PARENT SESSION
Poster Session # 10: Soil Ecology.
Tuesday, August 5 Presentation from 5:00 PM to 6:30 PM. SITCC Exhibit Hall B.
Divergence in microbial community structure and activities in managed ecosystems: Implications for soil carbon dynamic.
Zhang, Weijian*,1, 2, Wu, Jiansheng1, Tu, Cong1, Hu, Shuijin1, 1 North Carolina State University, Raleigh, NC2 Nanjing Agricultural University, Nanjing, Jiangshu, China
ABSTRACT- Carbon sequestration in agricultural soils may have the potential to significantly reduce the agricultural contribution to atmospheric carbon dioxide. Nevertheless, the magnitude of this C sequestration is unclear because the resulting effects of alternative management practices on soil microbes and microbially mediated processes are not well understood. We investigated the effects of different management regimes on soil microbial community structure and activities in six ecosystems near Goldsboro, NC. The six adjacent and replicated ecosystems studied included a successional ecosystem, a plantation forestry-woodlot, an integrated crop-animal production system, an organic production system and two row cropping systems with conventional tillage or no-tillage. After 5 years of continuous treatments, the soil microbial communities diverge, with microbial biomass, activities and diversity being significantly higher in the ecosystems with intermediate levels of disturbance and chemical inputs than in the ecosystems with high or low levels. Fungal contribution to the total microbial biomass increased as disturbance decreased except in the crop-animal production system. Increased fungal dominance coincided with a decrease in microbial respiration in ecosystems with high disturbance.These results suggest that reducing human disturbance and increasing the complexity of agroecosystems may facilitate the development of microbial communities that are conducive to C sequestration in agricultural soils.
Key words: microbial activity, carbon dynamic, Microbial community, managed ecosystem