Abstracts |
Some soil-quality parameters of four representative Hungarian soils were assessed following the alternative organic treatments with communal and industrial sewage sludge doses (0, 2.5, 5, 10 and 20 g kg-1, as 0, 7.5, 15, 30 and 60 kg ha-1) in a "long-term" pot-experiment. At the 3rd year (representing 12 years of field application) the colonization of arbuscular mycorrhiza (AM) fungi and among others coliforms as microbe of food-safety importance were assessed in the rhizosphere of green-pea (Pisum sativum). Soil-resilience, measured as the available nutrients (N, P) and the soil (rhizo-) microbiological status were found to be improved by the increasing doses of sewage sludge, more particularly at the sandy type of soils. After the repeated application, however, colonization value of the beneficial AM fungi was decreasing; the abundance of coliforms was increasing concomitant with the accumulation of toxic heavy metals, more particularly the Zn content. Care should be given for the acidic forest soils with its high elimination potential on the resilience-important biofertilizer-type of mycorrhiza fungi. |