bluuebunny/crossref_metadata_2025 huggingface dataset:
FLORALPEDOTURBATIONS IN BLACK CHERNOZEMIC SOILS OF THE LAKE EDMONTON PLAIN
Authors: PAWLUK S. , DUDAS M. J.
Published: March 2010

Investigations of soils at the Ellerslie Agricultural Research Station and adjacent areas in the Lake Edmonton Plain revealed pedoturbations ranging from 5 to 20% of the area. Turbated soils exhibited a bowl-shaped pattern with Ah horizons, frequently mixed down to a depth of 2 m or more and often extended over an area up to 7.5 m in diameter. Configurations of turbated A and B horizon materials were numerous and varied with no fixed pattern. Consistency was much more mellow than adjacent undisturbed material. Undistrubed soil had a thin eluviated horizon below the Ah and numerous argillans were evident in the B horizon. Such features were evident only in microfabrics of disturbed soils. There were no strongly contrasting analytical attributes between disturbed and undisturbed soils. 14C dating suggests a burial date for lower Ahu material at approximately 2500–3000 yr B.P. Mixing was attributed to floral turbation caused by tree-throw.
ANALYSIS OF MEASUREMENT AND NUMERICAL SCHEMES TO ESTIMATE FROST AND THAW PENETRATION OF A SOIL
Authors: HAYHOE H. N. , TOPP G. C. , EDEY S. N.
Published: March 2010

Frost penetration and soil temperature may determine the winter survival of crops or populations of insects. In this study, several techniques for measuring frost and thaw penetration are compared to a simplified numerical heat flow model in order to assess the range of applicability of the measurement and modelling systems. Two Uplands sand sites, one snow cleared and one with a natural snow cover were instrumented with thermocouples, frost-tubes and time-domain reflectometry to record soil temperature and frost penetration. The numerical model was used to simulate soil temperature and frost using daily maximum and minimum air temperature and snowfall from the nearby weather site. All methods used to measure frost penetration were found to be adequate where large temperature gradients occurred. Temperature-based determinations of the frozen zone have a more limited range of applicability than systems which indicate changes in liquid water content of the soil. The diffusion-based heat flow model provided useful estimates of soil temperature and frost penetration. Key words: Frost penetration, soil temperature modelling, frozen/unfrozen interfaces
SOME CHARACTERISTICS OF HUMIC MATERIALS IN CARIBBEAN VERTISOLS
Authors: HOLDER M. B. , GRIFFITH S. M.
Published: March 2010

A comparative investigation of the analytical features of organic matter fractions of acidic and calcium-saturated Vertisols (Ca-Vertisols) from the Caribbean was undertaken. The elemental composition and functional group content of the humic acids (HAs) and fulvic acids (FAs) were similar to previously reported values, except for the low yielding HAs of Ca-Vertisols which contained a greater proportion of O (35.82–47.17%). In addition, high values (8.38 meq/g–11.71 meq/g) for the COOH functional groups of the FAs emphasized the inherent high reactivity of the humic materials. Spectrophotometric analysis supported the view arrived at through chemical analysis that metal-organic (FA) complexes of Vertisols contained Al, Fe and Si with more soluble complexes in the Ca-Vertisols and in the presence of a basic cation (Ca). DTA analysis indicated that the organo-mineral complexes of Vertisols were regular and thermostable. Key words: Vertisols, humic materials, functional groups, infrared, DTA
MONOSACCHARIDES AS GEOCHEMICAL MARKERS IN PEAT
Authors: MORITA H.
Published: March 2010

The relative abundances of arabinose, xylose, mannose, galactose, glucose, total pentoses, total hexoses and total sugars in 50 soil horizon samples derived from two groups of Canadian peat soil profiles have been correlated with five characteristic soil properties, namely, fiber content, pyrophosphate index, ash content, C:N ratio and cation exchange capacity. The correlation coefficients demonstrated that of the monosaccharides or sugars examined, glucose and total sugar contents correlated best with the five soil properties. The coefficients also showed that sugar analysis is as reliable as the five soil properties for assessing the degree of decomposition of peat. Sugar analysis, therefore, can be used to differentiate peats. Key words: Peat, monosaccharides, soil properties, correlation, decomposition
EFFECTS OF SURFACE MINING ON THE MICROBIOLOGY OF A PRAIRIE SITE IN ALBERTA, CANADA
Authors: VISSER SUZANNE , GRIFFITHS CONNIE L. , PARKINSON D.
Published: March 2010

The effects of surface mining for coal on soil respiration (CO2), microbial biomass C, ATP levels, bacterial and actinomycete numbers, bacterial taxa, hyphal lengths, fungal taxa, N2 fixation and decomposition potential were determined for a short-grass prairie site in southern Alberta, Canada. Soil respiration, microbial biomass C, ATP, actinomycete numbers, hyphal lengths and N2-fixing potential were significantly lower in the mined soil particularly when compared to the undisturbed topsoil. Bacterial numbers were, however, greater in the mined soil than in the unmined soil. The bacteria isolated from the undisturbed soil were dominated by Bacillus spp., coryneforms and non-pigmented Gram-negative rods, while those from the disturbed soil belonged mainly to the coryneform group. Mining also caused the fungal community to shift from one dominated by Chrysosporium-Pseudogymnoascus and sterile dark organisms to one dominated by Alternaria spp., Cladosporium spp., sterile dark forms and yeasts. Decomposition of filter paper, 24 mo after their placement in the field, was significantly faster on the disturbed site than on the undisturbed site. Key words: Surface mining, microbiology, prairie soil
WATER RETENTION EQUATIONS AND THEIR RELATIONSHIP TO SOIL ORGANIC MATTER AND PARTICLE SIZE DISTRIBUTION FOR DISTURBED SAMPLES
Authors: JONG R. DE , CAMPBELL C. A. , NICHOLAICHUK W.
Published: March 2010

Functional relationships between soil water content and water suction were examined and related to textural and organic carbon content data. Soil water retention curves between 5 and 10 000 kPa were determined on disturbed samples of 18 soils representing various soil Great Groups in the Canadian prairies. The best fit was obtained with a two-straight-line regression model. Correlation and regression analysis showed that texture was the main soil property influencing the shape and position of the water retention curve. Organic matter influenced primarily the water content at which a break in the curve occurred. Soil zone and cultivation history had little effect on water retention. Key words: Water retention, texture, organic matter, two-straight-line regression
THE EFFECT OF PHOSPHATE FERTILIZER ON THE SALT TOLERANCE OF BARLEY GROWN ON SUMMERFALLOWED LAND
Authors: PETERS JOHN R.
Published: March 2010

The effect of fertilizer P on the salt tolerance of barley grown on previously summerfallowed land was studied under dryland field conditions. Linear regression equations showed that the yield response to added fertilizer P did not change significantly over the full range of salinity levels experienced. Linear regression equations using mean soil salinity levels to a 60-cm depth equal to or greater than 6 mS∙cm−1 appeared to describe the yield function of barley more realistically than did equations using the entire range of salinity levels. Both fertilized and unfertilized barley yields were not affected by salinity until a level of 4 mS∙cm−1 had been reached. Beyond this point yields were reduced by approximately 9–10% per unit increase in salinity. It was concluded that added fertilizer P did not improve the salt tolerance of barley grown under dryland conditions in Saskatchewan. Key words: Salinity, barley, P fertilizer, salt tolerance, yield
EFFECT OF LIMING ON YIELD AND NUTRIENT CONCENTRATION OF REED CANARYGRASS GROWN IN TWO PEAT SOILS
Authors: LEVESQUE M. P. , MATHUR S. P.
Published: March 2010

A Typic Mesisol (woody peat) and a Humic Mesisol (sedge peat), from Ormstown and Farnham bogs (Que.), respectively, were mixed with calcitic agricultural limestone at rates of 0.5–30 tonne/ha to find a suitable liming rate for growing reed canarygrass on peat soils. Liming increased soil pH from 3.0 to 5.8. Average yields (eight cuttings) of reed canarygrass (Phalaris arundinacea L.) were not increased by liming beyond 6 tonne/ha (pH 3.6). At low lime rates, Cu concentration in the grass was higher in the seventh and eighth cuts while at high liming rates the Mg and P concentrations declined as Ca absorption increased. Considering that pH of the treated peats declined in the year following liming, one-time application of 10 tonne of lime per hectare was judged to be optimal for sustaining yields while providing balanced plant nutrition in the forage crops. It was also concluded that 100 ppm of Cu, both as a fertilizer and mitigator of subsidence, could be added to these soils at a stabilized pH of 3.4 to 3.6 without adverse effects on plant nutrition. At lower pH, the Cu concentration of the crop was found to increase from an optimal 10 ppm to 17 ppm. Key words: Liming, peat soils, nutrient concentration, reed canarygrass
LATERAL VARIABILITY IN SOME PROPERTIES OF DISTURBED FOREST SOILS IN SOUTHWESTERN BRITISH COLUMBIA
Authors: COURTIN P. , FELLER M. C. , KLINKA K.
Published: March 2010

Lateral variability in a variety of physical and chemical properties was studied in the surface 30 cm of mineral soil taken from beneath young (5–12 yr) Douglas-fir plantations established after clearcutting and slashburning, primarily in the Coastal Western Hemlock Zone in southwestern B.C. Of the 19 soil properties considered, pH was the least variable while available P and extractable Ca concentrations and quantities tended to be the most variable. However, the order of variability was not consistent among the five plots studied. Estimation of mean values with an allowable error of 10% at the 95% confidence level would require a very large number of samples for most of the properties studied. Even with an allowable error of 20% at the 90% confidence level, more than 100 samples would be required in some instances. Methods of overcoming this need for a large sample size are discussed. A comparison of within-plot variability to among-plot variability for three situations produced no consistent trends. However, the among-plot variability of high forest productivity plots was greater than that of low forest productivity plots for nearly all soil properties considered. Key words: British Columbia, forest soil, soil chemistry, soil variability
THE FIRST 12 YEARS OF A LONG-TERM CROP ROTATION STUDY IN SOUTHWESTERN SASKATCHEWAN — NITRATE-N DISTRIBUTION IN SOIL AND N UPTAKE BY THE PLANT
Authors: READ D. W. L. , CAMPBELL C. A. , BIEDERBECK V. O. , WINKLEMAN G. E.
Published: March 2010

The distribution of NO3-N in the soil, and N uptake by the crop during the first 12 yr of a long-term rotation study at Swift Current, Saskatchewan were studied. A considerable amount of NO3-N appeared to be leached beyond the rooting zone of the cereal crop in years of above average precipitation and also in some relatively dry years with heavy spring rains. Thus, leaching of NO3-N seemed to occur even under continuous wheat rotations. At all times there was considerable NO3-N situated at the 60- to 120-cm depth. In wet years N uptake by the plants reduced the amount of NO3-N located in the subsoil, but in dry years the amount of NO3-N in the subsoil remained higher throughout the growing season. The latter could result in groundwater pollution, especially if such a soil was fallowed the next year. Fall rye (Secale cereale L.) made more efficient use of mineral N than spring-sown crops. In dry years more NO3-N persisted in the root zone of N-fertilized wheat than in the root zone of unfertilized wheat, but in wet and average years there was little difference due to N application. The average rate of net NO3-N production in fallow land from spring thaw to freeze-up (166 days) was 107 kg∙ha−1. Values ranged from about 60 to 175 kg∙ha−1 with the lowest values being obtained during very dry or very wet years. The quantity of N mineralized (kg∙ha−1) between spring thaw and freeze-up was related to precipitation (mm) by the equation Nmin = 29.0 + 0.20 precipitation for the 0- to 60-cm depth (R2 = 0.65*). Key words: Nitrate leaching, N uptake, crop rotations, N mineralization rate
THE EFFECT OF VARIOUS CLOVER MANAGEMENT PRACTICES ON GASEOUS N LOSSES AND MINERAL N ACCUMULATION
Authors: AULAKH M. S. , RENNIE D. A. , PAUL E. A.
Published: March 2010

A 2-yr field study was carried out to assess gaseous losses of N as N2O + N2 from two Black Chernozemic soils, where during year 1 wheat was underseeded to clover and in year 2, the clover in late June was (a) green-manured and the field fallowed, (b) harvested for hay and then fallowed, or (c) harvested for hay and allowed to regrow. Gaseous losses during year 1 were small and ranged from 1.3 kg N∙ha−1 (Blaine Lake clay loam) to 4.7 kg N∙ha−1 (Hoey clay loam). Gaseous losses were somewhat higher during the second year, but differences between the various clover management practices were generally small. The contribution of lower soil horizons towards gaseous nitrogen losses were shown to be negligible. Soil moisture, mean air temperature, nitrate + nitrite, and ammonia N concentrations collectively accounted for 37–66% of the variations in N2O fluxes. It is concluded that incorporation of clover followed by a partial fallow results in substantially less gaseous loss of nitrogen than the standard summerfallowing practice, and at the same time significantly increases mineral nitrogen accumulation in the soil. Key words: Acetylene inhibition technique, denitrification, nitrification, mineralization, green manuring
EFFECT OF TREATING FORAGE SEED WITH SELENIUM ON THE SELENIUM CONCENTRATION OF ALFALFA AND WESTERWOLDS RYEGRASS
Authors: GUPTA UMESH C. , WINTER K. A. , KUNELIUS H. T.
Published: March 2010

Rates of 50–200 g Se/ha, applied to the seed, maintained tissue Se levels greater than 0.1 ppm in three cuts of alfalfa (Medicago sativa L.) and Westerwolds ryegrass (Lolium multiflorum Lam.). The Se concentrations were generally higher in ryegrass than in alfalfa. Dry matter yields were not influenced by Se seed treatment. Key words: Ryegrass, alfalfa, selenium, seed treatment
SOIL WATER DESORPTION CURVES ESTIMATED FROM LIMITED DATA
Authors: JONG R. DE
Published: March 2010

A procedure is described by which the soil water desorption curve, modeled as a power curve, can be approximated from a limited number of measured water contents at specific tensions. Applicability of the model was tested on 90 soils. The results indicated that measurements at the two extremes were the most important, if only two water contents were measured. The best results were obtained when the curve was fitted through three measured water contents, respectively, at saturation, at an intermediate (5.0–35.0 kPa) tension and at a high (1500.0 kPa) tension. Key words: Soil water desorption curves, limited data, power curve
THE EFFECTS OF PHOSPHORUS AND NITROGEN FERTILIZER ON THE RELATIONSHIP BETWEEN SOIL SALINITY LEVELS AND THE GRAIN YIELD AND PROTEIN CONTENT OF BARLEY GROWN ON STUBBLE LAND
Authors: PETERS J. R.
Published: March 2010

The effect of fertilizer P, N and N-P combined on barley grain yield and protein content when grown on stubble land ranging widely in surface salinity (0–60 cm depth) was tested. Critical salinity levels were calculated from linear regression equations derived from sampling sites with surface salinity levels [Formula: see text]. Added P did not appear to affect the salt tolerance of barley. Yield increases due to fertilizer N were reduced rapidly as soil salinity levels increased and in one trial appeared to reduce the tolerance of barley to salinity. Calculated salinity levels at 50% and zero yield of N-fertilized barley were lower than for barley not fertilized with N. Calculated salinity levels at zero yield for the control and P treatments were 18.5 and 15.1 mS∙cm−1, respectively. These levels compared favorably with values reported in the literature for barley grown on saline fallowed land. Protein content of barley grain increased with an addition of N and with salinity. The latter fact could be largely explained by a strong positive correlation between soil salinity and soil NO3−-N levels and to a lesser degree by a reduction in yield with increasing salinity. Key words: Salinity, barley, fertilizer effects, yield, protein
INTERACTIONS BETWEEN OH− IONS AND SOIL SURFACES: A KINETIC STUDY
Authors: ARINGHIERI R. , PARDINI G.
Published: March 2010

A kinetic study, regarding the interactions between OH− ions and soil surfaces, was carried out in order to investigate the nature of the process, and calculate its specific rate. A two-step process took place when initial OH− ion activities were sufficiently high. A first rapid step was always followed by a relatively less rapid step. The two steps were ascribed to the interaction of OH− ions with external and internal soil surfaces, respectively. Experimental data fitted a pseudo-first-order kinetic equation very well over the time period examined, so that the values of the specific rate were calculated at different initial NaOH concentrations. Since a decrease of the specific rate was observed when the initial OH− ion activity was increased a diffusion-controlled mechanism was postulated to regulate the rate of the process. The change of the specific rate as a function of the supporting electrolyte concentration was also investigated. Key words: Deprotonation kinetics, permanent charge, pH-dependent charge, diffuse double layer
EFFECT OF APPLIED COPPER ON VEGETABLE CROPS GROWN IN PRINCE EDWARD ISLAND
Authors: CUTCLIFFE J. A. , GUPTA UMESH C.
Published: March 2010

The addition of Cu at 2 and 4 kg/ha did not increase the yields of carrots, beets, onions, or rutabagas grown in soils normally used for these crops in Prince Edward Island. Leaf tissue Cu concentrations of these crops were found to be in the range of 6–14 ppm and generally were not affected by the added Cu. Key words: Tissue copper, vegetable yields, podzol soil
RATE OF PODZOLIC SOIL FORMATION NEAR HUDSON BAY, ONTARIO
Authors: PROTZ R. , MARTINI I. P. , ROSS G. J. , TERASMAE J.
Published: March 2010

Six soil profiles on a transect orthogonal to the Hudson Bay coast of Ontario are shown to be of increasing age from approximately 100 yr near the coast to > 5000 yr 70 km inland. The stages of Podzolic soil development from calcareous parent materials are documented. The Ah horizons required at least 750 yr to develop. The Ae-Bh horizon sequence required at least 1893 yr to form. The Ae-Bf horizon sequence required at least 2300 yr to develop. The depth of carbonate leaching and vermiculite formation in the A horizons are very closely correlated to soil age. Key words: Vermiculite, Podzolic B horizon, carbon dating, carbonate leaching
MINERALOGY OF SURFACE SOIL SAMPLES OF SOME QUEBEC SOILS WITH REFERENCE TO K STATUS
Authors: AL-KANANI T. , MacKENZIE A. F. , ROSS G. J.
Published: March 2010

Surface samples of five Quebec soils (St. Bernard, Ormstown, Howick, Dalhousie and Bearbrook) were selected to represent typical agricultural soils with a range of parent material. Soil minerals were fractionated by size into five separates and examined using X-ray diffraction (XRD) techniques and chemical analyses. In nearly all cases the non-clay separates (250–2.0 μm) contained feldspars, amphiboles and quartz as dominant minerals with only small amounts of layer silicates. Feldspars, amphiboles and quartz were also relatively abundant in the clay separates. The layer silicates in the clay separates consisted mainly of mica, chlorite and vermiculite. The soils had similar mineral suites, considered indicative of a low degree of weathering. Considering the mineral composition and the low degree of weathering, it is proposed that primary K-bearing minerals, including K-feldspars, are important sources of K in these soils. Key words: K release, particle size, soil mineralogy
THE NECESSITY OF WASHING FILBERT LEAVES FOR MACRO- AND MICRONUTRIENT CONSIDERATIONS
Authors: KOWALENKO C. G.
Published: March 2010

Differences between analyses of washed and unwashed filbert leaves were found for N, P, Mg, S, B, Mn, Zn and Cu but not for K and Ca. The contamination was attributed primarily to particulates since washing reduced average leaf weight measurements. The magnitude of the contamination varied among orchards and between years. It was concluded that washing leaves is essential for both micro- and macronutrient considerations. Key words: Filberts, leaf washing, macronutrients, micronutrients, contamination
EFFECTS OF SOIL TEMPERATURE ON PHOSPHORUS EXTRACTABILITY. I. EXTRACTIONS AND PLANT UPTAKE OF SOIL AND FERTILIZER PHOSPHORUS
Authors: SHEPPARD S. C. , RACZ G. J.
Published: March 2010

The effect of 10, 15, 20 and 25 °C soil temperatures on the extractability of soil and fertilizer phosphorus (P) was examined in two soils, one containing free carbonate (pH 7.8) and the other non-carbonated (pH 6.9). The time course of fixation and desorption reactions were monitored. The extractability of P was also assessed using sodium bicarbonate (NaHCO3) extractions, desorption curves, and short-term uptake by wheat seedlings. Phosphorus-32 was used throughout. Opposing effects of temperature were found. An increase in incubation temperature from 10 to 25 °C decreased the amount of applied P extracted probably due to accelerated fixation reactions. This effect was established 1 day after the P was applied and persisted for 57 days. An increase in extraction temperature over the corresponding incubation temperature increased the extractability of P, indicating endothermic desorption reactions. This effect was established 1 h after the extraction began and persisted for 48 h. Hence, the net effect of temperature on the extractability of P will depend upon the balance of these opposing processes. The time course of these processes had two phases. The effects of temperature were established during the initial phase (< 1 day) of each process. The reactions continued more slowly after the initial phase but the later phases were not significantly affected by temperature. The P-desorption buffer capacity increased as temperature increased in the fertilized, carbonated soil. Isotopic exchange of applied 32P with native soil 31P increased as temperature increased. Isotopic exchange appeared to be more extensive when measured by plant uptake as opposed to NaHCO3 extraction, suggesting that the plants had access to a larger pool of soil 31P. Key words: Temperature, soil phosphorus, fertilizer, incubation, desorption, plant uptake, wheat
DICLOFOP-METHYL PERSISTENCE IN SOUTHWESTERN ONTARIO SOILS AND EFFECT OF PH ON HYDROLYSIS AND PERSISTENCE
Authors: GAYNOR J. D.
Published: March 2010

The persistence of the herbicide diclofop-methyl, methyl 2-(4-(2,4-dichlorophenoxy)) phenoxy)propionate, was measured in two soils under field conditions in southwestern Ontario. The hydrolysis of the herbicide ester to its corresponding acid, diclofop, 2-(4-(2,4-dichlorophenoxy)phenoxy)propionic acid, was slower at pH 5.5 than at higher pH but soil pH had no effect on subsequent degradation of diclofop or metabolites formed. After hydrolysis of the ester the acid degraded to 12–39% of the original concentration in 34 days and less than 14% of the applied herbicide, identified as diclofop, was recovered at the end of the growing season. During the course of the degradation small amounts of the metabolites 4-(2,4-dichlorophenoxy)phenol and 4-(2,4-dichlorophenoxy)phenetole were identified from their relative retention time (Rf) on silica gel plates along with traces of other nonidentified compounds. None of the identifiable products except diclofop was present at the last sampling date. Combustion of soils treated with 14C-diclofop-methyl revealed 26–32% of the radioactivity was not extracted at the end of the growing season. Key words: Hoegrass, diclofop degradation, soil residue, soil reaction, 14C-diclofop-methyl
SALINITY AND ALFALFA YIELD UNDER EFFLUENT IRRIGATION IN SOUTHWESTERN SASKATCHEWAN
Authors: JAME Y. W. , BIEDERBECK V. O. , NICHOLAICHUK W. , KORVEN H. C.
Published: March 2010

The effect of wastewater irrigation on soil salinity and crop yield was determined in a study at Swift Current, Saskatchewan. A toposequence consisting of the Orthic Regosol series, Calcareous Brown series, Orthic Brown series and Cumulic Orthic Brown series of the Birsay Association was seeded to alfalfa and irrigated with effluent from a secondary sewage lagoon. Since the applied effluent had a mean EC of 2.6 dS/m, soil salinization was a major concern. For 8 yr the four soils were sampled for salinity to a depth of 150 cm each fall. During the 8-yr period, alfalfa was sampled for dry matter yield twice each year from each soil. The results indicate that irrigation by 10–15% more than the normal recommended application rate (i.e., when low saline surface water is used for irrigation) will ensure sufficient leaching to maintain salt content in the root zone at a level not deleterious to plant growth. After 8 yr of effluent irrigation, new steady state salinity profiles were developed in the Orthic Regosol, Calcareous Brown and Orthic Brown series. At this steady state condition the salt contents in the upper 60 cm of the root zone in these three soil series were generally similar. They increased from the initial low ECe value of 0.6 dS/m to 2.5 dS/m. Salinity increased with depth toward the bottom of the root zone where the Orthic Brown series had an ECe value of 4.0 dS/m, while the Orthic Regosol and Calcareous Brown series had values of 6.0 dS/m. Effluent irrigation resulted in a small net reduction of salts in the 150-cm profile of the Orthic Regosol and the Calcareous Brown series, but caused an increase of salts in the Orthic Brown profile. In the Cumulic Orthic Brown series the salt content throughout the profile increased continually from a very low initial level, and had not reached a steady state condition after 8 yr of irrigation. The development of a high water table in this area resulted in salt movement into the root zone of the Cumulic Orthic Brown series that was distinctly higher than those of the other three series and caused alfalfa yields to decline from being highest at the start of this study to only about 80% of yields on the Orthic Brown series at the end. The observed yield reductions emphasize the importance of having adequate drainage to effect salt removal by leaching when crops are irrigated with saline sewage effluent. Key words: Wastewater irrigation, soil salinity, alfalfa yield
CHANGES IN NATURAL 15N ABUNDANCE OF SOILS ASSOCIATED WITH TILLAGE PRACTICES
Authors: SELLES F. , KARAMANOS R. E. , BOWREN K. E.
Published: March 2010

The objective of this study was to determine changes in N dynamics in an Orthic Black Chernozem as a result of two tillage practices (conventional and zero tillage) using the variations in the natural 15N abundance of different soil-N fractions. After 14 yr, no significant differences in isotope composition of total soil-N between the two tillage practices could be found. However, changes were detected in the natural 15N abundance of the acid-hydrolyzable N and various organo-mineral size fractions which led to useful comparisons of the nature of N under the two systems. The N-content of the hydrolyzable-N fraction was similar at the 0- to 4- and 8- to 16-cm depth under both tillage practices, while it was significantly different at the 4- to 8-cm depth. The δa15N of this fraction was consistently higher than that of total soil N at all depths only under zero tillage. This was associated with the presence of more labile N compounds under zero tillage. No differences in the isotopic composition of the organomineral size fractions were found at the 0- to 4-cm depth. At the 4- to 8- and 8- to 16-cm depths, the δa15N values of the finer particle size fractions were higher under zero tillage than under conventional tillage. This indicates a more labile nature of the N associated with these size fractions under zero tillage. Key words: δa15N, conventional tillage, zero tillage, total N, acid-hydrolyzable fraction, particle size fractions
FORMATION OF HYDROXY-Al-MONTMORILLONITE COMPLEXES AS INFLUENCED BY CITRIC ACID
Authors: GOH TEE BOON , HUANG P. M.
Published: March 2010

Montmorillonite from Upton, Wyoming (< 2 μn) was aged 30 days in the presence of Al-citrate solutions both in the absence of NaOH and at an initial NaOH/Al molar ratio of 2.5. The effect of citric acid on the formation of hydroxy-Al-montmorillonite complexes depended greatly on the initial citrate/Al molar ratio. A low citrate/Al ratio of 0.1 did not significantly affect the CEC and X-ray diffraction patterns of hydroxy-Al-montmorillonite complexes. An intermediate citrate/Al ratio of 0.5 reduced the amount of Al depleted from solution and increased the proportion of 1 M KCl-exchangeable Al and 0.2 M HCl-extractable Al and the CEC of the samples; the structural perturbation in the interlamellar hydroxide sheet as revealed by XRD is attributed to the fixation of hydroxy-Al-citrate in the interlamellar spaces. At a high citrate/Al ratio of 1.0, most of the Al remained in solution and was prevented from being adsorbed by montmorillonite. The complexation between Al and citrate is a competitive reaction for the fixation of hydroxy-Al by clay. The close association between hydroxy-Al and citrate in the system is demonstrated by the existence of organic carbon associated with the 1 M KCl-exchangeable Al and 0.2 M HCl-extractable Al. Key words: Exchangeable-Al-associated organic carbon, hydroxy-Al interlayers, structural perturbation, organic acid, smectite
EFFECT OF DIFFERENT INOCULANT ADHESIVE AGENTS ON RHIZOBIAL SURVIVAL, NODULATION, AND NITROGENASE (ACETYLENE-REDUCING) ACTIVITY OF SOYBEANS (Glycine max (L.) Merrill)
Authors: ELEGBA M. S. , RENNIE R. J.
Published: March 2010

Inoculation of soybeans is essential to the establishment of a successful N2-fixing symbiosis in western Canadian soils that lack indigenous soil Rhizobium japonicum. A comparison was thus made between commercial and non-commercial adhesive agents used to optimize inoculation of King Grain line X005 soybeans (Glycine max (L.) Merrill) with seed-applied powdered peat-based inoculant. Gum arabic (40%, wt/vol) and carboxymethyl cellulose (4% wt/vol), available only from chemical supply houses, were excellent adhesive agents, binding over 800 mg of the inoculant per seed and protecting bacteria from desiccation. Wallpaper glue (10%, wt/vol), readily available in the market place and in common use by some farmers, bound 894 mg of inoculant per seed. The two most readily available commercial adhesive agents, Nutrigum and Nitracoat, bound similar amounts of inoculant. The use of water as an adhesive agent did not nourish the bacteria or protect them from desiccation and can not be recommended. All 12 adhesive agents tested resulted in over 105 viable rhizobia per seed, satisfying inoculation requirements under the Fertilizers Act. However, the three best adhesive agents bound over 800 mg of inoculant to the seed resulting in over 106 viable rhizobia per seed and more than 100 nodules per plant. Key words: Rhizobium japonicum, N2 fixation
EVALUATION OF SOME FIELD TESTS FOR PODZOLIC B HORIZONS
Authors: SCHUPPLI P. A. , McKEAGUE J. A.
Published: March 2010

The potential of several field tests for differentiating podzolic B horizons from others was studied. The spodic horizon test involved determinations of 4 N KOH-extractable Al and the color of humic extracts. The 0.5% HCl-HF test and the acid oxalate test both involved a rating of the intensity of color of the extracts. For the samples tested, the HCl-HF test was the most promising on the basis of less dependence on correct sample weight, simplicity, and the best differentiation of the podzolic B horizons tested. For samples having borderline properties, however, such field tests might yield ambiguous results because sample weights and estimates of extract colors are not accurate. In most circumstances, sampling for laboratory analyses is recommended to resolve classification problems. Key words: Field test, podzolic B horizon, spodic horizon
ESTIMATED SOIL WATER RESERVES APPLICABLE TO A WHEAT-FALLOW ROTATION FOR GENERALIZED SOIL AREAS MAPPED IN SOUTHERN SASKATCHEWAN
Authors: JONG R. DE , SHIELDS J. A. , SLY W. K.
Published: March 2010

Long-term mean soil water reserves for a spring wheat-fallow rotation in the southern half of Saskatchewan were calculated using the Versatile Soil Moisture Budget. Four different available water-holding capacity classes and climatic data from 53 stations were used as input to the model. Soil water reserve data for the following times, seeding on 1 May in the crop year, at heading on 30 June, and on 1 May in the fallow year, were mapped. These were then combined with an available water-holding capacity map to portray in a single map the combined droughtiness due to climatic and soil attributes. Estimated soil water reserves compared well with measured data from one location in the Brown soil zone. The temporal and spatial changes in water reserves are discussed and related to summerfallowing. The maps provide information for use in making potential grain yield estimates. Key words: Soil water, wheat-fallow rotation, generalized soil areas, Saskatchewan, Versatile soil moisture budget
COMPARISON OF 1:1 AND 1:2 SUSPENSIONS AND EXTRACTS WITH THE SATURATION EXTRACT IN ESTIMATING SALINITY IN SASKATCHEWAN SOILS
Authors: HOGG T. J. , HENRY J. L.
Published: March 2010

Electrical conductivity of saturation extracts was related to that of 1:1 and 1:2 (soil:H2O) suspensions and extracts for a wide range of Saskatchewan soils. The conductivity of 1:1 extracts was 1.75 times greater than for 1:1 suspensions and the conductivity of 1:2 extracts was 1.38 times greater than that of 1:1 suspensions. The conductivity of the saturation extract was closely related to all of 1:1 extract or suspension; 1:2 extract or suspension (r = 0.96–0.98). The regression coefficient relating the conductivity of 1:1 and 1:2 extracts and suspensions to that of the saturated paste extract decreased in going from coarse to medium to fine soil textures. The concentrations of Na+, Ca2+ + Mg2+ and Cl− in 1:1 and 1:2 (soil:H2O) extracts were highly correlated with the amounts in the saturation extract (r = 0.93 to 0.99). Key words: Soil salinity, 1:1 and 1:2 suspension and extract, saturated paste
SILICA AND CHLORIDE IN INTERSTITIAL WATERS OF RIVER AND LAKE SEDIMENTS1
Authors: Harriss Robert C.
Published: March 2010

Interstitial waters of sediment from the Concord River, Massachusetts; Neuse River, North Carolina; and Seneca Lake, New York, have higher concentrations of dissolved silica and chloride and lower pH values than coexisting surface waters in equilibrium with the atmosphere. The highest silica concentrations in the interstitial waters (20–50 mg/liter greater than coexisting river water) are observed in organic bog sediments and in river sediments at depths of 6 cm or more below the sediment‐water interface. The high silica and low pH values appear to be primarily a result of the decomposition of organic matter. The high chloride concentrations are attributed to evaporation of rain water solutions in the soil.
THE SEASONAL AND DIEL CHANGES IN DISTRIBUTION OF DIAPTOMUS LEPTOPUS IN A SMALL EUTROPHIC LAKE
Authors: Healey M. C.
Published: March 2010

Little is known of the role in vertical migration of different age classes of migratory plankton populations. Differences in migratory behavior between age classes were examined in the Diaptomus leptopus population of Corbett Lake, British Columbia, during summer of 1963. Only the males of stages V and VI showed a significant vertical migration. Females of stages V and VI and copepodid stages I–IV showed diel changes in vertical distribution, but these were not consistent between samples. All three groups showed significant clumping in the vertical plane. The data suggest that the degree of aggregation in the vertical plane is related to population size. Some evidence for horizontal patchiness is also considered. The possibility that ontogenetic changes in migratory behavior provide new clues to the biological significance of vertical migration is emphasized.
COPEPOD INDICATORS OF SURFACE WATER MOVEMENTS OFF THE OREGON COAST1
Authors: Cross Ford A. , Small Lawrence F.
Published: March 2010

Two small copepods, Acartia danae and Centropages mcmurrichi, were used as reciprocal indicators of seasonal surface current changes off the Oregon coast in 1961 and 1962. A. danae was found inshore and offshore in winter, indicating the northward flow (with an onshore component) of the Davidson Current. C. mcmurrichi was found inshore in early summer and farther offshore by late summer, indicating a southerly flow (with an offshore component). In the spring and fall, these species occurred together inshore, indicating a transitional state.

Temperature‐salinity‐plankton (TSP) diagrams were used to examine the relationships between distributions of the copepods and local processes affecting near‐surface water properties (upwelling, rainfall and runoff, and the Columbia River plume). These diagrams emphasized that the major effect on copepod distribution was the seasonal shift of surface currents, with rainfall and runoff possibly affecting the inshore distribution of A. danae in winter. Upwelling had no apparent effect on the distribution of either species. Columbia River discharge, which flows southerly in summer, probably overwhelmed the general offshore (westerly) movement of surface currents, and hence the offshore movement of C. mcmurrichi, near the mouth of the river. The effect of the Columbia River plume farther out to sea was not shown conclusively to have an effect on the distribution of either species in summer.
ECOLOGY OF ORGANIC AGGREGATES IN THE VICINITY OF A CORAL REEF1
Authors: JOHANNES R. E.
Published: March 2010

A marked increase in the concentration of suspended particulate organic aggregates occurs in oceanic water as it crosses the windward coral reef at Eniwetok Atoll and enters the lagoon. Evidence is presented indicating that these aggregates consist of mucus released by corals. Export of mucus into the lagoon by the reef community was estimated at 20 mg m−2 hr−1. This accounts for about 2.0% of total reef community production and is equivalent to about 40% of coral respiration. Field observations and experimental evidence suggest that aggregates of mucus may be an important food source for zooplankton in the vicinity of coral reefs.
UPTAKE OF NEW AND REGENERATED FORMS OF NITROGEN IN PRIMARY PRODUCTIVITY1
Authors: Dugdale R. C. , Goering J. J.
Published: March 2010

The use of 15N‐labeled compounds to obtain specific uptake rates for the various nitrogen sources available to the phytoplankton makes it possible to separate the fractions of primary productivity corresponding to new and regenerated nitrogen in the euphotic zone of the ocean. Measurements of nitrate uptake as a fraction of ammonia plus nitrate uptake have been obtained from the northwest Atlantic and the northeast Pacific oceans. Mean values range from 8.3 to 39.5%, the former being characteristic of subtropical regions and the latter of northern temperate regions or coastal and inland waters.

Nitrogen fixation is also a source of new nitrogen. Rates of nitrogen fixation are found to be as high or higher than nitrate uptake, in some cases suggesting an important role for nitrogen‐fixing phytoplankton.

The role of zooplankton in regenerating nitrogen as ammonia in the Sargasso Sea is examined theoretically. Probably only about 10% of the daily ammonia uptake by phytoplankton is contributed by the zooplankton living in the upper 100 m.
LAKE CHELAN, WASHINGTON: BOTTOM AND SUB—BOTTOM TOPOGRAPHY1
Authors: Whetten John T.
Published: March 2010

Lake Chelan, a fjordlike lake in north‐central Washington, consists of two basins separated by a shallow constriction. The Lucerne Basin, at the upstream end of the lake, is 466 m deep and sediments in it are relatively thin except near the upper end. The Wapato Basin is shallow, but sediments are at least 178 m thick. Both basins probably had a glacial origin; however, they probably were carved by different glaciers of different ages. The thick sediment in Wapato Basin was probably deposited by meltwater from the Chelan glacier (which occupied Lucerne Basin) and the Okanogan glacier, which blocked the downstream end of Wapato Basin.
GROWTH OF MARINE BACTERIA AT LIMITING CONCENTRATIONS OF ORGANIC CARBON IN SEAWATER1
Authors: Jannasch Holger W.
Published: March 2010

Growth responses of several species of heterotrophic marine bacteria to limiting concentrations of lactate, glycerol, and glucose in seawater were determined in a chemostat. In all cases, threshold concentrations of the limiting substrates were found below which the organisms were unable to grow. This phenomenon is explained on the basis of a positive feedback mechanism, which is abolished below a certain minimum population density. The resulting inhibitory effect on growth leaves a corresponding concentration of the limiting substrate unattacked.

According to their growth parameters, two types of species could be distinguished, one adapted to the marine environment by its ability to grow at low substrate concentrations and one inactive in natural seawater but surviving.

The implications of these results on the rates of microbial transformations and on the occurrence and concentrations of dissolved organic material in the sea are discussed.
CALCULATION OF CALCIUM ANOMALIES ON THE GREAT BAHAMA BANK FROM ALKALINITY AND CHLORINITY DATA1
Authors: Traganza Eugene D. , Szabo Barney J.
Published: March 2010

Regional calcium anomalies can be calculated to ± 1% from alkalinity and chlorinity data. The “noncarbonate” calcium: chlorinity ratio is conserved. Deviations arise from random errors or processes other than CaCO3 precipitation, CO2 loss, or evaporation.

Calcium concentrations have been calculated from the equation [Ca2+ (meq/liter) = Cl‰ + ½C.A.] with a precision of ± 0.01 meq/liter. In the field the value of K varies— from 0.479 to 0.506 (avg = 0.490)—suggesting that on the Great Bahama Bank, an accuracy of no more than ± 0.44 meq/liter or ca. 4% can be expected. Variation of the mean values of K may arise from systematic errors or from true variation of the ion: chlorinity ratios in different water masses.

Dissolved calcium was determined using a high precision EDTA‐complexometric titration. The mean value for K, the “noncarbonate” : chlorinity ratio, was 0.481 ± 0.002 in July and 0.483 ± 0.003 in September 1964. The average : chlorinity weight ratios in July and September 1984 were 0.02113 at the bank edge, decreasing to 0.02033 with increased chlorinity.
TWO ANTARCTIC DESERT LAKES1
Authors: Goldman Charles R. , Mason David T. , Hobbie John E.
Published: March 2010

The optical and biological properties of ice‐covered Lakes Vanda and Bonney, Antarctica, were observed during two austral summers. The lakes arc among the clearest known, with extinction coefficients as low as 0.031 for blue light in Lake Vanda and 0.069 for green light in Lake Bonney.

Temperature and conductivity measurements in a shallow lake on Cape Evans, Antarctica, suggest a simple freezing‐out process as the possible origin of the monimolimnionic salt concentration in Lake Vanda.

The lakes have a variety of living organisms but low standing crops and production rates. Many of the organisms are facultatively heterotrophic and may use dissolved organic substances for maintenance in the dark half of the year.
VARIATIONS IN DISTRIBUTION OF 14C IN CELL EXTRACTS OF PHYTOPLANKTON LIVING UNDER NATURAL CONDITIONS1
Authors: Olive John H. , Morrison John H.
Published: March 2010

A modification of the 14C technique was used to study variations in the distribution of 14C in cell extracts of phytoplankton living under natural conditions. In the upper photic zone (0.5 m), cell volume declined steadily from April to June, but total 14C uptake increased gradually with increasingly large fractions of 14C incorporated into an ethanol‐soluble cell extract (probably low molecular weight carbohydrates and organic acids) rather than into an insoluble fraction (probably protein and polysaccharides). In the middle photic zone (3 m), cell volume also declined and total 14C uptake increased gradually, but increasingly large fractions of 14C were in the insoluble fraction. Cell volume and total 14C uptake in the lower photic zone (6 m) increased proportionally. Increasingly large fractions of 14C were in the insoluble fraction from March to June. Variations in 14C distribution appear to be related to active cell turnover during a Synedra sp. bloom on one occasion and to chromatic adaptation by the dominant phytoplankter Oscillatoria rubescens at another time.
SOME OBSERVATIONS ON THE HATCHING OF TORTANUS DISCAUDATUS EGGS SUBJECTED TO LOW TEMPERATURES1
Authors: Johnson Martin W.
Published: March 2010

Eggs of Tortanus discaudatus, a calanoid copepod, were sorted from the plankton at Friday Harbor, Washington, and set up in cultures subjected to temperatures ranging from 12.5C to −2C to observe the hatching rate and viability at low temperatures.

At the higher temperatures, the eggs hatch in three to four days. Hatching goes on slowly at 0C, and of 20 eggs held at −2C, one hatched in 17 days and 53% of the remaining eggs hatched in five days when returned to 11.5C after an exposure of 30 days. Thus, the eggs were viable after at least one month at −2C.
ESTIMATING THE ORGANIC CARBON CONTENT OF PHYTOPLANKTON FROM CELL VOLUME OR PLASMA VOLUME1
Authors: Strathmann Richard R.
Published: March 2010

Equations for estimating the organic carbon in phytoplankton from cell volume or plasma volume are derived from original data on five species of diatoms and from data in the literature. Differences among species are important sources of error in such estimates. Plasma volume provides a more precise estimate of cell carbon in diatoms than does cell volume. Diatoms, because of their lower carbon per cell volume, should probably be treated separately from other phytoplankton in such computations.
STUDIES ON THE SEASONAL VARIATION OF THE SUSPENDED MATTER IN THE MENAI STRAITS. I. THE INORGANIC FRACTION
Authors: Buchan S. , Floodgate G. D. , Crisp D. J.
Published: March 2010

The ash weight of material suspended in the waters of the Menai Straits was measured twice weekly between May 1962 and May 1963. The amount was much greater in winter than in summer and greater during spring than during neap tide periods. No differences could be detected between the ebb and flood periods within a single tidal cycle.

The variations in ash weight correlated strongly with temperature but not with rainfall. There was a significant correlation between ash weight and the temperature‐related variables, σt and estimated freshwater runoff, but neither was significant after the effect of temperature was eliminated. The suspended burden was greater during periods of easterly winds, but no relationship could be established with wind velocity. The seasonal changes could not be attributed to changes in thermal instability or viscosity. The variations are thought to be caused by biological rather than by physical processes.