Magazine et Edition

Volume 70 (2022): Edition 3 (September 2022)

Volume 70 (2022): Edition 2 (June 2022)

Volume 70 (2022): Edition 1 (March 2022)

Volume 69 (2021): Edition 4 (December 2021)

Volume 69 (2021): Edition 3 (September 2021)

Volume 69 (2021): Edition 2 (June 2021)

Volume 69 (2021): Edition 1 (March 2021)

Volume 68 (2020): Edition 4 (December 2020)

Volume 68 (2020): Edition 3 (September 2020)

Volume 68 (2020): Edition 2 (June 2020)

Volume 68 (2020): Edition 1 (March 2020)

Volume 67 (2019): Edition 4 (December 2019)

Volume 67 (2019): Edition 3 (September 2019)

Volume 67 (2019): Edition 2 (June 2019)

Volume 67 (2019): Edition 1 (March 2019)

Volume 66 (2018): Edition 4 (December 2018)

Volume 66 (2018): Edition 3 (September 2018)

Volume 66 (2018): Edition 2 (June 2018)

Volume 66 (2018): Edition 1 (March 2018)

Volume 65 (2017): Edition 4 (December 2017)

Volume 65 (2017): Edition 3 (September 2017)

Volume 65 (2017): Edition 2 (June 2017)

Volume 65 (2017): Edition 1 (March 2017)

Volume 64 (2016): Edition 4 (December 2016)

Volume 64 (2016): Edition 3 (September 2016)

Volume 64 (2016): Edition 2 (June 2016)

Volume 64 (2016): Edition 1 (March 2016)

Volume 63 (2015): Edition 4 (December 2015)

Volume 63 (2015): Edition 3 (September 2015)

Volume 63 (2015): Edition 2 (June 2015)

Volume 63 (2015): Edition 1 (March 2015)

Volume 62 (2014): Edition 4 (December 2014)

Volume 62 (2014): Edition 3 (September 2014)

Volume 62 (2014): Edition 2 (June 2014)

Volume 62 (2014): Edition 1 (March 2014)

Volume 61 (2013): Edition 4 (December 2013)

Volume 61 (2013): Edition 3 (September 2013)

Volume 61 (2013): Edition 2 (June 2013)

Volume 61 (2013): Edition 1 (March 2013)

Volume 60 (2012): Edition 4 (December 2012)

Volume 60 (2012): Edition 3 (September 2012)

Volume 60 (2012): Edition 2 (June 2012)

Volume 60 (2012): Edition 1 (March 2012)

Volume 59 (2011): Edition 4 (December 2011)

Volume 59 (2011): Edition 3 (September 2011)

Volume 59 (2011): Edition 2 (June 2011)

Volume 59 (2011): Edition 1 (March 2011)

Volume 58 (2010): Edition 4 (December 2010)

Volume 58 (2010): Edition 3 (September 2010)

Volume 58 (2010): Edition 2 (June 2010)

Volume 58 (2010): Edition 1 (March 2010)

Volume 57 (2009): Edition 4 (December 2009)

Volume 57 (2009): Edition 3 (September 2009)

Volume 57 (2009): Edition 2 (June 2009)

Volume 57 (2009): Edition 1 (March 2009)

Détails du magazine
Format
Magazine
eISSN
1338-4333
Première publication
28 Mar 2009
Période de publication
4 fois par an
Langues
Anglais

Chercher

Volume 68 (2020): Edition 4 (December 2020)

Détails du magazine
Format
Magazine
eISSN
1338-4333
Première publication
28 Mar 2009
Période de publication
4 fois par an
Langues
Anglais

Chercher

11 Articles
access type Accès libre

Preface to the special issue on biohydrology dedicated to the memory of Dr. Louis W. Dekker

Publié en ligne: 20 Oct 2020
Pages: 303 - 305

Résumé

access type Accès libre

Communication of soil water repellency causes, problems, and solutions of intensively managed amenity turf from 2000 to 2020

Publié en ligne: 20 Oct 2020
Pages: 306 - 312

Résumé

Abstract

Research and investigations of soil water repellency in turfgrass science is a relatively recent endeavor, with most notable progress beginning in the late 1990s and early 2000s and continuing into the present. The objectives of this review were to determine the extent of publications from 2000 to the present on the topic of soil water repellency in turfgrass science, and to assemble a list of soil surfactant product formulations currently available for the amenity turf industry in the USA and United Kingdom/Republic of Ireland in 2019. From 1 January 2000 through 1 June 2020, cumulative number of referred or peer-reviewed research journal articles was 64, the number of abstracts, reports, and proceedings was 87, and the number of professional and trade journal articles was 86. Published works in all categories represented a linear increase over time, and is indicative of increased research activity into this critical area of study. Soil surfactant products and formulations in the USA totaled 192, with 65 in UK/Ireland. The nonionic soil surfactant chemical category is the largest, representing 74% of products in the USA, and 66% of products in UK/Ireland. With formulation category, block copolymers and formulations that contain block copolymers or structurally modified block copolymers as a formulation component comprise the largest group with 58% of products in the USA, and 49% of products in UK/Ireland. Also by formulation category, 25% of USA products and 23% of UK/Ireland products are comprised of anionic and anionic blends and other formulations. Of note, 17% of products in the USA and 28% of products in UK/Ireland do not disclose their formulation.

Dr. Louis Dekker’s pioneering insight and advances in soil water repellency has provided turfgrass scientists with a firm foundation and guidance with which to pursue research into the causes, problems, and amelioration of soil water repellency in turfgrass ecosystems. The global amenity turf industry remains the segment where Dr. Dekker’s research has had the most influence and impact to both scientists and turf practitioners.

Mots clés

  • Soil hydrophobicity
  • Soil surfactants
  • Turfgrass science
  • Golf courses
  • Sports pitches
  • Localized dry patch
  • Rootzone
access type Accès libre

Connecting hillslope and runoff generation processes in the Ethiopian Highlands: The Ene-Chilala watershed

Publié en ligne: 20 Oct 2020
Pages: 313 - 327

Résumé

Abstract

Effective watershed planning requires an understanding of the hydrology. In the humid tropical monsoon climates and especially in volcanic highland regions such as the Ethiopian Highlands, the understanding of watershed processes is incomplete. The objective is to better understand the hydrology of the volcanic regions in the humid highlands by linking the hillslope processes with the discharge at the outlet. The Ene-Chilala watershed was selected for this study. The infiltration rate, piezometric water levels and discharge from two nested sub watersheds and at the watershed outlet were measured during a four-year period. Infiltration rates on the hillsides exceeded the rainfall intensity most of the time. The excess rain recharged a perched hillside aquifer. Water flowed through the perched aquifer as interflow to rivers and outlet. In addition, saturation excess overland flow was generated in the valley bottoms. Perched water tables heights were predicted by summing up the recharge over the travel time from the watershed divide. Travel times ranged from a few days for piezometers close to the divide to 40 days near the outlet. River discharge was simulated by adding the interflow from the upland to overland flow from the saturated valley bottom lands. Overland flow accounted only for one-fourth of the total flow. There was good agreement between predicted and observed discharge during the rain phase therefore the hillslope hydrologically processes were successfully linked with the discharge at the outlet.

Mots clés

  • Hillslope hydrology
  • Saturation
  • Rainfall intensity
  • Perched groundwater
  • Ethiopian Highlands
access type Accès libre

Land management impacts on soil properties and initial soil erosion processes in olives and vegetable crops

Publié en ligne: 20 Oct 2020
Pages: 328 - 337

Résumé

Abstract

This research aims to assess the impacts of soil use management on runoff, soil losses, and their main soil controls in vegetable cropland (CROP), tilled olives (OT), and grass-covered olive orchards (OGC) on Leptosol in Croatia. Soil analysis and rainfall simulation experiments were conducted to quantify runoff (Run), soil, and nutrient losses. Bulk density (BD) was significantly higher at OT plots, in addition to the CROP plots. Water-stable aggregates (WSA), mean weight diameter (MWD), and soil organic matter (OM) were significantly higher in OGC plots compared to the other land uses. Run and soil loss (SL) were significantly higher in CROP and OT plots compared to the OGC plots. The CROP plots showed soil management that can be considered as unsustainable with 52, 68- and 146-times higher losses of phosphorus (P loss), nitrogen (N loss), and carbon (C loss) compared to the OGC plots. The principal component analysis showed that MWD was associated with vegetation cover (VC), water-holding capacity (WHC), WSA, OM, total nitrogen (TN), time to ponding (TP), and time to runoff (TR). These variables were negatively related to P2O5, Run, SL, and P, N, and C loss. Results indicate the need for the adoption of conservation strategies in croplands and olive orchards.

Mots clés

  • Soil erosion
  • Tillage
  • Rainfall simulation
  • Agriculture land management
  • Mediterranean
access type Accès libre

On the transpiration of wild olives under water-limited conditions in a heterogeneous ecosystem with shallow soil over fractured rock

Publié en ligne: 20 Oct 2020
Pages: 338 - 350

Résumé

Abstract

Mediterranean ecosystems are typically heterogeneous and savanna-like, with trees and grass competing for water use. By measuring sap flow, we estimated high transpiration of wild olive, a common Mediterranean tree, in Sardinia despite dry conditions. This estimate agrees with independent estimates of tree transpiration based on energy balance, highlighting the wild olive’s strong tolerance of dry conditions. The wild olive can develop an adaptation strategy to tolerate dry conditions. In this Sardinian case study, the wild olive grew in shallow soil, and the tree roots expanded into the underlying fractured basalt. The trees survived in dry periods using water infiltrated during wet seasons into fractured rocks and held in soil pockets. We estimated a high upward vertical flux through the bottom soil layer from the underlying substrate, which reached 97% evapotranspiration in August 2011. The water taken up by tree roots from bedrock hollows is usually neglected in ecohydrological modeling.

Mots clés

  • Evapotranspiration
  • Rock moisture
  • Water uptake
  • Sap flow
  • Energy balance
access type Accès libre

An empirical model for describing the influence of water content and concentration of sulfamethoxazole (antibiotic) in soil on the total net CO2 efflux

Publié en ligne: 20 Oct 2020
Pages: 351 - 358

Résumé

Abstract

The aim of the study was to describe the impact of the soil water content and sulfamethoxazole, SUL, (antibiotic) concentration in soil on the net CO2 efflux. Soil samples were taken from topsoils of a Haplic Fluvisol and Haplic Chernozem. Soil samples were packed into the steel cylinders. The net CO2 efflux was measured from these soil columns after application of fresh water or SUL solution at different soil water contents. The experiments were carried out in dark at 20°C. The trends in the net CO2 efflux varied for different treatments. While initially high values for water treatment exponentially decreased in time, values for solution treatment increased during the first 250–650 minutes and then decreased. The total net CO2 effluxes measured for 20 hours related to the soil water content followed the second order polynomial functions. The maximal values were measured for the soil water content of 0.15 cm3 cm−3 (Haplic Fluvisol with water or solution, Haplic Chernozem with solution) and 0.11 cm3 cm−3 (Haplic Chernozem with water). The ratios between values measured for solution and water at the same soil water contents exponentially increased with increasing SUL concentration in soils. This proved the increasing stimulative influence of SUL on soil microbial activity.

Mots clés

  • Repacked soil columns
  • Antibiotics
  • Soil respiration
  • CO emission
  • Birch effect
  • CO efflux stimulation
access type Accès libre

Atmospheric humidity is unlikely to serve as an important water source for crustose soil lichens in the Tabernas Desert

Publié en ligne: 20 Oct 2020
Pages: 359 - 367

Résumé

Abstract

Dew is commonly regarded as an important water source for lichens. This is also the case for crustose lichens that are attached to the substrate, whether rocks or soil. While being verified during ample research on rock-dwelling lichens in the Negev, the findings from soil-dwelling lichens (lichen biocrusts) are not conclusive. In the Tabernas Desert, the soil surface is characterized by a lush cover of crustose lichens. These soil biocrusts (biological soil crusts) were reported to use dew for photosynthesis while, at the same time, it was also observed that these crustose chlorolichens are relatively non-wettable. In an attempt to explore the apparent controversy, two year-long meteorological data (minimum air temperature and relative humidity, RH), during which chlorolichens were thought to utilize dew for photosynthesis (2006–2007) were analyzed. The analysis includes a comparison to the meteorological conditions that prevailed in the Negev during 135 days of manual dew measurements. As found for the Negev, net photosynthesis by the chlorolichens is expected once the RH, as measured at the meteorological station, is ≥90% while vapor condensation (dew) is expected once RH is ≥95%. RH in the Negev was substantially higher than the average RH of 75.0–87.2% registered during the rainless days of 2006–2007 in the Tabernas, implying that RH in the Tabernas is too low to facilitate frequent dew formation and net photosynthesis by the lichens. Photosynthesis in the Tabernas is mainly confined to rainy periods, taking place either due to direct wetting by rain, or following vapor condensation from the subsurface (distillation). Our findings do not support the view that dew is an important water source for the establishment and growth of crustose soil lichens in the Tabernas. Moreover, the low RH in the Tabernas may also imply that dew may only have a very limited role in providing water to lithobionts in this ecosystem.

Mots clés

  • Biocrust
  • Cyanobacteria
  • Distillation
  • Lithobionts
  • Respiration
  • Negev Desert
access type Accès libre

Interspecific variation in growth and tree water status of conifers under water-limited conditions

Publié en ligne: 20 Oct 2020
Pages: 368 - 381

Résumé

Abstract

We monitored seasonal dynamics of stem water status of four coniferous species (Abies alba, Larix decidua, Picea abies and Pinus sylvestris) planted at the Borová hora Arboretum (300 m a.s.l., Zvolen valley, Central Slovakia) beyond their ecological and production optima, in the region with warmer and drier climate compared to the sites of their origin. Species-specific stem water deficit and maximum daily shrinkage were extracted from diurnal band dendrometer records of stem circumference recorded by digital band dendrometers DRL26 installed on five trees per species, and correlations with environmental variables were analysed. The seasonal stem circumference increment of all tree species was higher in 2017 than in the drier and hotter year of 2018. The greatest seasonal stem circumference increment in the observed periods of 2017 and 2018 was observed for A. alba and P. sylvestris, respectively. The highest and lowest values of daily and seasonal stem water deficit were observed for L. decidua and A. alba, respectively. The analysis of trees' short-term response to extreme climate events seems to be the promising and suitable method for detecting tree species tolerance towards drought.

Mots clés

  • Dendrometer
  • Circumference changes
  • Stem water deficit
  • Drought
  • Stem shrinkage
  • Wavelet analysis
access type Accès libre

Water repellency in eucalyptus and pine plantation forest soils and its relation to groundwater levels estimated with multi-temporal modeling

Publié en ligne: 20 Oct 2020
Pages: 382 - 391

Résumé

Abstract

Water repellency makes soils capable of resisting to the penetration of water applied on the surface and inflict various influences on groundwater. The objectives of the present study were to identify the water repellency under pine and eucalyptus plantations, to determine social impacts of water level changes, to find possible changes in groundwater levels in the surrounding areas during the past four decades, and to relate water repellent characteristics of soils with the groundwater level changes. The study was conducted in eucalyptus (Eucalyptus grandis) and pine (Pinus caribaea) plantation forests located in Upcountry intermediate zone, Sri Lanka. Each land was separated into three blocks (B1, B2, B3) based on the slope. Water repellency was measured with water drop penetration time (WDPT) and contact angle. The water entry value was estimated with the pressure head method. Interconnected social impacts was examined using a questionnaire based survey. Groundwater levels from 1980 to present were modeled with remotely sensed information. Both eucalyptus and pine forest soils showed water repellency, which decreased with increasing soil depth. Eucalyptus soils showed highly hydrophobic conditions on the surface (WDPT>7200 s). Ponding depths required for entry of water into the soil in eucalyptus soils was 4.6–5.3 cm, whereas that of pine soils was 1.5–4.0 cm, although achieving these levels would be difficult considering the steep slopes. Contact angle showed positive logarithmic correlation with water entry value. The people living in the surrounding areas expressed less water availability for their domestic purposes, decreased water level in household wells, and drying up of natural water resources at present compared with 1980s. Modelling with remotely sensed thematic maps confirmed that the groundwater levels in both areas has decreased over the time. It indicated that the eucalyptus and pine vegetation have created unfavorable conditions in regard with water entry and groundwater recharge. Proper attention from the responsible authorities will be essential to prevent the adverse impacts of on groundwater resources.

Mots clés

  • Groundwater modeling
  • Water repellency
  • Water entry value
access type Accès libre

Development of a universal microinfiltrometer to estimate extent and persistence of soil water repellency as a function of capillary pressure and interface chemical composition

Publié en ligne: 20 Oct 2020
Pages: 392 - 403

Résumé

Abstract

Microinfiltrometers to assess soil water repellency (SWR) are limited to small tension ranges and have different technical setups, hindering a comparison between results from different laboratories. Hence, a microinfiltrometer which considers various aspects like extent and persistence of SWR is needed. The technical update suggested here uses glass tubes (e.g., 3 mm inner diameter), a fabric of mesh size 15 µm around the tip to enable good contact between soil surface and tip, ultrapure degassed water, and an evaporation protection for tip and reservoir during long-term infiltration. The adjustment of a continuous range of pressures and tensions (i.e., +0.5 to –40 cm) was done using glass tubes of various lengths connected to the tip. Three soil samples with initial contact angles, CA, of 18°, 62°, and 91° after 25°C treatment were additionally treated at 80°C to increase SWR persistence and CA. The soil particle interface chemical composition was determined by X-ray photoelectron spectroscopy (XPS). The hydrophysical properties evaluated included water and ethanol sorptivity as well as very important aspects of SWR, i.e. water drop penetration time, water repellency cessation time, repellency index, and modified repellency index. The results derived from the technically modified microinfiltrometer setup showed consistent differences between initial wettability and the water repellency cessation time as a parameter describing the development of SWR with time. The interface O/C ratio as derived from XPS data was negatively correlated with CA (p <0.05), thus proving the close relationship between interface chemistry and wettability. Our findings illustrated a strong positive correlation (R2 = 0.99, p < 0.05) between sorptivity and O/C ratio under –2 cm tension which can be considered as the universal tension for different aspects of SWR.

Mots clés

  • Ethanol
  • Infiltration
  • Interface chemistry
  • Sorptivity
  • Thermal treatment
  • X-ray photoelectron spectroscopy
access type Accès libre

The effect of a prototype hydromulch on soil water evaporation under controlled laboratory conditions

Publié en ligne: 20 Oct 2020
Pages: 404 - 410

Résumé

Abstract

Organic hydromulches can be an interesting alternative for weed control in perennial crops, but can also reduce soil water evaporation. To examine the effect of a hydromulch layer on soil water content in dry conditions laboratory experiments were conducted at constant 25°C, 40% air RH. Both for small soil containers with a short time course and for larger soil columns (with two sensors at depths of 6 cm and 11 cm) with a longer time course, the presence and also the thickness of hydromulch were significant factors for the temporal evolution of soil water content. Two distinct stages of the evaporation process, the first or initial stage and the last or final stage, were identified, analysed and compared for these experiments. General linear models performed on the soil water content temporal evolutions showed significant differences for the first and last stages at the top and bottom of the soil columns with and without hydromulch. Hydromulch application delayed the evaporation process in comparison with the control. Moreover, the hydromulch layer, which was tested for mechanical resistance to punching, offered enough resistance to prevent its perforation by the sprouts of weed rhizomes.

Mots clés

  • Byproducts reuse
  • Punching resistance
  • Sandy loam soil
  • Water conservation
  • Weeds
11 Articles
access type Accès libre

Preface to the special issue on biohydrology dedicated to the memory of Dr. Louis W. Dekker

Publié en ligne: 20 Oct 2020
Pages: 303 - 305

Résumé

access type Accès libre

Communication of soil water repellency causes, problems, and solutions of intensively managed amenity turf from 2000 to 2020

Publié en ligne: 20 Oct 2020
Pages: 306 - 312

Résumé

Abstract

Research and investigations of soil water repellency in turfgrass science is a relatively recent endeavor, with most notable progress beginning in the late 1990s and early 2000s and continuing into the present. The objectives of this review were to determine the extent of publications from 2000 to the present on the topic of soil water repellency in turfgrass science, and to assemble a list of soil surfactant product formulations currently available for the amenity turf industry in the USA and United Kingdom/Republic of Ireland in 2019. From 1 January 2000 through 1 June 2020, cumulative number of referred or peer-reviewed research journal articles was 64, the number of abstracts, reports, and proceedings was 87, and the number of professional and trade journal articles was 86. Published works in all categories represented a linear increase over time, and is indicative of increased research activity into this critical area of study. Soil surfactant products and formulations in the USA totaled 192, with 65 in UK/Ireland. The nonionic soil surfactant chemical category is the largest, representing 74% of products in the USA, and 66% of products in UK/Ireland. With formulation category, block copolymers and formulations that contain block copolymers or structurally modified block copolymers as a formulation component comprise the largest group with 58% of products in the USA, and 49% of products in UK/Ireland. Also by formulation category, 25% of USA products and 23% of UK/Ireland products are comprised of anionic and anionic blends and other formulations. Of note, 17% of products in the USA and 28% of products in UK/Ireland do not disclose their formulation.

Dr. Louis Dekker’s pioneering insight and advances in soil water repellency has provided turfgrass scientists with a firm foundation and guidance with which to pursue research into the causes, problems, and amelioration of soil water repellency in turfgrass ecosystems. The global amenity turf industry remains the segment where Dr. Dekker’s research has had the most influence and impact to both scientists and turf practitioners.

Mots clés

  • Soil hydrophobicity
  • Soil surfactants
  • Turfgrass science
  • Golf courses
  • Sports pitches
  • Localized dry patch
  • Rootzone
access type Accès libre

Connecting hillslope and runoff generation processes in the Ethiopian Highlands: The Ene-Chilala watershed

Publié en ligne: 20 Oct 2020
Pages: 313 - 327

Résumé

Abstract

Effective watershed planning requires an understanding of the hydrology. In the humid tropical monsoon climates and especially in volcanic highland regions such as the Ethiopian Highlands, the understanding of watershed processes is incomplete. The objective is to better understand the hydrology of the volcanic regions in the humid highlands by linking the hillslope processes with the discharge at the outlet. The Ene-Chilala watershed was selected for this study. The infiltration rate, piezometric water levels and discharge from two nested sub watersheds and at the watershed outlet were measured during a four-year period. Infiltration rates on the hillsides exceeded the rainfall intensity most of the time. The excess rain recharged a perched hillside aquifer. Water flowed through the perched aquifer as interflow to rivers and outlet. In addition, saturation excess overland flow was generated in the valley bottoms. Perched water tables heights were predicted by summing up the recharge over the travel time from the watershed divide. Travel times ranged from a few days for piezometers close to the divide to 40 days near the outlet. River discharge was simulated by adding the interflow from the upland to overland flow from the saturated valley bottom lands. Overland flow accounted only for one-fourth of the total flow. There was good agreement between predicted and observed discharge during the rain phase therefore the hillslope hydrologically processes were successfully linked with the discharge at the outlet.

Mots clés

  • Hillslope hydrology
  • Saturation
  • Rainfall intensity
  • Perched groundwater
  • Ethiopian Highlands
access type Accès libre

Land management impacts on soil properties and initial soil erosion processes in olives and vegetable crops

Publié en ligne: 20 Oct 2020
Pages: 328 - 337

Résumé

Abstract

This research aims to assess the impacts of soil use management on runoff, soil losses, and their main soil controls in vegetable cropland (CROP), tilled olives (OT), and grass-covered olive orchards (OGC) on Leptosol in Croatia. Soil analysis and rainfall simulation experiments were conducted to quantify runoff (Run), soil, and nutrient losses. Bulk density (BD) was significantly higher at OT plots, in addition to the CROP plots. Water-stable aggregates (WSA), mean weight diameter (MWD), and soil organic matter (OM) were significantly higher in OGC plots compared to the other land uses. Run and soil loss (SL) were significantly higher in CROP and OT plots compared to the OGC plots. The CROP plots showed soil management that can be considered as unsustainable with 52, 68- and 146-times higher losses of phosphorus (P loss), nitrogen (N loss), and carbon (C loss) compared to the OGC plots. The principal component analysis showed that MWD was associated with vegetation cover (VC), water-holding capacity (WHC), WSA, OM, total nitrogen (TN), time to ponding (TP), and time to runoff (TR). These variables were negatively related to P2O5, Run, SL, and P, N, and C loss. Results indicate the need for the adoption of conservation strategies in croplands and olive orchards.

Mots clés

  • Soil erosion
  • Tillage
  • Rainfall simulation
  • Agriculture land management
  • Mediterranean
access type Accès libre

On the transpiration of wild olives under water-limited conditions in a heterogeneous ecosystem with shallow soil over fractured rock

Publié en ligne: 20 Oct 2020
Pages: 338 - 350

Résumé

Abstract

Mediterranean ecosystems are typically heterogeneous and savanna-like, with trees and grass competing for water use. By measuring sap flow, we estimated high transpiration of wild olive, a common Mediterranean tree, in Sardinia despite dry conditions. This estimate agrees with independent estimates of tree transpiration based on energy balance, highlighting the wild olive’s strong tolerance of dry conditions. The wild olive can develop an adaptation strategy to tolerate dry conditions. In this Sardinian case study, the wild olive grew in shallow soil, and the tree roots expanded into the underlying fractured basalt. The trees survived in dry periods using water infiltrated during wet seasons into fractured rocks and held in soil pockets. We estimated a high upward vertical flux through the bottom soil layer from the underlying substrate, which reached 97% evapotranspiration in August 2011. The water taken up by tree roots from bedrock hollows is usually neglected in ecohydrological modeling.

Mots clés

  • Evapotranspiration
  • Rock moisture
  • Water uptake
  • Sap flow
  • Energy balance
access type Accès libre

An empirical model for describing the influence of water content and concentration of sulfamethoxazole (antibiotic) in soil on the total net CO2 efflux

Publié en ligne: 20 Oct 2020
Pages: 351 - 358

Résumé

Abstract

The aim of the study was to describe the impact of the soil water content and sulfamethoxazole, SUL, (antibiotic) concentration in soil on the net CO2 efflux. Soil samples were taken from topsoils of a Haplic Fluvisol and Haplic Chernozem. Soil samples were packed into the steel cylinders. The net CO2 efflux was measured from these soil columns after application of fresh water or SUL solution at different soil water contents. The experiments were carried out in dark at 20°C. The trends in the net CO2 efflux varied for different treatments. While initially high values for water treatment exponentially decreased in time, values for solution treatment increased during the first 250–650 minutes and then decreased. The total net CO2 effluxes measured for 20 hours related to the soil water content followed the second order polynomial functions. The maximal values were measured for the soil water content of 0.15 cm3 cm−3 (Haplic Fluvisol with water or solution, Haplic Chernozem with solution) and 0.11 cm3 cm−3 (Haplic Chernozem with water). The ratios between values measured for solution and water at the same soil water contents exponentially increased with increasing SUL concentration in soils. This proved the increasing stimulative influence of SUL on soil microbial activity.

Mots clés

  • Repacked soil columns
  • Antibiotics
  • Soil respiration
  • CO emission
  • Birch effect
  • CO efflux stimulation
access type Accès libre

Atmospheric humidity is unlikely to serve as an important water source for crustose soil lichens in the Tabernas Desert

Publié en ligne: 20 Oct 2020
Pages: 359 - 367

Résumé

Abstract

Dew is commonly regarded as an important water source for lichens. This is also the case for crustose lichens that are attached to the substrate, whether rocks or soil. While being verified during ample research on rock-dwelling lichens in the Negev, the findings from soil-dwelling lichens (lichen biocrusts) are not conclusive. In the Tabernas Desert, the soil surface is characterized by a lush cover of crustose lichens. These soil biocrusts (biological soil crusts) were reported to use dew for photosynthesis while, at the same time, it was also observed that these crustose chlorolichens are relatively non-wettable. In an attempt to explore the apparent controversy, two year-long meteorological data (minimum air temperature and relative humidity, RH), during which chlorolichens were thought to utilize dew for photosynthesis (2006–2007) were analyzed. The analysis includes a comparison to the meteorological conditions that prevailed in the Negev during 135 days of manual dew measurements. As found for the Negev, net photosynthesis by the chlorolichens is expected once the RH, as measured at the meteorological station, is ≥90% while vapor condensation (dew) is expected once RH is ≥95%. RH in the Negev was substantially higher than the average RH of 75.0–87.2% registered during the rainless days of 2006–2007 in the Tabernas, implying that RH in the Tabernas is too low to facilitate frequent dew formation and net photosynthesis by the lichens. Photosynthesis in the Tabernas is mainly confined to rainy periods, taking place either due to direct wetting by rain, or following vapor condensation from the subsurface (distillation). Our findings do not support the view that dew is an important water source for the establishment and growth of crustose soil lichens in the Tabernas. Moreover, the low RH in the Tabernas may also imply that dew may only have a very limited role in providing water to lithobionts in this ecosystem.

Mots clés

  • Biocrust
  • Cyanobacteria
  • Distillation
  • Lithobionts
  • Respiration
  • Negev Desert
access type Accès libre

Interspecific variation in growth and tree water status of conifers under water-limited conditions

Publié en ligne: 20 Oct 2020
Pages: 368 - 381

Résumé

Abstract

We monitored seasonal dynamics of stem water status of four coniferous species (Abies alba, Larix decidua, Picea abies and Pinus sylvestris) planted at the Borová hora Arboretum (300 m a.s.l., Zvolen valley, Central Slovakia) beyond their ecological and production optima, in the region with warmer and drier climate compared to the sites of their origin. Species-specific stem water deficit and maximum daily shrinkage were extracted from diurnal band dendrometer records of stem circumference recorded by digital band dendrometers DRL26 installed on five trees per species, and correlations with environmental variables were analysed. The seasonal stem circumference increment of all tree species was higher in 2017 than in the drier and hotter year of 2018. The greatest seasonal stem circumference increment in the observed periods of 2017 and 2018 was observed for A. alba and P. sylvestris, respectively. The highest and lowest values of daily and seasonal stem water deficit were observed for L. decidua and A. alba, respectively. The analysis of trees' short-term response to extreme climate events seems to be the promising and suitable method for detecting tree species tolerance towards drought.

Mots clés

  • Dendrometer
  • Circumference changes
  • Stem water deficit
  • Drought
  • Stem shrinkage
  • Wavelet analysis
access type Accès libre

Water repellency in eucalyptus and pine plantation forest soils and its relation to groundwater levels estimated with multi-temporal modeling

Publié en ligne: 20 Oct 2020
Pages: 382 - 391

Résumé

Abstract

Water repellency makes soils capable of resisting to the penetration of water applied on the surface and inflict various influences on groundwater. The objectives of the present study were to identify the water repellency under pine and eucalyptus plantations, to determine social impacts of water level changes, to find possible changes in groundwater levels in the surrounding areas during the past four decades, and to relate water repellent characteristics of soils with the groundwater level changes. The study was conducted in eucalyptus (Eucalyptus grandis) and pine (Pinus caribaea) plantation forests located in Upcountry intermediate zone, Sri Lanka. Each land was separated into three blocks (B1, B2, B3) based on the slope. Water repellency was measured with water drop penetration time (WDPT) and contact angle. The water entry value was estimated with the pressure head method. Interconnected social impacts was examined using a questionnaire based survey. Groundwater levels from 1980 to present were modeled with remotely sensed information. Both eucalyptus and pine forest soils showed water repellency, which decreased with increasing soil depth. Eucalyptus soils showed highly hydrophobic conditions on the surface (WDPT>7200 s). Ponding depths required for entry of water into the soil in eucalyptus soils was 4.6–5.3 cm, whereas that of pine soils was 1.5–4.0 cm, although achieving these levels would be difficult considering the steep slopes. Contact angle showed positive logarithmic correlation with water entry value. The people living in the surrounding areas expressed less water availability for their domestic purposes, decreased water level in household wells, and drying up of natural water resources at present compared with 1980s. Modelling with remotely sensed thematic maps confirmed that the groundwater levels in both areas has decreased over the time. It indicated that the eucalyptus and pine vegetation have created unfavorable conditions in regard with water entry and groundwater recharge. Proper attention from the responsible authorities will be essential to prevent the adverse impacts of on groundwater resources.

Mots clés

  • Groundwater modeling
  • Water repellency
  • Water entry value
access type Accès libre

Development of a universal microinfiltrometer to estimate extent and persistence of soil water repellency as a function of capillary pressure and interface chemical composition

Publié en ligne: 20 Oct 2020
Pages: 392 - 403

Résumé

Abstract

Microinfiltrometers to assess soil water repellency (SWR) are limited to small tension ranges and have different technical setups, hindering a comparison between results from different laboratories. Hence, a microinfiltrometer which considers various aspects like extent and persistence of SWR is needed. The technical update suggested here uses glass tubes (e.g., 3 mm inner diameter), a fabric of mesh size 15 µm around the tip to enable good contact between soil surface and tip, ultrapure degassed water, and an evaporation protection for tip and reservoir during long-term infiltration. The adjustment of a continuous range of pressures and tensions (i.e., +0.5 to –40 cm) was done using glass tubes of various lengths connected to the tip. Three soil samples with initial contact angles, CA, of 18°, 62°, and 91° after 25°C treatment were additionally treated at 80°C to increase SWR persistence and CA. The soil particle interface chemical composition was determined by X-ray photoelectron spectroscopy (XPS). The hydrophysical properties evaluated included water and ethanol sorptivity as well as very important aspects of SWR, i.e. water drop penetration time, water repellency cessation time, repellency index, and modified repellency index. The results derived from the technically modified microinfiltrometer setup showed consistent differences between initial wettability and the water repellency cessation time as a parameter describing the development of SWR with time. The interface O/C ratio as derived from XPS data was negatively correlated with CA (p <0.05), thus proving the close relationship between interface chemistry and wettability. Our findings illustrated a strong positive correlation (R2 = 0.99, p < 0.05) between sorptivity and O/C ratio under –2 cm tension which can be considered as the universal tension for different aspects of SWR.

Mots clés

  • Ethanol
  • Infiltration
  • Interface chemistry
  • Sorptivity
  • Thermal treatment
  • X-ray photoelectron spectroscopy
access type Accès libre

The effect of a prototype hydromulch on soil water evaporation under controlled laboratory conditions

Publié en ligne: 20 Oct 2020
Pages: 404 - 410

Résumé

Abstract

Organic hydromulches can be an interesting alternative for weed control in perennial crops, but can also reduce soil water evaporation. To examine the effect of a hydromulch layer on soil water content in dry conditions laboratory experiments were conducted at constant 25°C, 40% air RH. Both for small soil containers with a short time course and for larger soil columns (with two sensors at depths of 6 cm and 11 cm) with a longer time course, the presence and also the thickness of hydromulch were significant factors for the temporal evolution of soil water content. Two distinct stages of the evaporation process, the first or initial stage and the last or final stage, were identified, analysed and compared for these experiments. General linear models performed on the soil water content temporal evolutions showed significant differences for the first and last stages at the top and bottom of the soil columns with and without hydromulch. Hydromulch application delayed the evaporation process in comparison with the control. Moreover, the hydromulch layer, which was tested for mechanical resistance to punching, offered enough resistance to prevent its perforation by the sprouts of weed rhizomes.

Mots clés

  • Byproducts reuse
  • Punching resistance
  • Sandy loam soil
  • Water conservation
  • Weeds

Planifiez votre conférence à distance avec Sciendo