TY - CHAP T1 - Belowground biology and processes T2 - Grassland Dynamics: Long-Term Ecological Research in Tallgrass Prairie Y1 - 1998 A1 - C. W. Rice A1 - Todd, T.C. A1 - John M. Blair A1 - Seastedt, T.R. A1 - Ramundo, R.A. A1 - G.T. Wilson ED - Alan K. Knapp ED - J. M. Briggs ED - D.C. Hartnett ED - Scott. L. Collins KW - tallgrass prairie JF - Grassland Dynamics: Long-Term Ecological Research in Tallgrass Prairie PB - Oxford University Press CY - New York ER - TY - CHAP T1 - Terrestrial nutrient cycling in tallgrass prairie T2 - Grassland Dynamics: Long-term Ecological Research Y1 - 1998 A1 - John M. Blair A1 - Seastedt, T.R. A1 - C. W. Rice A1 - Ramundo, R.A. ED - Alan K. Knapp ED - J. M. Briggs ED - D.C. Hartnett ED - Scott. L. Collins KW - tallgrass prairie JF - Grassland Dynamics: Long-term Ecological Research PB - Oxford University Press CY - New York ER - TY - JOUR T1 - Fire and topographic effects on decomposition rates and nitrogen dynamics of buried wood in tallgrass prairie JF - Soil Biology & Biochemistry Y1 - 1996 A1 - O'Lear, H.A. A1 - Seastedt, T.R. A1 - J. M. Briggs A1 - John M. Blair A1 - Ramundo, R.A. KW - tallgrass prairie AB - Decay rates and N dynamics of wood in soils of annually burned and unburned tallgrass prairie were measured over a 3-y period. Wooden dowels were placed at upland, mid-slope and lowland sites in two annually burned and two unburned watersheds. After 3 y, an average of only 15% of initial wood mass remained in burned watersheds, while 34% remained in unburned watersheds. Topographic position also significantly affected decay rates, with dowels decaying faster in the shallow-soil, upland sites and slope sites than in the deep-soil, lowland sites. This pattern is opposite of that generally observed for plant productivity (i.e. greater at lowland sites compared to uplands), and suggests that the controls of belowground decomposition and plant productivity are dissimilar. Dowels in both burned and unburned watersheds showed significant increases in N concentration over 3 y. Topographic position did not affect N concentration in the residual dowel material. Burn treatment, however, did affect N concentration, with dowels decomposing in burned watersheds having a higher average N concentration (0.5% after 3 y exposure) than dowels in unburned watersheds (0.43%). Relatively rapid decay rates resulted in net release of N, despite increased N concentration in the residual material. Faster net N release on the annually burned watershed was due to faster mass loss, since there were no differences in the rate of increase in N concentration per unit mass lost. Surface soil temperatures on burned prairie following spring fire usually exceed those on unburned prairie. However, average monthly summer soil temperatures (May–August) at a 10 cm depth in burned and unburned plots during the study were not statistically different and could not explain decay rate differences. Additionally, one of our unburned watersheds was accidentally burned during the first year of the study. Surprisingly, there were no significant differences in rates of wood decay between that watershed and the other unburned watershed. This suggests that indirect effects of annual fire (i.e. changes in the composition of soil flora and fauna) may override the short-term effects of fire (i.e. changes in soil temperature and moisture) on belowground decomposition in tallgrass prairie. VL - 28 ER - TY - JOUR T1 - Nitrogen transport from tallgrass prairie watersheds JF - Journal of Environmental Quality Y1 - 1996 A1 - W. K. Dodds A1 - John M. Blair A1 - Henebry, G.M. A1 - Koelliker, J.K. A1 - Ramundo, R.A. A1 - Tate, C.M. KW - tallgrass prairie AB - Discharge and N content of surface water flowing from four Karst watersheds on Konza Prairie Research Natural Area, Kansas, managed with different burn frequencies, were monitored from 1986 to 1992. The goal was to establish the influence of natural processes (climate, fire, and bison grazing) on N transport and concentration in streams. Streams were characterized by variable flow, under conditions that included an extreme flood and a drought during which all channels were dry for over a year. The estimated groundwater/stream water discharge ratio varied between 0.15 to 6.41. Annual N transport by streams, averaged across all watersheds and years, was 0.16 kg N ha−1 yr−1. Annual N transport per unit area also increased as the watershed area increased and as precipitation increased. Total annual transport of N from the prairie via streams ranged from 0.01 to 6.0% of the N input from precipitation. Nitrate and total N concentrations in surface water decreased (P < 0.001, r values ranged from 0.14–0.26) as length of time since last fire increased. Increased watershed area was correlated negatively (P < 0.0001) to stream water concentrations of NO−3N and total N (r values = −0.43 and −0.20, respectively). Low N concentration is typical of these streams, with NH+4-N concentrations below 1.0 µg L−1, NO−3-N ranging from below 1.4 to 392 µg L−1, and total N from 3.0 to 714 µg L−1. These data provide an important baseline for evaluating N transport and stream water quality from unfertilized grasslands. VL - 25 ER - TY - Generic T1 - Effects of tallgrass prairie vegetation on the concentration and seasonality of nitrate\-nitrogen in soil water and streams Y1 - 1992 A1 - Ramundo, R.A. A1 - Tate, C.M. A1 - Seastedt, T.R. ED - Smith, D.A. ED - Jacobs, C.A. KW - tallgrass prairie AB -

Inorganic nitrogen concentrations in tallgrass prairie soils and streams exhibit a sinusoidal seasonal pattern; nitrate levels are relatively high in winter and low in summer. The pattern is not observed in either rainfall or canopy drip (throughfall). Thus, the pattern is created by plant root-microbial interactions; when roots are not active, nitrates accumulate and can be leached from the soil. We used nitrogen fertilizer and herbicide in a factorial experiment to test the strength of root uptake activities on soil water nitrogen. Soil-water nitrate concentrations were 10 times higher when prairie roots were deactivated by application of a foliar herbicide. Ammonium nitrogen concentrations were unaffected. When fertilizer was added, nitrate levels of soil water beneath herbicide-treated vegetation were double that of untreated prairie. Mineralization of nitragen from herbicide-treated roots was not believed to be the source of the increased nitrate. These and previous studies at Konza Prairie emphasize the importance of plant cover in maintaining low nitrate concentrations of streams

PB - University of Northern Iowa ER - TY - CHAP T1 - The influence of fire on belowground processes of tallgrass prairies T2 - Fire in North American Tallgrass Prairie Y1 - 1990 A1 - Seastedt, T.R. A1 - Ramundo, R.A. ED - Scott. L. Collins ED - Wallace, L.L. KW - tallgrass prairie JF - Fire in North American Tallgrass Prairie PB - University of Oklahoma Press CY - Norman, OK ER - TY - JOUR T1 - Site-specific underestimation of wetfall NH+4 using NADP data JF - Atmospheric Environment Y1 - 1990 A1 - Ramundo, R.A. A1 - Seastedt, T.R. AB -

Estimates of NH4+ in weekly composited wetfall samples were measured by two laboratories, one at Kansas State University and that operated by the National Atmospheric Deposition Program (NADP) in Illinois. NH4+ samples were lower in the NADP estimates and exhibited a strong seasonal difference in concentrations. Losses were likely not due to volatilization; microbial immobilization of NH4+ likely occurred during transport of samples. Differences in estimates of annual ammonium ion deposition were larger than those observed for average weekly concentrations because of seasonal rainfall patterns. NADP values will require site-specific corrections for models describing or predicting regional or national patterns of nitrogen inputs in wetfall. Key words: Ammonium, NADP, nitrate, wetfall

VL - 24A ER - TY - Generic T1 - Effects of manipulation on foliage characteristics of Andropgon gerardii Vitman Y1 - 1989 A1 - Ramundo, R.A. A1 - Shapley, T.D. A1 - Turner, C.L. A1 - Dyer, M.I. A1 - Seastedt, T.R. ED - Bragg, T.B. ED - Stubbendieck, J. KW - burning AB -

The effects of burning, mowing, and nitrogen fertilizer on the chlorophyll, nitrogen, and phosphorus content of big bluestem were measured using a factorial experimental design at Konza Prairie Research Natural Area. While spring burning usually increased foliage production, burning had no effect on mid-season chlorophyll or nitrogen concentrations. Chlorophyll concentrations were significantly increased by fertilizer and mowing treatments. Nitrogen concentrations of foliage were higher on fertilized and mowed plots. Mowing also increased phosphorous concentrations of foliage, but nitrogen fertilizer significantly reduced phosphorus concentrations. These results support other research indicating that 1) nitrogen use efficiency (grams biomass produced per gram of foliage nitrogen) is higher on burned prairie, 2) removal of foliage by mowing results in more nutrient-rich regrowth, and 3) the amount of phosphorus available to big bluestem foliage is limited. The dilution of phosphorus caused by added nitrogen was a consequence of increased productivity on these plots and suggessts phosphorus uptake in excess of requirements for maximum growth. The relationships between burning, mowing, and nitrogen on the spectral reflectance patterns of vegetation indicated that chlorophyll (or nitrogen) concentrations of foliage appeared to more strongly affect indices of greenness and plant vigor than did the amount of plant biomass. Key words: biomass, burning, mowing, big bluestem, Andropogon gerardii, chlorophyll, nitrogen, phosphorus, Kansas

PB - University of Nebraska Press CY - Lincoln, NE ER - TY - Generic T1 - Silica, nitrogen and phosphorus dynamics of tallgrass prairie Y1 - 1989 A1 - Seastedt, T.R. A1 - Ramundo, R.A. A1 - Hayes, D.C. ED - Bragg, T.B. ED - Stubbendieck, J. KW - tallgrass prairie AB -

Experiments were conducted on big bluestem (Andropogon gerardii Vitman) in the greenhouse and on a tallgrass site on Konza Prairie to evaluate the effects of simulated grazing on the cycling of silica (SiO2), nitrogen, and phosphorus. Concentrations of all elements increased in vegetation that had been clipped or pruned. The absolute amount of nitrogen obtained by plants in the greenhouse experiment was increased by clipping foliage. Phosphorous exhibited only neutral or negative responses, while the absolute amount of silica declined in all but one experiment involving root pruning. In that experiment, the absolute amount of silica in roots was increased by 25% by cutting a portion of the root system. These results suggest that the direct effects of clipping or pruning on the absolute amounts of elements cycled through vegetation are usually neutral or negative. Increased silicification or grazed foliage is suggested to be a consequence of delayed senescence and reduced leaf area. This interpretation provides a proximate reason why silicification is an "inducible defense" against herbivores. Key words: big bluestem, Andropogon gerardii, simulated grazing, nutrients, productivity, roots, Kansas

PB - University of Nebraska Press CY - Lincoln, NE ER - TY - JOUR T1 - Maximization of densities of soil animals by foliage herbivory: empirical evidence, graphical and conceptual models JF - Oikos Y1 - 1988 A1 - Seastedt, T.R. A1 - Ramundo, R.A. A1 - Hayes, D.C. AB -

Feeding by consumers on one portion of a plant resource often results in benefits to consumer feeding on other portions of the same resource. Moderate grazing of foliage often increases densities and biomass of belowground herbivores and detritivores in spite of a neutral or reduced root growth response to foliage removal. Graphical and conceptual models are presented to describe these responses and suggest causal relationships. Empirical data and the models indicate that the positive numerical response of soil animals to foliage herbivory results from increased quality (nitrogen concentration) of roots and changes in consumer assimilation efficiencies. Root growth and senescence and acquisition of soil inorganic nitrogen by microbes colonizing senescent roots are hypothesized as additional causal agents for the soil animal response

VL - 51 ER -