Soil property changes following restoration in a tallgrass prairie ecosystem

Background/Question/Methods

Agriculture has altered native ecosystems across the United States, especially in the grasslands of the Great Plains.   Agricultural practices reduce soil quality primarily through losses in soil organic carbon (SOC).  Restoration activities attempt to return the system back to its previous native condition, but this process can take decades to centuries.  Soil organic carbon measurements allow for analysis of soil quality because it provides structure and retention of nutrients.  The objective of our study was to investigate the change in soil properties following restoration of tallgrass prairie, with the goal to find patterns in soil qualities due to timing of restoration.  The soil properties measured included SOC, soil active pH, bulk density, soil temperature and soil moisture measured in native tallgrass prairie and restored tallgrass prairie locations at the Ross Natural History Reservation in Americus, KS.  Soil samples were collected in April 2012.  Soil samples were collected at a 15 cm depth, dried at 105 C, and ground.  SOC was determined by loss-on-ignition, and pH was determined with a pH meter on a 2.5:1 ratio of distilled water to dry soil.  Soil temperature was measured at the surface (< 1 cm), 10 cm and 20 cm with a digital thermometer.

Results/Conclusions

The restored grassland locations differed for most of the measured soil characteristics compared to the native location.  Bulk density (p=0.0033), pH (p<0.0001), and soil organic carbon (p=0.0007) were all found to be significantly different between the restored and native locations.  Soil temperatures at all depths were lower at the native tallgrass prairies locations compared to the restored prairie locations, but soil moisture (p=0.0946) did not differ between native and restored grassland locations.  From our analysis, we found that 50 years is insufficient to restore SOC levels at this tallgrass prairie location.  Evaluating change in soil properties following restoration of agricultural sites can lead to a better understanding of restoration processes in grasslands.