Submitted to: Agronomy Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 10/24/2003
Publication Date: 11/2/2003
Citation: PENGTHAMKEERATI, P., MOTAVALLI, P.P., KREMER, R.J. EFFECTS OF COMPACTION AND APPLIED POULTRY LITTER ON SOIL MICROBIAL ACTIVITY AND DIVERSITY IN A CLAYPAN SOIL. AGRONOMY ABSTRACTS. 2003. CD-ROM (UNPAGINATED). AMERICAN SOCIETY OF AGRONOMY. MADISON, WI.
Technical Abstract: Negative effects of compaction on soil physical properties and agricultural production are well documented; however, few studies have involved effects on soil microbial properties in claypan soils. Our objective was to determine the effects of surface compaction on microbial activity and diversity in a claypan soil amended with poultry litter. Research was conducted over two growing seasons (2001-2002) on a Mexico silt loam (fine, montmorillonitic, mesic Mollic Endoaqualf) in North Central Missouri. In each year, poultry litter was incorporated in soil (0 and 16.0 Mg/ha) and uniformly compacted by a tractor-pulled water wagon. Surface soil CO2 efflux (respiration), microbial biomass C (MBC), and N (MBN) significantly decreased in compacted soils, likely due to changes in pore size distribution and saturated hydraulic conductivity . Compaction did not significantly reduce soil enzyme activities (b-glucosidase and b-glucosaminidase) possibly because compaction only increased average soil bulk density from 1.24 to 1.39 Mg/m**-3. The litter amendment promoted microbial activity and biomass relative to unamended soils. Soil microbial community analysis using substrate utilization (BIOLOG Ecoplate) was sensitive to compaction and litter effects. Results indicate that compaction limits decomposition rates and changes microbial diversity by altering soil physical properties and reducing soil respiration and microbial biomass.