Date of Award
Master of Science (MS)
Increasing atmospheric CO2 levels within the past few centuries have led to many studies about the global carbon cycle. An important aspect in balancing the modern global carbon budget revolves around a missing sink of carbon. It is thought that the carbon accumulation in soil may be a significant component in this loss. As changes in land use under natural conditions have increased over the years, it is not well understood how these changes may affect the soil carbon. A useful technique in determining these changes are with the use of archived samples. Within a Russian steppe preserve that has been protected since 1885, modern samples from three different land use plots (meadow steppe, planted forest, and tilled field) were compared to a 100-year-old archived sample of initial conditions in addition to archived samples from these some plots throughout the past 100 years. It was hypothesized that there would be both increases and decreases in soil carbon in addition to physical changes in the soil. Compared to the initial conditions of the pristine plot, organic carbon concentration decreased in the meadow steppe, remained about the same in the planted forest, and decreased in the tilled field. The conversion to tilling showed the greatest amount of change in organic carbon concentration. The organic carbon stock in the meadow steppe showed little change compared to the pristine stock. The planted forest and tilled field showed a significant decrease in carbon stocks. The bulk density in each land use plot increased in the upper half of the profile and decreased in the lower half compared to the pristine plot. Weathering has increased in each of the land use plots. Overall, the change in land use had varying effects on Russian steppe soil, which was determined by using archived samples starting from initial conditions 100 years ago and at various points throughout that time.
Ratigliano, Andrew M., "The effects of land use changes on soil carbon in the Russian steppe" (2006). Geology Theses and Dissertations. 71.