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Spatial Variability of Soil Properties at Capulin Volcano,New Mexico,usa:Implications for Sampling Strategy

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Pedosphere 2010年第2期20卷 185-197页

作者： D.C.WEINDORF School of Soil Plant and Environmental SciencesLouisiana State University

Non-agricultural lands are surveyed sparsely in ***,soils in these areas usually exhibit strong spatial variability which requires more samples for producing acceptable *** Volcano National Monument,as a typical sparsely-surveyed area,was chosen to assess spatial variability of a variety of soil properties,and furthermore,to investigate its implications for sampling *** hundred and forty one composited soil samples were collected across the Monument and the surrounding *** properties including pH,organic matter content,extractable elements such as calcium (Ca),magnesium (Mg),potassium (K),sodium (Na),phosphorus (P),sulfur (S),zinc (Zn),and copper (Cu),as well as sand,silt,and clay percentages were analyzed for each *** of all properties were constructed,standardized,and compared to estimate the spatial variability of the soil properties in the *** on the similarity among standardized semivariograms,we found that the semivariograms could be generalized for physical and chemical properties,*** generalized semivariogram for physical properties had a much greater sill value (2.635) and effective range (7 500 m) than that for chemical *** sampling density (OSD),which is derived from the generalized semivariogram and defines the relationship between sampling density and expected error percentage,was proposed to represent,interpret,and compare soil spatial variability and to provide guidance for sample scheme *** showed that chemical properties exhibit a stronger local spatial variability than soil texture parameters,implying more samples or analysis are required to achieve a similar level of precision.

关键词： generalized semivariogram GIS optimal sampling density sampling design

Effects of nitrogen management on the ratoon crop yield and head rice yield in South usa

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Journal of Integrative Agriculture 2021年第6期20卷 1457-1464页

作者： WANG Yue-chao LI Xiu-fen Lee TARPLEY PENG Shao-bing DOU Fu-gen Texas A&M AgriLife Research Center 1509 Aggie DriveBeaumontTX 77713USA National Key Laboratory of Crop Genetic Improvement/Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River Ministry of Agriculture and Rural Affairs/College of Plant Science and TechnologyHuazhong Agricultural UniversityWuhan 430070P.R.China

Ratoon rice cropping is an important component of the rice cropping system in Texas and south Louisiana,usa,and expanded to Asian countries in *** field studies were conducted with widely planted rice(Oryza sativa L.)cultivars at Eagle Lake,Texas,usa to determine the effects of nitrogen(N)management in main(first)crop(MC)and ratoon(second)crop(RC)on RC *** 2012 and 2013,one cultivar(Presidio)was adopted to determine the effects of RC N management on ratoon yield and head rice *** 2016 and 2017,CL153,CL163 and CL272 in addition to Presidio were adopted to examine the effect of MC N management on ratoon yield and head rice yield.N applied at preflood after MC harvest considerably improved RC *** of 99 kg N ha^(–1)at preflood after MC harvest was practically adequate for RC regrowth,development and approaching the yield potential for *** could produce quite high average grain yields of 5.90 to 6.53 t ha–1 in 2012 and 2013,*** crop N rate only significantly affected MC yield;however,given N applied of 99 kg ha^(–1)at preflood after MC harvest,ratoon yield was not significantly affected by MC N *** the main nor ratoon crop N management had a significant effect on RC head rice *** RC head rice yields(55–65%)were observed in all of the four cultivars and 4 years except for CL272 in *** results indicat that without very high N fertilizer application,rice ratoon crop could produce a considerable grain yield and an expectative head rice *** ratooning could be a practical way to increase rice yields with the minimal input in south Texas and regions with a similar climate.

关键词： rice nitrogen management main crop ratoon crop grain yield head rice yield

Transferability and Scalability of Soil Total Carbon Prediction Models in Florida, usa

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Pedosphere 2018年第6期28卷 856-872页

作者： Sabine GRUNWALD Congrong YU Xiong XIONG Department of Soil and Water Sciences University of Florida State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University College of Hydrology and Water Resource Hohai University Agricultural and Biological Engineering Department University of Florida

The applicability, transferability, and scalability of visible/near-infrared(VNIR)-derived soil total carbon(TC) models are still poorly understood. The objectives of this study were to: i) compare models of three multivariate statistical methods, partial least squares regression(PLSR), support vector machine(SVM), and random forest methods, to predict soil logarithm-transformed TC(logTC) using five fields(local scale) and a pooled(regional-scale) VNIR spectral dataset(a total of 560 TC spectral datasets), ii)assess the model transferability among fields, and iii) evaluate their up-and downscaling behaviors in Florida, usa. The transferability and up-and downscaling of the models were limited by the following factors: i) the spectral data domain, ii) soil attribute domain,iii) methods that describe the internal model structure of VNIR-TC relationships, and iv) environmental domain space of attributes that control soil carbon dynamics. All soil logTC models showed excellent performance based on all three methods with R^2> 0.86,bias 2.70%, and ratio of prediction error to interquartile range(RPIQ) > 4.54. The PLSR method performed substantially better than the SVM method to scale and transfer the TC models. This could be attributed to the tendency of SVM to overfit models, while the asset of the PLSR method was its robustness when the models were validated with independent datasets, transferred, and/or scaled. The upscaled soil TC models performed somewhat better in terms of model fit(R2), RPD, and RPIQ, whereas the downscaled models showed less bias and smaller RMSE based on PLSR. We found no universal trend indicating which of the four limiting factors mentioned above had the most impact that constrained the transferability and scalability of the models. Given that several factors can impinge on the empirically derived soil spectral prediction models, as demonstrated by this study,

关键词： attribute domain multivariate statistical methods partial least squares regression random forest support vector machine soil carbon dynamics visible-near infrared spectroscopy

Modeling waves and longshore transport potential in Half Moon Bay,Grays Harbor,Washington,usa

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Acta Oceanologica Sinica 2008年第Z1期27卷 46-59页

作者： PHILIP D Osborne Pacific International Engineering PLLC

A local-scale phase-resolving wave transformation model with CGWAVE is established in connection with a regional-scale coupled STWAVE-ADCIRC wave-current model for its application in the Half Moon Bay, Grays *** transformation from offshore to the harbor entrance is simulated by the STWAVE model which includes wave-current *** STWAVE results provide incident wave conditions for the local-scale CGWAVE model at its outer boundary. A simple method is developed to take into account the lateral variation of wave height in constructing the model’s wave boundary *** model was validated for three wave condition cases which yielded good agreement with field *** validated model was applied to predicting nearshore waves in the Half Moon Bay and longshore transport parameters along the wave breaking line for the existing condition and three engineering alternatives. A comparative analysis indicated that storm waves that have a combination of long period and large height are the most destructive to the crenulate shoreline in the Half Moon Bay; both 152 m jetty extension (Alt. 2) and diffraction mound enlargement (Alt. 3) would significantly reduce breaking wave height and longshore transport potential in the southwest corner of Half Moon Bay.

关键词： wave transformation model CGWAVE longshore transport crenulate shoreline

A preliminary analysis of the response of an avian community to silvicultural treatments in the southern Cumberland Plateau, Alabama, usa

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Integrative Zoology 2006年第3期1卷 126-129页

作者： Yong WANG Adrian ALESAK Zachary FELIX Callie Jo SCHWEITZER Center for Forestry and Ecology Department of Plant and Soil ScienceAlabama A&M UniversityNormalAlabamaUSA Ecology and Management of Southern Appalachian Hardwoods Southern Research StationForest Service of the Department of AgricultureNormalAlabamaUSA

We simulated a shelterwood forest regeneration treatment by reducing basal area,and monitored the response of an avian community in oak–hickory forest on the southern Cumberland Plateau,northern Alabama,*** used five treatments:control(no removal),clear-cut(100%removal),and 25,50,and 75%removal of basal *** mapping was used to quantify bird community between mid-April and July of both 2002 and *** variables were recorded at each *** residual basal area and canopy cover showed three distinct conditions after treatment:closed canopy,open forest,and *** microclimate varied among treatments:air temperature was highest in clear-cut plots and lowest in control plots,whereas soil moisture had the opposite pattern.A total of 71 bird species were detected,with 36 of them defending *** density,species richness,and Shannon diversity index differed among the treatments;the relationship between these bird community indices and the level of basal area removal was quadratic,lowest in the clear-cut plots and highest in the intermediate *** species richness was similar among the control,25,50,and 75%removal treatments,species composition *** richness difference among treatments became smaller in the second year post-treatment(2003)with an increase in bird density and richness occurring in the clear-cut plots.

关键词： avian community biodiversity Cumberland Plateau forestry silviculture

Periodic anoxic shelf in the Early-Middle Ordovician transition:ichnosedimentologic evidence from west-central Utah,usa

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Science China Earth Sciences 2001年第11期44卷 979-989页

作者：龚一鸣 MaryL.Droser China University of Geosciences Faculty of Earth Science Wuhan China Department of Earth Science University of California Riverside USA

Ichnosedimentologic evidence of periodic anoxic shelf in the Early-Middle Ordovician transition includes lower ichnodiversity, shallower bioturbation and burrowing depth (<4 cm), rare domichnia, tinyChondrites occupying shallower or shallowest tiering, widely distributed nodules of limonite pseudomorphs after pyrite, occurrence of trace fossils being closely associated with the storm event layers, and stratigraphic successions with orbital cyclostratigraphic architecture. It is suggested that lower atmospheric oxygen level during the Early Paleozoic, the Ordovician radiation, dramatic transgression and warmer temperatures would result in the periodic anoxia in the Early-Middle Ordovician transition. This episode began at the later Early Ordovician and lasted about 3.4 Ma on the basis of orbital cyclostratigraphy.

关键词： anoxic shelf ichnofossils event sedimentology Ordovician radiation Utah usa

Geomechanical properties will constrain CO_(2)injection into the lower Ordovician Rose Run sandstone deep saline reservoir,Appalachian Basin,Kentucky,usa

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第5期13卷 947-960页

作者： John Richard Bowersox Stephen F.Greb Junfeng Zhu David C.Harris Kentucky Geological Survey University of KentuckyLexingtonKY40506-0107USA

The Kentucky Geological Survey(KGS)1 Hanson Aggregates stratigraphic research well,Carter County,Kentucky,usa,was drilled to a total depth of 1474 m as a field-scale test of potential CO2 storage reservoir properties in the Central Appalachian *** properties of the Rose Run sandstone(upper Ordovician Knox group)were tested for its suitability as a storage reservoir.A 9.8-m thick section of the Rose Run was penetrated at 1000 m drilled depth and a whole-diameter core and rotary sidewall cores were *** porosity and permeability measured in core plugs were 9.1%and 44.6 mD,*** vertical stress gradient calculated in the wellbore was 26 MPa/*** fractures in dolomites underlying and overlying the Rose Run follow the contemporary N53E Appalachian Basin stress *** Rose Run elastic geomechanical properties were calibrated to values measured in core plugs to evaluate its fracturing risk as a CO2 storage *** Young’s modulus and Poisson’s ratio values of the Rose Run were 45 GPa and 0.23,respectively,whereas Young’s modulus and Poisson’s ratio values were 77.1 GPa and 0.28,respectively,in the overlying Beekmantown dolomite,suggesting the Rose Run may fracture if overpressured during CO2 injection but be confined by the *** compressive strength measured in core plugs found the Rose Run and Beekmantown fractured at mean axial stresses of 156.5 MPa and 282.2 MPa,respectively,confirming the Beekmantown as suitable for confining CO2 injected into the Rose Run.A step-rate test was conducted in a mechanically-isolated 18.6-m interval bracketing the Rose *** Rose Run reservoir pressure was 9.3 MPa,and fracture gradient under injection was 13.6 MPa/km,suggesting step-rate testing before CO2 injection,and subsequent pressure monitoring to ensure *** the region around the KGS 1 Hanson Aggregates well is underpressured and adjacent to faulted Precambrian basement,further research is neede

关键词： Appalachian Basin Rose Run sandstone Geomechanics Carbon sequestration Step-rate testing

Vegetation Geo-climatic Zonation in the Rocky Mountains, Northern Utah, usa

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Journal of Mountain Science 2014年第3期11卷 656-673页

作者： Antonin KUSBACH Helga VAN MIEGROET Janis L.BOETTINGER James N.LONG Department of Wildland Resources and Ecology Center Utah State University Utah State University Department of Forest Botany Dendrology and Geobiocoenology Mendel University in Brno

We developed a vegetation geo-climatic zonation incorporating the zonal concept, gradient and discriminant analysis in Wasatch Range, northern Utah, usa. Mountainous forest ecosystems were sampled and described by vegetation, physiographic features and soil properties. The Snowpack Telemetry and National Weather Service Cooperative Observer Program weather station networks were used to approximate the climate of sample plots. We analysed vegetation and environmental data using clustering, ordination, classification, and ANOVA techniques to reveal environmental gradients affecting a broad vegetation pattern and discriminate these gradients. The specific objective was to assess and classify the response of the complex vegetation to those environmental factors operating at a coarse-scale climatic level. Ordination revealed the dominant role of regional, altitude-based climate in the area. Based on vegetation physiognomy, represented by five tree species, climatic data and taxonomic classification of zonal soils, we identified two vegetation geo-climatic zones:(1) a montane zone, with Rocky Mountain juniper and Douglas-fir; and(2) a subalpine zone, with Engelmann spruce and subalpine fir as climatic climax species. Aspen was excluded from the zonation due to its great ecological amplitude. We found significant differences between the zones in regional climate and landformgeomorphology/soils. Regional climate was represented by elevation, precipitation, and air and soil temperatures; and geomorphology by soil types. This coarse-scale vegetation geo-climatic zonation provides a framework for a comprehensive ecosystem survey, which is missing in the central Rocky Mountains of the United States. The vegetation-geoclimatic zonation represents a conceptual improvement on earlier classifications. This framework explicitly accounts for the influence of the physical environment on the distribution of vegetation within a complex landscape typical of the central Rocky Mountains an

关键词： Ecological classification Ecosystemsurvey Land classification Zonal concept Vegetation zone Vegetation geo-dimatic zone Climate change

Long-Term Effects of Different Passages of Vehicular Traffic on Soil Properties and Carbon Storage of a Crosby Silt Loam in usa

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Pedosphere 2019年第2期29卷 150-160页

作者： Gulab Singh YADAV Rattan LAL Ram Swaroop MEENA Basant RIMAL Carbon Management and Sequestration Centre the Ohio State University

The passage of vehicles with heavy axle loads causes soil compaction, and this adversely affects soil properties and crop *** adverse effects can persist for several years due to significant changes in key soil properties. However, the mechanisms of the aforementioned effects are not well understood for conservation agriculture(CA)(e.g., no-till(NT)) wherein the use of heavy machinery is considerably common. Therefore, known compaction forces(0 Mg load for compaction(NT-0, control), two passages of 2.5 Mg water wagon axle load(NT-2), and four passages of 2.5 Mg water wagon axle load(NT-4)) were applied to all the plots annually for 20 consecutive years. The experiment was established in 1997 at the Waterman Agricultural and Natural Resources Laboratory(WANRL), Ohio State University, Columbus, Ohio. Each treatment was replicated thrice. Soil samples were obtained in November2016 to determine the effects of variations in the axle load and vehicular passages on carbon(C) and nitrogen(N) storage and selected soil properties of a Crosby silt loam soil under NT-based corn-soybean rotation with residue retention in Central Ohio, usa. Three locations were also randomly selected in an adjoining natural woodlot(WL) soil plot and sampled(30 m away from the compaction field) to compare the effects of vehicular traffic on soil under NT with WL soil. Results revealed that soil bulk density(ρb) and total porosity at 0–10 and 10–20 cm depths were not affected by the passages of vehicular traffic for 20 years under the NT *** penetration resistance(PR)(1.86 and 2.03 MPa at 0–10 and 10–20 cm soil depths, respectively) was significantly higher under NT-4 compared with that under other treatments. Saturated hydraulic conductivity at 0–10 and 10–20 cm soil depths ranged from19.7 to 31.4 and 18.5 to 29.5 mm d^(-1), respectively, across all the treatments. The proportion of macroaggregates(> 0.25 mm) and microaggregates(< 0.25 mm), mean weight diameter and geometric mean diam

关键词： carbon stock heavy machinery no-till residue retention soil aggregates soil compaction soil quality well-drained soil