Wednesday, November 7, 2007
302-12

Characterizing Soil Variability of a Research Farm Using Order 1 Soil Survey on Loess Covered Till Plain.

Bruce O. Kunze, US Dept. of Agriculture, Natural Resources Conservation Service, P. O. Box 626, Brookings, SD 57006, Douglas Malo, Box 2140C SNP 247C, South Dakota State Univ., South Dakota State University, Plant Science Dept, Brookings, SD 57007-2141, and Carrie E. Werkmeister, Plant Science Dept, South Dakota State University, Box 2140C SNP 247C, Brookings, SD 57007-2141.

Knowledge of spatial extent of soils on a research farm is imperative in designing and arraying test lots.  Soil variability should be minimized within experimental designs for most agronomic research.  The research farm is located in MLRA 102A near Brookings, SD.  Some of the variability in the research farm include:  (1) loess thickness over till, (2) thickness of mollic epipedon, (3) depth and concentration of carbonates, (4) presence of sand or gravel layer at the contact between the loess and till, (5) wetness characteristics of the soil, and (6) sand wedges within the till.  One hundred thirty five pedons were sampled to describe the soil properties, about one for each acre of land.  Sampling locations were found using GPS.  Soil fertility samples were taken at the same locations including:  organic carbon, nitrates, extractable phosphorous, pH, EC, and zinc.  A total of eleven consociations were mapped.  High resolution Digital Elevation Model and EM 38 data were useful in separating the soil series.  Research plots are being established using the order 1 soil survey data collected.