Nitrogen dynamics of soil water in burned and unburned tallgrass prairie

TitleNitrogen dynamics of soil water in burned and unburned tallgrass prairie
Publication TypeJournal Article
Year of Publication1989
AuthorsHayes, DC, Seastedt, TR
JournalSoil Biology & Biochemistry
Pagination1003 -1007
Accession NumberKNZ00231
Keywordstallgrass prairie

Porous cup lysimeters were used to study the effects of spring burning for 5 yr on soil water N dynamics of tallgrass prairie. NO3--N concentration within the the rooting zone (20 cm depth) were unaffected by burning and averaged 27 æg 1-1. Concentrations at 80 cm were also similar for burned and unburned prairie and averaged 13 æg 1-1. Organic N was the dominant form of N in soil water, and showed a strong effect of treatment and depth. Oraganic N concentration averaged 409 æg 1-1 at 20 cm depth on unburned watersheds versus 295 æg 1-1 on burned watersheds (P< 0.05). Values were not influenced by burning at 80 cm depths but were 30-50% lower than those observed at 20 cm. Soil water N concentrations averaged < 30% of those observed in bulk precipitation inputs, and while fire is responsible for the maintenance of the tallgreass prairie flora, fire does not appear to be an important factor affecting groundwater export of N in this biome. Total N concentrations increased from an average of ca.200 æg 1-1 in 1982 to an average of ca.400 æg 1-1 during 1986, while lysimeter volumes declined from > 400 to ca.200 sample-1. These changes were not related to precipitation, and suggests that the soil environment sampled by the lysimeters changes through time