Soil Organic Matter in the Sanborn Field Long-Term Plots.

Soil Organic Matter in Sanborn Field Long-Term Plots

 Author:

Randall J. Miles

 Affiliation:

University of Missouri-Columbia, Columbia, MO

 Abstract:

Historic Sanborn Field was established in the fall of 1888.  The longevity of Sanborn Field allows for the collection of cropping systems and soil data over a wide time span.  Soil organic matter (SOM) and soil organic carbon (SOC) are dynamic components which reflect changes in the environment and management practices.  Plot management treatment practices range from monocultures and rotations of 3 and 4 years, commercial fertilizer applications, to manure applications, as well as no fertility or manure additions.  Tillage practices on all plots but one are conventional moldboard plowing with one corn plot being in a continuous no-till management scheme since 1972.  Some of the plots have had similar crop and soil management practices since inception. The remaining plots have had periodic management changes.  One major change was the return of residues to the plot of origin in 1950.  A comparison of SOM and SOC from samples taken on Sanborn Field from 1915, 1938, 1963, and 1988 were compared to samples taken recently on the same plots and demonstrates the changes that have occurred under different management schemes.  With these different practices there are marked differences in the affect that these treatments have on the change in SOM and SOC in the soil over the life of the field.  Immediate large increases in SOM or SOC were not noted after the initiation of residue return.  Relatively recent increases in SOM and SOC have been noted in manured plots as modern day manure tends to be more concentrated and have less bedding than earlier manure sources.  Also, greater crop growth residue return could account for slight increases in SOM and SOC in some rotations.