Divergent effects of texture on C quantity and and quality in soil size fractions. (5437)
Authors:
J.B. Gruver* - N C State Univ.
M.G. Wagger - NC State Univ.
Abstract:
It is widely recognized that fine mineral materials contribute to the retention of C in soils but relatively little is known about the regulatory effects of fine mineral
materials on C quantity and quality in soil size fractions. Udipsamment and Hapludult soils were collected (0-7.5cm) from a 3 yr old cropping system
experiment located in the Central Coastal Plain of North Carolina. The soils were size fractionated (less than 20 microns = fine, 20 to 250 microns = medium, greater than 250 microns = coarse) and all fractions were analyzed for total and
permanganate oxidizable C (POC). Fine mineral content ranged from 117 to 288 g/kg. Soils receiving high C inputs contained greater total C than soils receiving low C inputs, but 55 % of the variation in total C was associated with variation in fine mineral content. When soils were pooled, strong relationships were identified between fine mineral content and C characteristics. Medium total C content, coarse total C content, fine POC content and fine C quality (POC/total C) increased with respect to fine mineral content. Fine total C loading (fine C/fine mineral content), coarse POC content and coarse C quality decreased with respect to fine mineral content. These relationships suggest that the regulatory effects of fine mineral materials on soil C are strong and scale dependent.
Speaker Information: Joel Gruver, N C State Univ., 2512 Vanderbilt Ave., Raleigh, NC 27607; Phone: (919) 833 - 4664; E-mail: [email protected]
Session Information: Thursday, November 4, 2004, 8:00 AM-12:10 PM Presentation Start: 9:30 AM
Keywords: C; texture; size fractions; permanganate
