Soil microbial activity and functional diversity changed by compaction, poultry litter and cropping in a claypan soil

Changes in soil physical characteristics induced by soil compaction may alter soil microhabitats and, therefore, play a significant role in governing soil microorganisms and their activities. Laboratory incubation and field experiments (in 2001 and 2002) were conducted to investigate the effect of soil compaction on soil microbiological properties in a claypan soil amended with poultry litter and cropped to corn (Zea mays L.). In both laboratory and field studies, moderate soil compaction increased total soil organic C. beta-glucosidase activity, microbial biomass C (MBC), and microbial functional diversity, but decreased soluble organic C (Sol C). However, more severe soil compaction imposed in the laboratory caused an adverse effect on these soil microbiological properties, except for Sol C. Turkey (Meleagris gallopavo) litter application and cropping significantly increased soil beta-glucosidase activity, MBC, Sol C and microbial functional diversity, partly due to inputs of labile C substrates from both litter and crops. Overall, modification of soil microhabitat by compaction could change soil microbial growth and activity in relation to C and shift soil microbial functional diversity; however, the positive effects of litter addition and cropping could overcome the compaction effect on these soil microbiological properties. (C) 2011 Elsevier B.V. All rights reserved.