University of Minnesota
University of Minnesota
College of Biological Sciences


Experiment 296 - Comparing nitrogen mineralization rates between old fields and virgin grasslands in both soil surface and subsoil horizon

Abandoned agricultural fields (old fields) are widely considered as net carbon sink. However, a 13-year study on soil C dynamic in old fields at Cedar Creek Ecosystem Science Reserve showed that the accumulation of C in surface soil (0 ??? 20 cm) was offset by significant losses of C in subsoil (20 ??? 100 cm). The mechanisms of C losses in subsoil horizon are not clear. We hypothesize that C losses in subsoil was caused by decreased organic C input and constant soil mineralization. Previous study showed up to 89 % of C was lost in surface soil during agricultural practice, thus the organic C input from soil surface to deeper depth may decline. In addition, tilling usually only disturb the surface soil (0 ??? 30 cm), and the microbial communities in subsoil horizon are likely to remain as active as they were before cultivation. To test our hypotheses, we propose a study to compare the soil mineralization rate in both surface and subsoil between old fields and virgin grasslands. We will also collect other factors that are related to soil C dynamics, such as above- and below-ground biomass, total C and N in soil and plant tissues. Old fields soils will be collected in E054 plots, and virgin grassland soils will be collected in 4 oak savannahs and Half-half Island.

Methods for e296


Dataset IDTitleRange of Years (# years with data)