Time filter

Source Type

Fine P.,Institute of Soil, Water and Environmental Sciences | Hadas E.,Ministry of Agriculture Investment and Financing Authority
Science of the Total Environment | Year: 2012

Treatment of primarily-domestic sewage wastewater involves on-site greenhouse gas (GHG) emissions due to energy inputs, organic matter degradation and biological nutrient removal (BNR). BNR causes both direct emissions and loss of fertilizer value, thus eliminating possible reduction of emissions caused by fertilizer manufacture. In this study, we estimated on-site GHG emissions under different treatment scenarios, and present options for emission reduction by changing treatment methods, avoiding BNR and by recovering energy from biogas. Given a typical Israeli wastewater strength (1050mg CODl -1), the direct on-site GHG emissions due to energy use were estimated at 1618 and 2102g CO 2-eqm -3, respectively, at intermediate and tertiary treatment levels. A potential reduction of approximately 23-55% in GHG emissions could be achieved by fertilizer preservation and VS conversion to biogas. Wastewater fertilizers constituted a GHG abatement potential of 342g CO 2-eqm -3. The residual component that remained in the wastewater effluent following intermediate (oxidation ponds) and enhanced (mechanical-biological) treatments was 304-254g CO 2-eqm -3 and 65-34g CO 2-eqm -3, respectively. Raw sludge constituted approximately 47% of the overall wastewater fertilizers load with an abatement potential of 150g CO 2-eqm -3 (385kg CO 2-eq dry tonne -1). Inasmuch as anaerobic digestion reduced it to 63g CO 2-eqm -3 (261kg CO 2-eq dry tonne -1), the GHG abatement gained through renewable biogas energy (approx. 428g CO 2-eqm -3) favored digestion. However, sludge composting reduced the fertilizer value to 17g CO 2-eqm -3 (121kg CO 2-eq dry tonne -1) or less (if emissions, off-site inputs and actual phytoavailability were considered). Taking Israel as an example, fully exploiting the wastewater derived GHG abatement potential could reduce the State overall GHG emissions by almost 1%. This demonstrates the possibility of optional carbon credits which might be exploited in the construction of new wastewater treatment facilities, especially in developing countries. © 2011 Elsevier B.V.

Shoresh M.,Institute of Soil, Water and Environmental Sciences | Harman G.E.,Cornell University | Mastouri F.,Cornell University
Annual Review of Phytopathology | Year: 2010

Biocontrol fungi (BCF) are agents that control plant diseases. These include the well-known Trichoderma spp. and the recently described Sebacinales spp. They have the ability to control numerous foliar, root, and fruit pathogens and even invertebrates such as nematodes. However, this is only a subset of their abilities. We now know that they also have the ability to ameliorate a wide range of abiotic stresses, and some of them can also alleviate physiological stresses such as seed aging. They can also enhance nutrient uptake in plants and can substantially increase nitrogen use efficiency in crops. These abilities may be more important to agriculture than disease control. Some strains also have abilities to improve photosynthetic efficiency and probably respiratory activities of plants. All of these capabilities are a consequence of their abilities to reprogram plant gene expression, probably through activation of a limited number of general plant pathways. © 2010 by Annual Reviews. All rights reserved.

Assouline S.,Institute of Soil, Water and Environmental Sciences | Or D.,ETH Zurich
Vadose Zone Journal | Year: 2013

The water retention curve (WRC) and the hydraulic conductivity function (HCF) are key ingredients in most analytical and numerical models for flow and transport in unsaturated porous media. Despite their formal derivation for a representative elementary volume (REV) of soil complex pore spaces, these two hydraulic functions are rooted in pore-scale capillarity and viscous flows that, in turn, are invoked to provide interpretation of measurements and processes, such as linking WRC with the more difficult to measure HCF. Numerous conceptual and parametric models were proposed for the representation of processes within soil pore spaces and inferences concerning the two hydraulic functions (WRC and HCF) from surrogate variables. We review some of the primary models and highlight their physical basis, assumptions, advantages, and limitations. The first part focuses on the representation and modeling of WRC, including recent advances such as capillarity in angular pores and film adsorption and present empirical models based on easy to measure surrogate properties (pedotransfer functions). In the second part, we review the HCF and focus on widely used models that use WRC information to predict the saturated and unsaturated hydraulic conductivity. In the third part, we briefly review issues related to parameter equivalence between models, hysteresis in WRC, and effects of structural changes on hydraulic functions. Recent technological advances and monitoring networks offer opportunities for extensive hydrological information of high quality. The increase in measurement capabilities highlights the urgent need for building a hierarchy of parameters and model structures suitable for different modeling objectives and predictions across spatial scales. Additionally, the commonly assumed links between WRC and HCF must be reevaluated and involve more direct measurements of HCF. The modeling of flow and transport through structured and special porous media may require special functions and reflecting modifications in the governing equations. Finally, the impact of dynamics and transient processes at fluid interfaces on flow regimes and hydraulic properties necessitate different modeling and representation strategies beyond the present REV-based framework. © Soil Science Society of America, All rights reserved.

Stanhill G.,Institute of Soil, Water and Environmental Sciences
Journal of Geophysical Research: Atmospheres | Year: 2011

A 120 year series of climate measurements at Armagh Observatory, a rural site in Northern Ireland, was analyzed to yield monthly, seasonal, and annual values of long- and short-wave irradiances which were then related to the measured changes in air temperature. Three quarters of the significant increase and large decadal variations in atmospheric long-wave radiation was associated with the concurrent changes measured in specific humidity; the remaining quarter was associated with increases in the concentrations of carbon dioxide and other anthropogenic radiatively active gases. Significant but smaller long-term decreases in short-wave solar irradiance reduced by half the net, all-wave radiation forcing at the surface. Together the changes in long- and short-wave irradiances at Armagh accounted for more than three quarters of the interannual variations in mean annual temperatures. Climate sensitivity to long-wave forcing at the surface, 0.121°C per W m-2, was 5 times greater than that to short-wave forcing, and two possible explanations for this difference, water vapor feedback and changes in atmospheric circulation, are discussed. Copyright 2011 by the American Geophysical Union.

Cohen E.,Institute of Soil, Water and Environmental Sciences | Levy G.J.,Institute of Soil, Water and Environmental Sciences | Borisover M.,Institute of Soil, Water and Environmental Sciences
Water Research | Year: 2014

Characterization of organic matter (OM) present in treated wastewater (TWW) after various treatment stages is important for optimizing wastewater recycling. The general aim of this research was to carry out a long-term examination of OM in wastewater along the treatment, by applying excitation-emission matrices (EEM) fluorescence spectroscopy and parallel factor analysis (PARAFAC). Fluorescent OM was examined in water samples obtained from four wastewater treatment plants (WWTPs) in Israel for 20 months. The PARAFAC analysis of EEMs of water samples from the four WWTPs yielded six components. The fluorescent components included proteinaceous tryptophan-like matter (C1), three humic-like components (C2-C4), a component (C5) that was characterized by excitation and emission with a distinct vibrational structure similar to that of pyrene and a component (C6) that was characterized by the excitation and emission spectra demonstrating two peaks where the appearance of two emission peaks was suggested to reflect the formation of an intra-molecular exyplex. The biological treatment strongly reduced the concentration of component C1 thus increasing the overall fraction of humic-like OM over the proteinaceous OM in the treated water. The fluorescence of component C1 could therefore be used as an indicator of the biological treatment efficacy. The concentration of the humic-like component C2 characterized by excitation and emission maxima at <240,305/422nm, respectively, was also sensitive to biological treatment. The soil aquifer treatment was not effective in completely eliminating the fingerprints of the initial wastewater. The concentrations of the fluorescent components in wastewater after the biological treatment were only slightly affected by filtration (0.45μm) of the samples. For water sampled prior to the biological treatment, the 0.45μm filtration had the most pronounced effect on concentrations of the proteinaceous matter and component C6. Strong positive correlations were found between concentrations of component C1 and total carbon (TC) in wastewater samples from the WWTPs thus suggesting the proteinaceous fluorescence in wastewater as an indicator for TC reduction. Chemical oxygen demand (COD) and the fluorescein diacetate hydrolyzing activity (a measure for the total microbial activity) were strongly positively correlated with the concentrations of components C1-C3 thus suggesting the fluorescence of these components as indicators for reduction in COD and the total microbial activity in wastewater. © 2014 Elsevier Ltd.

Tanny J.,Institute of Soil, Water and Environmental Sciences
Biosystems Engineering | Year: 2013

The use of porous screens to cover agricultural crops is constantly increasing. Screens are mainly used to reduce high radiation loads and wind speed, to protect the crop from hail storms and to minimise the invasion of insects thus allowing a significant reduction in pesticide application. Since screens impede the exchange rate of radiation, mass, heat and momentum between the crop and the atmosphere they modify the crop microclimate and its water requirements. The increased use of screens by growers has triggered the expansion of research on the effects of various screens and screenhouses on microclimate and crop evapotranspiration, as well as on produce quality and quantity. Although research on screenhouse microclimate can be traced back to the beginning of the 20th century, only during the past few decades has a much better understanding of the screenhouse environment been achieved. This paper reviews past research and recent advances regarding microclimate and evapotranspiration of crops under screens and in screenhouses. It covers the issues of radiation, air velocity, ventilation, turbulence, temperature, humidity, evapotranspiration and water use efficiency. The review shows that although screens reduce the transmission of total radiant energy, the effect on air temperature is complex, and depends on additional factors. Future research should focus on modelling the screenhouse-crop system under realistic conditions, using advanced simulation tools. High quality data sets from field studies will be needed to develop and validate such models. © 2012 IAgrE.

Kravchik M.,Institute of Soil, Water and Environmental Sciences | Bernstein N.,Institute of Soil, Water and Environmental Sciences
BMC Genomics | Year: 2013

Background: Salinity inhibits growth and development of most plants. The response to salinity is complex and varies between plant organs and stages of development. It involves challenges of ion toxicities and deficiencies as well as osmotic and oxidative stresses. The range of functions affected by the stress is reflected in elaborate changes to the transcriptome. The mechanisms involved in the developmental-stage specificity of the inhibitory responses are not fully understood. The present study took advantage of the well characterized developmental progression that exists along the maize leaf, for identification of salinity induced, developmentally-associated changes to the transcriptome. Differential subtraction screening was conducted for cells of two developmental stages: from the center of the growth zone where the expansion rate is highest, and from older cells at a more distal location of the growing zone where the expansion rate is lower and the salinity restrictive effects are more pronounced. Real-Time PCR analysis was used for validation of the expression of selected genes.Results: The salinity-induced changes demonstrated an age-related response of the growing tissue, with elevation of salinity-damages with increased age. Growth reduction, similar to the elevation of percentage dry matter (%DM), and Na and Cl concentrations were more pronounced in the older cells. The differential subtraction screening identified genes encoding to proteins involved in antioxidant defense, electron transfer and energy, structural proteins, transcription factors and photosynthesis proteins. Of special interest is the higher induced expression of genes involved in antioxidant protection in the young compared to older cells, which was accompanied by suppressed levels of reactive oxygen species (H2O2 and O2 -). This was coupled with heightened expression in the older cells of genes that enhance cell-wall rigidity, which points at reduced potential for cell expansion.Conclusions: The results demonstrate a cell-age specificity in the salinity response of growing cells, and point at involvement of the antioxidative response in cell growth restriction. Processes involved in reactive oxygen species (ROS) scavenging are more pronounced in the young cells, while the higher growth sensitivity of older cells is suggested to involve effects on cell-wall rigidity and lower protein protection. © 2013 Kravchik and Bernstein; licensee BioMed Central Ltd.

Assouline S.,Institute of Soil, Water and Environmental Sciences
Water Resources Research | Year: 2013

Infiltration is a key process in aspects of hydrology, agricultural and civil engineering, irrigation design, and soil and water conservation. It is complex, depending on soil and rainfall properties and initial and boundary conditions within the flow domain. During the last century, a great deal of effort has been invested to understand the physics of infiltration and to develop quantitative predictors of infiltration dynamics. Jean-Yves Parlange and Wilfried Brutsaert have made seminal contributions, especially in the area of infiltration theory and related analytical solutions to the flow equations. This review retraces the landmark discoveries and the evolution of the conceptual approaches and the mathematical solutions applied to the problem of infiltration into porous media, highlighting the pivotal contributions of Parlange and Brutsaert. A historical retrospective of physical models of infiltration is followed by the presentation of mathematical methods leading to analytical solutions of the flow equations. This review then addresses the time compression approximation developed to estimate infiltration at the transition between preponding and postponding conditions. Finally, the effects of special conditions, such as the presence of air and heterogeneity in soil properties, on infiltration are considered. © 2013. American Geophysical Union. All Rights Reserved.

Cytryn E.,Institute of Soil, Water and Environmental Sciences
Soil Biology and Biochemistry | Year: 2013

Antibiotic resistance is a global phenomenon with severe epidemiological ramifications. Although the spread of antibiotic resistance is generally associated with selection derived from clinical use of antibiotics, recent studies have indicated that global proliferation of antibiotic resistance is also affiliated with natural environmental reservoirs, which can potentially transfer antibiotic resistance genes to clinically relevant bacteria via drinking water and the food chain. Terrestrial antibiotic resistance reservoirs are traditionally linked to anthropogenic activities such as manure and biosolid application, wastewater irrigation and agricultural application of antibiotic compounds that transmit residual concentrations of antibiotic compounds (that exert selective pressure), antibiotic resistant bacteria and antibiotic resistance genes to the soil. Although some evidence correlates between anthropogenic factors and elevated levels of antibiotic resistance in soil, it is becoming increasingly clear that un-impacted and pristine soils contain highly diverse and abundant levels of antibiotic resistant bacteria, which harbor a wide array of clinically-associated and novel antibiotic resistance genes. This has led to the resistome hypothesis, which speculates that many pathogen-associated antibiotic resistance genes originated in antibiotic-producing soil bacteria and reached pathogens via horizontal gene transfer. This review provides a holistic overview of how external and intrinsic factors influence soil antibiotic resistance. •Antibiotic resistance (AR) is a major health concern.•Anthropogenic activities such as manure amendment can enhance soil AR reservoirs.•Non-impacted soils contain highly diverse collections of AR genes.•Native soil AR genes appear to be the source of many AR genes in pathogens. © 2013 Elsevier Ltd.

Tsechansky L.,Institute of Soil, Water and Environmental Sciences | Graber E.R.,Institute of Soil, Water and Environmental Sciences
Carbon | Year: 2014

The Boehm titration is frequently employed to characterize acidic groups at biochar surfaces. However, biochars contain inorganic basic components (carbonates, oxides, hydroxides), inorganic acidic species (silica, alumina) and organic acids (carboxylic acids, phenols, humic-like substances) that can be differentially solubilized in the Boehm bases, rendering invalid results. This is demonstrated for two biochars. Prior to titrations (Boehm or continuous), biochar should be pretreated with NaOH to remove solubilizable acidic species, and then with HCl to remove solubilizable basic components and protonate carbon acid sites. Pretreatment is successful when direct and indirect titrations yield identical results and no precipitate is observed. © 2013 Elsevier Ltd. All rights reserved.

Loading Institute of Soil, Water and Environmental Sciences collaborators
Loading Institute of Soil, Water and Environmental Sciences collaborators