Molecular diversity of arbuscular mycorrhizal fungi in relation to soil chemical properties and heavy metal contamination.

Abundance and diversity of arbuscular mycorrhizal fungi (AMF) associated with dominant plant species were studied along a transect from highly lead (Pb) and zinc (Zn) polluted to non-polluted soil at the Anguran open pit mine in Iran. Using an established primer set for AMF in the internal transcribed spacer (ITS) region of rDNA, nine different AMF sequence types were distinguished after phylogenetic analyses, showing remarkable differences in their distribution patterns along the transect. With decreasing Pb and Zn concentration, the number of AMF sequence types increased, however one sequence type was only found in the highly contaminated area. Multivariate statistical analysis revealed that further factors than HM soil concentration affect the AMF community at contaminated sites. Specifically, the soils' calcium carbonate equivalent and available P proved to be of importance, which illustrates that field studies on AMF distribution should also consider important environmental factors and their possible interactions.

Effects of temperature treatment on corn cob composting and reducing of composting time: a comparative study.

This study focuses on the effect of temperature on the compost quality and the processing time. Two temperature, namely 46°C (high temperature) and 30°C (low temperature) were considered for the composting trials. A mixture of 60% ground corn cob, 30% dried sports grass and 10% bio-activator was used as composting material. The composting process lasted for 120 days. The maturity indices at the end of composting indicate that, for the high-temperature treatment, the compost show an improved quality as compared to the low-temperature treatment. The maturity indices, namely carbon to nitrogen ratio, water extractable organic carbon, ratio of cation exchange capacity to total organic carbon and germination index, determined for the high temperature treatment are: 13.9, 1.48 mg mL⁻¹, 2.21, and 86%, respectively. On the basis of the compost characteristics, the processing time for the high- and low-temperature treatments was 75 days and 105 days, respectively. It can be concluded that treatment at the high-temperature level considered in this study presents a more suitable option for improvement of composting.