Native Prairie and Agroecosystem Effects on Soil Physical Properties and Runoff Water Quality in the Arkansas Delta

A single study was conducted in March 2004 on a Grenada silt loam (Fine-silty, mixed, active, thermic, Oxyaquic Fraglossudalfs) at the Roth Prairie and Harbecke Farms located near Stuttgart, Ark. Treatments consisted of three land uses: conventional till (CN), reduced till (RT), and native prairie (PR). The CN system had been tilled one month prior to rainfall simulation while the RT system had been under continuous CT management for eight years. The CT system was currently in wheat production and had been fallow the previous season. The RT system was previously planted in soybean and a typical soybean-corn rotation had been followed. Typical management practices associated with these two systems had been followed. The native prairie system had never been disturbed. All three systems experienced several rainstorms in the month prior to rainfall simulation. Plots (2by 1.5-m) were established and used for rainfall simulation. The experimental design was completely randomized with four replications for a total of 12 plots. Prior to rainfall simulation, residue cover was measured on all 12 plots using the string method (Hartwig and Laflen, 1978). Volumetric water content was also determined on the plots using dielectric voltage readings converted to volumetric water content using a soil-specific calibration. Soil samples were taken and analyzed for aggregate stability, bulk density, total organic carbon, and Mehlich-3-extractable nutrient concentrations. Soil samples were taken from the area immediately surrounding the plots using a 2-inch diameter core sampler. BACKGROUND INFORMATION AND RESEARCH PROBLEM