00450nas a2200121 4500008004100000245006800041210006800109260004300177490001400220100002300234700001700257856005400274 2020 eng d00aEffect of land use and land use management on methane oxidation0 aEffect of land use and land use management on methane oxidation aManhattan, KSbKansas State University0 vMS Thesis1 aWanithunga, Irosha1 aRice, C., W. uhttps://krex.k-state.edu/dspace/handle/2097/4032702331nas a2200181 4500008004100000245008900041210006900130300001200199490000800211520173900219100002501958700001801983700002402001700002802025700002702053700001702080856005202097 2019 eng d00aLong-term biomass and potential ethanol yields of annual and perennial biofuel crops0 aLongterm biomass and potential ethanol yields of annual and pere a74 - 830 v1113 a

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.

1 aRoozeboom, Kraig, L.1 aWang, Donghai1 aMcGowan, Andrew, R.1 aPropheter, Jonathan, L.1 aStaggenborg, Scott, A.1 aRice, C., W. uhttp://doi.wiley.com/10.2134/agronj2018.03.017203041nas a2200373 4500008004100000245008800041210006900129300001400198490000600212520192100218653001602139653002202155653001602177653002002193100002702213700001902240700002102259700002402280700002602304700002102330700001802351700002302369700001802392700001802410700001702428700002302445700002102468700002002489700002702509700002002536700002302556700002302579856006502602 2019 eng d00aMetaphenomic response of a native prairie soil microbiome to moisture perturbations0 aMetaphenomic response of a native prairie soil microbiome to moi ae00061-190 v43 a

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.

10ametaphenome10ametatranscriptome10amulti-omics10asoil microbiome1 aChowdhury, Taniya, Roy1 aLee, Joon-Yong1 aBottos, Eric, M.1 aBrislawn, Colin, J.1 aWhite, Richard, Allen1 aBramer, Lisa, M.1 aBrown, Joseph1 aZucker, Jeremy, D.1 aKim, Young-Mo1 aJumpponen, A.1 aRice, C., W.1 aFansler, Sarah, J.1 aMetz, Thomas, O.1 aMcCue, Lee, Ann1 aCallister, Stephen, J.1 aSong, Hyun-Seob1 aJansson, Janet, K.1 aHallam, Steven, J. uhttp://msystems.asm.org/lookup/doi/10.1128/mSystems.00061-1902010nas a2200277 4500008004100000022001400041245009300055210006900148300001600217490000700233520117700240100001601417700001701433700001301450700002101463700002101484700001901505700002001524700002801544700002301572700002201595700001701617700001601634700002001650856006201670 2019 eng d a1461-023X00aMore salt, please: global patterns, responses and impacts of foliar sodium in grasslands0 aMore salt please global patterns responses and impacts of foliar a1136 - 11440 v223 a

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.

1 aBorer, E.T.1 aLind, E., M.1 aFirn, J.1 aSeabloom, E., W.1 aAnderson, T., M.1 aBakker, E., S.1 aBiederman, L.A.1 aLa Pierre, Kimberly, J.1 aMacDougall, A., S.1 aMoore, Joslin, L.1 aRice, C., W.1 aschütz, M.1 aStevens, C., J. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/ele.1327000461nas a2200133 4500008004100000245007900041210006900120300001200189490000800201100002400209700002500233700001700258856005200275 2019 eng d00aNitrous oxide emissions from annual and perennial biofuel cropping systems0 aNitrous oxide emissions from annual and perennial biofuel croppi a84 - 920 v1111 aMcGowan, Andrew, R.1 aRoozeboom, Kraig, L.1 aRice, C., W. uhttp://doi.wiley.com/10.2134/agronj2018.03.018700468nas a2200121 4500008004100000245008100041210006900122260004300191490002100234100002000255700001700275856005400292 2019 eng d00aSoil and microbial response to manipulated precipitation and land management0 aSoil and microbial response to manipulated precipitation and lan aManhattan, KSbKansas State University0 vPhD Dissertation1 aCarter, Tiffany1 aRice, C., W. uhttps://krex.k-state.edu/dspace/handle/2097/3968200564nas a2200157 4500008004100000245011000041210006900151300001400220490000800234100002400242700002600266700002000292700002500312700001700337856005200354 2019 eng d00aSoil organic carbon, aggregation, and microbial community Structure in annual and perennial biofuel crops0 aSoil organic carbon aggregation and microbial community Structur a128 - 1420 v1111 aMcGowan, Andrew, R.1 aNicoloso, Rodrigo, S.1 aDiop, Habib, E.1 aRoozeboom, Kraig, L.1 aRice, C., W. uhttp://doi.wiley.com/10.2134/agronj2018.04.028400519nas a2200145 4500008004100000245010800041210006900149300001400218490000700232100002400239700001800263700002600281700001700307856004900324 2018 eng d00aImpact of nitrogen application rate on switchgrass yield, production costs, and nitrous oxide emissions0 aImpact of nitrogen application rate on switchgrass yield product a228 - 2370 v471 aMcGowan, Andrew, R.1 aMin, Doo-Hong1 aWilliams, Jeffery, R.1 aRice, C., W. uhttp://doi.wiley.com/10.2134/jeq2017.06.022603068nas a2200349 4500008004100000245014000041210006900181300000900250490000600259520197400265653001702239653001902256653002002275653001702295653001902312653001902331653002002350100002402370700002202394700002302416700002602439700001902465700001602484700002502500700001702525700002302542700001702565700002502582700002202607700002302629856006602652 2018 eng d00aMicrobial community structure and functional potential in cultivated and native tallgrass prairie soils of the midwestern united states0 aMicrobial community structure and functional potential in cultiv a17750 v93 a

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.

10acarbon cycle10aClimate change10aLand management10ametagenomics10anative prairie10anitrogen cycle10asoil microbiome1 aMackelprang, Rachel1 aGrube, Alyssa, M.1 aLamendella, Regina1 aJesus, Ederson, da C.1 aCopeland, Alex1 aLiang, Chao1 aJackson, Randall, D.1 aRice, C., W.1 aKapucija, Stefanie1 aParsa, Bayan1 aTringe, Susannah, G.1 aTiedje, James, M.1 aJansson, Janet, K. uhttps://www.frontiersin.org/articles/10.3389/fmicb.2018.0177501114nas a2200385 4500008004100000245008400041210006900125260004000194300001400234100002000248700002300268700001700291700001800308700001900326700002300345700002000368700001700388700001900405700002000424700001700444700002200461700001500483700001300498700001800511700001700529700001800546700001700564700001600581700001800597700001500615700001300630700002200643700001200665856005100677 2018 eng d00aSecond State of the Carbon Cycle Report (SOCCR2): A Sustained Assessment Report0 aSecond State of the Carbon Cycle Report SOCCR2 A Sustained Asses bU.S. Global Change Research Program a229 - 2631 aHristov, A., N.1 aJohnson, J., M. F.1 aRice, C., W.1 aBrown, M., E.1 aConant, R., T.1 aDel Grosso, S., J.1 aGurwick, N., P.1 aRotz, C., A.1 aSainju, U., M.1 aSkinner, R., H.1 aWest, T., O.1 aRunkle, B., R. K.1 aJanzen, H.1 aReed, S.1 aCavallaro, N.1 aShrestha, G.1 aCavallaro, N.1 aShrestha, G.1 aBirdsey, R.1 aMayes, M., A.1 aNajjar, R.1 aReed, S.1 aRomero-Lankao, P.1 aZhu, Z. uhttps://carbon2018.globalchange.gov/chapter/5/00585nas a2200169 4500008004100000245011800041210006900159300001600228490000700244100002100251700002200272700002100294700001900315700002200334700001700356856004200373 2016 eng d00aChanges in spatial and temporal trends in wet, dry, warm and cold spell length or duration indices in Kansas, USA0 aChanges in spatial and temporal trends in wet dry warm and cold  a4085 - 41010 v361 aAnandhi, Aavudai1 aHutchinson, Stacy1 aHarrington, John1 aRahmani, Vahid1 aKirkham, Mary, B.1 aRice, C., W. uhttp://doi.wiley.com/10.1002/joc.461900392nas a2200133 4500008004100000245004900041210004700090260001600137300001800153490000600171100002000177700001700197856004400214 2015 eng d00aSoil Degradation: Will Humankind Ever Learn?0 aSoil Degradation Will Humankind Ever Learn cJan-09-2015 a12490 - 125010 v71 aKarlen, Douglas1 aRice, C., W. uhttp://www.mdpi.com/2071-1050/7/9/1249000934nas a2200313 4500008004100000245005300041210005000094260008100144300001200225100001400237700001900251700001600270700001400286700001300300700002100313700001500334700001500349700001400364700001500378700001500393700001300408700002300421700001700444700001800461700002100479700001700500700001700517856008600534 2014 eng d00aAgriculture, Forestry and Other Land Use (AFOLU)0 aAgriculture Forestry and Other Land Use AFOLU bCambridge University Press, Cambridge, United Kingdom and New York, NY, USA. a811-9221 aSmith, P.1 aBustamante, M.1 aAhammad, H.1 aClark, H.1 aDong, H.1 aElsiddig, E., A.1 aHaberl, H.1 aHarper, R.1 aHouse, J.1 aJafari, M.1 aMasera, O.1 aMbow, C.1 aRavindranath, N.H.1 aRice, C., W.1 aAbad, Robledo1 aRomanovskaya, A.1 aSperling, F.1 aTubiello, F. uhttps://www.ipcc.ch/report/ar5/wg3/agriculture-forestry-and-other-land-use-afolu/00988nas a2200325 4500008004100000245011200041210006900153300001200222490000900234100002200243700002100265700002000286700001500306700002100321700001700342700001500359700002400374700001700398700002000415700002200435700002000457700001800477700001800495700002100513700002400534700001900558700001700577700001900594856004900613 2014 eng d00aKnowledge and tools to enhance resilience of beef grazing systems for sustainable animal protein production0 aKnowledge and tools to enhance resilience of beef grazing system a10 - 170 v13281 aSteiner, Jean, L.1 aEngle, David, M.1 aXiao, Xiangming1 aSaleh, Ali1 aTomlinson, Peter1 aRice, C., W.1 aCole, Andy1 aColeman, Samuel, W.1 aOsei, Edward1 aBasara, Jeffrey1 aMiddendorf, Gerad1 aGowda, Prasanna1 aTodd, Richard1 aMoffet, Corey1 aAnandhi, Aavudai1 aStarks, Patrick, J.1 aOcshner, Tyson1 aReuter, Ryan1 aDevlin, Daniel uhttps://www.ncbi.nlm.nih.gov/pubmed/2537688703323nas a2200217 4500008004100000245012400041210006900165300001500234490000700249520261700256100002202873700002002895700001802915700001702933700001502950700001702965700001602982700001602998700001703014856007403031 2013 eng d00aAltered precipitation regime affects the function and composition of soil microbial communities on multiple time scales0 aAltered precipitation regime affects the function and compositio a2334 -23450 v943 a

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.

1 aZeglin, Lydia, H.1 aBottomley, P.J.1 aJumpponen, A.1 aRice, C., W.1 aArango, M.1 aLindsley, A.1 aMcGowan, A.1 aMfombep, P.1 aMyrold, D.D. uhttps://esajournals.onlinelibrary.wiley.com/doi/abs/10.1890/12-2018.100790nas a2200241 4500008004100000245009700041210006900138300001000207490000800217100001800225700002200243700001400265700001600279700001400295700001600309700001700325700001600342700001600358700001700374700001500391700001700406856012500423 2013 eng d00aFungal community responses to discrete precipitation pulses under altered rainfall intervals0 aFungal community responses to discrete precipitation pulses unde a182 -0 v1031 aJumpponen, A.1 aZeglin, Lydia, H.1 aDavid, M.1 aPrestat, E.1 aBrown, S.1 aDvornik, J.1 aLothamer, K.1 aHettich, R.1 aJansson, J.1 aRice, C., W.1 aTringe, S.1 aMyrold, D.D. uhttp://knz.lternet.edu/content/fungal-community-responses-discrete-precipitation-pulses-under-altered-rainfall-intervals02680nas a2200229 4500008004100000245009800041210006900139300001300208490000700221520195100228653002002179653002102199653002002220653002402240653002202264653002302286100002002309700002002329700001702349700001802366856006602384 2013 eng d00aWoody vegetation removal stimulates riparian and benthic denitrification in tallgrass prairie0 aWoody vegetation removal stimulates riparian and benthic denitri a547 -5600 v163 a

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.

10adenitrification10anitrogen removal10aprairie streams10ariparian vegetation10atallgrass prairie10awoody encroachment1 aReisinger, A.J.1 aBlair, John, M.1 aRice, C., W.1 aDodds, W., K. uhttps://link.springer.com/article/10.1007%2Fs10021-012-9630-301638nas a2200169 4500008004100000245016200041210006900203300001300272490000700285520101200292100001701304700001701321700001701338700001701355700001901372856007701391 2009 eng d00aSoil aggregation and carbon sequestration are tightly correlated with the abundance of arbuscular mycorrhizal fungi: results from long-term field experiments0 aSoil aggregation and carbon sequestration are tightly correlated a452 -4610 v123 a

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.

1 aWilson, G.T.1 aRice, C., W.1 aRillig, M.C.1 aSpringer, A.1 aHartnett, D.C. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/j.1461-0248.2009.01303.x02839nas a2200265 4500008004100000245010400041210006900145300001500214490000700229520201100236653001802247653002402265653001402289653002102303653001402324653002202338653001902360653001802379653002102397653001202418100001902430700001702449700002002466856008702486 2008 eng d00aConversion of grassland to coniferous woodland has limited effects on soil nitrogen cycle processes0 aConversion of grassland to coniferous woodland has limited effec a2627 -26330 v403 a

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.

10aExtractable N10aForest encroachment10agrassland10aIsotope dilution10aJuniperus10aMicrobial biomass10aMineralization10anitrification10aNitrogen cycling10aprairie1 aMcKinley, D.C.1 aRice, C., W.1 aBlair, John, M. uhttps://www.sciencedirect.com/science/article/abs/pii/S0038071708002320?via%3Dihub03037nas a2200205 4500008004100000245014400041210006900185300001300254490000700267520228400274653002402558653001502582653000902597653001102606653002902617653002302646100001902669700001702688856012602705 2007 eng d00aSeven years of enhanced water availability influences the physiological, structural and functional attributes of a soil microbial community0 aSeven years of enhanced water availability influences the physio a535 -5450 v353 aWater 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.10aMicrobial community10aphysiology10aPLFA10aStress10aSubstrate use efficiency10aWater availability1 aWilliams, M.A.1 aRice, C., W. uhttp://knz.lternet.edu/content/seven-years-enhanced-water-availability-influences-physiological-structural-and-functional01710nas a2200145 4500008004100000245012600041210006900167300001300236490000700249520112700256100001701383700001901400700001701419856012801436 2006 eng d00aMycorrhizal-mediated phosphorus transfer between tallgrass prairie plants Sorghastrum nutans and Artemisia ludoviciana0 aMycorrhizalmediated phosphorus transfer between tallgrass prairi a427 -4350 v203 a1A 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.1 aWilson, G.T.1 aHartnett, D.C.1 aRice, C., W. uhttp://knz.lternet.edu/content/mycorrhizal-mediated-phosphorus-transfer-between-tallgrass-prairie-plants-sorghastrum-nutans02152nas a2200145 4500008004100000245009700041210006900138300001300207490000700220520160800227100001901835700001701854700001801871856011701889 2006 eng d00aNatural 15N abundances in a tallgrass prairie exposed to 8 years of elevated atmospheric CO20 aNatural 15N abundances in a tallgrass prairie exposed to 8 years a409 -4120 v373 a

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.

1 aWilliams, M.A.1 aRice, C., W.1 aOwensby, C.E. uhttp://knz.lternet.edu/content/natural-15n-abundances-tallgrass-prairie-exposed-8-years-elevated-atmospheric-co202311nas a2200145 4500008004100000245007600041210006900117300001500186490000700201520180500208100001502013700001902028700001702047856010102064 2005 eng d00aPartitioning of nitrogen over five growing seasons in tallgrass prairie0 aPartitioning of nitrogen over five growing seasons in tallgrass  a1280 -12870 v863 aAnnual 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.1 aDell, C.J.1 aWilliams, M.A.1 aRice, C., W. uhttp://knz.lternet.edu/content/partitioning-nitrogen-over-five-growing-seasons-tallgrass-prairie02095nas a2200133 4500008004100000245007300041210006900114300001300183490000700196520162900203100001501832700001701847856009701864 2005 eng d00aShort-term competition for ammonium and nitrate in tallgrass prairie0 aShortterm competition for ammonium and nitrate in tallgrass prai a371 -3770 v693 aThe 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 (35–80%) 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.1 aDell, C.J.1 aRice, C., W. uhttp://knz.lternet.edu/content/short-term-competition-ammonium-and-nitrate-tallgrass-prairie02166nas a2200157 4500008004100000245008800041210006900129300001300198490000700211520161100218100001901829700001701848700001301865700001601878856011401894 2004 eng d00aCarbon and nitrogen pools in a tallgrass prairie soil under elevated carbon dioxide0 aCarbon and nitrogen pools in a tallgrass prairie soil under elev a148 -1530 v683 a

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.

1 aWilliams, M.A.1 aRice, C., W.1 aOmay, A.1 aOwensby, C. uhttp://knz.lternet.edu/content/carbon-and-nitrogen-pools-tallgrass-prairie-soil-under-elevated-carbon-dioxide02696nas a2200205 4500008004100000245009500041210006900136300001500205490000700220520202100227653001402248653001302262653001402275653001402289100001502303700001802318700002002336700001702356856011702373 2002 eng d00aChanges in ecosystem structure and function along a chronosequence of restored grasslands0 aChanges in ecosystem structure and function along a chronosequen a1688 -17010 v123 aChanges 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 6–8 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.10aecosystem10afunction10agrassland10astructure1 aBaer, S.G.1 aKitchen, D.J.1 aBlair, John, M.1 aRice, C., W. uhttp://knz.lternet.edu/content/changes-ecosystem-structure-and-function-along-chronosequence-restored-grasslands02348nas a2200157 4500008004100000245009300041210006900134300001300203490000700216520177500223653002201998100001902020700001702039700001802056856011602074 2001 eng d00aNitrogen competition in a tallgrass prairie ecosystem exposed to elevated carbon dioxide0 aNitrogen competition in a tallgrass prairie ecosystem exposed to a340 -3460 v653 aBecause 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–no chamber (NC), ambient CO2–chamber (AC), and 2 × ambient CO2–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–microbial competition and altered allocation patterns of N under elevated CO2, 15NH4–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 CO210atallgrass prairie1 aWilliams, M.A.1 aRice, C., W.1 aOwensby, C.E. uhttp://knz.lternet.edu/content/nitrogen-competition-tallgrass-prairie-ecosystem-exposed-elevated-carbon-dioxide01409nas a2200145 4500008004100000245008900041210006900130300001300199490000700212520093600219100001501155700001701170700002001187856005601207 2000 eng d00aAssessment of soil quality in fields with short- and long-term enrollment in the CRP0 aAssessment of soil quality in fields with short and longterm enr a142 -1460 v553 aSurface [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.1 aBaer, S.G.1 aRice, C., W.1 aBlair, John, M. uhttp://www.jswconline.org/content/55/2/142.abstract02660nas a2200205 4500008004100000245010000041210006900141300001300210490000800223520195400231653001702185653002302202653002202225653001702247653001502264100001902279700001702298700001802315856012102333 2000 eng d00aCarbon dynamics and microbial activity in tallgrass prairie exposed to elevated CO2 for 8 years0 aCarbon dynamics and microbial activity in tallgrass prairie expo a127 -1370 v2273 aAlterations 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 5–15 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 5–15 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.10aelevated CO210amicrobial activity10aMicrobial biomass10aSoil C and N10asoil water1 aWilliams, M.A.1 aRice, C., W.1 aOwensby, C.E. uhttp://knz.lternet.edu/content/carbon-dynamics-and-microbial-activity-tallgrass-prairie-exposed-elevated-co2-8-years00554nas a2200169 4500008004100000245006100041210006100102260003700163300001300200653000900213100001700222700001800239700001500257700001700272700001200289856008300301 2000 eng d00aEffects of fire and grazing on soil carbon in rangelands0 aEffects of fire and grazing on soil carbon in rangelands aBoca Raton, FLbLewis Publishers a323 -34210afire1 aRice, C., W.1 aOwensby, C.E.1 aFollet, R.1 aKimble, J.M.1 aLal, R. uhttp://knz.lternet.edu/content/effects-fire-and-grazing-soil-carbon-rangelands03159nas a2200217 4500008004100000245009700041210006900138300001300207490000700220520243800227653003302665653001202698653001102710653002202721653001402743653001302757100001602770700001902786700001702805856011902822 2000 eng d00aEffects of long-term fungicide application on microbial processes in tallgrass prairie soils0 aEffects of longterm fungicide application on microbial processes a935 -9460 v323 aSeveral 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 1996–1997 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 (± 51.2 SE) to 1485 (± 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.10aArbuscular mycorrhizal fungi10aBenomyl10acarbon10aMicrobial biomass10aNematodes10anitrogen1 aSmith, M.D.1 aHartnett, D.C.1 aRice, C., W. uhttp://knz.lternet.edu/content/effects-long-term-fungicide-application-microbial-processes-tallgrass-prairie-soils02224nas a2200157 4500008004100000245013000041210006900171300001300240490000700253520161100260653002201871100001501893700001501908700001701923856012601940 1999 eng d00aChanges in enzyme activities and microbial biomass of tallgrass prairie soil as related to burning and nitrogen fertilization0 aChanges in enzyme activities and microbial biomass of tallgrass  a769 -7770 v313 aMicrobial 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 (0–5 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–unfertilized, (2) burned–unfertilized, (3) burned–fertilized, and (4) unburned–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–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.10atallgrass prairie1 aAjwa, H.A.1 aDell, C.J.1 aRice, C., W. uhttp://knz.lternet.edu/content/changes-enzyme-activities-and-microbial-biomass-tallgrass-prairie-soil-related-burning-and02190nas a2200145 4500008004100000245011300041210006900154300001300223490000700236520161900243653002201862100001801884700001701902856012501919 1999 eng d00aSoil air carbon dioxide and nitrous oxide concentrations in profiles under tallgrass prairie and cultivation0 aSoil air carbon dioxide and nitrous oxide concentrations in prof a784 -7930 v283 aAssessing 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 (0.184–2.25 µL L−1) but were significantly higher in the cultivated site (0.257–7.56 µL L−1). Annual mean N2O concentrations were 0.403 and 1.09 µL L−1 in the prairie and cultivated sites, respectively. Soil air CO2 annual mean concentrations were 1.56 × 104 and 1.10 × 104 µL L−1 and ranged from 0.096 × 104 to 6.45 × 104 µL L−1 and 0.087 × 104 to 3.59 × 104 µL 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.10atallgrass prairie1 aSotomayor, D.1 aRice, C., W. uhttp://knz.lternet.edu/content/soil-air-carbon-dioxide-and-nitrous-oxide-concentrations-profiles-under-tallgrass-prairie01818nas a2200229 4500008004100000245010800041210006900149300001300218490000700231520103400238653001901272653002301291653001901314653001701333653002301350653002501373100001601398700001601414700001801430700001701448856012301465 1999 eng d00aVariations in microbial activity due to fluctuations in soil water content at the water table interface0 aVariations in microbial activity due to fluctuations in soil wat a479 -5050 v343 aA 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.10abioremediation10amicrobial activity10asoil interface10asoil texture10aSoil water content10asubsurface sediments1 aBanks, M.K.1 aClennan, C.1 aDodds, W., K.1 aRice, C., W. uhttp://knz.lternet.edu/content/variations-microbial-activity-due-fluctuations-soil-water-content-water-table-interface00677nas a2200229 4500008004100000245003800041210003800079260003800117300001300155653002200168100001700190700001500207700002000222700001900242700001800261700001700279700002000296700001900316700001900335700002400354856006900378 1998 eng d00aBelowground biology and processes0 aBelowground biology and processes aNew YorkbOxford University Press a244 -26410atallgrass prairie1 aRice, C., W.1 aTodd, T.C.1 aBlair, John, M.1 aSeastedt, T.R.1 aRamundo, R.A.1 aWilson, G.T.1 aKnapp, Alan, K.1 aBriggs, J., M.1 aHartnett, D.C.1 aCollins, Scott., L. uhttp://knz.lternet.edu/content/belowground-biology-and-processes02225nas a2200157 4500008004100000245009100041210006900132300001300201490000700214520165500221653002201876100001501898700001701913700001801930856011901948 1998 eng d00aCarbon and nitrogen mineralization in tallgrass prairie and agricultural soil profiles0 aCarbon and nitrogen mineralization in tallgrass prairie and agri a942 -9510 v623 aIn 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°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 (0–0.2 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.10atallgrass prairie1 aAjwa, H.A.1 aRice, C., W.1 aSotomayor, D. uhttp://knz.lternet.edu/content/carbon-and-nitrogen-mineralization-tallgrass-prairie-and-agricultural-soil-profiles00576nas a2200205 4500008004100000245002500041210002500066260003800091300001100129653002200140100001700162700001700179700001500196700002100211700002000232700001900252700001900271700002400290856005600314 1998 eng d00aSoils and soil biota0 aSoils and soil biota aNew YorkbOxford University Press a48 -6610atallgrass prairie1 aRansom, M.D.1 aRice, C., W.1 aTodd, T.C.1 aWehmueller, W.A.1 aKnapp, Alan, K.1 aBriggs, J., M.1 aHartnett, D.C.1 aCollins, Scott., L. uhttp://knz.lternet.edu/content/soils-and-soil-biota00666nas a2200205 4500008004100000245005400041210005400095260003800149300001300187653002200200100002000222700001900242700001700261700001800278700002000296700001900316700001900335700002400354856008200378 1998 eng d00aTerrestrial nutrient cycling in tallgrass prairie0 aTerrestrial nutrient cycling in tallgrass prairie aNew YorkbOxford University Press a222 -24310atallgrass prairie1 aBlair, John, M.1 aSeastedt, T.R.1 aRice, C., W.1 aRamundo, R.A.1 aKnapp, Alan, K.1 aBriggs, J., M.1 aHartnett, D.C.1 aCollins, Scott., L. uhttp://knz.lternet.edu/content/terrestrial-nutrient-cycling-tallgrass-prairie02295nas a2200193 4500008004100000245009600041210006900137300001300206490000700219520163600226100001801862700001601880700001701896700001701913700001801930700001801948700001101966856012401977 1996 eng d00aBiological properties of soil and subsurface sediments under abandoned pasture and cropland0 aBiological properties of soil and subsurface sediments under aba a837 -8460 v283 aLittle 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.1 aDodds, W., K.1 aBanks, M.K.1 aClenan, C.S.1 aRice, C., W.1 aSotomayor, D.1 aStrauss, E.A.1 aYu, W. uhttp://knz.lternet.edu/content/biological-properties-soil-and-subsurface-sediments-under-abandoned-pasture-and-cropland01746nas a2200133 4500008004100000245007600041210006900117300001500186490000700201520126500208100001801473700001701491856010401508 1996 eng d00aDenitrification in soil profiles beneath grassland and cultivated soils0 aDenitrification in soil profiles beneath grassland and cultivate a1822 -18280 v603 aThe 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.1 aSotomayor, D.1 aRice, C., W. uhttp://knz.lternet.edu/content/denitrification-soil-profiles-beneath-grassland-and-cultivated-soils00666nas a2200205 4500008004100000245006700041210006700108260002700175300001300202653002200215100001800237700001400255700002000269700001700289700001600306700001500322700001400337700001700351856009200368 1996 eng d00aEcosystem level responses of tallgrass prairie to elevated CO20 aEcosystem level responses of tallgrass prairie to elevated CO2 aLondonbAcademic Press a147 -16210atallgrass prairie1 aOwensby, C.E.1 aHam, J.M.1 aKnapp, Alan, K.1 aRice, C., W.1 aCoyne, P.I.1 aAuen, L.M.1 aKoch, G.W1 aMooney, H.A. uhttp://knz.lternet.edu/content/ecosystem-level-responses-tallgrass-prairie-elevated-co200621nas a2200169 4500008004100000245007200041210006900113260005300182300001300235100002100248700002200269700001700291700001700308700001600325700001600341856009400357 1996 eng d00aPotentially mineralizable N as an indicator of active soil nitrogen0 aPotentially mineralizable N as an indicator of active soil nitro aMadison, WIbSoil Science Society of America Inc a217 -2991 aDrinkwater, L.E.1 aCambardella, C.A.1 aReeder, J.D.1 aRice, C., W.1 aDoran, J.W.1 aJones, A.J. uhttp://knz.lternet.edu/content/potentially-mineralizable-n-indicator-active-soil-nitrogen00531nas a2200157 4500008004100000245005400041210005400095260005300149300001300202100001700215700001600232700001400248700001600262700001600278856007900294 1996 eng d00aRole of microbial biomass C and N in soil quality0 aRole of microbial biomass C and N in soil quality aMadison, WIbSoil Science Society of America Inc a203 -2151 aRice, C., W.1 aMoorman, T.1 aBeare, M.1 aDoran, J.W.1 aJones, A.J. uhttp://knz.lternet.edu/content/role-microbial-biomass-c-and-n-soil-quality00575nas a2200157 4500008004100000245006700041210006700108260004900175300001300224653002200237100001700259700001700276700001600293700001600309856009200325 1994 eng d00aBiologically active pools of soil C and N in tallgrass prairie0 aBiologically active pools of soil C and N in tallgrass prairie aMadison, WIbSoil Science Society of America a201 -20810atallgrass prairie1 aRice, C., W.1 aGarcia, F.O.1 aDoran, J.W.1 aJones, A.J. uhttp://knz.lternet.edu/content/biologically-active-pools-soil-c-and-n-tallgrass-prairie01768nas a2200145 4500008004100000245005200041210005200093300001300145490000700158520132100165653002201486100001701508700001701525856008001542 1994 eng d00aMicrobial biomass dynamics in tallgrass prairie0 aMicrobial biomass dynamics in tallgrass prairie a816 -8230 v583 aThe 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.10atallgrass prairie1 aGarcia, F.O.1 aRice, C., W. uhttp://knz.lternet.edu/content/microbial-biomass-dynamics-tallgrass-prairie03390nas a2200205 4500008004100000245011900041210006900160300001500229490000700244520267700251100001402928700001502942700002002957700001702977700001702994700001303011700001803024700001703042856012503059 1994 eng d00aPlant production and the biomass of soil microorganisms in late-successional ecosystems: A continental-scale study0 aPlant production and the biomass of soil microorganisms in lates a2333 -23470 v753 aAnnual 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.1 aZak, D.R.1 aTilman, D.1 aParameter, R.R.1 aFisher, F.M.1 aRice, C., W.1 aVose, J.1 aMilchunas, D.1 aMartin, C.W. uhttp://knz.lternet.edu/content/plant-production-and-biomass-soil-microorganisms-late-successional-ecosystems-continental02376nas a2200157 4500008004100000245005300041210005300094300001300147490000700160520189700167653002202064100001902086700001702105700001702122856007902139 1993 eng d00aDenitrification in a tallgrass prairie landscape0 aDenitrification in a tallgrass prairie landscape a855 -8620 v743 aWe 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—slope, toe—slope), plus a cultivated site in a toe—slope position (10 sites total). Denitrification was measured using an acetylene—based soil core technique four times in 1987, once in early 1988, and six times in 1989. Cores were incubated under field—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— 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.10atallgrass prairie1 aGroffman, P.M.1 aRice, C., W.1 aTiedje, J.M. uhttp://knz.lternet.edu/content/denitrification-tallgrass-prairie-landscape