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| Titel |
Effects of treated wastewater irrigation on contents and dynamics of soil organic carbon and microbial activity |
| VerfasserIn |
E. Jüschke, B. Marschner, Y. Chen, J. Tarchitzky |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250023214
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| Zusammenfassung |
| In many arid and semi-arid regions, the demand for freshwater as drinking water and other
domestic uses is constantly growing due to demographic growth and increasing standard of
living. Therefore, less freshwater is available for agricultural irrigation and new water sources
are needed. Treated wastewater (TWW) already serves as an important water source in
Jordan, the Palestinian Territories and Israel. Related to its high loads with nutrients,
salts and organic materials within its use as irrigation water major effects on the
soil physical and chemical properties can occur, in the worst case leading to soil
degradation.
In an ongoing study we are investigated in the effects of TWW irrigation on agricultural
soils in the region. Here we present results from analyses of total soil carbon contents and
qualities in soils irrigated with freshwater and TWW. Furthermore microbiological
parameters were investigated as microbial biomass, microbial activities and enzyme
activities. In several sites, subsoils (50-160 cm) from TWW irrigated plots were depleted in
soil organic matter with the largest differences occurring in sites with the longest TWW
irrigation history. Laboratory incubation experiments with additions of 14C-labelled
compounds to the soils showed that microbial activity in freshwater irrigated soils was much
more stimulated by sugars or amino acids than in TWW irrigated soils. The lack of such
"priming effects" (Hamer & Marschner 2005) in the TWW irrigated soils indicates that
here the microorganisms are already operating at their optimal metabolic activity
due to the continuous substrate inputs with soluble organic compounds from the
TWW. Apparently, this higher microbial activity is causing an increased depletion of
soil organic matter, which may have negative long-term effects on soil quality. |
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