A sulphur budget for sour gas plants

The principal aim of this project is to produce a mass balance for the SO₂ that is emitted into the atmosphere from sour gas plants in various localities in Alberta. Partial S budgets for two plants at dissimilar locations are shown to exhibit major differences. The rise and dispersion of sour gas plant plumes have been investigated in detail. In order to investigate the chemical transformation of SO₂ within these plumes, the use of a conserved tracer that can be detected by neutron activation is discussed.     

Statistical spring wheat yield forecasting for the Canadian prairie provinces

A study to forecast regional spring wheat (Triticum aestivum L.) yields on the Canadian Prairies was conducted, based on simulated daily water use and soil water contents derived from the National Drought Model. Empirical linear regression models were calibrated from 1976 to 2006 spring wheat yield data for this purpose. Potential predictors assessed were mainly those indicators related to water stress conditions at different crop growth stages. Stepwise regression and cross-validation were employed for the selection of the predictors in multivariate linear regression models used for forecasting spring wheat yields from seeding to harvest. The cross-validated “forecasts” for 1976–2006, using data up to harvest, explained 77%, 64%, 63% and 70% of yield variances, respectively, for Alberta, Saskatchewan, Manitoba and the entire Prairie region. Root mean squared error of the “forecasts” ranged from 8% to 11% of the average yields. The prediction accuracy earlier in the season was often lower than later in the season. Usable prediction accuracy was found by the middle of the growing season (around heading or anthesis), but only marginally effective at seeding time, especially so for Saskatchewan.     

Use of powdered elemental sulphur as a sulphur source for grass and clover

Abstract

Upland pastures on coarse‐textured sulphur (S)‐deficient soils in moderate to high rainfall areas may benefit from S fertilization using elemental S to avoid leaching losses. Two grades of elemental S, 120 and 300 mesh, were assessed as a source of S for grass and clover. In laboratory incubations using an upland soil at 7 and 14°C, oxidation of the 120 mesh S was very slow while 65% of the 300 mesh S was oxidized after 48 days at 14°C. In pot trials of ryegrass in a lowland soil and of ryegrass and clover in the upland soil both elemental S grades gave satisfactory yield increases which were not significantly different from applying potassium sulphate. High ambient temperatures during the pot experiment probably ensured an adequate oxidation rate of both elemental S grades. High application rates of the potassium sulphate gave rise to luxury consumption while very high rates of elemental S (equivalent to 200 kg S ha^‐1) showed some toxicity. Application of a previously‐described model of S oxidation confirmed the importance of soil temperature in controlling S oxidation rates.     

Management-induced change in labile soil organic matter under continuous corn in eastern Canadian soils

Soil samples taken from four experimental sites that had been cropped to continuous corn for 3–11 years in Ontario and Quebec were analyzed to evaluate changes in quantity and quality of labile soil organic carbon under different nitrogen (N) fertility and tillage treatments. Addition of fertilizer N above soil test recommendations tended to decrease amounts of water-soluble organic carbon (WSOC) and microbial biomass carbon (MBC). The quality of the WSOC was characterized by ¹³C nuclear magnetic resonance and infrared spectrophotometry and the results indicated that carbohydrates, long-chain aliphatics and proteins were the major components of all extracts. Similar types of C were present in all of the soils, but an influence of management was evident. The quantity of soil MBC was positively related to the quantities of WSOC, carbohydrate C, and organic C, and negatively related to quantities of long-chain aliphatic C in the soil. The quantity of WSOC was positively related to the quantities of protein C, carbohydrate C, and negatively related to the quantity of carboxylic C. The quantity of soil MBC was not only related to quantities of soil WSOC but also to the quality of soil WSOC. Received: 2 April 1997     

Establishing a Holocene sediment budget for the river Dijle

A Holocene sediment budget was constructed for the 758 km² Dijle catchment in the Belgian loess belt, in order to understand long-term sediment dynamics. Hillslope sediment redistribution was calculated using soil profile information from 809 soil augerings, which was extrapolated to the entire catchment using morphometric classes. As large parts of the forests within the catchment prove to have undergone little or no erosion since medieval times, a correction was applied for the presence of forests. Total Holocene erosion amounts 817 ± 66 Mt for the catchment, of which 327 ± 34 Mt was deposited as colluvium. This corresponds with a net Holocene soil erosion rate of 10.8 ± 0.8 × 10³ Mg ha^− 1 for the entire Dijle catchment. Alluvial deposits were studied through 187 augerings spread over 17 cross-valley transects. The total alluvial sediment deposition equals 352 ± 11 Mt or 42% of total eroded sediment mass. Results indicate that at the scale of a medium-sized catchment the colluvial sediment sink is as important as the alluvial sediment sink and should not be neglected. As a result the estimation of erosion through alluvial storage and sediment export would yield large errors. Dating of sediment units show an important increase in alluvial deposition from medieval times onwards, indicating the important influence of agricultural activities that developed from that period. Mean sediment export rates from the catchment for the last 1000–1200 years range between 0.8 and 1.3 Mg ha^− 1 a^− 1 and are consistent with present suspended sediment measurements in the Dijle. Erosion for agricultural land for this period is 9.2 ± 2.2 Mg ha^− 1 a^− 1. Sediment budgets for the various tributary catchments provide an insight in the sources and sinks of sediment at different scales within the catchment.     

Nitrogen budget and relationships with riverine nitrogen exports of a dairy cattle farming catchment in eastern Hokkaido,Japan

Abstract

Dairy farming regions are important contributors of nitrogen (N) to surface waters. We evaluated the N budget and relationships to riverine N exports within the Shibetsu River catchment (SRC) of a dairy farming area in eastern Hokkaido, Japan. Five drainage basins with variable land-cover proportions within the SRC were also evaluated individually. We quantified the net N input (NNI) to the catchment from the difference between the input (atmospheric deposition, chemical fertilizers, N fixation by crops and imported food and feed) and the output (exported food and feed, ΔS _liv and ΔS _hu, which are the differences between input and output in livestock and human biomass, respectively) using statistical and measured data. Volatilized ammonia (NH₃) was assumed to be recycled within the catchment. The riverine export of N was quantified. Agricultural N was a dominant source of N to the SRC. Imported feed was the largest input (38.1?kg?N?ha^?1?year^?1), accounting for 44% of the total inputs, followed by chemical fertilizers (32.4?kg?N?ha^?1?year^?1) and N fixation by crops (13.4?kg?N?ha^?1?year^?1). The exported food and feed was 24.7?kg?N?ha^?1?year^?1 and the ΔS _liv and ΔS _hu values were 7.6 and 0.0?kg?N?ha^?1?year^?1, respectively. As a result, the NNI amounted to 54.6?kg?N?ha^?1?year^?1. The riverine export of total N from the five drainage basins correlated well with the NNI, accounting for 27% of the NNI. The fate of the missing NNI that was not measured as riverine export could possibly have been denitrified and/or retained within the SRC. A change in the estimate of the deposition rate of volatilized NH₃ from 100 to 0% redeposited would have decreased the NNI by 37%, although we believe that most NH₃ was likely to have been redeposited. The present study demonstrated that our focus should be on controlling agricultural N to reduce the impact of environmental pollution as well as on evaluating denitrification, N stocks in soil and the fate of NH₃ volatilization in the SRC.     

A preliminary mercury budget for Narragansett Bay (Rhode Island,USA)

The distribution of total Hg (Hg_t) and reactive (Hg_R) in Narragansett Bay, fresh water tributaries and point source discharges was determined during a synoptic survey, carried out in April, 1986. A Hg budget which includes fluvial inputs and atmospheric Hg deposition was constructed and the estuarine behavior of Hg assessed.     

柳河流域沙量平衡分析

柳河是东北地区泥沙问题最为严重的河流之一，该文分析了流域水沙运移特征，在此基础上建立起流域16年的沙量平衡关系，分析了流域产沙、沉积特征及沉积的分布格局。研究表明，53.5％的悬移质泥沙沉积在河道中，其中，87.9％沉积在闹德海至彰武之间；对流域上游产水、产沙与流域内泥沙沉积及流域产沙之间的关系进行了耦合分析，丰富了沙量平衡计算的内容，并可对深入认识流域泥沙发展趋势及泥沙治理提供参考。     

柳河流域沙量平衡分析

柳河是东北地区泥沙问题最为严重的河流之一,该文分析了流域水沙运移特征,在此基础上建立起流域16年的沙量平衡关系,分析了流域产沙、沉积特征及沉积的分布格局.研究表明,53.5%的悬移质泥沙沉积在河道中,其中,87.9%沉积在闹德海至彰武之间;对流域上游产水、产沙与流域内泥沙沉积及流域产沙之间的关系进行了耦合分析,丰富了沙量平衡计算的内容,并可对深入认识流域泥沙发展趋势及泥沙治理提供参考.     

A chloride budget for Onondaga Lake,New York,U.S.A.

A Cl budget is presented for a 12 yr period (1970–1981) for Cl enriched (approximate volume-weighted average concentration of 1500 mg Cl L^?1) Onondaga Lake, New York. The budget utilizes continuous discharge and lake and stream water chemistry data, collected at an interval of approximately 2 weeks, over the 12 yr study period. Budget calculations are supplemented by high frequency water chemistry data from the lake and the tributary carrying the major portion of the loading. More than 85% of the external load of Cl (approximately 9 × 10⁸ kg yr^?1) to the lake originates from an alkali manufacturer. Export of Cl from the lake was highly correlated to outflow from the lake (R = 0.915, for a resolution of 1 mo). A good balance between estimated external loads and lake export was obtained (within 7%) for the 12 yr period, indicating that lake concentrations are consistent with external loading of this conservative substance. The results of this analysis contradict previous calculations that indicated 40 to 50% of the Cl in the lake originated from natural internal sources.     

水稻需硫特性及硫对水稻产质量的影响

盆栽试验结果表明,黑土种植水稻适宜的硫肥品种为硫铵和硫磺,可分别使水稻增产28.8%和19.7%.水稻在前期和后期植株含硫较高,中期较低;但植株吸硫量则随其生物量的增大而迅速增加,以分蘖期最低,成熟期最高.田间试验结果表明,硫肥的适宜用量为S 36～54kg/hm2,增产9.7%～11.3%,增产的主要原因是硫促进了水稻的生长发育,增加了水稻分蘖数和穗粒数.分析结果表明,硫具有增加稻米蛋白质含量、降低淀粉含量的作用.适当施用硫肥既能充分满足水稻在整个生育期对硫素营养的需要,又能保持土壤中硫的平衡.     

The genetic diversity of Rhizobium leguminosarum bv. viciae in cultivated soils of the eastern Canadian prairie

Soil populations of Rhizobium leguminosarum bv. viciae (Rlv) that are infective and symbiotically effective on pea (Pisum sativum L.) have recently been shown to be quite widespread in agricultural soils of the eastern Canadian prairie. Here we report on studies carried out to assess the genetic diversity amongst these endemic Rlv strains and to attempt to determine if the endemic strains arose from previously used commercial rhizobial inoculants. Isolates of Rlv were collected from nodules of uninoculated pea plants from 20 sites across southern Manitoba and analyzed by plasmid profiling and PCR-RFLP of the 16S-23S rDNA internally transcribed spacer (ITS) region. Of 214 field isolates analyzed, 67 different plasmid profiles were identified, indicating a relatively high degree of variability among the isolates. Plasmid profiling of isolates from proximal nodules (near the base of the stem) and distal nodules (on lateral roots further from the root crown) from individual plants from one site suggested that the endemic strains were quite competitive relative to a commercial inoculant, occupying 78% of the proximal nodules and 96% of the distal nodules. PCR-RFLP of the 16S-23S rDNA ITS also suggested a relatively high degree of genetic variability among the field isolates. Analysis of the PCR-RFLP patterns of 15 selected isolates by UPGMA indicated two clusters of three field isolates each, with simple matching coefficients (SMCs) ≥0.95. However, to group all field isolates together, the SMC has to be reduced to 0.70. Regarding the origin of the endemic Rlv strains, there were few occurrences of the plasmid profiles of field isolates being identical to the profiles of inoculant Rlv strains commonly used in the region. Likewise, the plasmid profiles of isolates from nodules of wild Lathyrus plants located near some of the sites were all different from those of the field isolates. However, comparison of PCR-RFLP patterns suggested an influence of some inoculant strains on the chromosomal composition of some of the field isolates with SMCs of ≥0.92. Overall, plasmid profiles and PCR-RFLP patterns of the isolates from endemic Rlv populations from across southern Manitoba indicate a relatively high degree of genetic diversity among both plasmid and chromosomal components of endemic strains, but also suggest some influence of chromosomal information from previously used inoculant strains on the endemic soil strains.     

The cation denudation rate as a quantitative index of sensitivity of eastern Canadian rivers to acidic atmospheric precipitation

A model has been developed that relates the cation denudation rate (CDR) of a watershed (the rate that cations derived from chemical weathering are carried off by runoff), the atmospheric load of excess SO₄, and the pH of the river. Chemical and discharge data for rivers in Nova Scotia and Newfoundland were used to develop and test the model, which is based upon the common major ion chemistry of soft surface waters, and may be expressed by three statements: (1) CDR (meq m^?2 yr^?1) ? Excess SO₄ ^?? load (meq m^?2 yr^?1) = HCO₃ ^? (meq m^?2 yr^?1), (2) HCO₃ ^? (meq m^?2 yr^?1)/Runoff (m³ m^?2 yr^?1) = HCO₃ ^? (meq m^?3), (3) pH = pK + \(pP_{CO_2 } \) ? pHCO₃ ^?. The model in concentration form applies well to lakes. A detailed analysis of the data for the Isle aux Morts River, Newfoundland, is presented, showing that the CDR varies throughout the year, affected by both discharge and seasonal pattern.     

Assessment of C budget for grasslands and drylands of the world

Intergovernmental Panel on Climate Change (IPCC) estimates indicate that potential changes in seasonal rainfall and temperature patterns in central North America and the African Sahel will have a greater impact on biological response (such as plant production and biogeochemical cycling) and feedback to climate than changes in the overall amount of annual rainfall. Simulation of grassland and dryland ecosystem responses to climate and CO₂ changes demonstrates the sensitivity of plant productivity and soil C storage to projected changes in precipitation, temperature and atmospheric CO₂. Using three different land cover projections, changes in C levels in the grassland and dryland regions from 1800 to 1990 were estimated to be ?13.2, ?25.5 and ?14.7 Pg, i.e., a net source of C due to land cover removal resulting from cropland conversion. Projections into the future based on a double-CO₂ climate including climate-driven shifts in biome areas by the year 2040 resulted in a net sink of +5.6, +27.4 and +26.8 Pg, respectively, based upon sustainable grassland management. The increase in C storage resulted mainly from an increase in area for the warm grassland sub-biome, together with increased soil organic matter. Preliminary modeling estimates of soil C losses due to 50 yr of regressive land management in these grassland and dryland ecoregions result in a 11 Pg loss relative to current conditions, and a potential loss of 37 Pg during a 50 yr period relative to sustainable land-use practices, an average source of 0.7 Pg C yr^?1. Estimates of the cost of a 20 yr rehabilitation program are 5 to 8×10⁹ US$ yr^?1, for a C sequestering cost of approximately 10 US$ per tC.     

黑龙江省主要类型稻田土壤硫现状及硫肥效果的研究

不同品种硫肥在水稻土上应用结果表明:硫对水稻的生长发育有促进作用.提高水稻产量,增产效果较好的是硫铵和Sulfer95,增产8.8%～13.4%.另外,施含硫肥料能缓解土壤硫素的消耗,对保持土壤中硫的平衡有很大作用.     

The abundance and efficacy of Rhizobium leguminosarum bv. viciae in cultivated soils of the eastern Canadian prairie

For optimum production, the use of commercial rhizobial inoculant on pea (Pisum sativum L.) at seeding is necessary in the absence of compatible rhizobial strains or when rhizobial soil populations are low or symbiotically ineffective. Multiple site experiments were conducted to characterize the abundance and effectiveness of resident populations of Rhizobium leguminosarum bv. viciae (Rlv) in eastern Canadian prairie soils. A survey of 20 sites across a broad geographical range of southern Manitoba was carried out in 1998 and was followed by more intensive study of five of the sites in 1999 and 2000. Appreciable nodulation of uninoculated pea was observed at all sites which had previously grown inoculated pea. However, uninoculated pea grown at two sites, which had not previously grown pea, had negligible nodulation. Likewise, wild Lathyrus sp. and Vicia sp. plants collected from uncultivated areas adjacent to agricultural sites were poorly nodulated. In the more intensively studied sites, there was a tendency towards higher nodulation in pea plants receiving commercial inoculant containing Rlv strain PBC108 across all site-years (e.g., 4.7% in nodulation and 22% in nodule mass), but the effect was significant at only 2 of 10 site-years. Despite a relatively high range of soil pH (6-8), regression analysis indicated that decreasing soil pH resulted in lower nodulation rates. Likewise, electrical conductivity (EC) was correlated to nodulation levels, however the effect of EC was likely more indicative of the influence of soil texture and organic matter than salinity. As with nodulation, commercial inoculation tended to increase above-ground dry matter (DM) and fixed-N (estimated by the difference method) at the early pod-filling stage, but again the effects were significant at only 2 of 10 site-years. Specifically, above-ground DM and fixed-N levels were up to 29 and 51% greater, respectively, in inoculated compared to non-inoculated treatments at these sites. Addition of N-fertilizer at a rate of 100 kg N ha⁻¹ decreased nodulation at almost all site-years (by as much as 70% at one site), but rarely resulted in increases in above-ground DM compared to inoculated plots. The study indicates for the first time that populations of infective, and generally effective strains of Rlv occur broadly in agricultural soils across the eastern Canadian prairie, but that there is a tendency for increased symbiotic efficiency with the use of commercial inoculant.     

Soil carbon and nitrogen budget in Scots pine (Pinus sylvestris L.) stands along an air pollution gradient in eastern Germany

Litterfall, bio- and necromass of the forest floor vegetation, decomposition of recent organic material, soil respiration and humus stocks were examined in 3 Scots pine stands along an air pollution gradient in eastern Germany. High nitrogen loads and increased pH values due to Ca deposition caused shifts in the vegetation structure, and higher biomass production of the forest floor vegetation, whereas needle litter production was not impacted. Simultaneously, decomposition rates of the recently harvested forest floor vegetation decreased with increasing pollutant loads, but needle litter and soil organic matter decomposition rates did not differ between the sites. Consequently, soil carbon and nitrogen stocks increased with increasing pollutant input.     

Spatial variability in emissions reduction strategies for sulphur and nitrogen in the UK

The roles of sulphur (S) and nitrogen (N) in causing critical loads exceedance across the UK show considerable spatial variability at the present time. Over much of lowland Britain it appears that the environment can only be protected by reducing N deposition, whilst in upland areas (e.g. most of Scotland and Wales) reductions in S deposition are the primary requirement. Using the Hull Acid Rain Model (HARM) the effects of current and possible future emissions control legislation on critical loads exceedance can be explored. Based on HARM output, the implementation of the UNECE Sulphur Protocol (1994) will bring about a substantial reduction in the amount of S being deposited in the UK, especially in central and southern parts of the country. Some areas will remain where additional reductions in S are required. Over most of the country, however, the need to reduce N deposition will become paramount. The changing contributions and significance of non-UK sources can be estimated.     

Modelling sulphur dioxide levels in the Sarnia area

For environmental planning and policy-making purposes, this study was undertaken to apply the Ontario Ministry of the Environment Air Quality Model for SO₂ to an urban-industrial region, namely, the Sarnia and St. Clair River area. Predicted and measured SO₂ levels showed good agreement. A comparison of daily model predictions with 118 observations from 11 monitoring stations for 12 days in 1973 gave an overall correlation coefficient of 0.88.     

Canadian Environmental Quality Guidelines for mercury

CCME Canadian Environmental Quality Guidelines for mercury have been recommended or are under development for soil, water and sediments. These guidelines provide nationally consistent benchmarks for environmental quality across Canada and are intended as decision support tools in protecting and sustaining aquatic and terrestrial ecosystems in Canada and the beneficial uses they support. A Canadian water quality guideline for protection of aquatic life was recommended in 1987 as 0.1 μg·L^?1. Currently, mercury guidelines for soils and sediments are under development. Preliminary calculations indicate that interim marine and freshwater sediment guidelines for the protection of aquatic life will both be 0.14 mg·kg^?1; and that soil quality guidelines will be 2.0 mg·kg^?1 (agricultural and residential land uses), and 30.0 mg·kg (commercial and industrial land uses). Final recommended values are subject to change pending final approval by the Canadian Council of Ministers of the Environment.