Submitted to: Soil & Tillage Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 12/17/2011
Publication Date: 1/12/2012
Citation: Raczkowski, C.W., Mueller, J.P., Busscher, W.J., Bell, M.C., Mcgraw, M.L. 2012. Soil physical properties of agricultural systems in a large-scale study. Soil & Tillage Research. 119:50-59. Interpretive Summary: Between 1998 and 2007, a field experiment was performed at the Center for Environmental Farming Systems at North Carolina Agricultural and Technology State University in Goldsboro, North Carolina. The objectives of the experiment were to develop large-scale research plots and use them to determine the effects of agricultural management systems on soil physical properties. The 2.5- to 8-acre plots were set up on uniform soils. Plots included the following 6 treatments: best management practices with tillage (BMP); best management practices with no tillage (BCT); organic crop production (OCP); integrated crops with animals (ICA); plantation forestry for wood (PFW); and abandoned fields (AFS). Plots that were tilled (BMT and OCP) had relatively little change in soil physical properties over time. Plots with little or no tillage (BCT, PFW and AFS) had similar properties to each other but lower soil densities, lower porosity, more micro-pores, and better water holding capacities than tilled plots. ICA plots developed higher post-grazing densities, lower porosities and lower macropores than tilled plots. Each management system developed an array of physical properties that characterized its unique field conditions during production of trees and crops with or without livestock.
Technical Abstract: A large-scale field study was performed to determine the effects of agricultural management systems on soil physical properties, including their spatial and temporal variations. Replicates were established in 1998 at the Center for Environmental Farming Systems, Goldsboro, North Carolina; replicates were based on soil type in an area that had been intensively mapped. Agricultural management systems included five treatments: best management practices (BMP: split into conventional tillage – BCT and no-tillage - BNT); organic crop production (OCP); integrated crop-animal (ICA); plantation forestry-woodlot (PFW); and abandoned-field succession (AFS). Soil physical properties of bulk density (Db), saturated hydraulic conductivity (Ksat), field capacity (FC), saturated water content (SWC), total porosity (TP), micro- and macroporosity (MicP, MacP), and water stable aggregation (WSA) were measured in multiple years within the period 1999 through 2007. The experimental methods successfully produced data with acceptable levels of variability, discernable soil property differences between systems, and unambiguous relationships between soil properties. Blocking areas with large portions of a diagnostic soil maintained the homogeneity of experimental plots and produced acceptable error terms in statistical procedures. The sampling scheme used prevented sample collection in previously sampled areas. Tilled systems BCT and OCP did not differ in soil physical properties and their properties remained rather constant with time. The BNT, PFW and AFS systems had similar properties with higher Db, lower TP, higher MicP and higher FC than tilled systems. The ICA sub-treatments developed a post-grazing higher Db, lower TP and lower MacP. Each management system led to an array of physical properties that helped characterize the field during production of trees and crops with or without livestock.