Induced uneven spatial distribution of agrochemicals due to preferential flow in water repellent soils and its remediation by surfactant

2020 ◽  
Author(s):  
Felix Abayomi Ogunmokun ◽  
Rony Wallach
Keyword(s):  
Spatial Distribution ◽  
Soil Water ◽  
Soil Profile ◽  
Preferential Flow ◽  
Sandy Soils ◽  
Water Repellency ◽  
Treated Wastewater ◽  
Water Repellent ◽  
Soil Water Repellency ◽  
Mediterranean Countries

<p>Soil water repellency is a common feature of dry soils under permanent vegetation and drought conditions. Soil-water hydrology is markedly affected by soil-water repellency as it hinders infiltration, leading to enhanced surface runoff and soil erosion. Although this phenomenon was primarily ascribed to sandy soils, it has been observed in loam, clay, and peat soils in dry and humid regions. One detrimental effect of soil water repellency on plants is the reduction of soil water availability that stems from the non-uniform water retention and flow in preferential pathways (gravity-induced fingers) with relatively dry soil volume among these paths. It was recently discovered that prolonged irrigation with treated wastewater, a widely used alternative in Israel and other Mediterranean countries due to the limited freshwater, triggers soil water repellency which invariably resulted in preferential flow development in the field. Due to climate change events, the use of treated wastewater for irrigation as a means of freshwater conservation is expected to widen, including in countries that are not considered dry.</p><p>While a vast amount of research has been devoted to characterizing the preferential flow in water repellent soils, the effect of this flow regime on the spatial distribution of salt and fertilizers in the root zone was barely investigated. Results from a commercial citrus orchard irrigated with treated wastewater that includes the spatial and temporal distribution of preferential flow in the soil profile measured by ERT will be demonstrated. The associated spatial distribution of salinity, nitrate, phosphate, and SAR in the soil profile will be shown as well.  We investigated the efficacy of two nonionic surfactants application to remediate hydrophobic sandy soils both in the laboratory and field. The effect of the surfactant application to the water repellent soils in the orchards on the spatial distribution of soil moisture and the associated agrochemicals will be presented and discussed.</p>

Remediation of intrinsic preferential flow pathways in water repellent soils' profile using surfactant

2021 ◽  
Author(s):  
Felix Abayomi Ogunmokun ◽  
Rony Wallach
Keyword(s):  
Spatial Distribution ◽  
Soil Water ◽  
Soil Profile ◽  
Preferential Flow ◽  
Treated Wastewater ◽  
Water Repellent ◽  
Continuous Increase ◽  
Flow Pathways ◽  
Preferential Flow Pathways ◽  
Chemical Distribution

<p>Preferential flow pathways and uneven soil water and chemical distribution are intrinsic phenomena in water repellent soils. These uneven water and chemical distribution reduce water uptake by the plant roots on one hand and enhance deep percolation and chemical leaching, on the other hand, thereby enhancing soil and groundwater pollution. The results of attempts to remediate soil water repellency and heterogeneous spatial distribution of soil moisture and chemicals within the root zone by surfactant application will be addressed.  </p><p>This study was conducted in a commercial citrus orchard in central Israel that is irrigated with treated wastewater. Previous studies have revealed that prolonged irrigation using treated wastewater renders the soil water repellent with its associated adverse effects. The soil water distribution within the soil profile was monitored by frequent electrical resistance tomography (ERT) scans. The spatial distribution of different chemicals within the soil profile was obtained by chemical analysis of disturbed soil samples taken manually along a line transects. Two methods of surfactant application were used and compared: 1) on soil surface spraying (area source), 2) via drippers application (point source).</p><p>Surfactant spraying onto the water repellent soil's surface succeeded in turning the soil wettable, diminishing the preferential flow pathways, and renders the soil water and dissolved chemicals uniformly distributed. In contrast, drip applied surfactant exacerbated the incidence of preferential flow pathways and the leaching of solutes from the soil. Moreover, the overall average water content in the 0-40 cm soil layer significantly increased with surfactant spraying than with drip application even though both were higher than the control plots. These results substantiate previous laboratory-scale studies in which surfactant was applied to water repellent soils packed in a transparent flow chamber by these two methods. Additionally, the yield from the on-surface surfactant sprayed plots show a slight continuous increase compared to the untreated plots.</p>

scholarly journals Spatially variable soil water repellency enhances soil respiration rates (CO<sub>2</sub> efflux)

2017 ◽  
Author(s):  
Emilia Urbanek ◽  
Stefan H. Doerr
Keyword(s):  
Soil Moisture ◽  
Soil Respiration ◽  
Soil Water ◽  
Water Distribution ◽  
Preferential Flow ◽  
Water Repellency ◽  
Water Repellent ◽  
Co2 Efflux ◽  
Soil Co2 ◽  
Soil Water Repellency

Abstract. Soil CO2 emissions are strongly dependent on water distribution in soil pores, which in turn can be affected by soil water repellency (SWR; hydrophobicity). SWR restricts infiltration and movement of water, affecting soil hydrology as well as biological and chemical processes. Effects of SWR on soil carbon dynamics and specifically on soil respiration (CO2 efflux) have been studied in a few laboratory experiments but they remain poorly understood. Existing studies suggest that soil respiration is reduced in water repellent soils, but the responses of soil CO2 efflux to varying water distribution created by SWR are not yet known. Here we report on the first field-based study that tests whether soil water repellency indeed reduces soil respiration, based on in situ field measurements carried out over three consecutive years at a grassland and pine forest site under the humid temperate climate of the UK. CO2 efflux was reduced on occasions when soil exhibited consistently high SWR and low soil moisture following long dry spells. However, the highest respiration rates occurred not when SWR was absent, but when SWR, and thus soil moisture, was spatially patchy, a pattern observed for the majority of the measurement period. This somewhat surprising phenomenon can be explained by SWR-induced preferential flow, directing water and nutrients to microorganisms decomposing organic matter concentrated in hot spots near preferential flow paths. Water repellent zones provide air-filled pathways through the soil, which facilitate soil-atmosphere O2 and CO2 exchanges. This study demonstrates that SWR have contrasting effects on CO2 fluxes and, when spatially-variable, can enhance CO2 efflux. Spatial variability in SWR and associated soil moisture distribution needs to be considered when evaluating the effects of SWR on soil carbon dynamics under current and predicted future climatic conditions.

Pines influence hydrophysical parameters and water flow in a sandy soil

Biologia ◽  
2013 ◽  
Vol 68 (6) ◽  
Author(s):  
Ľubomír Lichner ◽  
Jozef Capuliak ◽  
Natalia Zhukova ◽  
Ladislav Holko ◽  
Henryk Czachor ◽  
...  
Keyword(s):  
Hydraulic Conductivity ◽  
Forest Soil ◽  
Soil Water ◽  
Water Flow ◽  
Sandy Soil ◽  
Preferential Flow ◽  
Water Repellency ◽  
Water Repellent ◽  
Wetting Front ◽  
Soil Water Repellency

AbstractPines, used for sand dune stabilization, can influence the hydrophysical parameters and water flow in an aeolian sandy soil considerably, mainly due to soil water repellency. Two sites, separated by distance of about 20 m, formed the basis of our study. A control soil (“Pure sand“) with limited impact of vegetation or organic matter was formed at 50 cm depth beneath a forest glade area. This was compared to a “Forest soil” in a 30-year old Scots pine (Pinus sylvestris) forest. Most of the hydrophysical parameters were substantially different between the two soil surfaces. The forest soil was substantially more water repellent and had two-times the degree of preferential flow compared to pure sand. Water and ethanol sorptivities, hydraulic conductivity, and saturated hydraulic conductivity were 1%, 84%, 2% and 26% those of the pure sand, respectively. The change in soil hydrophysical parameters due to soil water repellency resulted in preferential flow in the forest soil, emerging during a simulated heavy rain following a long hot, dry period. The wetting front established in pure sand exhibited a form typical of that for stable flow. Such a shape of the wetting front can be expected in the forest soil in spring, when soil water repellency is alleviated substantially.

Exponential increase of publications related to soil water repellency

Soil Research ◽  
2005 ◽  
Vol 43 (3) ◽  
pp. 403 ◽  
Author(s):  
Louis W. Dekker ◽  
Klaas Oostindie ◽  
Coen J. Ritsema
Keyword(s):  
Soil Water ◽  
Preferential Flow ◽  
Flow Behavior ◽  
Water Repellency ◽  
Water Repellent ◽  
Soil Water Repellency ◽  
Exponential Increase ◽  
Preferential Flow Paths ◽  
The Usa ◽  
Number Of Publications

Soil water repellency is much more wide-spread than formerly thought. During the last decades, it has been a topic of study for soil scientists and hydrologists in at least 21 States of the USA, in Canada, Australia, New Zealand, Mexico, Colombia, Chile, Congo, Nepal, India, Hong Kong, Taiwan, China, Ecuador, Venezuela, Brazil, Mali, Japan, Israel, Turkey, Egypt, South Africa, Germany, The Netherlands, Spain, Portugal, United Kingdom, Denmark, Sweden, Finland, Poland, Slovakia, Russia, France, Italy, and Greece. Although, water repellent soils already have been indicated at the end of the nineteenth century, they have been discovered and studied in most countries in the last decades. Water repellency is most common in sandy soils with grass cover and in nature reserves, but has also been observed in loam, heavy clay, peat, and volcanic ash soils. From 1940 to 1970 research was focussed on identifying vegetation types responsible for inducing water repellency and on developing techniques to quantify the degree of water repellency. Of special interest has been the effects of wildfire on the development of soil water repellency and its consequences for soil erosion. Due to increasing concern over the threat to surface and groundwater posed by the use of agrichemicals and organic fertilisers, studies on water repellent soils have also been focused on its typical flow behavior with runoff and the existence of preferential flow paths. Since the end of the 1950s, wetting agents and clay amendments have been studied to ameliorate water repellent soils. Since 1883, more than 1200 articles related to soil water repellency have been published in journals, reports, and theses. An exponential increase in number of publications started in 1960, resulting in an average of 200 publications per 5 years.

Organic Matter Fractions Controlling Soil Water Repellency in Sandy Soils From the Doñana National Park (Southwestern Spain)

2014 ◽  
Vol 27 (5) ◽  
pp. 1413-1423 ◽  
Author(s):  
Nicasio T. Jiménez‐Morillo ◽  
José A. González‐Pérez ◽  
Antonio Jordán ◽  
Lorena M. Zavala ◽  
José María Rosa ◽  
...  
Keyword(s):  
Organic Matter ◽  
Soil Water ◽  
National Park ◽  
Sandy Soils ◽  
Water Repellency ◽  
Soil Water Repellency ◽  
Doñana National Park ◽  
Organic Matter Fractions

scholarly journals Variability of water repellency in sandy forest soils under broadleaves and conifers in north-western Jutland/Denmark

2008 ◽  
Vol 3 (Special Issue No. 1) ◽  
pp. S155-S164 ◽  
Author(s):  
N.A Wahl
Keyword(s):  
Soil Water ◽  
Preferential Flow ◽  
Water Drop ◽  
Water Repellency ◽  
Climatic Conditions ◽  
Tree Age ◽  
Critical Surface ◽  
Soil Water Repellency ◽  
Wide Range ◽  
North Western

Soil water repellency has important consequences for ecological and hydrological properties of soils and usually retards infiltration capacity and induces preferential flow. This phenomenon has been known to occur on a wide range of sites under a variety of climatic conditions. The objective of this study was to investigate and characterize soil water repellency on forest sites with identical substrate and climatic conditions, differing in tree age and species. In the Vester Torup Klitplantage, an area comprising a conifer dominated forest plantation stocking on sandy deposits in a coastal setting near the Jammer Bay in north-western Jutland/Denmark, four different forest plots were investigated for water repellency effects four times in 2005. To measure soil water repellency, the water drop penetration time test and the critical surface tension test were carried out. Both tests revealed a seasonal variability in water repellency, exhibiting the highest water repellency for the upper 10 cm of the soil during the summer months, whereas the variability between the different plots seems to be less significant. There was no coherence between humus forms, thickness of litter layer and water repellency.

scholarly journals Eucalyptus reforestation induces soil water repellency

Soil Research ◽  
2015 ◽  
Vol 53 (2) ◽  
pp. 168 ◽  
Author(s):  
L. L. Walden ◽  
R. J. Harper ◽  
D. S. Mendham ◽  
D. J. Henry ◽  
J. B. Fontaine
Keyword(s):  
Soil Properties ◽  
Soil Water ◽  
Water Movement ◽  
Computer Modelling ◽  
Clay Content ◽  
Water Repellency ◽  
Water Repellent ◽  
Organic Carbon Content ◽  
Soil Water Repellency ◽  
Hydrophobic Compounds

There is an increasing interest in eucalypt reforestation for a range of purposes in Australia, including pulp-wood production, carbon mitigation and catchment water management. The impacts of this reforestation on soil water repellency have not been examined despite eucalypts often being associated with water repellency and water repellency having impacts on water movement across and within soils. To investigate the role of eucalypt reforestation on water repellency, and interactions with soil properties, we examined 31 sites across the south-west of Western Australia with paired plots differing only in present land use (pasture v. plantation). The incidence and severity of water repellency increased in the 5–8 years following reforestation with Eucalyptus globulus. Despite this difference in water repellency, there were no differences in soil characteristics, including soil organic carbon content or composition, between pasture and plantation soils, suggesting induction by small amounts of hydrophobic compounds from the trees. The incidence of soil water repellency was generally greater on sandy-surfaced (<10% clay content) soils; however, for these soils 72% of the pasture sites and 31% of the plantation were not water repellent, and this was independent of measured soil properties. Computer modelling revealed marked differences in the layering and packing of waxes on kaolinite and quartz surfaces, indicating the importance of interfacial interactions in the development of soil water repellency. The implications of increased water repellency for the management of eucalyptus plantations are considered.

Influence of burning intensity on water repellency and hydrological processes at forest and shrub sites in Portugal

Soil Research ◽  
2005 ◽  
Vol 43 (3) ◽  
pp. 327 ◽  
Author(s):  
A. J. D. Ferreira ◽  
C. O. A. Coelho ◽  
A. K. Boulet ◽  
G. Leighton-Boyce ◽  
J. J. Keizer ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Overland Flow ◽  
Water Repellency ◽  
Distribution Patterns ◽  
Hydrological Processes ◽  
Water Repellent ◽  
Water Fluxes ◽  
Soil Water Repellency ◽  
Spatial Distribution Patterns ◽  
Water Repellence

In addition to the incineration of vegetation and litter layer, fires are also responsible for the formation of a water repellent layer with significantly different severity and spatial distribution patterns following different burning intensities. Those spatial distribution patterns have an enormous influence on soil wetting patterns, and on hydrological processes at different scales. This study attempts to understand the role of water repellence severity and spatial distribution patterns on soil, slope, and catchment water processes, and on the transmission of hydrological processes between different scales. The comparison between microplot (0.24 m2), plot (16 m2), and catchment (<1.2 km2) scales shows that water repellence spatial homogeneity enhances water fluxes transfer between the different scales. In fact, the more intense the fires, the more severe and spatially uniform the soil water repellency became. For burned areas with heterogeneous soil water repellency, overland flow produced in water repellent patches infiltrated downslope at hydrophilic sites, thereby reducing superficial water fluxes at wider scales. For the more severe and homogeneous water repellent areas following forest wildfires, overland flow was enhanced downslope, increasing fast superficial water fluxes at wider scales.

Heating effects on water repellency in Australian eucalypt forest soils and their value in estimating wildfire soil temperatures

2004 ◽  
Vol 13 (2) ◽  
pp. 157 ◽  
Author(s):  
Stefan H. Doerr ◽  
William H. Blake ◽  
Richard A. Shakesby ◽  
Frank Stagnitti ◽  
Saskia H. Vuurens ◽  
...  
Keyword(s):  
Soil Temperature ◽  
Soil Water ◽  
Water Repellency ◽  
Water Repellent ◽  
Laboratory Studies ◽  
Soil Water Repellency ◽  
Eucalypt Forest ◽  
Heating Effects ◽  
Soil Temperatures ◽  
Eucalypt Forests

Wildfires can induce or enhance soil water repellency under a range of vegetation communities. According to mainly USA-based laboratory studies, repellency is eliminated at a maximum soil temperature (T) of 280–400°C. Knowledge of T reached during a wildfire is important in evaluating post-fire soil physical properties, fertility and seedbed status. T is, however, notoriously difficult to ascertain retrospectively and often based on indicative observations with a large potential error. Soils under fire-prone Australian eucalypt forests tend to be water repellent when dry or moderately moist even if long unburnt. This study aims to quantify the temperature of water repellency destruction for Australian topsoil material sampled under three sites with contrasting eucalypt cover (Eucalyptus sieberi, E. ovata and E. baxteri). Soil water repellency was present prior to heating in all samples, increased during heating, but was abruptly eliminated at a specific T between 260 and 340°C. Elimination temperature varied somewhat between samples, but was found to be dependent on heating duration, with longest duration resulting in lowest elimination temperature. Results suggest that post-fire water repellency may be used as an aid in hindcasting soil temperature reached during the passage of a fire within repellency-prone environments.

Sign in / Sign up

Export Citation Format

Share Document