@mastersthesis {KNZ001998, title = {Effect of land use and land use management on methane oxidation}, volume = {MS Thesis}, year = {2020}, school = {Kansas State University}, type = {M.S. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, url = {https://krex.k-state.edu/dspace/handle/2097/40327}, author = {Wanithunga, Irosha} } @article {KNZ001973, title = {Long-term biomass and potential ethanol yields of annual and perennial biofuel crops}, journal = {Agronomy Journal}, volume = {111}, year = {2019}, pages = {74 - 83}, abstract = {

Although energy crops could eventually supply a growing portion of cellulosic biofuel feedstocks, long-term comparisons of annual and perennial crops are rare. An experiment was established in 2007 near Manhattan, KS, to compare biomass productivity and ethanol yield of perennial and annual crops. Perennial crops included three C4 grasses: switchgrass (Panicum virgatum L.), big bluestem (Andropogon gerardii Vitman), and miscanthus (Miscanthus sacchariflorus). Annual C4 crops were corn (Zea mays L.) in two rotations: continuous and rotated with soybean [Glycine max (L.) Merr.]; and five types of sorghum [Sorghum bicolor (L.) Moench]: photoperiod sensitive, sweet, dual purpose (grain and biomass), brown mid-rib, and grain; all rotated with soybean. Annual crops produced 7 Mg ha\–1 yr\–1 more biomass than perennial crops throughout 11 yr, with sweet sorghum exceeding 22 Mg ha\–1 yr\–1, and 12 m3 ha\–1 yr\–1 of ethanol. Biomass yield of miscanthus approached 14 Mg ha\–1 yr\–1, essentially the same as for several annual crops but with half as much fertilizer nitrogen. Annual ethanol production from miscanthus and switchgrass was 3.6 m3 ha\–1 yr\–1, half as much as that of several annual crops that produced similar biomass yields. Big bluestem consistently produced the least biomass and ethanol, less than 7 Mg ha\–1 yr\–1 and 1.7 m3 ha\–1 yr\–1, respectively. Rotated corn averaged 7.1 m3 ha\–1 yr\–1 of ethanol. Eleven years of results indicate that annual corn and sorghum crops as well as perennial grasses such as miscanthus and switchgrass could play a role as potential bioenergy feedstocks in diversified production systems.

}, keywords = {LTER-KNZ}, doi = {0.2134/agronj2018.03.0172}, url = {http://doi.wiley.com/10.2134/agronj2018.03.0172}, author = {Roozeboom, Kraig L. and Wang, Donghai and McGowan, Andrew R. and Propheter, Jonathan L. and Staggenborg, Scott A. and C. W. Rice} } @article {KNZ001975, title = {Metaphenomic response of a native prairie soil microbiome to moisture perturbations}, journal = {mSystems}, volume = {4}, year = {2019}, pages = {e00061-19}, abstract = {

Climate change is causing shifts in precipitation patterns in the central grasslands of the United States, with largely unknown consequences on the collective physiological responses of the soil microbial community, i.e., the metaphenome. Here, we used an untargeted omics approach to determine the soil microbial community\’s metaphenomic response to soil moisture and to define specific metabolic signatures of the response. Specifically, we aimed to develop the technical approaches and metabolic mapping framework necessary for future systematic ecological studies. We collected soil from three locations at the Konza Long-Term Ecological Research (LTER) field station in Kansas, and the soils were incubated for 15 days under dry or wet conditions and compared to field-moist controls. The microbiome response to wetting or drying was determined by 16S rRNA amplicon sequencing, metatranscriptomics, and metabolomics, and the resulting shifts in taxa, gene expression, and metabolites were assessed. Soil drying resulted in significant shifts in both the composition and function of the soil microbiome. In contrast, there were few changes following wetting. The combined metabolic and metatranscriptomic data were used to generate reaction networks to determine the metaphenomic response to soil moisture transitions. Site location was a strong determinant of the response of the soil microbiome to moisture perturbations. However, some specific metabolic pathways changed consistently across sites, including an increase in pathways and metabolites for production of sugars and other osmolytes as a response to drying. Using this approach, we demonstrate that despite the high complexity of the soil habitat, it is possible to generate insight into the effect of environmental change on the soil microbiome and its physiology and functions, thus laying the groundwork for future, targeted studies.

}, keywords = {LTER-KNZ, metaphenome, metatranscriptome, multi-omics, soil microbiome}, doi = {10.1128/mSystems.00061-19}, url = {http://msystems.asm.org/lookup/doi/10.1128/mSystems.00061-19}, author = {Roy Chowdhury, Taniya and Lee, Joon-Yong and Bottos, Eric M. and Brislawn, Colin J. and White, Richard Allen and Bramer, Lisa M. and Brown, Joseph and Zucker, Jeremy D. and Kim, Young-Mo and A. Jumpponen and C. W. Rice and Fansler, Sarah J. and Metz, Thomas O. and McCue, Lee Ann and Callister, Stephen J. and Song, Hyun-Seob and Jansson, Janet K.}, editor = {Hallam, Steven J.} } @article {KNZ001939, title = {More salt, please: global patterns, responses and impacts of foliar sodium in grasslands}, journal = {Ecology Letters}, volume = {22}, year = {2019}, note = {

NSF-DEB-1234162

}, pages = {1136 - 1144}, abstract = {

Sodium is unique among abundant elemental nutrients, because most plant species do not require it for growth or development, whereas animals physiologically require sodium. Foliar sodium influences consumption rates by animals and can structure herbivores across landscapes. We quantified foliar sodium in 201 locally abundant, herbaceous species representing 32 families and, at 26 sites on four continents, experimentally manipulated vertebrate herbivores and elemental nutrients to determine their effect on foliar sodium. Foliar sodium varied taxonomically and geographically, spanning five orders of magnitude. Site-level foliar sodium increased most strongly with site aridity and soil sodium; nutrient addition weakened the relationship between aridity and mean foliar sodium. Within sites, high sodium plants declined in abundance with fertilisation, whereas low sodium plants increased. Herbivory provided an explanation: herbivores selectively reduced high nutrient, high sodium plants. Thus, interactions among climate, nutrients and the resulting nutritional value for herbivores determine foliar sodium biogeography in herbaceous-dominated systems.

}, keywords = {LTER-KNZ}, issn = {1461-023X}, doi = {10.1111/ele.13270}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.13270}, author = {E.T. Borer and Lind, E. M. and Firn, J. and Seabloom, E. W. and Anderson, T. M. and Bakker, E. S. and L.A. Biederman and Kimberly J. La Pierre and MacDougall, A. S. and Joslin L. Moore and C. W. Rice and sch{\"u}tz, M. and Stevens, C. J.} } @article {KNZ001977, title = {Nitrous oxide emissions from annual and perennial biofuel cropping systems}, journal = {Agronomy Journal}, volume = {111}, year = {2019}, pages = {84 - 92}, keywords = {LTER-KNZ}, doi = {10.2134/agronj2018.03.0187}, url = {http://doi.wiley.com/10.2134/agronj2018.03.0187}, author = {McGowan, Andrew R. and Roozeboom, Kraig L. and C. W. Rice} } @phdthesis {KNZ001984, title = {Soil and microbial response to manipulated precipitation and land management}, volume = {PhD Dissertation}, year = {2019}, school = {Kansas State University}, type = {Ph.D. Thesis}, address = {Manhattan, KS}, keywords = {LTER-KNZ}, url = {https://krex.k-state.edu/dspace/handle/2097/39682}, author = {Carter, Tiffany} } @article {KNZ001986, title = {Soil organic carbon, aggregation, and microbial community Structure in annual and perennial biofuel crops}, journal = {Agronomy Journal}, volume = {111}, year = {2019}, pages = {128 - 142}, keywords = {LTER-KNZ}, doi = {10.2134/agronj2018.04.0284}, url = {http://doi.wiley.com/10.2134/agronj2018.04.0284}, author = {McGowan, Andrew R. and Nicoloso, Rodrigo S. and Diop, Habib E. and Roozeboom, Kraig L. and C. W. Rice} } @article {KNZ001990, title = {Impact of nitrogen application rate on switchgrass yield, production costs, and nitrous oxide emissions}, journal = {Journal of Environmental Quality}, volume = {47}, year = {2018}, pages = {228 - 237}, keywords = {LTER-KNZ}, doi = {10.2134/jeq2017.06.0226}, url = {http://doi.wiley.com/10.2134/jeq2017.06.0226}, author = {McGowan, Andrew R. and Min, Doo-Hong and Williams, Jeffery R. and C. W. Rice} } @article {KNZ001891, title = {Microbial community structure and functional potential in cultivated and native tallgrass prairie soils of the midwestern united states}, journal = {Frontiers in Microbiology}, volume = {9}, year = {2018}, pages = {1775}, abstract = {

The North American prairie covered about 3.6 million-km2 of the continent prior to European contact. Only 1\–2\% of the original prairie remains, but the soils that developed under these prairies are some of the most productive and fertile in the world, containing over 35\% of the soil carbon in the continental United States. Cultivation may alter microbial diversity and composition, influencing the metabolism of carbon, nitrogen, and other elements. Here, we explored the structure and functional potential of the soil microbiome in paired cultivated-corn (at the time of sampling) and never-cultivated native prairie soils across a three-states transect (Wisconsin, Iowa, and Kansas) using metagenomic and 16S rRNA gene sequencing and lipid analysis. At the Wisconsin site, we also sampled adjacent restored prairie and switchgrass plots. We found that agricultural practices drove differences in community composition and diversity across the transect. Microbial biomass in prairie samples was twice that of cultivated soils, but alpha diversity was higher with cultivation. Metagenome analyses revealed denitrification and starch degradation genes were abundant across all soils, as were core genes involved in response to osmotic stress, resource transport, and environmental sensing. Together, these data indicate that cultivation shifted the microbiome in consistent ways across different regions of the prairie, but also suggest that many functions are resilient to changes caused by land management practices \– perhaps reflecting adaptations to conditions common to tallgrass prairie soils in the region (e.g., soil type, parent material, development under grasses, temperature and rainfall patterns, and annual freeze-thaw cycles). These findings are important for understanding the long-term consequences of land management practices to prairie soil microbial communities and their genetic potential to carry out key functions.

}, keywords = {LTER-KNZ, carbon cycle, Climate change, Land management, metagenomics, native prairie, nitrogen cycle, soil microbiome}, doi = {10.3389/fmicb.2018.01775}, url = {https://www.frontiersin.org/articles/10.3389/fmicb.2018.01775}, author = {Mackelprang, Rachel and Grube, Alyssa M. and Lamendella, Regina and Jesus, Ederson da C. and Copeland, Alex and Liang, Chao and Jackson, Randall D. and C. W. Rice and Kapucija, Stefanie and Parsa, Bayan and Tringe, Susannah G. and Tiedje, James M. and Jansson, Janet K.} } @inbook {KNZ001908, title = {Second State of the Carbon Cycle Report (SOCCR2): A Sustained Assessment Report}, booktitle = {Second State of the Carbon Cycle Report (SOCCR2): A Sustained Assessment Report}, year = {2018}, pages = {229 - 263}, publisher = {U.S. Global Change Research Program}, organization = {U.S. Global Change Research Program}, keywords = {LTER-KNZ}, doi = {10.7930/SOCCR2.2018.Ch5}, url = {https://carbon2018.globalchange.gov/chapter/5/}, author = {Hristov, A. N. and Johnson, J. M. F. and C. W. Rice and Brown, M. E. and Conant, R. T. and Del Grosso, S. J. and Gurwick, N. P. and Rotz, C. A. and Sainju, U. M. and Skinner, R. H. and West, T. O. and Runkle, B. R. K. and Janzen, H. and Reed, S. and Cavallaro, N. and Shrestha, G. and Birdsey, R.}, editor = {Cavallaro, N. and Shrestha, G. and Mayes, M. A. and Najjar, R. and Reed, S. and Romero-Lankao, P. and Zhu, Z.} } @article {KNZ002022, title = {Changes in spatial and temporal trends in wet, dry, warm and cold spell length or duration indices in Kansas, USA}, journal = {International Journal of Climatology}, volume = {36}, year = {2016}, pages = {4085 - 4101}, keywords = {LTER-KNZ}, doi = {10.1002/joc.4619}, url = {http://doi.wiley.com/10.1002/joc.4619}, author = {Anandhi, Aavudai and Hutchinson, Stacy and Harrington, John and Rahmani, Vahid and Kirkham, Mary B. and C. W. Rice} } @article {KNZ002021, title = {Soil Degradation: Will Humankind Ever Learn?}, journal = {Sustainability}, volume = {7}, year = {2015}, month = {Jan-09-2015}, pages = {12490 - 12501}, keywords = {LTER-KNZ}, doi = {10.3390/su70912490}, url = {http://www.mdpi.com/2071-1050/7/9/12490}, author = {Karlen, Douglas and C. W. Rice} } @inbook {KNZ002019, title = {Agriculture, Forestry and Other Land Use (AFOLU)}, booktitle = {Climate Change 2014: Mitigation of Climate Change. Contribution of Working Group III to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change }, year = {2014}, pages = {811-922}, publisher = {Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.}, organization = {Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.}, chapter = {11}, keywords = {LTER-KNZ}, url = {https://www.ipcc.ch/report/ar5/wg3/agriculture-forestry-and-other-land-use-afolu/}, author = {Smith, P. and Bustamante, M. and Ahammad, H. and Clark, H. and Dong, H. and Elsiddig, E. A. and Haberl, H. and Harper, R. and J. House and M. Jafari and O. Masera and C. Mbow and N.H. Ravindranath and C. W. Rice and C. Robledo Abad and A. Romanovskaya and F. Sperling and F. Tubiello} } @article {KNZ002020, title = {Knowledge and tools to enhance resilience of beef grazing systems for sustainable animal protein production}, journal = {Annals of the New York Academy of Sciences}, volume = {1328}, year = {2014}, pages = {10 - 17}, keywords = {LTER-KNZ}, doi = {10.1111/nyas.12572}, url = {https://www.ncbi.nlm.nih.gov/pubmed/25376887}, author = {Steiner, Jean L. and Engle, David M. and Xiao, Xiangming and Saleh, Ali and Tomlinson, Peter and C. W. Rice and Cole, N. Andy and Coleman, Samuel W. and Osei, Edward and Basara, Jeffrey and Middendorf, Gerad and Gowda, Prasanna and Todd, Richard and Moffet, Corey and Anandhi, Aavudai and Starks, Patrick J. and Ocshner, Tyson and Reuter, Ryan and Devlin, Daniel} } @article {KNZ001533, title = {Altered precipitation regime affects the function and composition of soil microbial communities on multiple time scales}, journal = {Ecology}, volume = {94}, year = {2013}, pages = {2334 -2345}, abstract = {

Climate change models predict that future precipitation patterns will entail lower-frequency but larger rainfall events, increasing the duration of dry soil conditions. Resulting shifts in microbial C cycling activity could affect soil C storage. Further, microbial response to rainfall events may be constrained by the physiological or nutrient limitation stress of extended drought periods; thus seasonal or multiannual precipitation regimes may influence microbial activity following soil wet-up. We quantified rainfall-driven dynamics of microbial processes that affect soil C loss and retention, and microbial community composition, in soils from a long-term (14-year) field experiment contrasting \“Ambient\” and \“Altered\” (extended intervals between rainfalls) precipitation regimes. We collected soil before, the day following, and five days following 2.5-cm rainfall events during both moist and dry periods (June and September 2011; soil water potential = \−0.01 and \−0.83 MPa, respectively), and measured microbial respiration, microbial biomass, organic matter decomposition potential (extracellular enzyme activities), and microbial community composition (phospholipid fatty acids). The equivalent rainfall events caused equivalent microbial respiration responses in both treatments. In contrast, microbial biomass was higher and increased after rainfall in the Altered treatment soils only, thus microbial C use efficiency (CUE) was higher in Altered than Ambient treatments (0.70 \± 0.03 \> 0.46 \± 0.10). CUE was also higher in dry (September) soils. C-acquiring enzyme activities (β-glucosidase, cellobiohydrolase, and phenol oxidase) increased after rainfall in moist (June), but not dry (September) soils. Both microbial biomass C:N ratios and fungal : bacterial ratios were higher at lower soil water contents, suggesting a functional and/or population-level shift in the microbiota at low soil water contents, and microbial community composition also differed following wet-up and between seasons and treatments. Overall, microbial activity may directly (C respiration) and indirectly (enzyme potential) reduce soil organic matter pools less in drier soils, and soil C sequestration potential (CUE) may be higher in soils with a history of extended dry periods between rainfall events. The implications include that soil C loss may be reduced or compensated for via different mechanisms at varying time scales, and that microbial taxa with better stress tolerance or growth efficiency may be associated with these functional shifts.

}, keywords = {LTER-KNZ}, doi = {10.1890/12-2018.1}, url = {https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/12-2018.1}, author = {Lydia H. Zeglin and Bottomley, P.J. and A. Jumpponen and C. W. Rice and Arango, M. and Lindsley, A. and McGowan, A. and Mfombep, P. and Myrold, D.D.} } @proceedings {KNZ001604, title = {Fungal community responses to discrete precipitation pulses under altered rainfall intervals}, volume = {103}, year = {2013}, pages = {182 -}, keywords = {LTER-KNZ}, author = {A. Jumpponen and Lydia H. Zeglin and David, M. and Prestat, E. and Brown, S. and Dvornik, J. and Lothamer, K. and Hettich, R. and Jansson, J. and C. W. Rice and Tringe, S. and Myrold, D.D.} } @article {KNZ001522, title = {Woody vegetation removal stimulates riparian and benthic denitrification in tallgrass prairie}, journal = {Ecosystems}, volume = {16}, year = {2013}, pages = {547 -560}, abstract = {

Expansion of woody vegetation into areas that were historically grass-dominated is a significant contemporary threat to grasslands, including native tallgrass prairie ecosystems of the Midwestern United States. In tallgrass prairie, much of this woody expansion is concentrated in riparian zones with potential impacts on biogeochemical processes there. Although the effects of woody riparian vegetation on denitrification in both riparian soils and streams have been well studied in naturally wooded ecosystems, less is known about the impacts of woody vegetation encroachment in ecosystems that were historically dominated by herbaceous vegetation. Here, we analyze the effect of afforestation and subsequent woody plant removal on riparian and benthic denitrification. Denitrification rates in riparian soil and selected benthic compartments were measured seasonally in naturally grass-dominated riparian zones, woody encroached riparian zones, and riparian zones with woody vegetation removed in two separate watersheds. Riparian soil denitrification was highly seasonal, with the greatest rates in early spring. Benthic denitrification also exhibited high temporal variability, but no seasonality. Soil denitrification rates were greatest in riparian zones where woody vegetation was removed. Additionally, concentrations of nitrate, carbon, and soil moisture (indicative of potential anoxia) were greatest in wood removal soils. Differences in the presence and abundance of benthic compartments reflected riparian vegetation, and may have indirectly affected denitrification in streams. Riparian soil denitrification increased with soil water content and NO3 \−. Management of tallgrass prairies that includes removal of woody vegetation encroaching on riparian areas may alter biogeochemical cycling by increasing nitrogen removed via denitrification while the restored riparian zones return to a natural grass-dominated state.

}, keywords = {LTER-KNZ, denitrification, nitrogen removal, prairie streams, riparian vegetation, tallgrass prairie, woody encroachment}, doi = {10.1007/s10021-012-9630-3}, url = {https://link.springer.com/article/10.1007\%2Fs10021-012-9630-3}, author = {Reisinger, A.J. and John M. Blair and C. W. Rice and W. K. Dodds} } @article {KNZ001248, title = {Soil aggregation and carbon sequestration are tightly correlated with the abundance of arbuscular mycorrhizal fungi: results from long-term field experiments}, journal = {Ecology Letters}, volume = {12}, year = {2009}, pages = {452 -461}, abstract = {

We examined the role of arbuscular mycorrhizal fungi (AMF) in ecosystems using soil aggregate stability and C and N storage as representative ecosystem processes. We utilized a wide gradient in AMF abundance, obtained through long-term (17 and 6 years) large-scale field manipulations. Burning and N-fertilization increased soil AMF hyphae, glomalin-related soil protein (GRSP) pools and water-stable macroaggregates while fungicide applications reduced AMF hyphae, GRSP and water-stable macroaggregates. We found that AMF abundance was a surprisingly dominant factor explaining the vast majority of variability in soil aggregation. This experimental field study, involving long-term diverse management practices of native multispecies prairie communities, invariably showed a close positive correlation between AMF hyphal abundance and soil aggregation, and C and N sequestration. This highly significant linear correlation suggests there are serious consequences to the loss of AMF from ecosystems.

}, keywords = {LTER-KNZ}, doi = {10.1111/j.1461-0248.2009.01303.x}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1461-0248.2009.01303.x}, author = {G.T. Wilson and C. W. Rice and Rillig, M.C. and Springer, A. and D.C. Hartnett} } @article {KNZ001202, title = {Conversion of grassland to coniferous woodland has limited effects on soil nitrogen cycle processes}, journal = {Soil Biology \& Biochemistry}, volume = {40}, year = {2008}, pages = {2627 -2633}, abstract = {

In the last century, conversion of native North American grasslands to Juniperus virginiana forests or woodlands has dramatically altered ecosystem structure and significantly increased ecosystem carbon (C) stocks. We compared soils under recently established J. virginiana forests and adjacent native C4-dominated grassland to assess changes in potential soil nitrogen (N) transformations and plant available N. Over a 2-year period, concentrations of extractable inorganic N were measured in soils from forest and grassland sites. Potential gross N ammonification, nitrification, and consumption rates were determined using 15N isotope-dilution under laboratory conditions, controlling for soil temperature and moisture content. Potential nitrification rates (Vmax) and microbial biomass, as well as soil physical and chemical properties were also assessed. Extractable NH4+ concentrations were significantly greater in grassland soils across the study period (P \≤ 0.01), but analysis by date indicated that differences in extractable inorganic N occurred more frequently in fall and winter, when grasses were senescent but J. virginiana was still active. Laboratory-based rates of gross N mineralization (ammonification) and nitrification were greater in grassland soils (P \≤ 0.05), but only on one of four dates. Potential nitrification rates (Vmax) were an order of magnitude greater than gross nitrification rates in both ecosystems, suggesting that nitrification is highly constrained by NH4+ availability. Differences in plant uptake of N, C inputs, and soil microclimate as forests replace grasslands may influence plant available N in the field, as evidenced by seasonal differences in soil extractable NH4+, and total soil C and N accumulation. However, we found few differences in potential soil N transformations under laboratory conditions, suggesting that this grassland-to-forest conversion caused little change in mineralizable organic N pools or potential microbial activity.

}, keywords = {LTER-KNZ, Extractable N, Forest encroachment, grassland, Isotope dilution, Juniperus, Microbial biomass, Mineralization, nitrification, Nitrogen cycling, prairie}, doi = {10.1016/j.soilbio.2008.07.005}, url = {https://www.sciencedirect.com/science/article/abs/pii/S0038071708002320?via\%3Dihub}, author = {McKinley, D.C. and C. W. Rice and John M. Blair} } @article {KNZ001100, title = {Seven years of enhanced water availability influences the physiological, structural and functional attributes of a soil microbial community}, journal = {Applied Soil Ecology}, volume = {35}, year = {2007}, pages = {535 -545}, abstract = {Water availability is known to influence many aspects of microbial growth and physiology, but less is known about how complex soil microbial communities respond to changing water status. To understand how long-term enhancement of soil water availability (without flooding) influences microbial communities, we measured the seasonal dynamics of several community-level traits following >7 years of irrigation in a drought-prone tallgrass prairie soil. From late May to mid-September, water was supplied to the irrigated treatments based on calculated plant water demand. Phospholipid fatty acids (PLFA) were used to assess changes in microbial community structure and physiology. To assess the community-level physiological profile, microbial utilization of BIOLOG substrates was determined. After incubation for 2 days, the distribution of added 13C-glucose in microbial and respired pools was used as an index of substrate utilization efficiency. We also measured the relative contribution of fungi and bacteria to soil microbial biomass via substrate-induced respiration (SIR). Multivariate analysis of mol\% PLFA and BIOLOG substrate utilization indicated that both water availability and sampling time influenced both the physiological and structural characteristics of the soil microbial community. Specific change in biomarker PLFA revealed a decreased ratio of cyclopropyl to ω7-precursors due to water addition, suggesting community-level stresses were reduced. Over the growing season, continuously greater water availability resulted in a 53\% greater ratio of fungal to bacterial biomass using SIR, and a 65\% increase in fungal PLFA. The number of substrates utilized by the cultivable microbial community tended to be greater in continuously wetted soil, especially during periods of low rainfall. While water dynamics appeared to be associated with some of the shifts in microbial community activity, structural and functional changes in the community appeared to be more closely linked to the cumulative effects of water regime on ecosystem properties. Seasonality strongly influenced microbial communities. The environmental factors associated with seasonal change need to be more closely probed to better understand the drivers of community structure and function.}, keywords = {LTER-KNZ, Microbial community, physiology, PLFA, Stress, Substrate use efficiency, Water availability}, doi = {10.1016/j.apsoil.2006.09.014}, author = {Williams, M.A. and C. W. Rice} } @article {KNZ001046, title = {Mycorrhizal-mediated phosphorus transfer between tallgrass prairie plants Sorghastrum nutans and Artemisia ludoviciana}, journal = {Functional Ecology}, volume = {20}, year = {2006}, pages = {427 -435}, abstract = {1A glasshouse 32P-labelling study examined arbuscular mycorrhizal (AM)-mediated transfer of phosphorus between individuals of two tallgrass prairie species, an obligately mycotrophic grass (Sorghastrum nutans Vitm.) and a facultatively mycotrophic forb (Artemisia ludoviciana Nutt.). 2Regardless of which species served as donor, 32P was transferred between both intra- and interspecific neighbours via AM mycelia. However, nutrient transfer via AM fungi was not uniform between neighbouring species. 3Conservative estimates indicate that interplant transfer via AM fungi accounted for >50\% of the total 32P acquisition by S. nutans, but accounted for only 20\% of 32P uptake into A. ludoviciana. 4While this study did not show conclusively that a common mycelial network acted as a conduit for nutrient transfer, it clearly demonstrated that mycorrhizae facilitated transfer. 5The results indicate that differential movement of plant resources via AM mycelium may be a mechanism whereby a dominant, highly mycotrophic grass extends competitive advantage over a less mycotrophic, subdominant forb species in grasslands.}, keywords = {LTER-KNZ}, doi = {10.1111/j.1365-2435.2006.01134.x}, author = {G.T. Wilson and D.C. Hartnett and C. W. Rice} } @article {KNZ001066, title = {Natural 15N abundances in a tallgrass prairie exposed to 8 years of elevated atmospheric CO2}, journal = {Soil Biology \& Biochemistry}, volume = {37}, year = {2006}, pages = {409 -412}, abstract = {

After 8-y of elevated CO2, we previously detected greater amounts of total soil nitrogen, suggesting that rates of ecosystem N flux into or out of tallgrass prairie had been altered. Denitrification and associative N fixation rates are the two primary biological processes that are known to control N loss and accumulation in tallgrass prairie soil. Therefore, our objective was to assess the natural abundance of plant and soil 15N isotopes as a cumulative index of potential change in efflux or influx of N into and out of the tallgrass prairie after 8-y of exposure to elevated CO2. Aboveground plant delta 15N values of Andropogon gerardii were close to zero and more positive as a result of elevated CO2, but whole-soil values at the 5\–30 cm depth were significantly reduced (6.8 vs 7.3; P\<0.05) under elevated CO2-chamber (EC) relative to ambient CO2- chamber (AC). Total, aboveground plant biomass, root-in-growth, extractable N, microbial biomass N, and soil pools collectively exhibited a range of delta 15N values from \−2.8 to 7.3. Measurements of surface soil 15N indicate that a change in N inputs and outputs has occurred as a result of elevated atmospheric CO2. In addition to possible changes in denitrification and N2 fixation, other sources of N such as the re-translocation of N to the surface from deeper soil layers are needed to explain how soil N accrues in surface soils as a consequence of elevated CO2. Our results support the notion that C accrual may promote N accrual, possibly driven by high plant and microbial N demand amplified by soil N limitation.

}, keywords = {LTER-KNZ}, doi = {10.1016/j.soilbio.2005.06.009}, author = {Williams, M.A. and C. W. Rice and Owensby, C.E.} } @article {KNZ001009, title = {Partitioning of nitrogen over five growing seasons in tallgrass prairie}, journal = {Ecology}, volume = {86}, year = {2005}, pages = {1280 -1287}, abstract = {Annual spring burning of tallgrass prairie increases plant biomass production despite losses of N and lower net N mineralization. To better understand how burning influences the cycling of N in prairie, 15N was injected to soil as NH4+, and the partitioning between plant and soil N pools was followed over five growing seasons in annually burned and unburned prairie. Applied 15N was rapidly immobilized with <2\% and 11\% of the 15N remaining in inorganic forms six days after application in burned and unburned prairie, respectively. Seventy-seven percent (burned prairie) and 70\% (unburned prairie) of the applied 15N was initially recovered as soil organic N (oN), with a majority accounted for in microbial biomass. Plants contained \~{}20\% of the applied N with the largest portion recovered from roots regardless of burning. At the end of the first growing season, only 55\% of the applied 15N was recovered from the unburned prairie, while 85\% was recovered from burned prairie. The total 15N content of the plants changed little during the first growing season, but the portion recovered in the rhizomes increased, indicating belowground N storage. Total recovery and distribution of applied N changed little from the end of the first to the end of the second season growing season. Accumulations of 15N within the plants decreased greatly between the second and fifth growing seasons, but N lost from plants was accounted for in oN. Conservation of N by plants and tight cycling of N within the root zone suggest mechanisms by which prairie can be a highly productive ecosystem despite limited N availability. The immobilization of potentially mineralized N within the root zone increased with burning, offsetting the loss of N to fire probably by reducing leaching and denitrification losses.}, keywords = {LTER-KNZ}, doi = {10.1890/03-0790}, author = {Dell, C.J. and Williams, M.A. and C. W. Rice} } @article {KNZ00989, title = {Short-term competition for ammonium and nitrate in tallgrass prairie}, journal = {Soil Science Society of America Journal}, volume = {69}, year = {2005}, pages = {371 -377}, abstract = {The availability of N limits productivity in tallgrass prairie. Spring burning is common because it results in greater plant productivity despite reducing net N mineralization. To better explain how burning affects inorganic N availability in tallgrass prairie, the partitioning of 15N among plant and soil pools was measured in June and August 1994. Approximately 2.5 μg N g-1 soil was injected as either NH4 or NO3 to a depth of 15 cm within cores in burned and unburned prairie. Cores were removed from the field 6 d after injection, and 15N recovery in plant and soil N pools was determined. No more than 14\% of the applied 15N remained in inorganic form 6 d after application. The largest portion of the applied 15N (35{\textendash}80\%) was recovered in the soil organic nitrogen pool (No). Burning significantly increased the immobilization of both NH4 and NO3 within No, and microbial biomass accounted for >=50\% of the 15N recovered in No Accumulation of 15N in plants accounted for <=35\% of the applied 15N with a majority recovered from roots. Burning had little effect on 15N recovery in plants; however, 15N accumulations in roots were significantly greater when NO3 was used. Results indicate that immobilization within soil organic matter (SOM) controls the availability of both NH4 and NO3 to plants. Increased immobilization in soils with burning probably results largely from increased microbial N demand resulting from greater litter inputs with wider C to N ratios. Further research is needed to determine if abiotic mechanisms for N immobilization also significantly influence N availability in prairie soils.}, keywords = {LTER-KNZ}, doi = {10.2136/sssaj2005.0371}, author = {Dell, C.J. and C. W. Rice} } @article {KNZ001067, title = {Carbon and nitrogen pools in a tallgrass prairie soil under elevated carbon dioxide}, journal = {Soil Science Society of America Journal}, volume = {68}, year = {2004}, pages = {148 -153}, abstract = {

Soil is a potential C sink and could offset rising atmospheric CO2 The capacity of soils to store and sequester C will depend on the rate of C inputs from plant productivity relative to C exports controlled by microbial decomposition. Our objective was to measure pools of soil C and N to assess the potential for C accrual and changes to N stocks as influenced by elevated atmospheric CO2 Treatments (three replications, randomized complete block design) were ambient CO2\—no chamber (NC), ambient CO2\—chamber (AC), and two times ambient CO2\—chamber (EC). Long-term (290 d) incubations (35\°C) were conducted to assess changes in the slow soil fractions of potentially mineralizable C (PMC) and potentially mineralizable N (PMN). Potentially mineralizable C was enhanced (P \< 0.1) by 19 and 24\% in EC relative to AC and NC soil at the 0- to 5- and 5- to 15-cm depths, respectively. Potentially mineralizable N was significantly greater by 14\% at the 0- to 5-cm depth in EC relative to AC, but decreased by 12\% in EC relative to NC (P \< 0.1). Measurements of PMC indicate that increases in total soil C under elevated CO2 in a previous study were a consequence of accrual into the slow pool. Relatively large amounts of new C deposited as a result of elevated CO2 (Cnew) remained in the soil after the 290-d incubation. In contrast to accumulation of C into the slow fraction, Cnew was integrated into a passive fraction of soil organic matter (SOM). Accumulation of N was also detected in the whole soil, which cannot be explained by current estimates of ecosystem N flux.

}, keywords = {LTER-KNZ}, doi = {10.2136/sssaj2004.1480}, author = {Williams, M.A. and C. W. Rice and Omay, A. and Owensby, C.} } @article {KNZ001, title = {Changes in ecosystem structure and function along a chronosequence of restored grasslands}, journal = {Ecological Applications}, volume = {12}, year = {2002}, pages = {1688 -1701}, abstract = {Changes in aboveground vegetation, roots, and soil characteristics were examined from a 12-yr chronosequence of formerly cultivated fields restored to native C4 grasses through the Conservation Reserve Program (CRP). Following 6{\textendash}8 yr in the CRP, the native grasses dominated vegetation composition, and the presence of forbs was negligible. Productivity of the restored grasslands did not exhibit any directional changes with the number of years in the CRP, and productivity was generally higher than native prairie in this region. Over time, the restored grasslands accumulated root biomass of decreasing quality as indicated by increasing root biomass and C:N ratio of roots along the 12-yr chronosequence. Root biomass, root C:N ratio, C storage in roots, and N storage in roots of restored grasslands approached that of native tallgrass prairie within the 12 yr of restoration. Establishment of the perennial vegetation also affected soil physical, chemical, and biological characteristics. Soil bulk density in the surface 10 cm decreased with time since restoration. Total C, microbial biomass C, and C mineralization rates increased as a function of time since restoration. The greatest change in total C occurred in the surface 5 cm, where total C was 26\% greater in 12- vs. 2-yr restored grasslands. Extractable soil nitrate and soil N transformations (i.e., net N mineralization rates and net nitrification rates) declined over the restoration chronosequence, but these values were not representative of steady-state conditions due to the high variability in these measures among the native prairies. Although complete restoration of ecosystem structure and function was not the primary intention of the CRP, this study demonstrates that establishment of the matrix vegetation (i.e., native C4 grasses) drives ecosystem processes in the trajectory of the original system. Moreover, restoration may hasten the recovery of soil C pools relative to formerly cultivated systems undergoing natural succession.}, keywords = {LTER-KNZ, ecosystem, function, grassland, structure}, doi = {10.1890/1051-0761(2002)012[1688:CIESAF]2.0.CO;2}, author = {S.G. Baer and Kitchen, D.J. and John M. Blair and C. W. Rice} } @article {KNZ00796, title = {Nitrogen competition in a tallgrass prairie ecosystem exposed to elevated carbon dioxide}, journal = {Soil Science Society of America Journal}, volume = {65}, year = {2001}, pages = {340 -346}, abstract = {Because N is a limiting nutrient in tallgrass prairie and most ecosystems, changes in N availability or N cycling could control the long-term response of ecosystems to elevated atmospheric CO2 If more C is sequestered into the soil, then greater microbial demand for N could decrease plant-available soil N. Alterations in N dynamics such as plant uptake, N fixation, nutrient cycling, microbial utilization, and partitioning of N into plant and soil fractions ultimately could affect the capability of ecosystems to sequester C. Our objective was to determine if competition for N between plants and microorganisms changes after 8 yr of elevated CO2 relative to ambient conditions. Treatments (three replications, randomized complete block design) were ambient CO2{\textendash}no chamber (NC), ambient CO2{\textendash}chamber (AC), and 2 {\texttimes} ambient CO2{\textendash}chamber (EC). Several short laboratory incubations assessed whether turnover rates of N in soil would be altered under elevated CO2 Gross transformations of N were not altered significantly under elevated CO2 compared with ambient conditions. To examine plant{\textendash}microbial competition and altered allocation patterns of N under elevated CO2, 15NH4{\textendash}N was added to 25-cm-diam. polyvinyl chloride (PVC) cores (15-cm depth) in the field, which were destructively sampled after ≈5 mo. Microbial biomass contained ≈75\% of the total 15N that occurred in the soil organic matter (SOM) and, thus, appeared to be a significant regulator of plant-available N. The SOM under elevated CO2 contained significantly more (>27\%) 15N compared with ambient CO2 conditions. Though a chamber effect was apparent, greater 15N in the SOM pool and greater percentage 15N SOM/percentage 15N plant suggest greater microbial demand for N under elevated CO2}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2136/sssaj2001.652340x}, author = {Williams, M.A. and C. W. Rice and Owensby, C.E.} } @article {KNZ00719, title = {Assessment of soil quality in fields with short- and long-term enrollment in the CRP}, journal = {Journal of Soil and Water Conservation}, volume = {55}, year = {2000}, pages = {142 -146}, abstract = {Surface [5 to10 cm, (2 to 4 in) depth] soil quality was examined from fields representing short and long term enrollment in the Conservation Reserve Program (CRP). Total carbon (C) and nitrogen (N) amounts were similar in soil with recent and long term enrollment in the CRP and were lower than a native prairie field. Active pools of C and N, however, did increase through the CRP. Soil with long term establishment of native grasses in the CRP exhibited 141\% and 33\% greater microbial biomass C and N, respectively, than soil recently enrolled in the CRP. Total inorganic N was significantly lower in CRP soil with ten versus no growing seasons and was more representative of levels in a native prairie due to reductions in nitrate availability. Our study indicates that CRP promotes soil restoration; however, ten growing seasons are not adequate for recovery of total soil C and N pools at this depth to pre-cultivation levels.}, keywords = {LTER-KNZ}, url = {http://www.jswconline.org/content/55/2/142.abstract}, author = {S.G. Baer and C. W. Rice and John M. Blair} } @article {KNZ00752, title = {Carbon dynamics and microbial activity in tallgrass prairie exposed to elevated CO2 for 8 years}, journal = {Plant and Soil}, volume = {227}, year = {2000}, pages = {127 -137}, abstract = {Alterations in microbial mineralization and nutrient cycling may control the long-term response of ecosystems to elevated CO2. Because micro-organisms constitute a labile fraction of potentially available N and are regulators of decomposition, an understanding of microbial activity and microbial biomass is crucial. Tallgrass prairie was exposed to twice ambient CO2 for 8 years beginning in 1989. Starting in 1991 and ending in 1996, soil samples from 0 to 5 and 5 to 15 cm depths were taken for measurement of microbial biomass C and N, total C and N, microbial activity, inorganic N and soil water content. Because of increased water-use-efficiency by plants, soil water content was consistently and significantly greater in elevated CO2 compared to ambient treatments. Soil microbial biomass C and N tended to be greater under elevated CO2 than ambient CO2 in the 5{\textendash}15 cm depth during most years, and in the month of October, when analyzed over the entire study period. Microbial activity was significantly greater at both depths in elevated CO2 than ambient conditions for most years. During dry periods, the greater water content of the surface 5 cm soil in the elevated CO2 treatments increased microbial activity relative to the ambient CO2 conditions. The increase in microbial activity under elevated CO2 in the 5{\textendash}15 cm layer was not correlated with differences in soil water contents, but may have been related to increases in soil C inputs from enhanced root growth and possibly greater root exudation. Total soil C and N in the surface 15 cm were, after 8 years, significantly greater under elevated CO2 than ambient CO2. Our results suggest that decomposition is enhanced under elevated CO2 compared with ambient CO2, but that inputs of C are greater than the decomposition rates. Soil C sequestration in tallgrass prairie and other drought-prone grassland systems is, therefore, considered plausible as atmospheric CO2 increases.}, keywords = {LTER-KNZ, elevated CO2, microbial activity, Microbial biomass, Soil C and N, soil water}, doi = {10.1023/A:1026590001307}, author = {Williams, M.A. and C. W. Rice and Owensby, C.E.} } @inbook {KNZ00746, title = {Effects of fire and grazing on soil carbon in rangelands}, booktitle = {The Potential of U.S. Grazing Lands to Sequester Carbon and Mitigate the Greenhouse Effect}, year = {2000}, pages = {323 -342}, publisher = {Lewis Publishers}, organization = {Lewis Publishers}, address = {Boca Raton, FL}, keywords = {LTER-KNZ, fire}, author = {C. W. Rice and Owensby, C.E.}, editor = {Follet, R. and Kimble, J.M. and Lal, R.} } @article {KNZ00749, title = {Effects of long-term fungicide application on microbial processes in tallgrass prairie soils}, journal = {Soil Biology \& Biochemistry}, volume = {32}, year = {2000}, pages = {935 -946}, abstract = {Several studies investigating the role of arbuscular mycorrhizal (AM) fungi in plant communities have included manipulations of AM fungal symbiosis using the fungicide benomyl. The objectives of this study were to evaluate the potential non-target effects of benomyl on soil biota and nutrient cycling in tallgrass prairie and to determine how mycorrhizae may influence these belowground properties. To accomplish these objectives, soil samples were collected during the 1996{\textendash}1997 growing seasons from long-term benomyl-treated plots established on tallgrass prairie (Manhattan, KS) in 1991, and the following measurements were made: total bacterial and fungal biomass; abundance of nematodes; microbial biomass carbon and nitrogen; substrate-induced respiration; and potentially mineralizable C and N. Long-term benomyl applications resulted in an 80\% reduction in mycorrhizal root colonization. By reducing root colonization, benomyl applications resulted in significant decreases in total bacterial biomass and abundance of fungal-feeding and predatory nematodes (20, 12 and 33\% reductions compared to control, respectively). Total microbial potential activity (i.e., substrate-induced respiration) increased by 10\% with benomyl treatment, whereas the relative contribution of fungi to total microbial activity decreased significantly with benomyl applications. In addition, microbial biomass C increased from 1364 ({\textpm} 51.2 SE) to 1485 ({\textpm} 51.2 SE) with benomyl treatment, and total carbon increased significantly (\~{}8\%) only in annually burned soils treated with benomyl. The magnitude of benomyl effects on soil components and processes were small (<33\% change with benomyl) relative to effects on mycorrhizal root colonization (80\% decrease with benomyl). These results indicate that rather than having large non-target effects, benomyl applications principally affect mycorrhizal root colonization, thereby indirectly influencing soil biota and nutrient availability. Results also indicate that mycorrhizal fungi play an important role in altering the availability and flow of carbon in prairie soil and may influence the composition and abundance of groups of some soil biota. Changes in soil organisms and nutrient availability associated with altered mycorrhizal symbiosis may influence aboveground plant species responses to mycorrhizal suppression, but further research is needed to understand these potential effects.}, keywords = {LTER-KNZ, Arbuscular mycorrhizal fungi, Benomyl, carbon, Microbial biomass, Nematodes, nitrogen}, doi = {10.1016/S0038-0717(99)00223-0}, author = {M.D. Smith and D.C. Hartnett and C. W. Rice} } @article {KNZ00671, title = {Changes in enzyme activities and microbial biomass of tallgrass prairie soil as related to burning and nitrogen fertilization}, journal = {Soil Biology \& Biochemistry}, volume = {31}, year = {1999}, pages = {769 -777}, abstract = {Microbial biomass and enzyme activities are affected by management practices and can be used as sensitive indicators of ecological stability. Microbial biomass C (MBC), microbial biomass N (MBN) and eight enzyme activities involved in the cycling of C, N, P and S were studied in the surface (0{\textendash}5 cm) of an Irwin silty clay loam soil (fine, mixed, mesic, Pachic Arguistoll) in a tallgrass prairie ecosystem. Treatments of annual spring burning and N fertilization were initiated in 1986 and encompassed: (1) unburned{\textendash}unfertilized, (2) burned{\textendash}unfertilized, (3) burned{\textendash}fertilized, and (4) unburned{\textendash}fertilized. Activities of dehydrogenase, β-glucosidase, urease, deaminase, denitrifying enzyme, acid phosphatase, alkaline phosphatase, and arylsulfatase were assayed. Long-term burning and N fertilization of the tallgrass prairie soil reduced MBC and MBN relative to the unburned{\textendash}unfertilized treatment. The effects of burning and N fertilization varied among the enzymes and the time of sampling. Long-term burning significantly (P<0.05) increased activities of urease and acid phosphatase, but decreased activities of β-glucosidase, deaminase and alkaline phosphatase. Long-term N fertilization significantly increased activities of β-glucosidase and acid phosphatase but decreased urease activity. This study found that several soil enzyme activities can be used as indicators of ecological changes caused by N fertilization and long-term burning management practices. The relevance of these changes in surface soil to the long-term sustainability of this ecosystem needs further evaluation.}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.1016/S0038-0717(98)00177-1}, author = {Ajwa, H.A. and Dell, C.J. and C. W. Rice} } @article {KNZ00712, title = {Soil air carbon dioxide and nitrous oxide concentrations in profiles under tallgrass prairie and cultivation}, journal = {Journal of Environmental Quality}, volume = {28}, year = {1999}, pages = {784 -793}, abstract = {Assessing the dynamics of gaseous production in soils is of interest because they are important sources and sinks of greenhouse gases. Changes in soil air carbon dioxide (CO2) and nitrous oxide (N2O) concentrations were studied in a Reading silt loam (fine-silty, mixed, mesic Typic Argiudolls) under prairie and cultivation. Concentrations were measured in situ over a 17-mo period to a depth of 3 m. Multilevel samplers permitted collection of gases with subsequent measurement by gas chromatography in the laboratory. Soil air N2O concentrations were near atmospheric levels for a majority of the study period in the prairie site (0.184{\textendash}2.25 {\textmu}L L-1) but were significantly higher in the cultivated site (0.257{\textendash}7.56 {\textmu}L L-1). Annual mean N2O concentrations were 0.403 and 1.09 {\textmu}L L-1 in the prairie and cultivated sites, respectively. Soil air CO2 annual mean concentrations were 1.56 {\texttimes} 104 and 1.10 {\texttimes} 104 {\textmu}L L-1 and ranged from 0.096 {\texttimes} 104 to 6.45 {\texttimes} 104 {\textmu}L L-1 and 0.087 {\texttimes} 104 to 3.59 {\texttimes} 104 {\textmu}L L-1 in the prairie and cultivated sites, respectively. Concentrations generally increased with depth, with maximum soil air N2O and CO2 concentrations at 1.0 m in the prairie site and 0.5 m in the cultivated site. Nitrous oxide in the cultivated site and CO2 at both sites did not change markedly over winter months, but CO2 and N2O concentrations reached maximums during the summer months and decreased as the year progressed. Although soil air concentrations peaked and decreased faster at shallower depths, deeper depths exhibited relative maximum concentrations for longer time periods.}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2134/jeq1999.00472425002800030008x}, author = {Sotomayor, D. and C. W. Rice} } @article {KNZ00673, title = {Variations in microbial activity due to fluctuations in soil water content at the water table interface}, journal = {Journal of Environmental Science and Health}, volume = {34}, year = {1999}, pages = {479 -505}, abstract = {A soil column experiment was designed to investigate the response of an indigenous microbial population to a vertically fluctuating water table. A subsurface environment with a transitional zone was simulated. The water table in the soil columns was raised and lowered, and compared to columns under static conditions. Carbon dioxide and oxygen concentrations were measured. Peaks of CO2 occurred in the fluctuating columns immediately following a rise in the water table. Dissolved O2 in the fluctuating columns was consistently lower throughout the experiment, but these lower concentrations were exaggerated immediately following a rise in the water table. Values for total organic carbon in the pore water were slightly lower in the fluctuating columns. The results of this soil column study indicate that vertical fluctuation of the water table can enhance microbial activity of indigenous soil microbial populations. This increase in microbial activity suggests an increased rate of available carbon under these conditions.}, keywords = {LTER-KNZ, bioremediation, microbial activity, soil interface, soil texture, Soil water content, subsurface sediments}, doi = {10.1080/10934529909376849}, author = {Banks, M.K. and Clennan, C. and W. K. Dodds and C. W. Rice} } @inbook {KNZ00661, title = {Belowground biology and processes}, booktitle = {Grassland Dynamics: Long-Term Ecological Research in Tallgrass Prairie}, year = {1998}, pages = {244 -264}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York}, keywords = {LTER-KNZ, tallgrass prairie}, author = {C. W. Rice and Todd, T.C. and John M. Blair and Seastedt, T.R. and Ramundo, R.A. and G.T. Wilson}, editor = {Alan K. Knapp and J. M. Briggs and D.C. Hartnett and Scott. L. Collins} } @article {KNZ00618, title = {Carbon and nitrogen mineralization in tallgrass prairie and agricultural soil profiles}, journal = {Soil Science Society of America Journal}, volume = {62}, year = {1998}, pages = {942 -951}, abstract = {In situ mineralization of N may contribute significantly to total inorganic-N pools deep in the soil profile. We conducted long-term laboratory incubation experiments to evaluate the net C and N mineralization in soils collected from various depths in tallgrass prairie and agricultural fields of the same geological materials and soil type. Samples were packed to a bulk density of 1.4 g cm-3 in 5-cm-diameter by 10-cm-long cores. The cores were incubated at 35{\textdegree}C for 40 wk in sealed containers. Net C mineralization was measured by evolved CO2, and N mineralized was measured by periodic leaching with NH+4 and NO-3 measured in the leachate. Carbon and N mineralization in the surface horizon were greater in the tallgrass prairie than in the agricultural soil. In both the tallgrass prairie and agricultural soil profiles, C mineralization was least at the water-table depth. Carbon mineralization was described by a first-order kinetic model, but N mineralization was described better by a consecutive (sigmoidal) reaction model. At most depths, the ratios of potentially mineralizable organic C (C0) to total organic C (C0/TOC) and potentially mineralizable organic N (N0) to total N (N0/TN) were greater in the agricultural soil profile than in the tallgrass prairie soil profile. The C0 and N0 in the surface soil (0{\textendash}0.2 m) represented 11.6 and 12.2\% of the total organic C and N pools for the tallgrass prairie soil profile, respectively, and 21.0 and 10.2\% of the total organic C and N pools for the agricultural soil profile. Management practices affected the mineralization potentials and rates of both the surface and subsurface soils.}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2136/sssaj1998.03615995006200040014x}, author = {Ajwa, H.A. and C. W. Rice and Sotomayor, D.} } @inbook {KNZ00660, title = {Soils and soil biota}, booktitle = {Grassland Dynamics: Long-Term Ecological Research in Tallgrass Prairie}, year = {1998}, pages = {48 -66}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Ransom, M.D. and C. W. Rice and Todd, T.C. and Wehmueller, W.A.}, editor = {Alan K. Knapp and J. M. Briggs and D.C. Hartnett and Scott. L. Collins} } @inbook {KNZ00620, title = {Terrestrial nutrient cycling in tallgrass prairie}, booktitle = {Grassland Dynamics: Long-term Ecological Research}, year = {1998}, pages = {222 -243}, publisher = {Oxford University Press}, organization = {Oxford University Press}, address = {New York}, keywords = {LTER-KNZ, tallgrass prairie}, author = {John M. Blair and Seastedt, T.R. and C. W. Rice and Ramundo, R.A.}, editor = {Alan K. Knapp and J. M. Briggs and D.C. Hartnett and Scott. L. Collins} } @article {KNZ00532, title = {Biological properties of soil and subsurface sediments under abandoned pasture and cropland}, journal = {Soil Biology \& Biochemistry}, volume = {28}, year = {1996}, pages = {837 -846}, abstract = {Little is known about the effects of most surface land-use practices on shallow subsurface microbial communities. We analyzed duplicate cores taken aseptically from up to 10 m depth from unconsolidated valley sediments (soils) beneath an abandoned pasture reverting to tall grass prairie and cropland. Both profiles had similar soil texture, with moderately higher silt under cropland and a slight decrease in clay with depth. Soluble organic C was about two times higher in the grassland site and dissolved O2 was about 8\% lower compared with the cropland site. Water content and C-to-N ratios were greatest at the grassland surface but were less in the grassland than the cropland site within 2 m depth. In general, numbers of aerobic heterotrophic bacteria and protozoa decreased with depth until the saturated zone (4.3 m in grassland and 5.3 m in the cropland site). Bacterial numbers as determined by plate counts were about 10-fold less at the groundwater interface than in the surface soils at both sites. Direct microscopic counts of total bacteria were approximately the same in the surface soil and the sediments at the top of the water table at both sites. The top of the water table generally did not exhibit elevated microbial biomass or activity relative to deeper sediments. There was no significant relationship between protozoan numbers and microbial thymidine uptake at the cropland site, but a negative relationship was observed at the grassland site. The data suggest that cultivation may affect microbial biomass and activity in the subsurface, as well as community interactions between protozoa and bacteria.}, keywords = {LTER-KNZ}, doi = {10.1016/0038-0717(96)00057-0}, author = {W. K. Dodds and Banks, M.K. and Clenan, C.S. and C. W. Rice and Sotomayor, D. and Strauss, E.A. and Yu, W.} } @article {KNZ00567, title = {Denitrification in soil profiles beneath grassland and cultivated soils}, journal = {Soil Science Society of America Journal}, volume = {60}, year = {1996}, pages = {1822 -1828}, abstract = {The denitrification potential of subsoils and aquifers must be characterized to assess the ultimate fate of soil N. This experiment was conducted to study changes in the subsurface distribution and activity of denitrifying bacteria as a result of cultivation. We examined soil profiles for their capacity (N addition) and potential (N + C addition) to denitrify as well as for denitrifying bacterial numbers in a Reading silt loam (fine, mixed, mesic Typic Argiudoll) soil under grassland and cultivation. Denitrifying enzyme activity was undetectable throughout the subsurface of soil profiles at both sites. Overall, the cultivated site had significantly higher NO-3 concentrations, denitrifier populations, and denitrification potential. Denitrifying bacteria were stratified in the vadose zone at the prairie site, with lowest numbers and lowest denitrification potential occurring at the interface of the water table. Although C addition enhanced denitrification at this site, the profile was not nearly as limited by C as that of the cultivated site. The results demonstrated that increased N inputs and cultivation during approximately 50 yr changed the denitrifying population and denitrification potential in the vadose and saturated zones of soils.}, keywords = {LTER-KNZ}, doi = {10.2136/sssaj1996.03615995006000060030x}, author = {Sotomayor, D. and C. W. Rice} } @inbook {KNZ00564, title = {Ecosystem level responses of tallgrass prairie to elevated CO2}, booktitle = {Carbon Dioxide and Terrestrial Ecosystems}, year = {1996}, pages = {147 -162}, publisher = {Academic Press}, organization = {Academic Press}, address = {London}, keywords = {LTER-KNZ, tallgrass prairie}, author = {Owensby, C.E. and J.M. Ham and Alan K. Knapp and C. W. Rice and Coyne, P.I. and Auen, L.M.}, editor = {Koch, G.W and Mooney, H.A.} } @inbook {KNZ00537, title = {Potentially mineralizable N as an indicator of active soil nitrogen}, booktitle = {Methods for Assessing Soil Quality}, year = {1996}, pages = {217 -299}, publisher = {Soil Science Society of America Inc}, organization = {Soil Science Society of America Inc}, address = {Madison, WI}, keywords = {LTER-KNZ}, author = {Drinkwater, L.E. and Cambardella, C.A. and Reeder, J.D. and C. W. Rice}, editor = {Doran, J.W. and Jones, A.J.} } @inbook {KNZ00566, title = {Role of microbial biomass C and N in soil quality}, booktitle = {Methods for Assessing Soil Quality}, year = {1996}, pages = {203 -215}, publisher = {Soil Science Society of America Inc}, organization = {Soil Science Society of America Inc}, address = {Madison, WI}, keywords = {LTER-KNZ}, author = {C. W. Rice and Moorman, T. and Beare, M.}, editor = {Doran, J.W. and Jones, A.J.} } @inbook {KNZ00465, title = {Biologically active pools of soil C and N in tallgrass prairie}, booktitle = {Defining Soil Quality for a Sustainable Environment}, year = {1994}, pages = {201 -208}, publisher = {Soil Science Society of America}, organization = {Soil Science Society of America}, address = {Madison, WI}, keywords = {LTER-KNZ, tallgrass prairie}, author = {C. W. Rice and Garcia, F.O.}, editor = {Doran, J.W. and Jones, A.J.} } @article {KNZ00441, title = {Microbial biomass dynamics in tallgrass prairie}, journal = {Soil Science Society of America Journal}, volume = {58}, year = {1994}, pages = {816 -823}, abstract = {The temporal dynamics and effects of burning, mowing, and N fertilization on microbial biomass (MBM) in tallgrass prairie were studied in a field experiment established in 1986. Microbial C (MC) and microbial N (MN), determined by the fumigation-incubation procedure during the growing seasons of 1989 through 1991, averaged 217 mg C kg-1 and 32.6 mg N kg-1, respectively, for the 0- to 30-cm depth. Accumulation of litter and greater production of roots near the surface resulted in stratification of MBM. Seasonally, MBM was higher in early spring, decreased with the initiation of plant growth, and then recovered by late summer or early fall. Decreases of MN between March and July coincided with plant N uptake. The increase of MC and decrease of MN during the 3 yr of the study were related to increased plant production. Burning had a short-term and variable effect on MC. Burning tended to reduce MC during dry years and increase it in normal to wet years. Mowing and raking decreased MC and MN, probably because of reduced root biomass and removal of standing vegetation. Nitrogen addition resulted in higher MN and tended to reduce MC, possibly by modifying the composition of the microbial population. Microbial biomass seems to play a critical role in conserving N in the tallgrass prairie ecosystem.}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2136/sssaj1994.03615995005800030026x}, author = {Garcia, F.O. and C. W. Rice} } @article {KNZ00472, title = {Plant production and the biomass of soil microorganisms in late-successional ecosystems: A continental-scale study}, journal = {Ecology}, volume = {75}, year = {1994}, pages = {2333 -2347}, abstract = {Annual C inputs from plant production in terrestrial ecosystems only meet the maintenance energy requirements of soil microorganisms, allowing for little or no net annual increase in their biomass. Because microbial growth within soil is limited by C availability, we reasoned that plant production should, in part, control the biomass of soil microorganisms. We also reasoned that soil texture should further modify the influence of plant production on soil C availability because fine-textured soils typically support more microbial biomass than coarse-textured soils. To test these ideas, we quantified the relationship between aboveground net primary production (ANPP) and soil microbial biomass in late-successional ecosystems distributed along a continent-wide gradient in North America. We also measured labile pools of C and N within the soil because they represent potential substrate for microbial activity. Ecosystems ranged from a Douglas-fir forest in the western United States to the grasslands of the mid-continent to the hardwood forest in the eastern U.S. Estimates of ANPP obtained from the literature ranged from 82 to 1460 g@?m^-^2@?yr^-^1. Microbial biomass C and N were estimated by the fumigation-incubation technique. Labile soil pools of C and N and first-order rate constants for microbial respiration and net N mineralization were estimated using a long-term (32 wk) laboratory incubation. Regression analyses were used to relate ANPP and soil texture with microbial biomass and labile soil C and N pools. Microbial biomass carbon ranged from 2 g/m^2 in the desert grassland to 134 g/m^2 in the tallgrass prairie; microbial N displayed a similar trend among ecosystems. Labile C pools, derived from a first-order rate equation, ranged from 115 g/m^2 in the desert grassland to 491 g/m^2 in the southern hardwood forest. First-order rate constants for microbial respiration (k) fell within a narrow range of values (0.180 to 0.357 wk^-^1), suggesting that labile C pools were chemically similar among this diverse set of ecosystems. Potential net N mineralization rates over the 32-wk incubation were linear in most ecosystems with first-order responses only in the alpine tundra, tallgrass prairie, and forests. Microbial biomass C displayed a positive, linear relationship with ANPP (r^2 = 0.51), but was not significantly related to soil texture. Labile C also was linearly related to ANPP (r^2 = 0.32) and to soil texture (r^2 = 0.33). Results indicate that microbial biomass and labile organic matter pools change predictably across broad gradients of ANPP, supporting the idea that microbial growth in soil is constrained by C availability.}, keywords = {LTER-KNZ}, doi = {10.2307/1940888}, author = {Zak, D.R. and Tilman, D. and Parameter, R.R. and Fisher, F.M. and C. W. Rice and Vose, J. and Milchunas, D. and Martin, C.W.} } @article {KNZ00403, title = {Denitrification in a tallgrass prairie landscape}, journal = {Ecology}, volume = {74}, year = {1993}, pages = {855 -862}, abstract = {We characterized factors controlling denitrification and quantified rates of N gas production by this process in a tallgrass prairie landscape in central Kansas. The experimental design included three land use classes (unburned, annually burned, and annually burned and grazed) in factorial combination with three slope positions (summit, back{\textemdash}slope, toe{\textemdash}slope), plus a cultivated site in a toe{\textemdash}slope position (10 sites total). Denitrification was measured using an acetylene{\textemdash}based soil core technique four times in 1987, once in early 1988, and six times in 1989. Cores were incubated under field{\textemdash}moist conditions and after amendment with water or water plus nitrate. Microbial biomass and nitrification and dentrification enzyme activities were also measured. Denitrification was higher (P < .05) in unburned sites than in burned, and grazed, and cultivated sites in both 1987/1988 and 1989. The cultivated site consistently had low rates of denitrification relative to the native prairie sites, even when water and nitrate were added. Levels of microbial biomass C and nitrification and denitrification enzyme activities were an order of magnitude lower in the cultivated site than in the native prairie sites. Denitrification rates were highest in the early spring of 1987 and were low at all other times. Although temporal patterns of activity were generally related to patterns of soil moisture, water additions did not stimulate activity in ungrazed prairie soils. Water plus nitrate additions consistently gave significant increases in activity. The results are consistent with previous research that has found that unburned prairie is wetter and has higher concentrations of NO3{\textemdash} in soil solution than burned sites. In certain years, denitrification may be significant to site fertility, landscape water quality, and atmospheric chemistry in the tallgrass prairie region.}, keywords = {LTER-KNZ, tallgrass prairie}, doi = {10.2307/1940811}, author = {Groffman, P.M. and C. W. Rice and Tiedje, J.M.} }