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Karsten Schacht Yona Chen Jorge Tarchitzky Lubomir Lichner Bernd Marschner 《Irrigation Science》2014,32(5):369-378
Irrigation with treated wastewater (TWW) is gaining importance due to declining water availability in dry regions. TWW irrigation has various potential adverse effects on soil quality such as hydrophobic effects on soil surfaces, reducing initial sorptivity and promoting the formation of preferential flow paths. In May and June 2010, in situ infiltration measurements using mini disk tension infiltrometer were deployed in five different orchard plots in Israel to assess the impact of different irrigation water qualities on the soil water repellency index R. In most plantations, long-term test sites were accessed to compare adjacent plots irrigated with fresh water (FW) or TWW. Topsoil samples were analyzed for selected physical and chemical characteristics. The mean R values increased at all TWW sites, from +15 up to +55 % compared with FW sites. The water drop penetration time (WDPT) increased up to 30 fold at three of five TWW sites compared with FW sites. Subsequent U tests and multilevel analysis indicated an impact of the type of irrigation water on R and WDPT. Moreover, soil electrical conductivity and exchangeable sodium percentage were consistently higher at all TWW sites. These results show that irrigation water quality clearly influences physical and chemical properties of the soil. 相似文献
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Drip irrigation systems are prone to changes in flow rate (FR) and increasing coefficients of variation (CV) when fed with treated wastewater, due to fouling inside the drippers. A model system was designed to measure the FR and fouling accumulation in laterals and drippers under different treatment conditions. A novel approach was taken to compare the different maintenance treatments. A comparison of chlorination and acidification strategies showed that daily chlorination and periodic acidification may prolong proper functioning of the drippers by maintaining a normal FR [(up to ±7 %) of nominal FR] and CV (<7 %) index in correlation with low fouling accumulation in the pipeline (<0.01 mg deposit/cm pipe 2 ). Current recommendations for the frequency of conventional treatments were found to be insufficient. Chemical analyses of the fouling inside the dripper and accumulated on the pipe wall showed that biofilm can survive inside the dripper under harsh environmental conditions, even when the pipeline stays clean. These results shed light on biofilm growth and survival mechanisms inside the dripper and may pave the way to developing new treatments or improving dripper design. 相似文献
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Induction of soil water repellency following irrigation with treated wastewater: effects of irrigation water quality and soil texture 总被引：2，自引：1，他引：1
We hypothesized that organic matter (OM) content originating from treated wastewater (TWW) irrigation and soil texture dominate the intensity of soil water repellency. The relationship between soil texture, wastewater treatment level, and water repellency was examined in a 3-year lysimeter experiment (2008–2010). Soil type–water quality combinations, consisting of three soils with different specific surface area (SSA) and four levels of water quality differing in OM content, were tested. In each year, water repellency developed in all TWW quality treatments, but not in freshwater-irrigated controls. At the end of each year (except 2009), the highest degree of repellency was exhibited by sandy soil treated with the lowest quality TWW (highest OM content). The lowest degree of water repellency was consistently exhibited by the soil with the highest SSA irrigated with the highest quality TWW (lowest OM content). Water quality, rather than SSA, was the dominant factor in determining degree of repellency induced by TWW irrigation. 相似文献
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Purpose
Metal distribution patterns among geochemical fractions are informative for metal phytoavailability. Compost added to polluted soils may adsorb metals on the less phytoavailable fractions. A bioassay experiment was conducted to establish possible correlations between metal concentrations in different soil fractions and metal contents in edible plant parts and to investigate the influence of different compost loads on heavy metal availability to plants.Materials and methods
Chinese cabbage plants were grown in pots with sandy and clayey soils and soils mixed with different doses of biosolid compost spiked with soluble heavy metal salts (Cd, Cu, and Pb). The metals’ distribution pattern in the soil and mixed samples was determined by sequential extraction procedure (modified BCR protocol). The studied fractions, from most to least bioavailable, were water-extractable (WE), exchangeable-adsorbed (EXC), associated with carbonates and acetic acid-soluble forms (CARB), occluded by reducible (hydro)oxides of Fe and Mn (RO), and associated with organic matter (OM) and a residual fraction (RES). Metal concentrations in soil extracts and in the digested plant tissue were measured by ICP-AES.Results and discussion
The highest compost doses (72 and 115 Mg ha?1) enhanced cabbage yield significantly. No excessive phytoaccumulation of metals was observed in plants grown in the clayey soil or its mixtures with compost. The compost dose of 72 Mg ha?1 was optimal in decreasing Cu accumulation by plants grown in sandy soil, and 28.8 Mg ha?1 was found to be effective in reducing Cd and Pb uptake. Metals were accumulated in plants primarily from the WE, EXC, and CARB fractions, whereas other fractions decreased phytoaccumulation. Compost addition suppressed heavy metal mobility, but different fractions were active in pollutant sorption, depending on soil type and metal.Conclusions
Compost addition increased metal proportions in the RO and OM fractions, reducing metal phytoavailability. This is especially important for sandy soils with low adsorption ability and higher vulnerability to metal pollution than clayey soils. A compost dose of 20% v/v (or 28.8 Mg ha?1) effectively reduced plant accumulation of Cd and Pb. We propose using the first three steps of the modified BCR protocol as a three-step sequential-extraction procedure for the most phytoavailable fractions of heavy metal: WE, EXC, and CARB. 相似文献7.
Siebner-Freibach H Yariv S Lapides Y Hadar Y Chen Y 《Journal of agricultural and food chemistry》2005,53(9):3434-3443
FTIR spectra of the microbial siderophore, ferrioxamine B, and its nonchelated form (iron free; desferrioxamine B) were studied to facilitate in-depth investigation on the undisrupted structure of the siderophore and its interactions with the environment. Effects of iron chelation as well as those of various levels of pH and temperature on the stereochemical structure of the free ligand and the ferric complex were examined. The presence of a number of functional groups in these compounds and the mutual interaction between them resulted in significant shifts and overlapping of their characteristic absorption bands. Thermal and pH treatments combined with a comprehensive use of curve-fitting analysis facilitated bands resolution. Absorption bands of all functional groups were identified. The results imply that the compact and rigid structure of the ferric complex (ferrioxamine B) is sustained by intense and specific intramolecular hydrogen bonds. Dehydration was the main process observed at low temperature (25-60 degrees C). At 105 degrees C the free ligand form (desferrioxamine B) had already begun to decompose, whereas ferrioxamine B exhibited stability. The thermal destruction became acute at the 170 degrees C treatment for both molecules. The secondary amide groups and the hydroxamate groups, which comprise the binding site for the Fe atom in the complex, were found to be the most sensitive to the thermal degradation. Significant pH effects were observed only for desferrioxamine B samples at pH 9, accompanied by partial decomposition, similar to that observed at 105 degrees C. Deprotonation of desferrioxamine B was found to begin with the deprotonation of the NH(3+) group. Characteristics of the rigid conformational structure of the ferric complex and the state of the NH(3+) group, both assumed to play an important role in the recognition and uptake of the siderophore by membranal receptors, were elaborated by means of FTIR and are discussed in detail. 相似文献
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Yona Chen 《Compost science & utilization》2013,21(2):152-168
Compost maturity or stability reflects the degree of decomposition of the organic matter (OM). Since stability of natural OM is a relative term, defining it is not a trivial challenge. In addition, it requires a series of chemical, physico-chemical and spectroscopic determinations. Among the methods applied, 13C-NMR and FTIR (or DRIFT) and pyrolysis have been shown to be of significance and therefore this review will be dedicated to studies focusing on the application of these methods to composting research. In fact, solid-state 13C-NMR spectroscopy has become the most important tool for examining the chemical structure of natural OM (NOM) and the chemical changes associated with OM decomposition. Changes can be measured on the bulk OM either fresh or composted, on humic substances (HS) extracted from the compost or on dissolved organic matter (DOM). Recently, 2D 1H NMR has been employed to study properties of HS extracted from MSW compost. In general, changes measured on decomposing OM are more distinct in the following order of tested materials: DOM > Bulk OM > HS > Core HS. In conclusion, compost HS which are “young” relative to soil HS were shown to differ from the latter mostly in their high levels of aliphatic and polysaccharide components, which tend to decompose during composting. 13C-NMR is the most effective instrument applied to date to structural studies of NOM. 相似文献
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A novel automated method for the adjustment of ionic metal concentrations in soil extracts 
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下载免费PDF全文 A novel method is proposed for correcting metal fraction concentrations remaining within the sediment containing the solid residue of the sequentially extracted fraction. An easy‐to‐use Excel spreadsheet was prepared to assist adjustment of concentration in each fraction and demonstrate the difference between adjusted and non‐adjusted metal concentration of the fraction. The demonstration of a calculation of the modified BCR protocol data showed that this difference may reach 10–15% of the result value. The spreadsheet is available to download at: http://departments.agri.huji.ac.il/zabam/Rosen_Chen_Fraction_Adjustment_Formulae.xls 相似文献
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Siebner-Freibach H Hadar Y Yariv S Lapides I Chen Y 《Journal of agricultural and food chemistry》2006,54(4):1399-1408
The behavior of iron-chelating agents in soils is highly affected by interactions with the solid phase. Still this aspect is frequently ignored. In this research the adsorption of the siderophore ferrioxamine B by Ca-montmorillonite, as a free ligand (desferrioxamine B, DFOB) and as a complex with Fe3+ (ferrioxamine B, FOB), was studied, using thermo X-ray diffraction (thermo-XRD) in the temperature range 25-360 degrees C and thermo-FTIR spectroscopy in the temperature range 25-170 degrees C. The effect of pH (4-7.5) on the adsorption was examined. Extensive use of curve-fitting analysis was required due to significant overlapping of the characteristic absorption bands of the various functional groups. Thermo-XRD analysis showed that both DFOB and FOB penetrated into the interlayer space of Ca-montmorillonite. FTIR results indicated strong interactions of DFOB within the interlayer, which involved all functional groups (NH3+, secondary amide groups, and hydroxamate groups). In contrast, the folded Fe complex of FOB retained its molecular configuration upon adsorption, and the basal spacing of the clay increased correspondingly. FOB interacted in the interlayer space of the clay, mainly through the NH of the secondary amide groups and NH3+, while the functional groups bound to the central Fe cation remained unchanged. The suspension pH had no significant effect on both DFOB and FOB adsorption at the examined range. Adsorption protected the adsorbates from thermal degradation compared to the nonadsorbed samples up to 105 degrees C. At 170 degrees C both DFOB and FOB were already partially degraded, but to a lesser extent than the nonadsorbed samples. Degradation of the molecules occurred mainly through the hydroxamic groups, which constitute the Fe-chelating center in the hydroxamic siderophore. 相似文献