Monday, November 13, 2006
83-3

Agroforestry and Grass Buffer Effects on Computed Tomography-evaluated Pore Characteristics.

Ranjith P. Udawatta, Center for Agroforestry, 203 Anheuser Busch Natural Resources Building, University of Missouri, Columbia, MO 65211, Clark Gantzer, Univ. of Missouri, 330 AB Natural Resources, 330 AB Natural Resources, Columbia, MO 65211, United States of America, and Stephen H. Anderson, University of Missouri, Dept. of Soil, Environmental & Atmospheric Sciences, 302 ABNR Building, Columbia, MO 65211.

Agroforestry, a land management practice that intersperses agricultural crops with trees, has recently received attention in the temperate zone due to its environmental and economic benefits.  Water quality improvements due to adoption of these practices have been associated with improvements in soil properties and water and nutrient use by the permanent vegetation.  A paired watershed study consisting of tree buffers, grass buffers, and row crop management with a corn (Zea mays L.)-soybean [Glycine max (L) Merr.] rotation was used to examine treatment effects on changes in pore characteristics.  Undisturbed soil cores were collected from the surface 100 mm using 76 mm diameter acrylic plastic cylinders from tree buffer (Quercus palustris. Muenchh.), grass-legume buffer (Agrostis gigantea Roth., Bromus spp., and Lotus corniculatus L.), and row crop treatment areas.  Soil cores were scanned at 70 μm resolution to examine macroporosity, mesoporosity, pore connectivity, and tortuosity as influenced by treatments at 4.47*105 μm3 voxel size.  Soil near the trees had significantly higher macroporosity and tortuosity compared to the row crop areas.  Soils from the grass areas had the greatest tortuosity while soils from crop areas had the lowest.  Treatment effects were significant for macroporosity, tortuosity and pore cluster coordination.  Results indicate that the buffer systems influence soil pore properties.  It is anticipated as roots of the buffer vegetation occupy more soil volume and add more root channels and organic matter, the differences among the treatments may increase.

Handout (.pdf format, 196.0 kb)