Evaluating Soil Change Using Standardized Dynamic Soil Properties Comparison Projects.

The National Cooperative Soil Survey is implementing a new protocol to evaluate dynamic soil properties (DSP), as defined in the “Soil Change Guide” (available online at www.soils.usda.gov/technical reference/soil change).  This protocol promises to provide much needed information on the effects of land management practices on soil properties that are important to sustained functionality of soils in their ecosystems.  Two projects have been undertaken this year following the prescribed protocol: one on the Amarillo soils of the Southern High Plains (SHP) of Texas, and the other on the Kennebec soils of the Nebraska-Kansas Loess Drift Hills.  The results from these studies show that there are tractable differences in DSP between managements.  Lands under CRP and irrigated cotton in the SHP project show significant loss of subsurface carbon compared to rangeland, as well as loss of aggregate stability and nutrients.  In the Kennebec study, differences in physical properties between conventional and no-till are not as significant, but carbon stocks under no-till are significantly higher.  Organic practices show higher C storage in soils, but the use of tillage to suppress weeds has similar effects as conventional tillage.  The sampling/observational methods provided in the “Soil Change Guide” are very useful in collecting information that is critical to intelligent land use and conservation planning.