ARS | Publication request: LINKING NITRIFICATION AND MICROBIAL COMMUNITY DYNAMICS OF B-AMMONIA OXIDIZERS IN MANURED SOILS OF CONTRASTING ECOREGIONS

Submitted to: American Society of Agronomy
Publication Type: Abstract Only
Publication Acceptance Date: November 7, 2005
Publication Date: November 11, 2005
Citation: Fortuna, A., Honeycutt, C.W., Marsh, T.L. 2005. Linking nitrification and microbial community dynamics of b-ammonia oxidizers in manured soils of contrasting ecoregions. American Society of Agronomy. On CD.

Technical Abstract: The amount of N transformed via nitrification is dependent on a variety of biotic and abiotic factors including microbial community composition and soil type. Nitrification should be linked to the microbial community of keystone organisms that control nitrification, the ß-ammonia oxidizers. Two soils from different ecoregions, Mississippi (clay) and Illinois (clay loam), were incubated in microcosms for 150-d to determine the effect of manuring and soil type on N transformations and nitrifier community structure. Nitrification potentials determined via the shaken slurry method, 2M KCl extractable N and the community structure of ß-ammonia oxidizers measured via terminal restriction fragment length polymorphism (T-RFLP) were monitored at six time intervals. Extractable N was higher in the clay loam than in the clay. Manuring resulted in higher extractable N in the clay relative to the clay loam. Nitrification was highest in the clay on manured and unmanured treatments. Greater nitrification rate in the clay was not directly related to the quantity of extractable N. Differences in T-RFLP patterns will be compared to nitrification rates. Management strategies and soil conditions that affect ß-ammonia oxidizer populations such that nitrification is reduced can limit N losses and provide new insight into the link between process level function and microbial community structure.