Soil Carbon and Nitrogen Accumulation As Influenced By Turfgrass Selection and Grass Clipping Management.

Soil carbon (C) is made up of different pools that vary in their turnover time or rate of decomposition; labile soil C is broken down in less than 5 yr, and, due to its rapid turnover, is considered a more sensitive indicator of changes in soil quality and function than total soil C, which includes both organic and inorganic components.  Different grass species and certain management practices, such as grass clipping management, are thought to influence soil C and nitrogen (N) accumulation.  Thus, the objective of this experiment was to determine the labile soil C, total soil C, and total soil N accumulation of Kentucky bluegrass (Poa pratensis L.) and tall fescue (Schedonorus arundinaceus (Schreb.) Dumort.) cultivars with differing growth rates under different grass clipping management practices.  Differences in labile and total soil C were realized between turfgrass species after 3 yr of growth post-planting, with tall fescue having 10.0% more labile soil C and 4.6% more total soil C than Kentucky bluegrass.  After 2 yr under different mowing practices, plots where grass clippings were returned had 3.3% more labile soil C, 3.5% more total soil C, and 4.6% more total soil N than those where clippings were collected.  The results of this study highlight the importance of turfgrass selection and grass clipping management on soil C and N accumulation.