bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of water and sediment quality of urban streams in Santa Cruz do Sul County, RS, Brasil, using ecotoxicological assays
Authors: Vargas Luã de , Athanásio Camila , Düpont Adriana , Costa Adilson Ben da , Lobo Eduardo Aléxis
Published: July 2014

AIM: This study aimed to assess the quality of water and sediment of urban streams (Lajeado, Preto, Pedras and Lewis-Pedroso) located in Santa Cruz do Sul County, RS, Brazil, using the microcrustacean Ceriodaphnia dubia as test-organism. METHODS: Quarterly scientific excursions to the streams were held on August and November 2011, February and May of 2012 in order to collect water and sediment samples, in the upper reaches (P1, P3, P5, P7) and lower reaches (P2, P4, P6, P8), totalizing 8 points. To evaluate the toxicity (acute and chronic), the microcrustacean C. dubia was used. RESULTS AND CONCLUSION: The results indicated high toxicity levels detected in samples P2, P6 and P8 (lower reaches), as they caused the mortality of 100% of organisms in the water samples (P6 and P8) and sediment samples (P2 and P8), denoting acute effect. Yet, all upstream sites showed chronic effects in sediment samples, at least for one collection period, with the highest significant toxicity level among all samples (55.2%), which indicates the presence of contamination even in upper areas. These results indicated a strong degradation of the water and sediment quality of urban streams coming from the wastewater and industrial discharges of the urban area, which can cause damage to the biota as well as the public health, due to the multiples uses of water that the local population does, highlighting many of them as inappropriate to the water quality detected, such as the primary contact recreation (balneability).
Change and continuity in post-Katrina New Orleans
Authors: Hewitt John , Wilkinson Suzanne , Potangaroa Regan
Published: July 2014

In post-Katrina New Orleans the City Charter endorses the designation of the City Planning Commission (CPC) as the lead agency for both urban and recovery planning. The municipal level of government and the theory and practice of planning thus achieve positions of dominance in the recovery process. The paper notes a number of correspondences between the New Orleans model and Habraken's hierarchy of control of urban change, in which control over the top level, the city, confers dominance over the actions of agents operating at all lower levels. The post-Katrina planning literature records, however, that despite its mandate the CPC becomes just one agency operating within a competitive context in which the cataclysmic destruction of the physical environment is not reflected in the associated social structure of the city's agents of change. A considerable continuity of tenure within the membership of the city level's agents emerges from the literature, and the control of the recovery planning process becomes a common objective. The paper concludes with an assessment of the degree to which they succeed in exerting a controlling influence on the content and implementation of the recovery plans.
Demographic drivers of tree biomass change during secondary succession in northeastern Costa Rica
Authors: Rozendaal Danaë M. A. , Chazdon Robin L.
Published: July 2014

Second‐growth tropical forests are an important global carbon sink. As current knowledge on biomass accumulation during secondary succession is heavily based on chronosequence studies, direct estimates of annual rates of biomass accumulation in monitored stands are largely unavailable. We evaluated the contributions of tree diameter increment, recruitment, and mortality to annual tree biomass change during succession for three groups of tree species: second‐growth (SG) specialists, generalists, and old‐growth (OG) specialists. We monitored six second‐growth tropical forests that varied in stand age and two old‐growth forests in northeastern Costa Rica. We monitored these over a period of 8 to 16 years. To assess rates of biomass change during secondary succession, we compared standing biomass and biomass dynamics between second‐growth forest stages and old‐growth forest, and evaluated the effect of stand age on standing biomass and biomass dynamics in second‐growth forests. 

Standing tree biomass increased with stand age during succession, whereas the rate of biomass change decreased. Biomass change was largely driven by tree diameter increment and mortality, with a minor contribution from recruitment. The relative importance of these demographic drivers shifted over succession. Biomass gain due to tree diameter increment decreased with stand age, whereas biomass loss due to mortality increased. In the age range of our second‐growth forests, 10–41 years, SG specialists dominated tree biomass in second‐growth forests. SG specialists, and to a lesser extent generalists, also dominated stand‐level biomass increase due to tree diameter increment, whereas SG specialists largely accounted for decreases in biomass due to mortality.

Our results indicate that tree growth is largely driving biomass dynamics early in succession, whereas both growth and mortality are important later in succession. Biomass dynamics are largely accounted for by a few SG specialists and one generalist species, Pentaclethra macroloba. To assess the generality of our results, similar long‐term studies should be compared across tropical forest landscapes.
Thermal Recovery of Bitumen From the Grosmont Carbonate Formation—Part 2: Pilot Interpretation and Development Strategy
Authors: Yang Daniel , Hosseininejad Mohebati Moslem , Brand Steve , Bennett Caralyn
Published: July 2014

Bitumen production from the Grosmont formation is enabled by bitumen-viscosity reduction caused by heating with steam, and is driven by three processes: thermal expansion, gravity drainage, and spontaneous imbibition. Gravity drainage is the dominant recovery mechanism. Maintaining a balance of injected and produced fluid is indicative of good performance. The projected steam/oil ratio (SOR) for the carbonate Grosmont formation is comparable to that of the clastic Clearwater formation; the impact of lower porosity is compensated by lower water saturation. On the basis of the experience from the pilot project, a followup development of the Grosmont formation relies on cyclic operation of injection and production. Saleski Phase 1, approved by the Alberta Energy Regulator, is designed for 1700-m3/d oil capacity from the Grosmont formation. For the first time, probable undeveloped reserves have been assigned to a fractured-carbonate bitumen reservoir. The cyclic-to-continuous steam-assisted-gravity-drainage drainage (C2C-SAGD) concept, where initial cyclic operation of individual wells is converted into continuous injection and production with well pairs as the reservoir depletion matures, intends to maximize recovery in future exploitation projects.
Corn Root Effects on the Nitrogen‐Supplying Capacity of a Conditioned Soil
Authors: Sanchez Jose E. , Paul Eldor A. , Willson Thomas C. , Smeenk Jeffrey , Harwood Richard R.
Published: July 2014

The design of sustainable N management strategies requires a better understanding of the processes influencing the ability of soils to supply N to a growing crop. Although commonly ignored, the release of C by plant roots may have a tremendous impact on soil organic matter turnover under certain soil conditions. The main objective of this study was to determine if living corn (Zea maysL.) roots would increase the N‐supplying capacity of a soil with an enhanced mineralizable N pool. A rotation of corn–corn–soybean [Glycine max(L.) Merr.]–wheat (Triticum aestivumL.) in combination with cover crops and the application of composted manure were used to increase the mineralizable N pool. The N‐supplying capacity of bare soil and soils planted with corn and wheat was calculated, and changes in N and C pool sizes were determined by laboratory incubations. Living corn roots increased the inorganic N–supplying capacity of the conditioned soil by >50%. We suggest that this increase is caused by an increase in net N mineralization. This is supported by the considerable size reduction of the 70‐d N pool in the soil planted with corn. No significant increase in the soil N‐supplying capacity was observed when wheat was planted, indicating the possibility that this effect may vary dramatically among plant species. The contribution of corn and wheat root rhizodeposition to the active C pool and as energy source to enhance microbial activity and organic matter turnover is discussed.
Nitrogen Fertilizer Use Efficiency of Furrow‐Irrigated Onion and Corn
Authors: Halvorson Ardell D. , Follett Ronald F. , Bartolo Michael E. , Schweissing Frank C.
Published: July 2014

Furrow‐irrigated onion (Allium cepa L.) production, with high N fertilization rates, may be contributing NO3–N to ground water in southeastern Colorado. This study determined the growth and N uptake patterns of onion grown on a silty clay soil, N fertilizer use efficiency (NFUE) of onion, and recovery of residual N fertilizer by corn (Zea mays L.) following onion in rotation. Onion was sampled biweekly from 18 May to 15 Sept. 1998 from plots receiving 0 and 224 kg N ha−1. Nonlabeled N and labeled 15N fertilizer were band‐applied near the onion row in split applications of 112 kg N ha−1 each on 18 May and 25 June. Onion dry matter accumulation was slow from planting to about late May, followed by a rapid increase in biomass production and N uptake. Because residual soil NO3–N was high, N fertilization resulted in only a small increase in bulb yield. Greatest demand for N by onion occurred during bulb development. Fertilizer N recovery by onion was 11 and 19% for May and June N applications (average 15%), respectively. Much of the fertilizer N remained in the upper 60‐cm soil profile at harvest and had moved toward the onion bed center. Fertilizer 15N detected at 180‐cm soil depth indicated leaching losses from the root zone. The unfertilized 1999 corn crop recovered 24% of fertilizer N applied to onion for a total fertilizer N uptake by the two crops of 39%. Delaying N fertilizer application until onion bulbing begins may improve NFUE. Planting corn directly on the previous onion bed may result in greater N fertilizer recovery by corn.
BokerTov
Authors: Ungar Eugene D.
Published: July 2014

Many aspects of managing and studying animal production systems require information at the level of the individual animal to be gathered and processed. BokerTov is a biologically oriented, computerized database for managing beef suckler herds at pasture, with individual‐based records. It was developed for research and commercial purposes and aims to meet the needs of a busy but computer literate manager. A defining feature of the program is the ability to track an animal's location in the system by recording every location change and its date for each cow (Bos taurus) and each calf. For each cow, information is stored regarding the identity, parentage, birth, entry into and exit from the system, liveweight, body condition score, and pregnancy diagnosis. A record is maintained of dates of calving (or abortion) and the identity of calves born. For the calf population, information is stored regarding the identity, parentage, birth, weaning, exit from the system, sale, price, and performance from weaning to exit. There are routines for editing existing data and creating criteria‐based lists. Data analysis includes the creation of dynamic and flexibly structured multiseason summary tables on various aspects of system performance, including cow and calf population dynamics, calf performance, animal‐days accumulated at different locations over time, calving intervals, and productivity. The program was developed within the spreadsheet program Microsoft Excel, with a macro interface, and it runs on Mac and PC computers. Data are stored in simply structured worksheet files, which are directly accessible in read‐only mode on quitting BokerTov.
Influence of Winter Cover Crop and Residue Management on Soil Nitrogen Availability and Corn
Authors: Kuo Shiou , Jellum Eric J.
Published: July 2014

Removing cover crop top growth in the spring for forage or to prevent incorporation problems is one management option. The effects of this residue management on soil quality and productivity need to be determined. This study, conducted from 1994 to 1998 at Puyallup, WA, determined effects of various winter cover crops and residue management on soil N availability, soil C and N, and corn (Zea maysL.) yield. Included in the study were monocultures of rye (Secale cerealeL.), ryegrass (Lolium multiflorumLam), and vetch (Vicia villosaRoth subsp.villosa) and biculture of vetch and rye or ryegrass. Each year, the cover crops were seeded in the fall and incorporated into, or removed from, the soil in the spring. Average top‐growth biomass was higher for the bicultures than for the monocultures. Total N accumulation was generally greatest under vetch, followed by the bicultures, and lowest for the monocultured rye or ryegrass. Whereas removing top growth of monocultured vetch or bicultures depressed presidedress soil NO3–N (Ni), the effect was generally not found for monocultured rye or ryegrass. Corn yields were affected by amounts of Niand N fertilizer applied (r2> 0.789), irrespective of cover crop species and residue management. Removing top growth of the cover crops limited residue C input and reduced soil organic C and N after 5 yr. Soil organic C and N accumulation, as well as increasing soil C sequestration to reduce CO2release into atmosphere, should be considered when deciding which residue management option to choose.
Feasibility of Four‐Year Crop Rotations in the Central High Plains
Authors: Schlegel Alan J. , Dumler Troy J. , Thompson Curtis R.
Published: July 2014

In the central Great Plains, there has been an increase in summer crops, such as grain sorghum [Sorghum bicolor (L.) Moench] or corn (Zea mays L.), grown in a wheat (Triticum aestivum L.)–summer crop–fallow rotation. This field study quantified the effects of increasing cropping intensity beyond a 3‐yr rotation on soil water dynamics and wheat and grain sorghum production and profitability and determined the grain yields necessary to ensure greater profitability over 3‐yr rotations. Cropping systems evaluated were wheat–wheat–sorghum–fallow (WWSF), wheat–sorghum–sorghum–fallow (WSSF), and continuous wheat (WW). Available soil water (ASW) at wheat planting was 82 mm greater following sorghum than following wheat; however, fallow efficiency decreased from 50% following wheat to 20% following sorghum. At sorghum planting, ASW was 22 to 32 mm greater following wheat than sorghum. Before sorghum, soil water accumulation during fallow was much greater following wheat than sorghum (168 vs. 60 mm). Fallow efficiency was also greater (34 vs. 23%). Wheat yields were 43% (1.2 Mg ha−1) greater following sorghum than wheat. Grain sorghum yields were 36% (1.5 Mg ha−1) greater following wheat than sorghum. Production costs were similar for all rotations. The WSSF rotation had the highest net returns, about $95 ha−1 compared with $92 ha−1 for a simulated WSF rotation, $76 ha−1 for WWSF, and $49 ha−1 for WW. In this study, grain yields required to make 4‐yr rotations more profitable than a 3‐yr WSF rotation were recrop sorghum yields of 3.5 to 4.0 Mg ha−1 and recrop wheat yields of 2.5 to 3.0 Mg ha−1
Bermudagrass–White Clover–Bluegrass Sward Production and Botanical Dynamics
Authors: Belesky David P. , Fedders James M. , Ruckle Joyce M. , Turner Kenneth E.
Published: July 2014

Cool‐season forages dominate pastures in the Appalachian region where midsummer weather conditions often depress productivity. Warm‐season forages can buffer variation in available herbage, but land resources may limit the area dedicated to special‐use crops. A replicated field plot experiment was conducted for 3 yr (1995–1997) in a bermudagrass (Cynodon dactylon L.) stand oversown with Kentucky bluegrass (Poa pratensis L.) and white clover (Trifolium repens L.) to determine the influence of defoliation on productivity, nutritive value, and botanical dynamics of the mixture. Botanical composition changed with defoliation and varied among years. Bermudagrass comprised as much as 55% of the sward in mid‐ and late‐season 1995. By 1997, the proportion was similar to other grasses and rarely exceeded 20%. Maximum instantaneous growth rates occurred later in the growing season in 1995 when bermudagrass was a dominant sward component compared with subsequent years when bermudagrass was <10% of the sward. Rates in 1995 were greatest for swards clipped at 6‐wk intervals (70 kg ha−1 d−1) or when 20‐cm tall and least when clipped at 2‐wk intervals (33 kg ha−1 d−1) and at 10‐cm height (45 kg ha−1 d−1). The trend was reversed by 1997 when sward composition shifted away from bermudagrass to cool‐season grasses and white clover. Yields were greatest when cool‐season species dominated the sward. Creating a self‐regulating mixture of warm‐ and cool‐season perennial forages may be a means of achieving some stability in sward productivity and might be useful where wide fluctuations in growing conditions occur among years.
Soil Organic Matter and Tomato Yield following Tillage, Cover Cropping, and Nitrogen Fertilization
Authors: Sainju Upendra M. , Singh Bharat P. , Yaffa Sidat
Published: July 2014

Management practices can influence soil C and N and tomato (Lycopersicon esculentum Mill) yield. We examined the influence of tillage practices [no‐till (NT), chisel plowing (CP), and moldboard plowing (MP)], cover crops [hairy vetch (Vicia villosa Roth) vs. winter weeds], and N fertilization rates (0, 90, and 180 kg N ha−1) on soil organic C and N, potential C and N mineralization (PCM and PNM, respectively), inorganic N contents, and tomato yield and N uptake. A 3‐yr experiment was conducted on a Dothan sandy loam (fine‐loamy, siliceous, thermic, Plinthic Paleudults) in central Georgia. Soil organic C and N after 3 yr were greater in NT with vetch than in CP and MP with vetch or weeds at 0‐ to 20‐cm depth. The PCM, PNM, and inorganic N were greater in MP than in NT and CP at 7.5 to 20 cm in May 1996 but were greater in NT and CP than in MP at 0 to 7.5 cm in April 1997. At 0 to 20 cm, PNM and inorganic N were also greater with vetch than with weeds in April 1996 and 1997 and with 180 than with 0 kg N ha−1 in May 1996 and August 1997. Tomato yield and N uptake were greater in CP and MP than in NT and with 90 and 180 kg N ha−1 than with 0 kg N ha−1. Although NT with vetch can improve soil organic matter, CP can sustain tomato yield compared with MP, thereby reducing the potential for soil erosion. Hairy vetch can increase labile soil N pool and 90 compared with 180 kg N ha−1 can sustain tomato yield, thereby reducing the amount of N fertilizer and potential for N leaching.
Genetic Diversity for Stripe Rust Resistance in Wheat Landraces and Identification of Accessions with Resistance to Stem Rust and Stripe Rust
Authors: Sthapit Jinita , Newcomb Maria , Bonman J. Michael , Chen Xianming , See Deven R.
Published: July 2014

Stripe rust, caused by Puccinia striiformis f. sp. tritici, and stem rust, caused by P. graminis f. sp. tritici, are economically important diseases of wheat (Triticum aestivum L.). Stripe rust continues to cause huge economic losses in major wheat‐growing regions as new races of the pathogen frequently emerge. Wheat landraces from diverse geographic regions are a potential source of novel rust resistance genes. In search of multiple rust resistance, a total of 652 landrace accessions from 54 countries previously screened for resistance to stem rust pathogen (race Ug99) were tested for resistance to current races of stripe rust in Pullman and Mt. Vernon, WA. Of the accessions, 165 showed resistance to stripe rust in the field, and 30 of them also had resistance to stem rust. The 652 landraces were genotyped with 72 simple sequence repeat markers, and 500 of them had data for 8633 single nucleotide polymorphism (SNP) markers covering the whole wheat genome. Genetic analysis based on SNP markers grouped the resistant landraces into nine different clusters in an unweighted pair group with arithmetic mean dendrogram and three groups in principal coordinates analyses, suggesting that resistant genotypes are genetically diverse and are expected to possess diverse resistance genes. Landraces with resistance to stem rust and stripe rust have both global and regional importance as sources of developing new and diverse resistant germplasm.
Impact of Agromanagement Practices on Rice Elongation: Analysis and Modelling
Authors: Confalonieri R. , Stella T. , Dominoni P. , Frasso N. , Consolati G. , Bertoglio M. , Bianchi E. , Bortone L. , Cairo V. , Cappelli G. , Cozzaglio G. , Fattorossi G. , Garbelli A. , D'Incecco P. , Marazzi A. , Marescotti M.E. , Marziali F. , Maserati S. , Mazza M. , Mottadelli G. , Negrini G. , Nutini F. , Orasen G. , Pacca L. , Pinnetti M. , Pirotta M. , Porta R. , Riva A. , Riva M. , Scaramelli A. , Sessa F. , Uggeri S. , Urbinati F. , Russo G. , Chiodini M. , Bregaglio S. , Acutis M.
Published: July 2014

Plant height has a deep influence on the productivity of many crops, as it involves susceptibility to lodging, crop–weed competition, and the achievement of favorable harvest index. Nevertheless, modellers have practically ignored related ecophysiological processes, especially those modulated by management practices. The aim of this study was to analyze and model the processes involved with the effects of management on rice (Oryza sativa L.) elongation. Data were collected in two greenhouse experiments (2010–2011) where three factors (floodwater level, N fertilization, sowing density) were arranged in a split‐plot design with three replicates. The model proposed demonstrated its suitability in reproducing both the dynamics involved with tissue elongation in the different phenological phases and the effects of submergence and N luxury consumption on elongation rates. Relative root mean square error (RRMSE) ranged between 4.23 and 12.41% for different treatments and years. The inclusion of algorithms for the impact of agronomic practices on plant height in cropping system models would increase their suitability for scenario analyses and for in silico ideotyping studies, owing to the great interest shown by geneticists in related traits. Moreover, this study—performed with students of a Cropping Systems MS course—demonstrated once more the power of modeling within educational activities. In this case, models were not the subject of the teaching but tools for analyzing processes and formalizing new knowledge.
Evaluation of Perennial Warm‐Season Grass Mixtures Managed for Grazing or Biomass Production
Authors: Bonin Catherine L. , Lal Rattan , Tracy Benjamin F.
Published: July 2014

Perennial warm‐season grasses (WSG) have potential for use as forage in grazing systems and as biomass for bioenergy production. Managing WSG stands for these purposes could affect ecosystems differently. The goal of this study was to evaluate how management of WSG stands, for either grazing or as a bioenergy crop, would impact weedy and sown biomass, community composition, and total soil C pools. Mixtures containing 1, 4, and 10 native species were established in Blacksburg, VA, and managed for grazing or as a biomass crop from 2009 to 2012. Initially, switchgrass (Panicum virgatum L.) monocultures yielded less sown biomass and had more weed pressure than the more diverse mixtures. Grazing promoted weed invasion in all mixtures, especially in 2012 when grazed areas contained over four times more weed biomass than biomass plots. Forage species composition shifted over time, as forbs, which contributed over 50% of herbage mass in the first year, were replaced by WSG. Total soil C was not affected by management or species composition of WSG stands but did increase 17% over 4 yr. The amount of new soil C added by warm‐season species (C4) was higher in 4‐ and 10‐species mixtures, likely the result of greater WSG biomass and cool‐season species (C3) weeds that invaded switchgrass monocultures. Planting diverse WSG mixtures (4 to 10 species) and managing initially for biomass production may help accelerate stand establishment, produce high herbage yields, and reduce weed pressure.
Testing an Infiltration Method for Estimating Soil Hydraulic Properties in the Laboratory
Authors: Bruckler L. , Bertuzzi P. , Angulo-Jaramillo R. , Ruy S.
Published: July 2014

Solving soil unsaturated flow problems requires knowledge of the water retention, θ(h), and unsaturated hydraulic conductivity, K(θ), relationships. The purpose of this study was to adapt to infiltration conditions the so‐called Wind method previously described for evaporation conditions for determining θ(h) and K(θ) and from laboratory cores. Infiltration in a vertical column of soil was first simulated using the numerical solution of Richards' equation for two soils. The simulated data were then used to evaluate the ability of the method to provide estimations of the hydraulic properties, whether measurement errors on tensiometric data were taken into account or not. In the laboratory, a sandy and a loamy soil sample were used in infiltration experiments. The experimental equipment consisted of (i) a metal cylinder containing the soil sample placed on an automatic balance, (ii) a set of tensiometers inserted in the soil sample, and (iii) a drip infiltrometer placed horizontally above the soil surface of the sample. Pressure head profiles and the weight of the sample was recorded at constant time steps. The infiltration method is able to provide estimates of the retention curve as was shown by numerical and laboratory experiments. Estimating the unsaturated hydraulic conductivity was possible by applying Wind's method to infiltration conditions, but as with the evaporation method, the variance of the hydraulic conductivity estimates was high.
Sorption of Iron‐Cyanide Complexes in Soils
Authors: Rennert Thilo , Mansfeldt Tim
Published: July 2014

The Fe‐cyanide complexes ferricyanide, [Fe(CN)6]3−, and ferrocyanide, [Fe(CN)6]4−, are of an anthropogenic source in soils. As the complexes are largely charged, sorption on the soil matrix is a possible retention mechanism for these anions. To evaluate soil properties controlling Fe‐cyanide complex sorption, experiments were performed with 17 uncontaminated soil horizons by a batch technique. Soil organic matter (SOM) was destroyed in six horizons. The experiments were conducted at soil pH, reaction time of 24 h, and an ionic strength of 0.01 (NaNO3). The affinity of the Fe‐cyanide complexes for the soil matrix differed, because 14 samples sorbed higher amounts of ferrocyanide than of ferricyanide. Calculated sorption maxima were quantitatively explained by physical and chemical soil properties using multiple regressions. The regression equations were checked by variance analysis. The regression equations for all samples showed that the sorption of both complexes depended on organic C (Corg), clay, and oxalate‐extractable Fe (Feo). The sorption of the complexes on soils containing <10 g Corg kg−1 was governed by pH and clay contents. Clay and oxalate‐extractable Al (Alo) were the most important properties influencing ferricyanide sorption on samples containing high amounts of Corg On the same samples, ferrocyanide sorption was governed by Alo Organic matter promotes the sorption of both complexes, especially on Fluvisol samples. Destruction of SOM of these samples minimized the sorption by up to 99%. Therefore organic matter in these soils may have a special affinity for Fe‐cyanide complexes possibly because of the reaction between Fe‐cyanide N and reactive groups of SOM.
Phosphate and Sulfate Sorption in Spodosols with Albic Horizon from Northern Spain
Authors: Arbestain M. Camps , Barreal M. E. , Macías F.
Published: July 2014

The affinity of PO4and SO4for reactive Al and Fe compounds may differ between the Bh and Bs horizons of Spodosols. Sorption of SO4and PO4in soils was investigated in four Spodosols from Northern Spain. Sorption experiments were carried out by adding 1.6 and 16.1 mMKH2PO4or 0.4 and 1.6 mMK2SO4to soils (soil/solution, 1:10). Most (98.5–99.8%) of the PO4added at 1.6 mMwas retained by the illuvial Bh, Bhs, Bsh, and Bs horizons. The SO4retained by the same horizons at the same initial concentration was below 28%. Phosphate sorption at 16.1 mMin the Bh and Bhs horizons was significantly (P< 0.05) greater than in the Bsh and Bs, corresponding to their greater oxalate extractable‐Al and –Fe contents, whereas the opposite was observed for SO4absorption. Sorption of PO4primarily displaced mineral‐bound organic C and, to a lesser extent, Si into solution, whereas sorption of SO4increased solution pH. The molar ratios of organic C released into solution and PO4sorbed were greater in the Bsh and Bs horizons than in the Bh and Bhs horizons. The differences observed in PO4and SO4sorption between Bh and Bs horizons were mainly attributed to the different organic C contents of the horizons and to the dissimilar affinities of the inorganic anions studied for reactive sites.
Evaluation of numerical techniques applied to soil solution speciation including cation exchange
Authors: Vaughan Peter J.
Published: July 2014

Most existing models of soil solution speciation utilize either Newton–Raphson or Picard iteration to obtain a numerical solution to the nonlinear set of algebraic equations expressing mole balance and charge balance of free ions for major species as well as cation exchange. A computer program was written to test speed and accuracy of these and other methods. Picard iteration was fastest but produced a mean relative error (MRE) for mole and charge balance of 0.03 with no further convergence after a few iterations. A tensor (quadratic) method and two simplex methods converged to the correct result. The tensor method was preferable because the final result was more accurate; the rate of convergence was faster by 10 to 100 times, and convergence occurred for all compositions tested up to an ionic strength of 0.25. These results point out the value of testing various algorithms prior to implementation of speciation code applied to soils.
A Proposed Method for Measuring Subsoil Denitrification In Situ
Authors: Well Reinhard , Myrold David D.
Published: July 2014

We present and test a new approach for measuring denitrification in unsaturated subsoils in situ. The procedure consists of applying a test solution containing 15NO−3 to the subsoil, measuring steady‐state 15(N2 + N2O) concentration in the pore space of the 15N‐labeled soil, and determining denitrification rates by fitting measured and simulated concentrations. We adapted and evaluated a numerical, spherical diffusion model to simulate production and diffusion of 15(N2 + N2O) evolved from a 15(N2 + N2O)‐producing subsoil volume surrounded by an infinite nonproducing soil volume. The effects of gas diffusivity, gas production rate, and spatial distribution of 15NO−3 on steady‐state 15(N2 + N2O) concentrations were investigated with computer simulations, which proved the methodological principle theoretically. Field experiments were done using two different probe designs. Initially, multipurpose probes were used for applying 15NO−3 solution to the subsoils and subsequent collection of gas samples, but denitrification rates were unrealistically high, probably because of depressed soil gas diffusivity caused by the probe installation procedure. Nondisturbing capillary probes were used for two subsequent in situ experiments. Here, in situ 15(N2 + N2O) concentrations were near the detection limit and resulted in denitrification rates between 0 and 7 g N ha−1 d−1 10 cm−1, which were comparable to rates determined by laboratory reference methods. We concluded that the in situ 15N gas emission method is a promising tool for measuring subsoil denitrification because it overcomes some of the limitations of the alternative techniques.
Contributions of Shoot and Root Nitrogen‐15 Labeled Legume Nitrogen Sources to a Sequence of Three Cereal Crops
Authors: Glasener Karl M. , Wagger Michael G. , MacKown Charles T. , Volk Richard J.
Published: July 2014

Legume mulches are important sources of N for cereal crop production, particularly for organic and resource‐poor producers. A field study was conducted using a direct method to determine if the amount of N in cereal crops derived from either the shoots or roots of preceding tropical legume cover crops was affected by their chemical composition and mineralization potential. Desmodium ovalifolium Guill. & Perr. [= D adscendens (Sw.) DC. and Pueraria phaseoloides (Roxb.) Benth.], were grown in 6.0‐m2 microplots and foliar‐labeled with 99 atom % 15N urea. A cereal sequence of maize (Zea mays L.)–rice (Oryza sativa L.)–maize followed the legumes. Cereal accumulation of legume N from either the shoot (shoot + leaf litter) or the root‐soil sources was evaluated by spatially separating the legume N sources. This was achieved by interchanging surface applications of nonlabeled and 15N‐labeled legume shoots with in situ 15N‐labeled and nonlabeled legume roots. Initially the Desmodium shoot N source contained 316 kg N ha−1 and roots contained 12.5 kg N ha−1 Pueraria shoots and root N sources initially contained 262 and 14.8 kg N ha−1, respectively. About 90 g kg−1 of the initial N of each legume shoot was recovered in the total aboveground tissues from the three cereal crops, while 490 g kg−1 of Desmodium and 280 g kg−1 of Pueraria root‐soil N sources were recovered. Of the 181 kg N ha−1 accumulated aboveground by the cereal sequence, the contribution of shoot plus root‐soil N sources was 200 g kg−1 from Desmodium and 150 g kg−1 from Pueraria Cereal N was derived primarily from mineralization of soil organic matter present before the legumes and possibly from N deposition (precipitation and dry) occurring during the cereal crop sequence. After harvest of the last cereal crop, 13 and 180 g kg−1 of the initial legume N was present as inorganic and organic N fractions, respectively, in the top 75 cm of soil. Even though Pueraria shoots had a lower C:N ratio and concentration of polyphenols than Desmodium shoots, the relative contributions of the shoot N source were similar for both legumes. Decomposition of legume residues, particularly legume shoots, make a meaningful contribution to the N economy of cereal crops grown in the tropics. The legume cover crops (root + shoot) contributed nearly 280 g kg−1 of the aboveground N in the first cereal crop and as much as 110 g kg−1 of the N in the third crop during the 15‐mo sequence of cereals.
Classification of Forested Histosols in Southeast Alaska
Authors: D'Amore David V. , Lynn Warren C.
Published: July 2014

Organic soils are an important substrate for cycling carbon between terrestrial and atmospheric pools. The degree of decomposition of organic soil material influences the physical and chemical characteristics that control the carbon cycles in these soils. Although organic soils are abundant in southeast Alaska, little information is available on the state of decomposition or variability within organic soil mapping units. Determination of physical (fiber content) and chemical (sodium pyrophosphate extract color, SPEC) decomposition is used to classify organic soils and subsequently establish map units. The purpose of this study is to provide physical and chemical decomposition data to better characterize and classify forested organic soils in southeast Alaska and to improve our understanding of the distribution of fiber within these soils. Fiber content and pyrophosphate color were determined on 115 samples from 23 organic soils from throughout the Tongass National Forest. These samples show that complexes of hemic and sapric suborders mapped in the Tongass Soil Survey are dominantly hemic. Some fiber analyses differ considerably from statements in descriptions of established series in the Tongass Soil Survey. Physical decomposition of the fibers is in the hemic range, but chemical decomposition indicated by SPEC is sapric due to accumulation of soluble organic matter by water movement down steep slopes as well as in situ decomposition. Suborder classes provide a means to incorporate appropriate decomposition levels into existing soil series.
Control‐Bag Correction for Forest Floor Litterbag Contamination
Authors: Idol Travis W. , Holzbaur Kristen A. , Pope Phillip E. , Ponder Felix
Published: July 2014

Although contamination of litterbags by organic matter is potentially important, there are no standard methods to correct for it. Organic and mineral contamination of field‐incubated forest floor litterbags was investigated using the standard ash‐free dry mass (AFDM) correction and a correction based on increases in the mass of field‐incubated litterbags filled with undecomposable control material. After 120 d, mineral contamination of Oi horizon litter averaged 5.2% of initial litter mass in stands ranging from 7 to 100 yr since cutting. There were no consistent changes in mineral contamination of Oe horizon litter. The mass of nylon control material increased by an average of 22% of initial litter mass after 120 d. Decomposition rates of Oi and Oe litter corrected using increases in control bag mass were significantly higher than uncorrected or AFDM‐corrected rates. Forest stand age did not significantly affect mineral contamination, but mass gain after 120 d in the control bags was significantly higher in the 7‐yr‐old stand (32%) than in 13‐, 32‐, or 80‐ to 100‐yr‐old stands (17–20%).
Development and Calibration of Dual‐Permeability Flow Models with Discontinuous Fault Networks
Authors: Reeves Donald M. , Parashar Rishi , Pohlmann Karl , Russell Chuck , Chapman Jenny
Published: July 2014

A sophisticated dual‐permeability flow model of the T‐tunnel complex, Rainier Mesa, Nevada National Security Site, was developed and calibrated to facilitate predictions of radionuclide transport from underground nuclear tests within a perched zone of saturation downward through a series of variably saturated, sparsely fractured and faulted Tertiary tuff units to a regional flow system. The hydrogeologic complexity of the site necessitated a multistage calibration effort to capture the dominant flow characteristics of the site including: laterally and vertically extensive saturation in the Tertiary volcanics, pressure heads consistent with water level measurements, variably saturated flow conditions involving a thin unsaturated zone situated between two saturated zones, unsaturated Paleozoic carbonates located immediately adjacent to saturated Tertiary volcanic units, and fracture saturations congruent with field observations that range from fully saturated to dry. The incorporation of discontinuous fault networks into the dual‐permeability model played a key role in reproducing the salient hydrologic features of the site. Successful model reproduction of observed cumulative tunnel discharge volume and tunnel discharge rates before tunnel sealing served as a novel transient test of the ability of the discontinuous fault networks to realistically honor field‐scale fault network connectivity and permeability. The excellent reproduction of field observations by the numerical model, and the uniqueness of the primary parameters used to calibrate the model, demonstrate the advantage of incorporating discontinuous fault networks over equivalent fracture properties in sparsely fractured, dual‐permeability media.
Reproducing Field‐Scale Active Layer Thaw in the Laboratory
Authors: Mohammed Aaron A. , Schincariol Robert A. , Nagare Ranjeet M. , Quinton William L.
Published: July 2014

A method to simulate freeze–thaw and permafrost conditions on a large peat‐soil column, housed in a biome, was developed. The design limits ambient temperature interference and maintains one‐dimensional freezing and thawing. An air circulation system, in a cavity surrounding the active layer, allows manipulation of the lateral temperature boundary by actively maintaining an air temperature matching the average temperature of the soil column. Replicating realistic thermal boundary conditions enabled field‐scale rates of active‐layer thaw. Radial temperature gradients were small and temperature profiles mimicked those for similar field conditions. The design allows complete control of key hydrologic processes related to heat and water movement in permafrost terrains without scaling requirement; and presents a path forward for the large‐scale experimental study of frozen ground processes. Because subarctic ecosystems are very vulnerable to climate and anthropogenic disturbances, the ability to simulate perturbations to natural systems in the laboratory is particularly important.
Urinary tract in jury associated with pelvic fractures
Authors: Milenkovic Sasa , Mitkovic Milan , Basic Dragoslav , Arsic Stojanka , Hadzi-Djokic Jovan , Mitkovic Milorad
Published: July 2014

INTRODUCTION: Pelvic trauma associated with urinary tract injury is a severe
trauma, mostly caused by traffic accidents and falls from heights. These
injuries require urgent treatment and close teamwork between urologic and
orthopaedic surgeons. MATERIAL AND METHODS: In this retrospective study there
were analyzed patients with pelvic trauma and extraperitoneal injury of
urinary tract, treated surgically at Clinic for Ortopaedic Surgery and
Traumatology and Urology Clinic in Clinical Center Nis. Surgical intervention
in these patients had been realized as the synchronized work of both
orthopaedic and urologic surgeons. The pelvis was treated by external and
internal fixation. Mitkovic type external fixator was used for pelvic
external fixation. Plating was used for pelvic internal fixation. Pelvic
fractures were classified using Tile?s classification system. The final
functional results had been scored using Majeed score system. RESULTS: There
were 42 patients with the injury of pelvic ring, treated at Clinic for
Ortopaedic Surgery and Traumatology and at Urology Clinic, Clinical Center
Nis, in the period of 01.01.2011. to 31.12.2013, 30 males and 12 females,
with average age of 53.69 (19-84) years old. In 80% of cases pelvic fractures
were caused by high energy trauma in traffic accidents. According to Tile?s
classification, 9 patients (21,42%) had pelvic fracture type A, 23 patients
(54,46%) had pelvic fracture type B and 10 patients (23,80%) had pelvic
fracture type C. Urinary tract in- jury was diagnosed in 9 patients (21,42%):
5 patients (11,9%) with bladder injury, 3 patients (7,14%) with posterior
urethra injury and 1 patient (2,38%) with both bladder and posterior urethra
injury. CONCLUSION: Urgent repair of extraperitoneal urinary tract injury by
urologic surgeons and synchronized pelvic reduction and fixation using
external or internal fixation by ortopaedic surgeon, in the same surgical
procedure, is the standard method for treatment of this severe injury.
Retrospective evaluation of male slings for patients with urinary incontinence after radical prostatectomy - one surgeon’s experience
Authors: Acimovic Miodrag , Babic Uros , Argirovic Aleksandar , Jovanovic Mirko , Stanic Miodrag , Kajmakovic Boris , Dzamic Zoran
Published: July 2014

Introduction: Stress urinary incontinence is one of the main complications
after radical prostatectomy (RP) with a significant percentage of patients
reporting bothersome incontinence >1 year after surgery Objective: Assessment
of one surgeon?s results in surgical treatment of urinary stress incontinence
of patients with radical prostatectomy applying transobturator and suprapubic
slings. Patients and methods: From February 2010. - February 2014., 20
patients, age 57 - 76, with moderate and severe stress urinary incontinence
(SUI) were treated surgically. All patients previously had radical
prostatectomy due to prostate cancer. Results: All 20 patients with stress
urinary incontinence (PRPUI) had Argus slings placement after radical
prostatectomy. Patients were followed for a longer period of time, 6 months
minimum, 48 months maximum.18 patients (90%) had negative, dry PAD test after
surgery, one patient (5%) had positive PAD test, and one patient (5%) who
previously had Advance transobturator sling placement with no positive
results, had sling removed due to an infection. 6 patients (30 %) needed
additional sling adjustment, performed between 9 - 21st day after the
surgery. Conclusion: We concluded that Argus sligs, suprapubic or
transobturatory are an effective and safe treatment for PRPUI. This procedure
is minimal invasive and our results clearly demonstrate that both heavy and
moderate incontinence responds well.
Surgical care vesicovaginal fistulas in women with malignant gynecological disease
Authors: Dzamic Zoran , Radovanovic Miodrag , Acimovic Miodrag , Babic Uros , Jovanovic D. , Pejcic Tomislav
Published: July 2014

Vesicovaginal fistulae (VVF)represents one of the most frequent complications
of various gynecological and obstetric procedures. In presence of a
gynecological malignant tumor, fistula could be the outcome of surgical
complications, radiotherapy or consequence of the tumor process. Reparation
of these fistulae is a very complex problem. Our aim was to analyze the
results of surgical care VVF-s occurred in women with malignant gynecological
disease which was treated surgically or with radiotherapy. Out of the 48
surgically treated patients with primary VVF, in 28 of them fistula occurred
after hysterectomy, and in 20 patients after radiotherapy. In 15 patients
(31.25%) transvaginal approach was applied, and in 33 patients (68.75%)
abdominal approach was applied, with the interposition of a well vascularized
lobe being used in 25 patients. All the VVFs that occurred after radiotherapy
were repaired by using the abdominal approach. The efficiency of surgical
treatment of VVFs after hysterectomy due to a malignant disease was 78.5%,
and after radiotherapy 65%. In patients that have not been subjected to
radiotherapy, depending on the characteristics of the fistula, transvaginal
or abdominal approach is applicable in VVF reparation, while the abdominal
approach remains a golden standard in post-radiation fistula treatment,
despite the fact that it has not solved the problem after the first medical
treatment in as far as 35% of patients.
Sigma-rectum pouch (Mainz Pouch II)
Authors: Hadzi-Djokic Jovan , Milojevic Bogomir , Pejcic Tomislav , Acimovic Miodrag , Stamenkovic Vladimir , Dzamic Zoran
Published: July 2014

The Mainz pouch II is a well tolerated form of continent urinary diversion in
terms of morbidity, protection of the upper urinary tract and continence
rate, even in patients aged >65 years. Mainz pouch II was described by Fisch
and Hohenfellner in 1991. They viewed the simplicity and reproducibility of
the operation as one of its major advantages. A good continence rates between
93%-100% after this procedure has been shown in previous studies. The longer
follow up will show whether these high rates of continence can be maintained
with increasing age. The Mainz Pouch II serves as a satisfying continent
urinary diversion for both sexes in selected patients in terms of quality of
life. Evaluation of overall quality of life in patients with Mainz pouch II
urinary derivation has given encouraging results. Compliance and cooperation
of the patients, together with preoperative tests for anal competence, are
mandatory to avoid complications. The Mainz group reported that the overall
complication rate was low and comparable with other techniques of continent
urinary diversion. During the past years modifications of the original
technique have been described. These represent an increasing interest in the
procedure. Today, the techniques of low-pressure and reservoirs have
completely replaced classical ureterosigmoidostomy. In this review article
the main focus is aimed at history, complications, continence and quality of
life of patients with Mainz pouch II.