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| Titel |
Ni and Cd bioavailable fraction in mediterranean soils cultivated with Cynara cardunculus L. and amended with different sewage sludge compost doses |
| VerfasserIn |
Alfonso Lag, Ignacio Gómez, Jose Navarro-Pedreño, María Belén Almendro, Mª Victoria Bas |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250055257
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| Zusammenfassung |
| Contaminated and degraded lands should change their use, firstly to improve their status and
secondly to obtain some benefit, reaching a desirable equilibrium. Mediterranean soils are
characterized because of its low organic matter content, loss of structure, high erosion
rate and, in some cases, salinization processes. To avoid undesirable effects over
soil dynamics, compost amendment could supply organic matter, nutrients and
protect soil from erosion in the long term. However, solving one problem may cause
another one, so the solutions are complexes. In the previous example, compost
application implies by-side effects, like the rise in soil heavy metal concentration,
which provoke another kind of pollution to the environment, so motorization and
extraction of those pollutants is needed. Cynara cardunculus L. (cynara) is considered
an energy crop in Mediterranean environments, characterized because of its high
biomass production, high protection from erosion and Cd accumulator traits. This
experiment was conducted to study heavy metal bioavailable fraction in mediterranean
soils, amended with different sewage sludge compost doses and cultivated with
cynara.
Two low productive agricultural soils, located in the South East of Spain under
semi-arid conditions in a saline area were chosen for the experiment and cultivated
with cynara. Four compost treatments were applied (D1=0; D2=30; D3=50; D4=70
ton/ha) at the beginning of the experiment. During a year period, three sampling were
carried out (October, April and July), taking four samples from each (top soil layer:
0-15 cm). Soil and sewage sludge compost were analyzed (physical and chemical
properties). Bioavailable Ni and Cd were extracted with DTPA and determined by atomic
absorption flame technique. Bioavailable/ Total heavy metal content were calculated in
percentage.
No differences were found in bioavailable Cd and Ni levels between D1 (blank) and the
other treatments in each sampling, neither for the same treatment through the experiment
period. Biovailable/Total heavy metal ratio showed that bioavailable fraction did not increase
with compost application or plant cultivation. The data suggest that heavy metals are strongly
bound or chelated to soil components, probably because of soil characteristics:
high pH (-8.5), clay texture and organic carbon (endogenous and exogenous). To
ensure this hypothesis, longer test time is needed; new data is advisable and more
parameters should be included into consideration, like cynara root development and
Ni and Cd content to establish phyto-extraction potential and mobilisation of soil
fractions.
References
Papazoglou E.G., Responses of Cynara cardunculus L. to single and combined cadmium and
nickel treatment conditions. Ecotoxicol.Environ.Saf.(2010), doi:10.1016/j.ecoenv.2010.06.026.
Kirkham M.B., Cadmium on plants on polluted soils: Effects of soil factors,
hyperaccumulation, and amendments. Geoderma 137 (2006), pp 19-32.
Antoniadis V., Tsadilas C.D., Samaras V., Sgouras J.; Availability of heavy metals applied
to soil through sewage sludge. In: Prasad M.N.V., Sajwan K.S., Naidu R., Trace elements in
the environment. (2006) pp 39-57. |
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