scholarly journals Recovery of small-scale infiltration and erosion after wildfires

2018 ◽  
Vol 66 (3) ◽  
pp. 261-270 ◽  
Author(s):  
Sierra S. Larson-Nash ◽  
Peter R. Robichaud ◽  
Fredrick B. Pierson ◽  
Corey A. Moffet ◽  
C. Jason Williams ◽  
...  
Keyword(s):  
Soil Surface ◽  
Water Repellency ◽  
Rainfall Simulation ◽  
Small Scale ◽  
Soil Water Repellency ◽  
P Values ◽  
Sediment Yields ◽  
Erosion Models ◽  
And Control ◽  
The Impact

Abstract Wildfires naturally occur worldwide, however the potential disruption to ecosystem services from subsequent post-fire flooding and erosion often necessitates a response from land managers. The impact of high severity wildfire on infiltration and interrill erosion responses was evaluated for five years after the 2003 Hot Creek Fire in Idaho, USA. Relative infiltration from mini-disk tension infiltrometers (MDI) was compared to rainfall simulation measurements on small burned and control plots. Vegetation recovery was slow due to the severity of the fire, with median cover of 6-8% on burned sites after 5 years. Consequently, interrill sediment yields remained significantly higher on the burned sites (329-1200 g m-2) compared to the unburned sites (3-35 g m-2) in year 5. Total infiltration on the burned plots increased during the study period, yet were persistently lower compared to the control plots. Relative infiltration measurements made at the soil surface, and 1- and 3-cm depths were significantly correlated to non-steady state total infiltration values taken in the first 10 minutes of the hour-long rainfall simulations. Significant correlations were found at the 1-cm (ρ = 0.4-0.6) and 3-cm (ρ = 0.3-0.6) depths (most p-values <0.001), and somewhat weaker correlations at the soil surface (ρ = 0.2-0.4) (p-values <0.05 and up). Soil water repellency is often stronger below the soil surface after severe wildfire, and likely contributes to the reduced infiltration. These results suggest that relative infiltration measurements at shallow depths may be useful to estimate potential infiltration during a short-duration high-intensity storm and could be used as an input for post-fire erosion models.

The role of soil water repellency in overland flow generation in pine and eucalypt forest stands in coastal Portugal

Soil Research ◽  
2005 ◽  
Vol 43 (3) ◽  
pp. 337 ◽  
Author(s):  
J. J. Keizer ◽  
C. O. A. Coelho ◽  
R. A. Shakesby ◽  
C. S. P. Domingues ◽  
M. C. Malvar ◽  
...  
Keyword(s):  
Soil Water ◽  
Overland Flow ◽  
Slope Angle ◽  
Soil Surface ◽  
Water Repellency ◽  
Rainfall Simulation ◽  
Soil Water Repellency ◽  
Infiltration Capacity ◽  
Eucalypt Forest ◽  
Flow Generation

Soil water repellency is now known to occur in diverse soils in various parts of the world. One of the possible adverse effects of soil water repellency is that it can reduce infiltration capacity and hence, on sloping terrain, enhance overland flow and soil erosion. The main aim of the present work is to assess the effects of soil water repellency on surface runoff production in the inner coastal dune areas of central Portugal. This was done for a pine and a eucalypt forest stand and, within each stand, for 2 slopes with contrasting aspect and somewhat different slope angles. Overland flow was measured for 4 pairs of unbounded plots of about 5 m2 at fortnightly intervals from February to October 2001. Over the same period, soil water repellency at and immediately below the soil surface was measured next to the plots at monthly intervals. The runoff–repellency relationship was also studied by carrying out rainfall simulation experiments on 0.24-m2 plots and associated repellency measurements. The effect of soil water repellency was most clearly demonstrated by statistically significant higher runoff coefficients under strong-to-extremely than under none-to-slightly hydrophobic conditions immediately below the soil surface. Such a difference in runoff over the measurement period was, however, restricted to 2 unbounded plots, both of which were located on the eucalypt slope with a southerly aspect and the greater slope angle. At the scale of these plots, the increase in runoff coefficient due to soil water repellency is moderate, when integrated over the entire period of strong–extremely repellent conditions, but can be quite substantial for individual 2-weekly periods. With respect to the observed differences in runoff between plots, be it plots on the same slope or not, it has proved difficult to distinguish the effect of soil water repellency from that of other factors likely to affect overland flow generation.

scholarly journals Testing soil water repellency in a Sicilian area two years after a fire

2019 ◽  
Author(s):  
Vincenzo Bagarello ◽  
Giuseppe Basile ◽  
Gaetano Caltabellotta ◽  
Giuseppe Giordano ◽  
Massimo Iovino
Keyword(s):  
Soil Water ◽  
Water Drop ◽  
Soil Layer ◽  
Soil Surface ◽  
Water Repellency ◽  
Soil Conditions ◽  
Small Scale ◽  
Water Repellent ◽  
Soil Water Repellency ◽  
Mountain Area

The water drop penetration time (WDPT) technique was applied in 2018 to check persistence of soil water repellency (SWR) in a Sicilian mountain area affected by a wildfire on June 2016. A total of four sites, that were severely water repellent immediately after burning, were sampled. Depending on the site, wettable soil conditions, less SWR and maintenance of a noticeable SWR were detected two years later. At the site showing a near-constant SWR, WDPTs were particularly high in the top soil layer (0-0.03 m) and they appreciably decreased more in depth. Signs of decreasing SWR in drier soil conditions and in association with coarser soil particles were also detected at this site. High gradients of the WDPT can occur at very small vertical distances and a depth increment of approximately 0.01 m should be appropriate to capture small-scale vertical changes in SWR, especially close to the soil surface. Occurrence of SWR phenomena is easily perceivable and explainable if an inverse relationship between WDPTs and antecedent soil water content is obtained. A direct relationship between these two variables is more difficult to interpret because infiltration times that increase in wetter soil are expected according to the classical infiltration theory. A hypothesis that should be tested in the future is to verify if WDPTs that decrease in drier soil conditions signal less SWR as a consequence of a reduced biological activity of the soil. Finally, long-term monitoring projects on longevity of fire effects on SWR should be developed, even because an in depth knowledge of the involved processes is relevant for the civil protection system.

Intimacies of Exchange

2017 ◽  
Author(s):  
Kelly O'Neill
Keyword(s):  
Black Sea ◽  
Economic Geography ◽  
Small Scale ◽  
Key Sites ◽  
Economic Landscape ◽  
And Control ◽  
The Impact ◽  
Key Nodes

This chapter examines the flow of goods across and through Crimea in an attempt to understand the impact of Russian rule on the economic landscape. It focuses on the patterns of exchange and consumption, arguing for the significance of small-scale transactions for understanding the economic geography of the region. While Russian officials were eager to facilitate and control Black Sea trade, farmers and gardeners and craftsmen began participating in the system of overland markets and fairs that connected the southern provinces to merchants and consumers everywhere from Kharkov and Moscow to Nizhnii Novgorod and Kazan. The Crimean economy thus moved southward toward Constantinople and northward toward Moscow, yet the towns of the peninsula remained key nodes of consumption and production, the orchards and vineyards key sites of prosperity.

Sediment content and chemical properties of water runoff on biocrusts in drylands

Biologia ◽  
2014 ◽  
Vol 69 (11) ◽  
Author(s):  
Roberto Lázaro ◽  
Juan Mora
Keyword(s):  
Dry Matter ◽  
Chemical Properties ◽  
Soil Surface ◽  
Water Erosion ◽  
Rainfall Simulation ◽  
Water Runoff ◽  
Protective Capacity ◽  
Runoff Water ◽  
Wide Range ◽  
The Impact

AbstractIn drylands, water erosion can be a process with important economic and ecological implications, and is very dependent on the soil surface cover. There is broad agreement that biocrusts protect the soil from erosion in a wide range of circumstances. However, there is little information available on the effect of rain and biocrust types on this protective capacity and there is particularly very little knowledge on the erosive effects of runoff on biocrusts, which are expected to be larger in larger drainage areas, on the resistance of biocrusts to the combined effect of raindrops plus runoff flow and on the solute mobilisation by runoff in biocrusts. To answer these questions, we performed 96 rainfall-simulation in situ factorial experiments, including two biocrust types (cyanobacteria and lichens), three rain types (42, 63 and 77 mm h−1, always 20 min rain), four plot lengths (1, 2, 3 and 4 m long) and four replicates. In each experiment, runoff volume was measured and a runoff sample was taken to determine (i) the amount of dry matter in runoff, (ii) the amount of organic matter among the dry matter, (iii) the electrical conductivity, pH and alkalinity in runoff water. The main findings were: biocrusts strongly protected soil against water erosion, even under the most erosive conditions, and the protection increased with the successional development. Biocrusts were very resistant to the impact of raindrops and also to runoff flow, although an emergent hypothesis arose: under the most erosive conditions, a threshold of erodibility could be reached at the cyanobacterial biocrust. The lichen crust also protected the soil against the removal of soil soluble substances. The development of a biocrust could change the chemical composition of the solutes in runoff.

The impact of supportive supervision of infection prevention and control practices on Ebola outbreak in Liberia

2018 ◽  
Vol 19 (6) ◽  
pp. 287-293
Author(s):  
Ogbaini-Emovon Ephraim ◽  
Sneh Cyrus ◽  
Pajibo Myer ◽  
Abah Steve
Keyword(s):  
Prevention And Control ◽  
Infection Prevention ◽  
Virus Disease ◽  
Health Facilities ◽  
Infection Prevention And Control ◽  
Small Scale ◽  
Supportive Supervision ◽  
And Control ◽  
Isolation Facilities ◽  
The Impact

Background: Supportive supervision of infection prevention and control (IPC) practices was one of a range of interventions employed at the county level in the control of the world’s most deadly Ebola virus disease outbreak that affected Liberia during 2013–2016. Methods: Datasets generated from four consecutive assessment visits to 25 health facilities in Maryland County, in Liberia, were analysed. Information on IPC practices was obtained by interview, direct observation and completion of a standardised assessment tool. For each of the IPC fields assessed, a score < 50% was graded poor, 50–75% as fair, while > 75% was rated as good. Results: Before the intervention, the first assessment (baseline) indicated that the majority of the health facilities scored low in terms of isolation facilities, IPC administration, supply and equipment, personnel and staffing, triage and waste management. Following the application of supportive supervision and monitoring, all the facilities recorded moderate to good performance in all the fields during the fourth round of assessment, except for isolation facilities, which scored low. Conclusion: Supportive supervision and monitoring of healthcare facilities appeared to have contributed to the improvement in IPC standards and compliance during the Ebola outbreak as demonstrated in this small-scale study and should be sustained as a core component of IPC programs, particularly in prolonged outbreak situations.

Soil erosion controlled by biota along a climate gradient in Chile

2020 ◽  
Author(s):  
Nicolás Riveras ◽  
Kristina Witzgall ◽  
Victoria Rodríguez ◽  
Peter Kühn ◽  
Carsten W. Mueller ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Biological Soil Crust ◽  
Environmental Filtering ◽  
Soil Surface ◽  
Climatic Conditions ◽  
Rainfall Simulation ◽  
Soil Erodibility ◽  
Rainfall Gradient ◽  
The Impact ◽  
Semi Arid

&lt;p&gt;Soil erosion is one of the main problems in soil degradation nowadays and is widely distributed in many landscapes worldwide. Particularly water erosion is widespread and determined by rain erosivity, soil erodibility, topographic factors and the management carried out to mitigate this phenomenon. Although this process is mostly known as a consequence of human management such as agriculture or forestry, it is a process that also occurs naturally, being one of the factors that regulate the shape of the landscape.&lt;/p&gt;&lt;p&gt;One of the main agents that stabilize the soil surface is biota and its activity, either in the form of plants, microorganisms or as an assemblage in the form of a biological soil crust (biocrusts). However, there are limited studies about how and what extent biota drives soil-stabilizing processes. With particular view on the impact of biocrusts on soil erosion, most studies have been carried out in arid and semi-arid regions, so its influence under other climates is largely unknown.&lt;/p&gt;&lt;p&gt;This study focuses on the influence of biota on soil erosion in a temperature and rainfall gradient, covering four climate zones (arid, semi-arid, mediterranean and humid) with very limited human intervention. Other variables such as the origin of the geological formation, geographical longitude and glacial influence were kept constant for all study sites. The effect of vegetation (biocrusts) and its abundance, microbiology and terrain parameters are investigated using rainfall simulation experiments under controlled conditions and by a physico-chemical evaluation of the soil, surface runoff, percolation and sediment discharge, in order to determine the different environmental filtering effects that the soil develops under different climatic conditions.&lt;/p&gt;&lt;p&gt;It is expected that as vegetation vigor and cover increase, soil erodibility will decrease. The biocrust is the protagonist of this stabilization in conditions of low pedological development and will become secondary as edaphoclimatic conditions favor the colonization of plants.&lt;/p&gt;&lt;p&gt;The results of this study will help to achieve a better understanding of the role of biota in soil erosion control and will clarify its influence on soil losses under different climate and slope conditions. Analyses are currently ongoing and first results of our work will be presented at the EGU 2020.&lt;/p&gt;

A novel approach to quantify the impact of soil water repellency on run-off and solute loss

Geoderma ◽  
2014 ◽  
Vol 221-222 ◽  
pp. 121-130 ◽  
Author(s):  
Paramsothy Jeyakumar ◽  
Karin Müller ◽  
Markus Deurer ◽  
Carlo van den Dijssel ◽  
Karen Mason ◽  
...  
Keyword(s):  
Soil Water ◽  
Water Repellency ◽  
Soil Water Repellency ◽  
Novel Approach ◽  
Run Off ◽  
The Impact

Natural terrace formation through vegetative barriers on hillside farms in Honduras

1998 ◽  
Vol 13 (2) ◽  
pp. 79-82 ◽  
Author(s):  
Robert J. Walle ◽  
Brian G. Sims
Keyword(s):  
Soil Erosion ◽  
Crop Yields ◽  
Fertility Restoration ◽  
Soil Surface ◽  
Small Scale ◽  
South Central ◽  
The Difference ◽  
Small Scale Farmers ◽  
And Control ◽  
Soil Accumulation

AbstractThe effects of contour live barriers of vetiver and pennisetum on soil erosion were studied on four small farms in south central Honduras. Paired plots were installed and soil erosion measured by changes in the soil surface level of transects 0.3 and 6.0 m up the slope from the barrier. After three years, transects 0.3 m above the barriers significantly retained eroded soil compared with control transects. Soil accumulation by barriers ranged from 2.6 to 11.2 cm, and natural terrace formation (the difference between the barrier and corresponding control transect) ranged from 5.2 to 13.8 cm. No difference was detected between barrier and control for the transects 6.0 m above the barrier. Deposition in front of the barriers and reduction in surface rilling were apparent to farmers. Erosion from up slope on the barrier plots and from both transects in the control sections was not obvious. Direct measurement and farmer observation of sediment deposition by live barriers will help evaluate farmer-identified species for future use. The deposition helps farmers become aware of sheet erosion before the effects of soil degradation on crop yields become grossly apparent and soil fertility restoration becomes too costly for small-scale farmers.

scholarly journals Effects of a Canary pine forest wildfire (Tenerife, Canary Islands, summer 2007) on selected soil properties and their relationship with short- to medium-term soil water repellency .

2014 ◽  
Vol 2 ◽  
Author(s):  
Alexis Hernández ◽  
Natalia Rodríguez ◽  
Marcelino del Arco ◽  
Carmen Dolores Arbelo ◽  
Jesús Notario del Pino ◽  
...  
Keyword(s):  
Soil Properties ◽  
Soil Water ◽  
Forest Fires ◽  
Sampling Site ◽  
Aggregate Stability ◽  
Water Repellency ◽  
Pine Forest ◽  
Soil Water Repellency ◽  
Soil Hydrophobicity ◽  
The Impact

Forest fires modify the soil environment, often triggering severe soil degradation. In this paper, we studied the impact of a large northern Tenerife Canariy pine forest wildfire on a set of relevant soil properties, focusing on their evolution in time and relationship with soil water repellency. To do this, soils were sampled at four sites (burned and non-burned) and several soil physical and chemical parameters were measured. The results show significant variations for soil pH, electric conductivity (CE<sub>1:5</sub>), and NH<sub>4</sub><sup>+</sup>-N between burned and non-burned samples, whereas non-significant increases were found in burned soils for oxidizable carbon (C<sub>ox</sub>), total nitrogen (N<sub>tot</sub>) , Ca<sup>2+</sup>, Mg<sup>2+</sup>, Na<sup>+</sup> and K<sup>+</sup>, and soil hydrophobicity. The differences caused by the fire were no longer evident one year later. Furthermore, in one sampling site (Vitric Leptosols under low pine forest with a mixed heath/beech tree understory) a wide variation in the content of C<sub>ox</sub> and N<sub>tot</sub> and high water repellency was observed relative to the other sites. These differences can be attributed to the composition of the understory vegetation. Significant correlations between soil hydrophobicity with CE<sub>1:5</sub>, aggregate stability and the contents of C<sub>ox</sub>, N<sub>tot</sub>, NH<sub>4</sub><sup>+</sup>-N, Ca<sup>2+</sup>, Mg<sup>2+</sup>, Na<sup>+</sup> and K<sup>+</sup> were found.

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