worms (control), and treatments with one, two or three species of earthworms. Both compacting and decompacting earthworms increased water infiltration rate in all treatments, with marked impact in H. africanus and M. omodeoi+D. terraenigrae treatments. Interactions between compacting and decompacting species resulted in more large aggregates in comparison to when the compacting species D. terraenigrae was alone. This may be accounted for by their compacting attribute as compacting earthworms are responsible for producing the highest number of large aggregates. The low values of mean weight diameter in treatments combining decompacting and compacting earthworms compared with compacting “M. omodeoi” one also confirmed the trend of decline in soil compaction in the presence of the decompacting species. These results showed positive impact of species richness on soil structure regulation, which is crucial in ecosystem productivity and support consequently the insurance hypothesis. In fact, this study showed that the preservation of earthworm species belonging to these two contrasting functional groups is essential for the maintenance of stable soil structure regulation in agro-tropical ecosystems.

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