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Compost from municipal sewage sludge, bark plus zeolite, and zeolite alone were used in this study to evaluate their influence on soil properties and humus characteristics. Two incubation experiments were conducted in two low humus content soils from Bulgaria (Typic Xerochrept) and Greece (Typic Rhodoxeralf). Soil alone, soil with zeolite, and soil with compost in various rates were incubated for 90 days (24^18C, moisture content about 60% of field capacity). The experimental design was randomized complete blocks with four treatments each replicated four times. At the end of incubation experiment samples were taken, and the basic chemical properties as well as humus composition were determined. The pH, electrical conductivity and NO 3 -N concentration were determined in samples taken every 15 days. The results showed that zeolite increased soil pH and exchangeable potassium (K). Compost increased available phosphorus (P) in the low P Bulgarian soil and electrical conductivity. A strong positive relationship between electrical conductivity and NO 3 -N was recorded. Soil pH was negatively 595

The ability of hydrous oxides of iron (Fe) and manganese (Mn) in municipal biosolids to adsorb metals in the biosolid and in amended soils, and limit the phytoavailability of many trace elements has been documented. We conducted an experiment to test whether deliberate addition of Fe or Mn to sludge compost would reduce the potential for cadmium (Cd) uptake by lettuce (Lactuca sativa L.) from soils that had been amended with high Cd sewage sludge in the 1970s. Results from this study may be applicable to remediation of contaminated soils, as well as to preparation of designer biosolids, which lower metal phytoavailability and bioavailability. Soils were obtained from fields that received high Cd sludge (",1000 mg Cd kg-' and 1000 mg zinc (Zn) kg-', dry wt); the Cd was discharged by a user of Cd pigments. In field trials with 2% limestone addition to a depth of 30 cm, lettuce and spinach (Spinacia oleracea L.) contained >50 mg Cd kt', dry wt. In addition to Fe and Mn addition to increase metal adsorption, Zn addition was included in the study because our research has demonstrated that added Zn inhibits Cd uptake and translocation by plants. The treatments included factorial additions of Fe, Mn, and Zn to the compost; 10% compost by dry weight was added to the test soil; 2% reagent

The reclamation of surface (opencast) coal mines is not always successful; there remains a legacy of degraded land that burdens local communities. This article evaluates a community-oriented, low-cost means of geoecological regeneration, the “Cradle for Nature” strategy, which uses mosaic tree planting to foster positive natural ecological processes. Results show that, while the autocompaction of minestones quickly raises soil densities to levels hostile to plant growth, forestation helps moderate soil densities. Weathering concentrates metals in minestones, but 14 years of forestation reduced the loadings of five metals by 35–52%. Twenty years of forestation doubled soil organic carbon to >7%; increased bacilli from 7% to 46%; actinomycetes from 10% to 26%; and soil microbe counts 12–15 times, especially in tree plantings treated with fertiliser. Soils under trees also supported a significantly greater earthworm biomass than under grass but, while open-canopy plantings had increased ground flora biodiversity, closed-canopy plantings had lower diversity and biomass. Following closure to grazing, ground biomass increased sevenfold. Young trees act as bird perches and significantly increase seed fall. Small mammal biomass and biodiversity increases after tree planting and higher predators appear. Varteg’s constructed forest provides an effective “cradle” for an emergent geoecological system and its habitat mosaic maximises biodiversity.

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