Abstract
The aim is to address underlying factors and ecological processes driving spatial patterns of the nitrifying microbial communities at the field and landscape scale, and how this relates to nitrification and nitrate leaching in different crop production systems. Nitrification is a two-step process, in which NH3 is oxidized to NO2- by the ammonia-oxidizing bacteria (AOB) or archaea (AOA), and further to NO3 by the nitrite oxidizing bacteria (NOB). Predicting spatial patterns at the field scale is the first step in identifying the soil-based resources of nitrifier communities at a scale compatible with land management strategies. Increased knowledge on nitrifier ecology integrated with the knowledge and tools within precision agriculture has a potential to accommodate measures in agricultural for mitigation of nitrate leaching. Using a molecular and phylogentic approach combined with geostatistical modelling we will 1) compare the influence of integrated and organic farming systems on spatial patterns of size, structure and activity of AOB, AOA and NOB communities in relation to nitrate leaching, 2) identify the management induced soil factors defining spatial patterns of nitrifying communities and 3) spatial modelling of the phylogenetic structure of nitrifier communities at the field scale to address the relative importance of different underlying ecological processes leaving their signature on the phylogenetic structure of the AOB, AOA and NOB communities.
Sweden