See more from this Session: Soil Carbon, Nitrogen and GHG Fluxes: I
Wednesday, November 3, 2010: 11:15 AM
Long Beach Convention Center, Room 104A, First Floor
Any change in land use will influence the quantity and quality of C entering the soil hence soil C sequestration. Soil management practices also impact microbial communities involved in C dynamics. Mycorrhizae play an important role in C translocation and are impacted by soil management. The objective of this study was to investigate how land use and soil management impacts soil microbial communities and soil C accumulation. The study area was located at the Konza Prairie Biological Station (KPBS). The experimental design was a split plot with main plots arranged in a randomized complete block. Main plots were no-till (NT) and conventional till (CT) continuous grain sorghum and restored prairie (RP) planted to big bluestem. Phosphorus (+ P) was applied to suppress mycorrhizae or no addition (- P) (n = 4). Soil samples were collected at two depths (0-5 and 5-15 cm). Microbial communities were determined by PLFA. The microbial categories identified were Gram –ve and Gram +ve bacteria, fungi, arbuscular mycorrhizae fungi (AMF), and actinomycetes. Soil was separated into aggregate size classes by wet sieving. Phosphorus addition significantly influenced % AM root colonization, fungi, actinomycetes and Gram-ve bacteria. Microbial biomass, macroaggregate, % AM fungal root colonization was highest in RP with total C being higher in undisturbed systems (RP and NT) than CT at 0 - 5 cm depth. There was significant correlation between macroaggregate and % AM root colonization. Therefore during the six years of this study, soil microbial community structure and total C were impacted by land use change and soil management.