Relationships Between Selected Prairie Plant Species and Soil TOC and DOC.

Dissolved organic carbon (DOC)  in addition to total organic carbon (TOC) are important components of soil carbon sequestration, biogeochemical cycles, and soil quality.  Limited research has been conducted on DOC concentration and distribution by depth in relation to total organic carbon (TOC) in a soil profile as affected by plant species.  This study attempts to determine 1) the amount of DOC in soil in relation to TOC;   2) location of  DOC found in the soil profile; and 3) TOC and DOC concentration and distribution by depth as affected by plant species.   Soil cores were collected at two sites in North Dakota utilizing a randomized complete block with split plot sampling design.  The soil textures were a fine sandy loam with the average annual precipitation ranging from 520 mm near Kindred on the eastern border to 385 mm near Carrington in central North Dakota.  Soils were sampled under the following prairie plant species: big bluestem (Andropogon gerardii Vitman),  switchgrass (Panicum virgatum L.),  crested wheatgrass (Agropyron cristatum (L.) Gaertn.), ) Sideoats  grama (Bouteloua curtipendula (Michx.) Torr.),  Canada wildrye  (Elymus Canadensis L.),  Smooth brome (Bromus inermis Leyss.),  Kentucky bluegrass (Poa pratensis L.),  Maximillian sunflower (Helianthus maximilliana),  and Canadian/Missouri goldenrod (Solidago canadensis/missouriensis Nutt.).  The relationships between plant species and TOC and DOC changes in the soil will be discussed.