Зміна біотичних властивостей ґрунтів унаслідок сильватизації колишніх сільськогосподарських угідь (Сколівські Бескиди, Українські Карпати)

Abstract

Listen

Translate article

The article deals with an impact of the former agriculture land abandonment on biotic properties of soils. In order to better comprehend the processes of spontaneous reforestation (sylvatisation) in a mountain region (the Pohartsi boundary, Koziova village, Stryi district, Lviv regionthe (Skolivski Beskydy physiographic region, the Ukrainian Carpathians) four study plots were selected representing the successional sequence: forest → pasture → hay meadow → arable lands. The study revealed that indicators of microbiological activity is positively affected by the forest floor presence. A zone of the highest soil biotic activity coincides with the limits of the humus horizon Н. Getting deeper into soil profile microbiological activity falls manifold due to changes in physical, hydrophysical and physical-chemical soil properties. In the pasture lands that were least affected by the past agricultural activities, we found both increase and decrease in soil biotic properties. This is foremost caused by the environmental changes. Absence of the forest floor, as a major nutrient source, leads to the 30% decrease in the biomass microorganisms while soil pH shift from a largely to moderately acidic reaction causes 1,5-times higher catalase activity. The latter was the highest in the former pasture lands among all study plots and was assessed as “moderate”. Increase in the urease activity was documented, as well. However its highest values were measured in upper soil horizons of both past and present arable lands. Such an increase of the urease activity is caused by application of organic fertilizers. Despite slightly acidic reaction of the soil water extract from upper horizons of ploughed-up soils the catalase activity here decreases up to 2–2.5 times. This is caused by deterioration of hydric and aeration properties of soils due to their compaction. We noted manifold decrease in the С-СО2 production, as well. The most optimal soil parameters were characteristic for the hay meadow plot despite being significantly affected by anthropogenic activities while the succession of ‘arable lands → pasture → hay meadow’ took a path. Similar moderate soil biotic activity was distinguished for the former pasture land plots. This indicates on the self-restoration and self-regulation capacities of natural ecosystems in the region. We concluded that major indicators of soil biotic activity in the past arable lands are the urease activity, microbial biomass, and soil respiration. The catalase activity makes an additional value for soil degradation assessment of the post-agricultural land uses.