Influence of Prairie Restoration on CT-Measured Soil Pore Characteristics

Principle Investigators: Ranjith P. Udawatta, Stephen H. Anderson, Clark J. Gantzer, and Harold E, Garrett

Institution and/or Affiliation: University of Missouri 

Abstract:

Restored prairies are expected to improve soil physical properties, yet little is known about the extent of change to soil properties and how rapidly these changes take place. The objective of this study was to compare eff ects of prairie restoration on computed tomography (CT)-measured pore parameters. Undisturbed soil cores (76 mm diam. by 76 mm long) from
native prairie (NP), restored prairie (RP), conservation reserve program (CRP), and no-till corn (Zea mays L.)-soybean (Glycine max (L.) Merr.; CS) sites were collected with six replicates from the 0- to 40-cm depth in 10-cm increments. Five CT images were acquired from each soil core using a medical CT scanner with 0.2 by 0.2 mm pixel resolution with 0.5 mm slice thickness, and then the images were analyzed. Soil bulk density and hydraulic conductivity (Ksat) were also measured. Soils under NP, RP, CRP, and CS areas had 83, 43, 48, and 26 pores on a 2500 mm2 area, respectively, for the 0- to 40-cm depth. Th e number of pores, number of macropores (>1000 μm diam.), macroporosity, mesoporosity (200-1000 μm diam.), and fractal dimension were significantly higher and pore circularity was lower for NP, RP, and CRP than the CS treatment. Th e CT-measured mesoporosity and macroporosity of the CS treatment were 20 and 18% of the values for the NP site. CT-measured number of pores and macropores explained 43 and 40% of the variation for Ksat. The study showed that prairie restoration improves CT-measured soil pore parameters and decreases bulk density which are related to soil water infi ltration.