EXPLORING THE EFFECTS OF LAND USE CHANGE ON CRITICAL ZONE PROCESSES AT GLACIER CREEK PRESERVE, A 45-YEAR OLD RESTORED TALLGRASS PRAIRIE IN EASTERN NEBRASKA

Anthropogenic land use may significantly influence critical zone processes but the rate and extent of such changes on soil formation and geochemical cycling have not been well quantified. In the Midwest, much of the native prairie has been converted to agriculture, but increasing efforts aim to restore some to prairie ecosystems. The study site, Glacier Creek Preserve (GCP) located near Omaha, Nebraska, consists of loess parent material with some glacial till exposed near the creek. The original 52 ha of GCP were donated to the University of Nebraska at Omaha in 1959, although the preserve recently expanded to 172 ha to encompass the entire Glacier Creek watershed. In 1970 the original 52 ha of the preserve were reseeded to native tallgrass prairie following over one hundred years of corn and soybean cultivation. The recently acquired northern portion of the site (31 ha Hayes Overlook) is currently used for corn-soybean agriculture but will be restored to tallgrass prairie within the next five years. Two meteorological stations, one on a ridgetop on the original restored prairie and one on the agriculture ridgetop of the Hayes Overlook, currently provide hourly measurements of atmospheric and soil parameters that provide baseline data for all studies. Previous work at the site focused largely on the effect of land management, especially burning and mowing, on grassland vegetation but more recently includes research focused on the soils and hydrology. To investigate the effects of land management on soils we measured geochemical data, including pH and carbon, nitrogen, and elemental concentrations to 930 cm depth under ridgetop topographic positons on both restored prairie and no till corn-soybean agriculture at GCP. Preliminary data show greater carbon and enhanced hydrologic connectivity in the upper meter of the restored prairie soil compared to the agricultural soil. Such measurements will provide a baseline that can be compared to other studies across the region, including the Intensively Managed Landscapes Critical Zone Observatory (IML CZO), and help improve our understanding of anthropogenic effects on critical zone processes.