Spatial variability in dynamic soil properties: sampling requirements for a national database

Title	Spatial variability in dynamic soil properties: sampling requirements for a national database
Publication Type	Conference Paper
Year of Publication	2001
Authors	Herrick JE, Tugel A.J., Remmenga M.D., Burkett LM, Norfleet L.M., Ditzler C.
Conference Name	Annual Meeting, Soil Science Society of America
Date Published	October 15, 2001
ARIS Log Number	129787
Abstract	Sampling protocols that account for the spatial variability of near-surface dynamic soil properties are required in order to adequately characterize the temporal variability of these properties. The spatial variability of dynamic properties (e.g., SOC, bulk density and infiltration capacity) is not known for most rangeland soils. In order to better define sampling requirements for rangelands, we measured a suite of near-surface dynamic soil properties in paired degraded and relatively undegraded plots located on four different soils representing four different ecological sites in the northern Chihuahuan Desert, southern New Mexico, USA. We calculated the variance in soil and vegetation properties at three different spatial scales: (1) pedon (shrub-interspace), (2) polypedon of a soil map unit component (i.e., 60m diameter circle), and (3) ecological site. Preliminary results suggest that (1) both the scale and magnitude of spatial variability are correlated with vegetation type, (2) sampling requirements can be significantly reduced by using stratified random sampling at the pedon (plant-interspace) scale, and (3) analysis costs can be further reduced by varying the number of samples depending on the level of spatial variability for a particular property.