Peter Oduor
North Dakota State University, Geosciences, Faculty Member
The occurrence of the manure-borne estrogen, 17β-estradiol (E2), was investigated in laboratory and field soils. In the laboratory, E2 was applied to soil to simulate concentrations found in swine (Sus scrofa domestica) manure... more
The occurrence of the manure-borne estrogen, 17β-estradiol (E2), was investigated in laboratory and field soils. In the laboratory, E2 was applied to soil to simulate concentrations found in swine (Sus scrofa domestica) manure (5000 ng L−1). The aqueous-extracted E2 dissipated in the soil by 98% within 1 h and was not significantly different from background concentrations (18 ng L−1) for the duration of the experiment (64 h). In the field study, soil cores were taken before and several dates after swine manure application. Equivalent porewater concentrations of water-extractable E2 were determined in 0.15-m increments down to the water table (0.70–2.00 m deep). The average frequency of detection for 168 samples was 38% (average = 40 ng L−1 porewater equivalents). Eleven days after manure application there was no significant effect on E2 detection frequency or concentration. However, E2 concentrations significantly increased by 6 months after manure application, and appeared to be related to precipitation. Concentrations then returned to original levels by 17 months after manure application. Manure did not have an immediate effect on E2 occurrence due to the capacity of the soil to rapidly sorb E2. However, it appears that soil may act as a long-term reservoir for E2 in the environment, which may be periodically released through desorption.► Estradiol concentrations in soil profile of field receiving manure fertilization. ► Field soil profile concentrations of estradiol increase months after manure application. ► Soil may bind manure-borne estradiol releasing it months after manure application.
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Essential to analyses of forest-cover change is application of geospatial empirical or semi-empirical models of transition potentials based on the likelihood that forest land would change to non-forested land or vice versa depending on... more
Essential to analyses of forest-cover change is application of geospatial empirical or semi-empirical models of transition potentials based on the likelihood that forest land would change to non-forested land or vice versa depending on prevailing conditions of land-use change. Modeling land-cover as a function of land-use aids in understanding pertinent land-cover dynamics. This can enable forecasting of ramifications of current
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Markov chains have been widely used to model land-use/cover changes in both urban and nonurban areas. This study estimates pixel-wise land-use/cover variation in response to forest transition probabilities for McLean County in North... more
Markov chains have been widely used to model land-use/cover changes in both urban and nonurban areas. This study estimates pixel-wise land-use/cover variation in response to forest transition probabilities for McLean County in North Dakota. Grid data from National Agricultural Statistic Service (NASS) published by USDA for the years 2006-2012 were used as preliminary inputs to ascertain land-use/cover dynamics pertaining to forest transition. Two prevalent transition probabilities of a pixel changing, (a) forested to non-forested, Pfnf (b) and from non-forested to forested, Pnff, were derived. The maximal transition probability for Pfnf was 0.2171 for wetlands and 0.3295 for grass, pasture, non-agriculture. The maximal transition probability for Pnff was 0.1853 for urban/developed for 2011-2012 periods. The highest transition probability for the unchanged forest (Pff) recorded in the period of 2011-2012 was 0.7207, and the lowest transition probability recorded in the period of 2009...
ArcGIS Explorer Desktop and ArcGIS Explorer Online are useful platforms designed to rapidly create maps for non-GIS professionals. This paper provides an overview of how to use some of these versatile mapping tools to generate and publish... more
ArcGIS Explorer Desktop and ArcGIS Explorer Online are useful platforms designed to rapidly create maps for non-GIS professionals. This paper provides an overview of how to use some of these versatile mapping tools to generate and publish maps. In this study, we are utilizing practical examples of watershed related projects in North Dakota. Topics and skillsets include how to use base maps from the ArcGIS Online map gallery, entering GPS points and importing images into a mapping system, tips for the utilization of raster and vector data, creating and publishing final maps using ArcGIS Online. Practical examples on how (a) to use online resources to determine flood risk areas and (b) how to blend in situ water quality data with GIS data are demonstrated. Overlaying vector features, a generic GIS technique, on top of the raster layer provides a valuable tool for visualizing and delineating vulnerable areas in a flooding scenario. The examples employed in this study stem from Devils L...
Understanding forest C sequestration (CS) of the tropical region and managing to maximize C retention in biomass and to conserve soil C is important in reducing atmospheric CO2 levels. The associations between traits and ecosystem... more
Understanding forest C sequestration (CS) of the tropical region and managing to maximize C retention in biomass and to conserve soil C is important in reducing atmospheric CO2 levels. The associations between traits and ecosystem processes can help to identify the better management strategies for forest CS. The present study investigated the relationships amongst floristic, soil and climatic parameters and their control on C sequestration in two selected dry zone and wet zone forests of Sri Lanka. Soil fulvic fraction was found to act as a focal point of interacting with or influencing the other variables in dry zone and wet zone forests. Only in the dry zone forest, maximum relative humidity and rainfall during dry and wet periods, respectively, governed soil moisture through an atmosphere-floor litter-soil continuum. Our study revealed that air temperature and labile fraction (fulvic fraction) play a vital role in determining soil N. Interactions of variables, which control the C...
This study compares characteristics of reflectance spectra of leaf samples of mixed forest trees in temperate forest. Spectral signatures of native-exotic trees at wavelengths between 350 nm and 2500 nm were acquired using an ASD... more
This study compares characteristics of reflectance spectra of leaf samples of mixed forest trees in temperate forest. Spectral signatures of native-exotic trees at wavelengths between 350 nm and 2500 nm were acquired using an ASD FieldSpec 4 Hi-Res Spectroradiometer.
Long term deposition of atmospheric C as lithosphere formation is known as carbon sequestration (CS), the main remedial measures for global climatic change. Most studies on C budgeting have considered soil organic carbon (SOC) as a whole... more
Long term deposition of atmospheric C as lithosphere formation is known as carbon sequestration (CS), the main remedial measures for global climatic change. Most studies on C budgeting have considered soil organic carbon (SOC) as a whole without taking into account its constituent fractions. In the present study therefore, an attempt was made to understand variability of the SOC fractions of two selected dry and wet zone forests of Sri Lanka. Monthly soil core samples were collected up to 30 cm depth from permanent sampling plots of two wet and dry zone forests. Loss on ignition, a thermal oxidation method, was used to recognize the different SOC fractions. The study fractionated SOC as free litter fraction (active pool), fulvic fraction (inter mediate pool) and humic fraction (passive pool), as recognized by weight loss from 150-200 oC, 200-400 oC and 400-550 oC, respectively. The analysis revealed that free soil litter, fulvic and humic fractions constituted 16%, 53% and 31%, resp...
Most studies on C budgeting have considered soil organic carbon (SOC) as a whole without taking into account its constituent fractions. Present study reports dynamics of SOC fractions, litterfall, above-belowground C stock and climatic... more
Most studies on C budgeting have considered soil organic carbon (SOC) as a whole without taking into account its constituent fractions. Present study reports dynamics of SOC fractions, litterfall, above-belowground C stock and climatic parameters and their control on CS in a dry zone forest (DZF) and a dry zone arboretum (DZA) in the same eco-climatic zone of Sri Lanka. The DZF contained higher plant biomass C (77.21 t C/ha), litter fall C (4.76 t C/ha), floor litter C (2.36 t C/ha) and total ecosystem C (180.42 t/ha) stocks than the DZA of which corresponding values were 47.38 t C/ha, 4.35 t C/ha, 2.34 t C/ha and 151.69 t C/ha respectively. Higher amounts of fine root C stock was present in the DZA (3.70 t C/ha) than DZF (2.69 t C/ha). Thermal oxidation (i.e. loss on ignition, LOI) technique revealed that fulvic fraction (FF) represented ca. 50%, humic fraction ca. 30% and free soil litter fraction (FLF) ca. 20% of total soil SOC in both DZF and DZA. During seasonal dynamics of the...
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Forest cover change prediction is crucial for forest managers and for urban developers to make better management of forest resources especially in a highly vulnerable watershed such as Devil’s Lake Basin Watershed. This paper presents the... more
Forest cover change prediction is crucial for forest managers and for urban developers to make better management of forest resources especially in a highly vulnerable watershed such as Devil’s Lake Basin Watershed. This paper presents the dynamics of forest to non-forest (FNF) and vice versa transition using stochastic models and affiliated statistical analyses. National Agricultural Statistic Service (NASS) grid data published by the USDA for years 2001 to 2005 were used to make transition probability matrices for each combination of time steps using SemGrid an open-source software. FNF transition probabilities were further subjected to multivariate analysis. The Detrended Correspondence Analysis (DCA) showed that forest to forest (FF) transition is deviated along the axis 1 of the ordination diagram from other land use class transitions. Three distinguished groups were separated from the ordination diagram: (a) grass, pastureland and grain, hay, seeds (b) idle cropland and row cro...
We examined forest cover changes from one cover type to another based on pairs of classified images of Cass County from 2000 to 2010. Grid data from National Agricultural Statistic Service (NASS) published by USDA was used as preliminary... more
We examined forest cover changes from one cover type to another based on pairs of classified images of Cass County from 2000 to 2010. Grid data from National Agricultural Statistic Service (NASS) published by USDA was used as preliminary inputs to ascertain land-use/land-cover dynamics and Markovian stochastic models were generated. Transition probabilities for each pair of years were subjected to multivariate analyses. Results showed that forest to non-forest transition probabilities (Pfnf) conversion was high with forest land transiting to agricultural use, namely, (a) grain, hay & seeds for years 2002 to 2010 and 2005 to 2010 and (b) for row crops for years 2006 to 2010 with a time step of 1-year. The transition probabilities for unchanged forest (Pff) were significant from 2007 to 2010 time range. Trend and relationship between each pair of years yielded three distinct statistical clusters. The main group comprised of ten pairs of year combinations with 2002 & 2005, which showed...
Understanding spectral properties of plant leaves is useful in detection of seasonal variation of species (a) within a genera, and (b) among genera between families. This study compares spectral reflectance of leaf samples of 20 trees... more
Understanding spectral properties of plant leaves is useful in detection of seasonal variation of species (a) within a genera, and (b) among genera between families. This study compares spectral reflectance of leaf samples of 20 trees comprising of four genera, namely Acer spp. (six Aceraceae species), Pinus spp. (six Pinaceae species), Fraxinus spp. (four Oleaceae species), and Populus spp. (four Salicaceae species) that was obtained from Lincoln Oakes Nursery in Bismarck in North Dakota. A total of 432 reflectance spectra (at wavelengths between 350 nm and 2500 nm) of 14 broad-leaf and 6 needle-leaf species were acquired using an ASD FieldSpec 4 Hi-Res Spectroradiometer. A mean spectral reflectance for each species was calculated using ASD ViewSpecPro software. Two classification algorithms namely, principal component analysis (PCA) and cluster analysis (CA), were performed using the Primer 5 statistical package to detect the spectral similarity among species. A pairwise compariso...
Land use and land cover change may influence biological invasion of exotic plants widely. Modelling vulnerable habitats provides a tool for researchers and forest managers to understand the potential extent of distribution of an invasive... more
Land use and land cover change may influence biological invasion of exotic plants widely. Modelling vulnerable habitats provides a tool for researchers and forest managers to understand the potential extent of distribution of an invasive species. The goal of this study was to map distributional range of Russian olive (Elaeagnus angustifolia) at Bismarck-Mandan Wildland-Urban Interface. National Agricultural Imagery Program 2010 (NAIP) and in situ reference data was used to map potential habitat of the Russian olive using ArcGIS-Arc/Info® 9.3. Results showed that 3.61 % (287.80 acres) of the forests/trees were occupied by Russian olive. Of the total acreage of Russian olive, 21.47% was inundated in the historic 2011 flooding of Missouri River. Our findings revealed that the species is well established at riparian habitats and other open niches such as roadside, agricultural lands and grass pastureland. From this study, we also found out that at Bismarck-Mandan interface, which is a h...
Russian olive plants are discernible on aerial photographs because of silvery grey-green leaves in the upper strata of their canopies. Most efforts to map the Russian olive involve laborious manual digitizing techniques because automated... more
Russian olive plants are discernible on aerial photographs because of silvery grey-green leaves in the upper strata of their canopies. Most efforts to map the Russian olive involve laborious manual digitizing techniques because automated pixel-based approaches are inadequate. However, ENVI EX® provides a platform to process multiple aerial photographs using a defined spectral motif for automatically extracting unique landscape features. We provide a comparative analysis of Russian olive distributions across a riparian landscape based on manual digitizing and automated extraction techniques. The study site is located within the Bismarck-Mandan Wildland-Urban interface of North Dakota. The confining boundaries of the site were determined by identifying maximum inundation extents in riparian zones via Landsat TM 4-5 imagery and aerial photography. 2010 National Agricultural Imagery Program photography and in-situ reference data were used for mapping the Russian olive with ArcGIS-Arc/In...
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ABSTRACT In compacted Na-montmorillonite membranes, the pore size and surface charge will influence filtration processes of solutes. A dead-end hyperfiltration setup was utilized to (1) study the intrinsic retention, membrane filtration... more
ABSTRACT In compacted Na-montmorillonite membranes, the pore size and surface charge will influence filtration processes of solutes. A dead-end hyperfiltration setup was utilized to (1) study the intrinsic retention, membrane filtration coefficient, and solution flux of different membrane configurations and (2) model nitrate breakthrough effluent concentrations through the membrane. Scanning electron microscopy and solute analytical techniques were employed to assess what critical components at micrometer scale would prevail in a non-bio-stimulated remediation of simulated agricultural wastewater. The results reveal hyperfiltration of nitrate ions is a function of the compaction pressure and composition of bentonite in the mixed soils. Although high-content bentonite membrane configurations (5 g clay at 2500 psi) offered better solute rejections with a 30% increase in the cell concentration, the compaction of the membrane had the most deterministic influence on the solution flux. We can adduce that for permselective membranes, it is more probable that a size exclusion mechanism predominates ion exclusion in solute sieving.
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ABSTRACT The microbial pathway of nitrate assimilation may have bioremediation potential in cases where the need for nitrate removal is paired with a desire to reuse the captured nitrogen in biomass form. In order to assess the nitrate... more
ABSTRACT The microbial pathway of nitrate assimilation may have bioremediation potential in cases where the need for nitrate removal is paired with a desire to reuse the captured nitrogen in biomass form. In order to assess the nitrate bioremediation potential of Methylobacterium fujisawaense, both freely suspended cells and those immobilized on calcium alginate beads were assessed in aerobic test tube and batch reactor settings for their ability to reduce NO3-N. Nitrate removal results were as high as 100% for freely suspended cells after 96 h and 95% for immobilized cells also after 96 h. A statistical analysis of the first order kinetic/exponential decay trend found in both free cell and immobilized cell systems found no significant difference in overall nitrate removal rates between the two systems. These findings suggest that the organism is capable of a significant assimilation of NO3-N. The assimilating ability of M. fujisawaense is also not greatly altered by immobilization, a characteristic that adds to the list of its potential benefits in a bioremediation setting.