Autotransporto taršos ir sunkiųjų metalų sorbcijos poveikis dirvožemio biologiniam aktyvumui

Abstract

Biological activity of soil is an important factor of productivity from agronomy and ecology standpoint as well as sensitive indicator of anthropogenic impact. Present day concern regarding a great attention for its investigations in World, because that connected with rapid anthropogenic destruction of soil, attached to a pollution of atmosphere and emissions of motor transport, a waste disposal and etc. Four soil sites to highway Vilnius - Kaunas - Klaipėda, near Giraitė (Kaunas district) and Kryžkalnis (Raseiniai district) have been selected for experiment: 20 m form roadside and heavily influenced emissions of motor transport (I and III objects), 350 m form roadside and background pollution (II and IV objects). Soil samples for analyses of soil biological activity were taken from soil profile at depth 0-10, 20-25, 39-43, 56-61, 78-83 and 95-100 cm, according genetic soil horizon. United soil samples for replication were taken from soil site at same depth. The experimental data showed that in both soils a significantly decrease of urease activity in soil under the influence from highway: 20 m from roadside it was 2-3 times lower then 350 m. However, the activity of sacharase and dehydrogenase was influenced less. On contrary, soil respiration intensity increases when distance to highway decreases. Comparison of both soils biological activity shows that oxidation - reduction processes were more intensive in Luvisols (Giraitė, Kaunas district) and hydrolysis processes, which reflect more intensive mineralization of organic matter – in Albeluvisol (Kryžkalnis, Raseiniai district). The investigations shows a significant decrease of enzyme activity and respiration intensity in modelling Luvisol and Albeluvisol saturated with solutions of heavy metals salts in comparison with natural soils observed: sacharase activity up to 57-77 percent, dehydrogenases – 95-98 percent, urease – 65-97 percent and soil respiration – 38-65 percent. Similarly effect shows a comparison of modelling Luvisol and Albeluvisol, saturated with solutions of heavy metals salts and saturated with distilled water observed: dehydrogenases activity up to 91-97 percent, urease – 67-95 percent, sacharase – 33-59 percent and soil respiration – 6-30 percent. According sensitivity of soil biological activity to critical contamination with heavy metals such descending order may be derived: dehydrogenase urease sacharase soil respiration. Key words: enzyme activity, heavy metals, highway.