38 research outputs found
Long-lasting effects of bentonite on properties of a sandy soil deprived of the humus layer
Bentonite has been recognized as a very good
material for the improvement of coarse textured soils. In microplot
experiment, of a sandy soil deprived of the humus layer was enriched
in 1973 with waste bentonite at the rates of 0, 3, 6 and 12 kg m
-2
.
Until 2002, the microplots were planted with different crops and
regularly enriched with mineral a
nd organic fertili
zers. Since 2003,
the microplots were left barren. In 2009, determinations of several
features of the soils (in 5-30, 30-55 and 55-80 cm layers) showed
that the historical amendment of the sandy soil with bentonite
(especially its highest dose) ensured significantly higher contents
of water, organic C, clay, silt and a sand fraction with particle
diameter <0.1 mm in 5-30 cm layer. Proportions of non-dispersible
clay in the total clay of bentonite soils in the two upper soil layers
were significantly lower than those of the control soil. A significant
increase in the penetrometer resistance was observed in 40-58 cm
layers of the control soil and the soil with 3 kg m
-2
bentonite
amendment, contrary to the soils with two highest bentonite doses
Issues of biological and agricultural treatment of municipal sewage sludge
Increase of sewage sludge production in Poland requires undertaking specific methods for their utilization and disposal. The reason is that sewage sludge, in addition to being rich in organic matter, and biogenic compounds such as nitrogen and phosphorus, which are beneficial from an agricultural point of view, also contain heavy metals, toxic organic pollutants such as persistent organic pollutants and polycyclic aromatic hydrocarbons, inorganic compounds such as silicates and clay, and pathogenic bacteria and other microbial contaminants. This implies problems with further use of such polluted sludge as fertilizer in agriculture. The aim of this paper is to analyze the possibilities and limitations of natural management of sewage sludge, taking into account their effects on the restoration and conservation of organic matter in the soil and the yielding of plants. In addition, the main methods of treatment of polluted sludge before introducing it into the environment are considered
Management with willow short rotation coppice increase the functional gene diversity and functional activity of a heavy metal polluted soil
We studied the microbial functional diversity, biochemical activity, heavy metals (HM) availability and soil toxicity of Cd, Pb and Zn contaminated soils, kept under grassland or short rotation coppice (SRC) to attenuate the risks associated with HM contamination and restore the soil ecological functions. Soil microbial functional diversity was analyzed by the GeoChip, a functional gene microarray containing probes for genes involved in nutrient cycling, metal resistance and stress response. Soil under SRC showed a higher abundance of microbial genes involved in C, N, P and S cycles and resistance to various HM, higher microbial biomass, respiration and enzyme activity rates, and lower HM availability than the grassland soil. The linkages between functional genes of soil microbial communities and soil chemical properties, HM availability and biochemical activity were also investigated. Soil toxicity and N, P and Pb availability were important factors in shaping the microbial functional diversity, as determined by CCA. We concluded that in HM contaminated soils the microbial functional diversity was positively influenced by SRC management through the reduction of HM availability and soil toxicity increase of nutrient cycling. The presented results can be important in predicting the long term environmental sustainability of plant-based soil remediation
Performances of gentle (phyto)remediation options at field scale in the EU FP7 GREENLAND network of trace element-contaminated sites
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