ALBERT

Description: The stylonurid eurypterid Leiopterella tetliei Lamsdell, Braddy, Loeffler, and Dineley, 2010 (Chelicerata: Eurypterida: Rhenopteridae) from the Early Devonian (Lochkovian) of Nunavut in Arctic Canada is redescribed. Restudy of the holotype under polarized light revealed a labrum, epistomal sutures, prosomal appendage III, and deltoid plates anterior to the genital appendage. An additional new specimen preserves the distal podomeres of appendage VI and gradually tapering opisthosomal tergites. The characters resolved here support the hypothesis that L. tetliei was relatively basal within the wider Stylonurina clade, with its tapering postabdomen supporting a more basal position within Rhenopteridae than previously suggested.

Description: We developed an experimental program to monitor how interparticle forces control fine-grained soils' mechanical behavior when saturation changes from the tightly adsorbed regime to saturation. The testing program uses stiffness (i.e., S-wave velocity) and strength (i.e., Brazilian tensile strength) tests on kaolinite, silica flour, and diatomaceous earth soil samples at very low confining stresses (〈 5 kPa). Three fine-grained soils yield a range of different properties, including particle size, specific surface area, negative charge density, and internal/external particle porosity. Results show that shear stiffness and tensile strength follow similar trends, emphasizing that the same interparticle forces control the mechanical responses. In particular, the interpretation of S-wave velocity measurements shows three different behavior ranges: a van der Waals attraction range, a capillary-dominated interparticle forces range, and the continuous decrease in the capillary forces from the saturation at the air-entry pressure until full saturation. We show that the interparticle forces respond to a complex function of water content, particle size, particle separations, surface charge density, and the presence of internal particle porosity.

Description: Abstract: Strandlines document the former presence of lakes and a sea in east-central North America along the southern margin of the retreating Laurentide Ice Sheet (LIS). The strandlines of these formerly level water bodies are uplifted to the north and provide evidence of glacial isostatic adjustment (GIA) of the Earth’s crust to the former ice load. We compile published ages and measurements of the present elevation and location of shore features in the strandlines of 8 major paleo-waterbodies from the St. Lawrence Valley to the northern Great Plains in digital format as an aid for the numerical modelling of GIA. Data for eastern water bodies were extracted and digitized from publications during the past 120 years. Digital position co-ordinates were scaled from published maps of survey sites or were determined using Google Earth Pro software. Published data for paleo-lakes Duluth and Agassiz were mainly obtained from field measurements and digital elevation models (DEMs). Two-sigma or 95% probability values are provided for the strandline ages and for isobase (contour) positions representing the deformed water surfaces. Peak strandline gradients reported here were largest at about ca. 13,000 years ago. Lower strandline gradients for older shores may reveal areas closer to the peripheral bulge and areas of thinner ice (lighter crustal loads). Concave upward strandline profiles characterize most paleo-basins whereas a linear uplift profile characterizes the Champlain Sea strandline. Directions of strandline maximum uplift within the former water body basins point towards the thickest part of the LIS near the Québec-Labrador ice dome.

Description: The assessment of the strain rate effect on the geotechnical properties of soils constitutes an important step toward a more accurate analysis of their response. This study presents the experimental results of monotonic and cyclic simple shear tests performed to examine the strain rate effect on the behavior of eastern Canada soils. Eight natural soils sampled from different locations in eastern Canada were used in this study. The tests were performed on a simple shear device using a strain-controlled mode. In addition to the obtained experimental results, published data in the literature were used to draw the conclusions of this study. Analysis of the data indicates that the undrained shear strength increases proportionally with the strain rate by approximately 10–17% per log cycle of . The results also show that the secant shear modulus G increases with the strain rate, especially at large strain amplitude. Moreover, the analysis of the data revealed that the magnitude of the strain rate effect seems to be correlated with the shear strain amplitude and plasticity index (Ip). A practical application of the outcomes on the backbone curves is given in which illustrates the influence of and on the strain rate effect.

Description: Quantification of calcium carbonates in a light-colored matrix or disseminated calcium carbonates cannot be obtained directly from impregnated blocks by image analysis. A method that combined staining by alizarin red-S with digital image analysis made it possible to identify and quantify soil calcium carbonates including the disseminated form in thin sections. Best results were obtained under reflected light using a tungsten lamp source. Photographic filters did not improve the image quality of stained calcium carbonates. Key words: Image analysis, soil micromorphometry

Description: K deficiency was identified for the first time in British Columbia orchard soils. Greenhouse-grown apple seedlings responded to K in soils low in available K. MacSpur McIntosh (Malus domestica Borkh.) had increased leaf K (above deficiency) and improved initial fruiting after surface applications of KCl in an orchard with low soil K. Key words: Potassium deficiency, apple, leaf and soil potassium

Description: Growth chamber experiments were conducted to investigate the effect of size of fertilizer reaction zone, rate of added zinc and method of placement of added zinc on the dry matter yield, zinc concentration and zinc uptake of blackbeans grown on a calcareous soil. Relationships between zinc concentrations in the plant, zinc utilization by the plant and zinc concentration in the soil reaction zone were obtained. An equation was developed relating zinc utilization to zinc concentration in the fertilizer band, and a figure was derived showing how increasing the size of the fertilizer zone impacts upon the zinc concentration of the plant. The results indicate that inorganic zinc fertilizers must be mixed as uniformly as possible for maximum effectiveness. Key words: Zinc, placement, calcareous, soil, blackbean, Phaseolis vulgaris

Description: Organic C, N, P, and S contents in soil are thought to be the result of interactions among soil-forming processes, which occur in all soils but to different degrees. To test this hypothesis, the effect of climate, vegetation and topography on the organic matter composition in cultivated soil profiles was examined along an environmental gradient, from semiarid to subhumid regions in Saskatchewan. This transect encompasses a narrow environmental gradient of decreasing evapotranspiration and increasing precipitation (350–450 mm). Representative catenas selected from Brown, Dark Brown, Black and Gray Luvisol soil zones showed changes in the quantity and composition of organic matter. Concentrations of organic C, N, P and S progressively increased from the Brown to the Black soils and then decreased substantially in the Gray soils. Nutrient concentrations also increased from the upper to the lower slope positions of the catenas and decreased with depth in the soil profile. However, the distribution of organic elements across the soil zones, relative to each other (i.e. C:N, C:P, or C:N:P:S ratios), did not follow the same trends as concentration of the individual elements. The most consistent trends were observed in the lower slope soils, where organic C:N (9.8 to 12.5:1), C:P (48 to 78:1) and C:N:P:S (68:6.9:1.4:1 to 145:11.6:1.8:1) ratios widened from the Brown to the Gray soils. Within any one catena, organic C:N:P:S ratios narrowed with depth in the soil profile, often showing a several-fold decrease relative to the C:N:P:S ratios of the surface horizons. This study demonstrates the value of recognizing integrative relationships among soil processes. It provides a mechanism for better understanding and explaining the patterns of distribution and behavior of various soil chemical, physical and biological properties. Key words: Catenary sequence, Chernozem, Luvisol, hierarchical relationships

Description: In an 8-yr experiment on an irrigated Dark Brown Chernozemic soil, four rates of N (0, 34, 67 and 101 kg ha−1), applied annually with 45 t ha−1 of manure containing softwood shavings (avg. of 46% dry wt) produced a linear yield response (from 3.5 with the check to 4.3 t ha−1 at the highest rate) of barley grain (Hordeum vulgare L. 'Galt'). There were large differences in yields among years, which could be attributed to weather factors, but there was no significant N × year response. Protein content increased linearly (from 11.2 to 13.5%), and both kernel weights and "test weights" (kg hL−1) decreased slightly but significantly with N applications. There was a pronounced "residual" effect of N rates on both grain yield (from 3.8 to 6.3 t ha−1) and protein content (from 10 to 13%) in the first year after applications of manure and N fertilizer ceased. These effects decreased rapidly and had practically disappeared by the end of the 3rd yr, although yields of all treatments remained high (about 5 t ha−1). Organic matter and N contents of the soil were increased by 70 and 41%, respectively, from the cumulative applications of shavings manure. It is concluded that application of manure containing large quantities of softwood shavings has a negligible effect on the N fertilizer requirements of the crop being grown. Beneficial residual effects of N fertilizer applied with the manure may result because of buildup of NO3-N throughout the soil profile, and likely also because of N release from readily mineralized organic compounds or microbial biomass. However, this effect was not reflected in soil tests for readily mineralizable N by NO3 incubation or KCl digestion methods and the effects were practically dissipated after 3 yr. The recovery of applied N fertilizer by the crops was high at all rates (61–79%), and essentially all of the N applied (fertilizer + manure) was accounted for by crop removal + increased soil N. Key words: Mineralizable-N soil tests, Chernozemic soil, repeated fertilizer applications, residual effects

Description: The objective of this study was to evaluate the Kelowna multiple element extractant and some EDTA and DTPA modifications for simultaneous determination of potassium and sodium in acid and calcareous soils. To that end, the relationships between K and Na concentrations extracted with 1 N NH4OAc and the Kelowna multiple element extractant (0.25 N HOAc + 0.015 N NH4F) were assessed. However, relationships between K and Na concentrations removed by the modified Kelowna multiple element extractants containing either EDTA or DTPA (KEDTA & KDTPA with NH4F; and AAEDTA & AADTPA without NH4F) were evaluated by comparing values against those obtained with the Kelowna extractant. Addition of these complexing agents was of interest because of their potential in enabling simultaneous extraction of available Zn. The procedures were evaluated by contrasting K and Na concentrations extracted from 100 Canadian soils — half which had pH values between 4.1 and 6.9 (H2O) and a second group with values between 7 and 9.6 — by means of graphing, regression and correlation techniques. Potassium and sodium concentrations removed by the Kelowna extractant ranged from 25 to 510 μg and from 10 to 1420 μg mL−1 soil, respectively. The Kelowna and its EDTA and DTPA modifications extracted K and Na as effectively from acid as calcareous soils. This conclusion was supported by the similar regression slopes obtained when relating concentrations of K and Na removed from these soil groups by the multiple element extractants against those removed by 1 N NH4OAc (r-values ≥ 0.97**). However, the new multiple element extractants removed an average of about 20% less K than 1 N NH4OAc from these soils, though similar Na levels. The lower K levels removed from the Kelowna extractant, or by one of its modifications, may require that soil test interpretation norms be adjusted to compensate for the lower values when using one of these to determine K-availability. A significant correlation was found between extracted Na levels and 1:2 vol/vol water-extract conductivities (r ≥ 0.83**) suggesting that "higher" Na levels may be soluble instead of exchangeable. Some Na test interpretations are discussed in the text. Key words: EDTA, DTPA

Description: Low recovery of recently added [Formula: see text] fertilizer as [Formula: see text] was observed in a Bainsville (Orthic Humic Gleysol) and a Dalhousie (Gleyed Eutric Brunisol) soil, whereas a Brookston (Orthic Humic Gleysol) and a Conestogo (Gleyed Melanic Brunisol) soil had a high recovery. The former two soils had higher vermiculite contents than the latter two soils. Therefore, [Formula: see text] fixation was believed to be responsible for the low recovery. Between 18 and 23% of added [Formula: see text] was fixed after 15 d in the Bainsville and Dalhousie soils whereas only 1–3% of added [Formula: see text] was fixed in the Brookston and Conestogo soils. Potassium pre-addition (with/without air drying) increased the apparent recovery in the Bainsville and Dalhousie soils but did not affect the actual recovery. Potassium pre-addition did not block subsequent [Formula: see text] fixation, rather it resulted in a release of native 14N. Gamma irradiation was used to inhibit biological activity. Between 1 and 7% of added 15N was immobilized in these soils after 15 d. Key words: Ammonium fixation, immobilization, vermiculites, 15N gamma radiation, potassium, native N, ammonium exchange

Description: Field experiments were conducted during 1982–1983 at two locations (Rimbey and Ellerslie) in north-central Alberta to determine the influence of date of application (mid-October, late October and spring), method of placement (incorporation, banding and nesting) and straw (0 and 3.4 t ha−1) on the recovery of 15N-labelled urea in plants and soil at harvest. The rate of N was 50 kg N ha−1. The recovery of 15N in mature barley plants at both locations was greater with spring application as compared to fall application, and greater with banding or nesting compared to incorporation. At Rimbey, the average recovery, in plants plus soil, of incorporated urea N was lower with October applications (43% for mid and 55% for late) as compared to spring application (89%). Banding or nesting increased the N recovery of October applications. With spring application, there was more immobilization of applied N when incorporated into soil as compared to band or nest placement. Also there was more immobilization of applied N when straw was added to the soil, but banding or nesting tended to overcome the immobilization effect of straw so that the plant N recovery was greater with banding or nesting as compared to incorporation. At the Ellerslie location, there was heavy rain with consequent saturated topsoil in late June and early July. Recovery of fall-applied N in plants was low, and even with nesting the recovery was only 13%. There was substantial immobilization of applied N at Ellerslie. With spring application, nesting overcame the large immobilization effect and produced normal recovery of applied N in the plants. Addition of straw resulted in more immobilization of applied urea N, particularly when urea was incorporated. The 15N recovery in plants plus soil of spring-applied N indicated N losses during the growing season and the losses were much greater at Ellerslie than at Rimbey. Key words: Band placement, fall application, immobilization of N, incorporation, 15N, N losses, nest placement, spring application

Description: The Ap horizons of two conservation tillage studies on Dark Brown Chernozemic soils in southern Alberta were sampled in 1986 following the fallow year. The first study, started in 1967, consisted of a wheat-fallow rotation under either no-till chemical fallow, blade-cultivate, or chemical fallow + blade-cultivate management. The second study, started in 1977, consisted of continuous winter wheat, winter wheat-barley-fallow, and winter wheat-fallow rotations under either no-till or conventional tillage management. Nine years of no-till continuous wheat and 19 yr of no-till in a wheat-fallow rotation both led to 40% of the dry aggregates being 〉 0.84 mm in diameter. The parameters selected helped to characterize differences in organic matter between soil tillage systems. Dehydrogenase and phosphatase activities were twice as high under no-till as under the blade-cultivate treatment. No-till also led to the largest monosaccharide accumulation in the soil. Carbohydrates, solvent-extractable organic matter, and chitin N were significantly higher in the 〉 0.84 mm diameter dry aggregates from the no-till treatment. The monosaccarides under the blade-cultivate regime were generally of microbial origin whereas those under the no-till regime were generally of plant origin. Key words: Water-stable aggregates, dry aggregates, enzyme activities, organic carbon, monosaccharides, fallow

Description: Linear equations were developed for converting electromagnetic induction readings (ECa) from EM38 meters to saturated paste electrical conductivity values (ECc). To correlate EM38 readings with measured ECe values, field sites representing a range of salinity conditions were sampled in 0.30-m increments to a depth of 1.5 m. Adapting a weighting procedure based on the EM38 meter's response to depth, ECe values were condensed into a single weighted value. The weighted ECe values were linearly correlated with temperature-corrected ECa readings. Equations were designed for soils of various textures under varying temperature and moisture conditions. For accurate ECa to ECe conversions, soil temperature correction of ECa is essential. When a frozen layer is present, EM38 readings are unreliable. EM38 horizontal and vertical modes show different ECa readings for the same depth-weighted ECe. Variability of ECa to ECe conversion was greater on coarse-textured than medium- or fine-textured soils. Available soil moisture should be above 30% for accurate ECe determinations from ECa readings. Key words: Salinity methods, soil salinity, saturated paste extract method, electromagnetic inductance meters, soil temperature

Description: A field experiment was conducted to examine the interaction of fertilizer placement and moisture level on barley (Hordeum vulgare 'Gait') utilization of urea-N during early growth. The 15N labelled urea (50 kg ha−1) was either deep-banded or broadcast-incorporated, and plant samples were taken from the two-leaf stage until anthesis, then again at maturity. Five moisture regimes were created using rain shelters, with 0, 10, 15, 20 and 25 mm water applied per week until anthesis. A natural precipitation treatment was also included. All barley plants were unsheltered from anthesis to maturity. Weekly fertilizer recoveries by the crop with no water additions were much less for broadcast-incorporated N than deep placement. The differences narrowed with increasing rates of water additions. Apparently, broadcast-incorporated fertilizer N remained in dry surface layers of the no-water treatment, and was positionally unavailable for absorption by the crop. Compared to deep-banded N, broadcast-incorporated N resulted in 37% less grain when drought stress occurred from seeding to anthesis. Broadcast-incorporated N was more susceptible to immobilization by the soil than was deep-banded N. Key words: Barley, drought stress, 15N-urea, fertilizer positional unavailability, N immobilization

Description: This research examined the effects of soil environment on the decomposition of cereal crop residues and stabilization of microbial products in the field. Microplots at semi-arid and subhumid field sites were amended with 14C-, 15N-labelled wheat straw and with 14C-labelled glucose plus 15N-labelled NH4NO3 and the fate of the residual C and N was monitored over 10 yr. Mineralization of C and N derived from wheat straw was greater at the site in the more moist environment in the short term (2 yr). In the long term (up to 10 yr), however, the residual C and N at this site decayed at a slightly slower rate, providing evidence of stabilization of organic material in chemically resistant forms, as compared to possible physical protection in the semi-arid clay-textured soil. The total recovery of labelled N was 22.5–24% in the harvested crops with 13.4–16% remaining in the surface soil by the end of the study. Mineralized labelled organic N was used with an efficiency ranging from 32 to 51%. However, after summer fallow the crop apparently used mineralized labelled N with an efficiency of only 7%. This study showed that moistness of the soil environment has a considerable effect on residue decomposition. Stabilization of humic material derived from residues relates more to the recalcitrance of microbial products and their interactions with soil mineral colloids than to the nature of the original residue. Key words: Mineralization rates, crop residues, microbial turnover, chemical recalcitrance, physical protection, plant N use-efficiency

Description: Sulfate sorption and desorption as a function of pH were measured for six podzolic horizons from two forested watersheds of the southern Laurentians. The results showed a rapid increase in sulfate sorption with decreasing pH to a maximum sorption capacity at pH values between 3.8 and 4.2 depending on the horizon considered. Below this pH retention decreased except for the Coniferous (Con) B horizon where sorption remained almost constant. This drop in the sorption capacity of the soils is related to the partial dissolution of Al, and possibly Fe, surface coatings. Levels of up to 15.9 mmol L−1 of total dissolved Al were measured at pH 3.0 for the Herminc (Her) B horizon. The amount of sorbed and total native sulfate and the maximum sorption during the experiment are positively correlated (R2 = 0.986, 0.982 and 0.800) with the oxalate extractable Al content of the soils. Except for the Con B horizon, amorphous plus crystalline Fe make up the bulk of the inorganic coatings in all six horizons. For the Con B horizon, which has the highest sorption capacity of the horizons tested, the composition of these coatings is dominated by Al materials. In all soils, the variations in sulfate sorption as a function of solution concentration are best described by the Gunary equation in the range of pH values tested. Key words: Sulfate, pH-dependent sorption, dissolution, Podzol

Description: The objective of this study was to compare the values, statistical characteristics and relationships of partition coefficients (Kd) computed from a short-term study of 54Mn sorption with those computed from DTPA extractions of soil Mn. Of particular interest were the frequency distributions, which must be very well known for use in stochastic modelling of environmental impacts. The study used 69 soils. Sorption of 54Mn, applied with stable 54Mn carrier, was measured after 24 h equilibration in suspension. The Kd for 54Mn was based on the single measurement of 54Mn in solution. Total soil Mn and DTPA + NaHCO3-extractable Mn were also measured and used to compute a Kd from two measurements. The frequency distributions of Kd values measured by either method were strongly skewed and conformed to lognormal, regardless of the statistical properties of the underlying measurements. The geometric mean Kd for 54Mn was 44 L kg−1 and was highest for high pH, high clay content and high organic matter content soils, as expected. The geometric mean Kd for DTPA-extractable Mn was 1070 L kg−1 and was not related in the same way to the soil properties. Clearly, the two Kd measurements were quite different. A significant correlation (r = 0.54, P 

Description: A tracer (15N) study using fallowed field microplots was conducted at Agassiz Research Station to examine the fate of applied N over an entire year. The tracer confirmed nontracer (difference between fertilized and control treatments) observations that applied N does not leach beyond the rooting zone (45 cm) during the growing season, despite the considerably more than average precipitation that occurred in July, but that all residual [Formula: see text] is leached over the winter. The tracer did, however, show that net immobilization of applied N occurred late in the fall resulting in 17% of the N recovered in the 75-cm profile 1 yr after application even though the nontracer method showed that none of the applied N remained. There was significant net mineralization of soil N over the summer (100 kg N ha−1 from early May to late August) and nitrification of the applied [Formula: see text] (120 kg ha−1) was essentially complete within 14 d of application. Tracer analyses suggested that 36% of the applied [Formula: see text] was immediately fixed by the clays but after 14 d in the field it decreased to less than 1%. The fixed [Formula: see text] remained at this level throughout the rest of the year. The apparent large decrease in fixed [Formula: see text] within the first 14 d may have been an analytical artifact which resulted when the initial soil was air dried. Negligible denitrification was observed during the growing season despite the soil remaining quite moist throughout most of the year. Delta 15N measurements of total N, fixed [Formula: see text] and extractable inorganic N fractions showed only enrichment of total N. The delta 15N results support the observation that denitrification tends to be low under Agassiz soil and weather conditions. Comparisons and contrasts to previously reported similar tracer studies in Ottawa were made. Key words: Leaching, clay fixation, N mineralization, N immobilization, nitrification, denitrification, delta 15N

Description: Ten soil properties, including texture, pH, available phosphorous, cation exchange capacity, exchangeable cations and organic carbon, were determined from the Ap horizons of 91 map units of two Montreal Lowlands counties. Multivariate analysis techniques were used to classify the soils into fertility groups. Nine fertility groups were derived from cluster analysis. Principal component analysis yielded two components which accounted for more that 75% of the variance. These principal components were related to soil texture and fertilizer management factors. They confirmed the grouping obtained by cluster analysis. Multiple discriminant analysis distinguished these fertility groups and allocated new soil mapping units to one of them using discriminant functions. Clay content, pH, exchangeable Ca and available P were selected as the more potent and significant variables in descriminating groups. This work demonstrated that multivariate analysis has considerable promise in deriving meaningful interpretive grouping from selected soil parameters. Key words: Fertility, interpretive grouping, soil quality, multivariate analysis

Description: Fertilizer P was applied annually (0, 15, 29 and 44 kg P ha−1 yr−1) for 26 yr to an acidic loam cropped to timothy (Phleum pratense L.). Some fertilizer P was translocated into the 30- to 45-cm depth of soil when 15 kg P ha−1 yr−1 was applied and into the 45- to 60-cm depth when 44 kg P ha−1 yr−1 was applied. The amount of P translocated increased with increasing rates of applied P. Key words: Fertilizer, phosphorus, leaching, translocation, movement

Description: Natural radionuclides of the uranium (U) and thorium (Th) decay series contribute to the radiation dose received by humans. In the context of U mining and refining, it is important to accurately assess the pathway for these radionuclides from soils to food plants. The Canadian Standards Association model of this pathway for dose estimation is based on the plant/soil concentration ratio (CR). In a controlled outdoor lysimeter setting, we measured CR values for experimentally applied U at 100 mg kg−1, 230Th at 8 kBq kg−1 and 210Pb (lead) at 20 kBq kg−1 using a sand, a loam, a clay and an organic soil in 12 soil and crop combinations. The overall geometric mean CR values were 0.013, 0.0022 and 0.0050 for U, 230Th and 210Pb, respectively. A second experiment using one soil and crop showed CR to be dependent on soil concentration for U, but not for Th and Pb. The final two experiments dealt with uptake of U, Th, Pb, Ra (radium), Cs (cesium), Po (polonium), and As (arsenic) from soils contaminated by a former Ra processing facility, both in a controlled lysimeter setting and in uncontrolled home-garden settings. The results generally agreed with those of the initial experiment, although the overall geometric mean CR for Th was higher at 0.02. Most of the recommended Th CR values for dose estimation are tenfold below those for U; our garden-setting results suggest they should be equal or higher. The effects on soil properties and crop type on CR values are discussed. Key words: Concentration ratio, uranium, thorium, lead

Description: Humic acid (HA) and alkali-insoluble residue fractions (Residue) were isolated from four types of peat from the Fraser River Delta area. The peat fractions were characterized with respect to sulphur forms and response to acid hydrolysis. Total S content of HA fractions ranged from 0.3 to 5.5% on an ash-free basis, with 69–83% in C-bonded S form. Nitrogen: sulphur ratios varied between 0.64 and 5.9. The highest S contents and lowest N:S ratios were associated with peats formed under the influence of brackish water. Similar patterns were observed for the Residue fractions. Only small proportions of S (7.9–17.3%) were recovered in soluble form from the peat fractions after acid hydrolysis, and hydrolysis was accompanied by S losses attributed to volatilization. On average 4% of the initial C-bonded S was recoverable in that form in the hydrolysates, whereas 46% of the initial organic sulphate appeared in the hydrolyzate in sulphate form. The low recovery of S in hydrolyzates indicated a correspondingly small contribution of S-amino acids to the C-bonded S fraction. The large proportions of sulphur and carbon resistant to hydrolysis indicated a rather high degree of chemical (and perhaps biological) stability. Key words: Sulphur forms, hydrolyzable-S, peat humic acid, gyttja, peat fractions

Description: Ground-penetrating radar (GPR) is a geophysical tool designed for subsurface probing of materials with contrasting dielectric properties. The applicability of this technique to locate agricultural drain tiles or tubes under some soil types and moisture conditions found in New Brunswick and Nova Scotia was evaluated. A method using GPR graphical outputs from adjacent, paired parallel traverses was developed to verify tile drain signatures. Over 50 drains, installed from 1 to 50 years ago, in soils developed in morainal till, glaciofluvial, and glaciomarine deposits were detected with the GPR system and confirmed by excavation. These included both clay and plastic drains. With experience, reliability was found to be close to 100%. The possibility of using the system for determining depth to the drain is also discussed briefly. Key words: Ground-penetrating radar, tube drain location, apparent dielectric constant, propagation time, electromagnetic wave, propagation velocity

Description: This study was conducted to compare the long-term (20 yr) effects of conventional tillage, minimum tillage and no-till on various soil-water related properties within the tilled layer (0–30 and 30–60 mm) and immediately below the tilled layer (90–120 mm) under a spring cereal-summerfallow rotation cropping system. Parameters measured included saturated hydraulic conductivity, saturation percentage, plant-available water-holding capacity, large pore porosity, bulk density, and infiltration rate of the soil. Tillage treatment effects on these soil properties in each of the four sampling periods were not significantly different. The confidence interval test showed some temporal changes in these soil physical properties, of which hydraulic conductivity was the most affected. In the summerfallow field, regardless of the previous cereal crops, the steady infiltration rate was significantly lower in the soil under conventional tillage than with that under no-till. The results indicate that the surface soil structure was most stable under no-till. In the fresh stubble field, the type of cereal crop had an effect on the infiltration rate of the soil. The mean infiltration rate was higher in the summerfallow field than in the fresh stubble field and also was higher in the fresh barley stubble than in the fresh wheat stubble. Except for infiltration rates, there is no significant advantage of one tillage method over the other with respect to the soil physical properties measured in this Brown Chernozemic clay loam soil. Key words: No-till, minimum tillage, hydraulic conductivity, bulk density, infiltration

Description: Long-term (8 yr) K+ fertilization experiments were started in 1983 on Jeddo clay loam, Smithville silt loam, Oneida loam, and Vineland sandy loam in the Niagara region of southern Ontario to study K+ exchange and fixation in relation to K+ uptake by grapes. Potassium fertilization at rates of 0, 100, 200, 400, and 600 kg K+ ha−1 was discontinued after 4 yr to record the build-up of soil K+ with fertilization and its decline after fertilization ceased. This paper reports the results on K+ exchange and fixation during the 4-yr K+ fertilization period. The clay mineralogy of the soils was similar with their clays containing mainly mica and smaller amounts of vermiculite, chlorite, quartz, and feldspars. There was a highly significant linear relationship between rates of applied K+ and K+ fractions of exchangeable cations for every soil in every year of K+ application. Exchangeable K+ concentrations in the coarse-textured Vineland soil increased sharply from the first to the second year of K+ application. However, there was no consistent increase of exchangeable K+ concentrations with time in the finer-textured soils for the first 2-4 years of K+ application. This was attributed mainly to K+ fixation. This interpretation was supported by chemical and X-ray evidence that showed reduced K+ fixation capacity and transformation of vermiculite to a mica-like mineral at the high rate of K+ application. Potassium exchange equilibria and standard Gibbs free energies for the exchange of (Ca2+ + Mg2+) by K+ were calculated using the theory of multiple ion exchange equilibria. Standard Gibbs free energy values for this exchange became more negative with increase in clay and vermiculite contents of the soils which was attributed to the strong adsorption of K+ in vermiculite and vermiculite-like minerals that were concentrated in the clay fraction. Clay content is therefore the dominant factor determining K+ exchangeability in the soils of the Niagara region of southern Ontario. Key words: soil mineralogy, vermiculite contents, potassium exchange equilibria, standard Gibbs free energy

Description: Air-drying decreased (〉 80%) microbial activity, microbial biomass carbon (MB-C) and sulfur (MB-S) levels of both native and cultivated soils. This resulted in a flush (~ 4 μg g−1) in the 0.01 M CaCl2 extractable SO4-S. Rewetting soils restored microbial activity and biomass contents to their original levels, but this led to immobilization of the SO4-S. Restoration of the MB-S levels was slower than MB-C levels. Thus, during drying and rewetting cycles, the MB-S pool acts as both a source and sink for the SO4-S pool in soil. Key words: Microbial activity, microbial biomass sulfur, extractable sulfate sulfur

Description: Impacts of silvicultural practices on soil structure were evaluated in hardwood plantations. On two different sites, four treatments (mechanical weed control, herbicide weed control, seeding of nitrogen-fixing companion species and a control) were undertaken, with and without earthworm introduction, according to a complete randomized block design. Treatments had significant effects on the water stability of soil aggregates, macroporosity and bulk density. Earthworm introduction significantly increased macroporosity in control plots while decreasing it in the three other treatments. Key words: Soil structure, silvicultural practices, earthworm, Lumbricus terrestris

Description: Rainfall simulation by sprinkler irrigation was used to evaluate the characteristics of sediment and runoff water from erosion plots on a Dark Brown Chernozemic soil near Lethbridge, Alberta. Replicated land treatments consisted of bare fallow, perennial alfalfa/wheat grass forage (Medicago sativa L./Agropyron riparium Scribn. & Smith) planted in rows parallel to the slope, barley (Hordeum vulgare L.) planted in rows parallel to the slope (barley-S) and barley on contour (barley-C). The eroded sediment from all four treatments was generally enriched in organic matter (OM), NH4-N, total N (TN), and PO4-P, but not in NO3-N or total P (TP). The sediment from the bare fallow treatment was enriched in silt-size particles and had the highest OM enrichment. Maximum NH4-N and TN enrichment occurred in the sediment from the barley-S treatment, and maximum PO4-P in that from the forage treatment. This selective removal of plant nutrients was attributed mainly to erosion processes and to cropping-induced differences in C:N:P ratios of organic complexes. The runoff water from all four treatments was enriched in NO3-N, TN, and PO4-P. For the three cropping treatments in this experiment, nutrient enrichment of the runoff water decreased from forage 〉 barley-S 〉 barley-C treatment. In general, more NO3-N was lost in the runoff water than in the sediment. Key words: Erosion, sediment quality, water quality, nutrient loss, nitrogen forms, phosphorus forms.

Description: Flax (Linum usitatissimum L.) was grown in two growth chamber experiments on a total of 16 Black Chernozemic soils varying in content of Mg, Ca, P, and Zn. On three of the soils, dry matter yield of flax increased in response to application of P. Phosphorus availability was greater with broadcast than with banded fertilizer applications. Increased yield in response to Zn application was observed on one-half of the soils. Applications of P that increased P level in the tissue above 0.46% led to consistent but nonsignificant decreases in yield and reduced the level of Zn in the tissue. Zinc fertilization increased Zn and decreased P level in the tissue. Yield response to P application was not strongly related to soil chemical parameters measured, but increased as tissue P level decreased and tissue Zn level increased. High levels of soil Mg and soil pH and high tissue levels of Mg and P were the factors most closely associated with a yield response to Zn applied with P. Key words: Flax, Linum usitatissimum, Ca, Zn, P, Mg, fertilizer placement

Description: Prairie farmers are interested in applying nitrogen (N) in the fall or winter to reduce fertilizer costs and allow a better distribution of labor and machinery use. Two studies were conducted in southwestern Saskatchewan to determine the consequences of applying N in late fall. In the laboratory, fertilizer N barely penetrated into the snow at constant subzero temperatures, but under freeze-thaw conditions, urea and ammonium nitrate descended 27 cm in 3 d. In the field, ammonium nitrate and urea were applied to snow-covered and bare microplots of grass sod and cereal stubble (1981–1982) and grass sod only (1985–1986). Nitrogen from ammonium nitrate penetrated deeper into the snow than N from urea. Nitrogen recovery in April 1982 was 55–59% from ammonium nitrate and 39–51% from urea, but was near 100% for both sources on bare soil treatments in April 1986. More N was recovered when fertilizer was applied to bare than to snow-covered soil, especially during 1985–1986 when all the applied fertilizer was blown off the snow-covered plots. Mineral N generally declined from fall to spring in all treatments, probably because of denitrification and immobilization. In 1985–1986, a period of extremely low temperatures in late fall resulted in no movement or transformation of N until after early December. By late January, periods of above-zero soil temperatures resulted in substantial mineralization of soil organic N, in the fertilized plots. This apparent priming effect was attributed to perturbations in the organic matter and microbial biomass due to fertilizer application and freezing and thawing. Following this period there was a general decrease in mineral N towards spring, as observed in 1981–1982. Producers must consider the benefits of using labor and equipment more efficiently and of lower fertilizer cost in the fall against the risk of large potential N losses over winter. Key words: Urea, ammonium nitrate, N recovery, frozen soils, fertilizing in winter

Description: Organic matter (OM) in the Bainsville and Melfort soils, and in coarse clay and medium silt fractions separated from these soils, was extracted under N2 with 0.5 M NaOH and unadjusted 0.1 M Na4P2O7 solutions. pH ranges of the soils and fractions in contact for 24 h with 0.5 M NaOH and 0.1 M Na4P2O7 solutions extended from 12.2 to 12.6 and 9.0 to 9.4, respectively. Slightly greater proportions of the soil-carbon were extracted by 0.5 M NaOH than by 0.1 M Na4P2O7 solution. The differences, however, did not appear to be significant and may vary from soil to soil. The efficiency of extraction and the characteristics of the extracted materials were assessed on humic acids (HAs), which were isolated from the extracts. From the Bainsville soil and fractions, 0.1 M Na4P2O7 solution extracted more high-molecular weight and more deeply colored HAs than did 0.5 M NaOH solution. But HAs extracted from the Melfort soil and fractions had similar molecular weights and colours. 13C NMR spectra showed that HAs extracted by 0.1 M Na4P2O7 solution tended to be more aromatic than HAs extracted by 0.5 M NaOH solution. Well defined solid-state 13C NMR spectra of HAs, containing up to 69.0% ash, could be recorded. Unadjusted 0.1 M Na4P2O7 solution under N2 was found to be an attractive alternative to 0.5 M NaOH solution as an extractant for soil OM. Key words: Humic acids, E4:E6 ratios, IR spectra, 13C NMR spectra, aromaticity

Description: The objective of this study was to determine the effect of adding either 0.001M EDTA or 0.005M DTPA on the amount of P removed from acid and calcareous soils by the Kelowna and 0.25M HO Ac extractants. These complexing agents were studied for possible simultaneous extraction and determination of available Zn. To achieve that end, P-concentrations removed by these solutions from a group of acid, calcareous, and combined soils were compared against reference values obtained with 0.5M NaHCO3 (Olsen et al.) and the Kelowna extractant (0.25M HOAc + 0.015M NH4F) by means of graphing, correlation and regression techniques. Of the 80 soils studied, 40 were acid with pH (H2O) values ranging from 4.2 to 6.9 and the remainder having higher values up to 9.3. Results indicated that additions of either 0.001M EDTA or 0.005M DTPA to the Kelowna solution increased average extracted P concentrations by about 20 and 60%, respectively. Values removed by either of the new KEDTA and KDTPA solutions were closely related to those extracted with 0.5M NaHCO3 and Kelowna solutions on acid and calcareous soils (r values ≥ 0.96**). As EDTA and DTPA increased extracted soil P, these were added at 0.001 and 0.005M as NH4 preparations to 0.25M HOAc (AADTPA & AAEDTA; without fluoride), respectively, for determining whether these complexing agents could supplant F for P extraction. These solutions removed proportionally related amounts (r ≈ 0.94**) of P from calcareous, compared to the Kelowna and 0.5M NaHCO3 solutions, but relationships were less precise for acid soils (r ≈ 0.76**). These results suggest that the AADTPA or AAEDTA solution should be evaluated further before adoption for routine P determination in multiple element extractions. Key words: Mehlich in, acid soils, calcareous soils

Description: A combination of field and laboratory procedures was used to estimate moisture-retention parameters of four coarse-textured soil series in southern Alberta. In situ field capacity moisture content was substantially higher than estimates based on conventional laboratory methods, resulting in significant underestimation of total available moisture. Moisture-retention capacity of all four soil series was found to be adequate for irrigation development. Empirical equations were developed to estimate the upper and lower limits of moisture retention on the basis of particle-size distribution, as determined by the Bouyoucos hydrometer method. Five alternative empirical methods were also evaluated for use in predicting moisture-retention parameters of coarse-textured soils. Equations presented by Rawls et al. (1982) were found to have the best relationship with southern Alberta data for both field capacity and wilting point. Key words: Coarse-textured soils, moisture-retention parameters, particle-size distribution, empirical models, irrigation suitability

Description: Application of N fertilizer in the fall as opposed to spring has been a controversial recommendation for cereal crops grown in Western Canada. Also, oilseed crops such as rapeseed may not respond to N in the same way as cereals. To investigate spring and fall application of N on barley and rapeseed, factorial split plot experiments were designed with three N treatments of 45, 90 and 134 kg N ha−1 and four P treatments of 0, 9.4, 18.8 and 28.2 kg P ha−1, as main plots. A control without fertilizer was included and the subplots were spring and fall times of broadcast application of ammonium nitrate fertilizer. Barley (Hordeum vulgare L.), cultivar Conquest and rapeseed (Brassica campestris L.) cultivar Arlo were seeded as the test crops over a 5-yr period and a 6-yr period, respectively, at separate sites on Melfort silty clay soil to determine the differences in yield and quality of grain between spring and fall applied N. In some years yield response to N fertilizer was greater when applied in the spring and in other years when applied in the fall, resulting in a significant time of N × year interaction effect on yield. However, on the average, there was no significant difference in yield of barley or rapeseed grain between fall and spring applied N, 3.51 vs. 3.59 and 1.39 vs. 1.41 t ha−1, respectively. Nitrogen and P fertilizer increased yield as much as 2.17 t of barley and 0.76 t of rapeseed ha−1 although the concentration of mineralized ammonium- and nitrate-N in the soil was rated medium according to provincial soil test standards. The difference in yield response of barley (Y, t ha−1) between spring and fall applied N among years was related to the rainfall (X, mm) in May by the equation:[Formula: see text]and for rapeseed:[Formula: see text]Because N was applied relatively late in the fall, the available soil N was medium and the conditions for N loss in these experiments minimal, differences in barley and rapeseed yield response to N fertilizer between spring and fall applied N were small. When P fertilizer was applied at a heavy rate, fall application of N produced a higher yield of rapeseed than spring application in all years. Key words: P, protein, rainfall, interaction, N, barley, rapeseed, time

Description: A greenhouse study was conducted on a fine sandy loam to determine the effect of adding different sources of Se on the Se concentration of forages and cereals. The three sources of Se were: NH4NO3 prills containing (i) 1.20% Se as sodium selenate, (ii) 1.02% Se as sodium selenite and (iii) urea prills containing 1.00% Se as sodium selenite. Application of 20 g Se ha−1 as sodium selenate (source i) produced Se concentrations of 1.02 and 1.05 mg kg−1 in timothy and 1.04 and 0.55 mg kg−1 in alfalfa in the two cuts, respectively, and 0.78 mg kg−1 in barley grain. This application rate of Se in the form of selenite resulted in 0.07–0.09 mg Se kg−1 in the two forages and barley grain. At similar application rates of Se, the ammonium nitrate doped with sodium selenate produced about 5–18 times more Se in the forages and barley than when doped with sodium selenite. Overall no significant difference was found in the plant Se concentration between ammonium nitrate or urea prills as the carrier for selenite. Key words: Sodium selenate and selenite doped NH4NO3, greenhouse, Se in forages and cereals

Description: In Kings County Nova Scotia, soils have developed over pre-Wisconsinan basaltic saprolite and basaltic and granitic till. The clay fraction of the soil developed on the saprolite is predominantly a trioctahedral smectite and apparently has not been significantly changed by post-Wisconsinan weathering. The clay fraction of the Aej horizon of the soil developed on granitic till is dominantly composed of dioctahedral layer silicates, mainly mica with some montmorillonite and vermiculite, and that developed on basaltic till by smectite and vermiculite. Key words: Basaltic saprolite, trioctahedral smectite, post-Wisconsinan weathering

Description: Recent work suggests that climate change will impact negatively on Canadian prairie wheat through more severe and frequent droughts and increased yield variability, and adaptive strategies have been called for to meet the coming change. However, previous studies have not determined if climate change has already affected wheat yields, nor has the entire prairie region been examined. Using a prairie wheat yield simulation model (PWYSM) at current (constant) technology, it is shown that the weather as it affects wheat, has had a zero trend over the 1900–1988 period. Also, there is no evidence that yield variability has recently increased. Prairie wheat yields therefore appear so far unconnected to the global warming trend this century, suggesting no current need to adapt to a changing climatic regime. Results also show that, at current technology, departures from mean weather may cause decade-long average yield fluctuations as large as ± 10% from the long-term mean, and climate change effects must be detected against this background fluctuation. Also, a 35% decline in actual wheat yields from the first to fourth decades of this century was not matched by deteriorating weather although weather contributed to the decline, and improved yields since 1940 are not explained by better weather. The study of Williams et al. (1988) concluded that a 1930s type dry spell would reduce Saskatchewan wheat yield by 20%, compared to the 1961–1979 mean That applied only to stubble-sown wheat. When adjusted here for the contribution of fallow-sown wheat, the reduction became 16.7%. With Alberta and Manitoba included, the yield reduction for the whole prairie became 13.8% — in good agreement with a 14.0% reduction obtained with the PWYSM. Yield reductions for Saskatchewan are larger than for the prairie as a whole. The reference period chosen also significantly affects findings, and, because the last decade has been relatively unfavourable, PWYSM results show that 1930s type weather would lower mean prairie wheat yield by only 11.0% relative to the 1979–1988 mean. Grain industry decision makers would more likely refer to the last decade than to a more distant period such as 1961–1979, and applying relative yield reductions to the 1979–1988 mean would result in substantial yield underestimates for drought scenarios. Reference periods must be carefully selected for consistent results. Key words: Climate change, wheat yield

Description: The percentage of soil material 〉 0.84 mm obtained by dry sieving is commonly used as an index of the wind erodibility of soils. Present sieving procedures do not account for the breakdown of friable aggregates during sieving so that results do not necessarily represent aggregation in the original sample. An equation was fitted to soil sieving data from a modified rapid rotary sieve. It successfully evaluated aggregate attrition during sieving for 397 out of 404 samples representing a wide variety of textures. Good reproducibility of results using the methodology was obtained for 45 paired soil samples. Results obtained employing the new method will relate more closely to field conditions allowing a better estimate of soil erodibility. Key words: Wind erosion, aggregate breakdown, sieving, soil erodibility, modified rapid rotary sieve

Description: Sieve loading in a modified rapid rotary sieve (MRRS) was investigated and data from the MRRS and a rotary sieve were compared; 1.5–2 kg sieve loadings gave the best precision. Correlation between the rotary sieve and the MRRS was 0.63; it improved to 0.79 when aggregate comminution in the MRRS was considered. Key words: Wind erosion, aggregate breakdown, sieving, modified rapid rotary sieve

Description: For 9 yr, subsurface return flow measurements from irrigated lysimeters containing "Macspur McIntosh" apple trees (Malus domestica Borkh.) on MM 111 rootstocks were collected. Water use with and without a grass cover crop was calculated as irrigation plus summer precipitation minus drainage. Drainages were consistently and significantly lower, and therefore water use higher, under grass than under bare soil but the differences were not large. The times of irrigation and drainage events were not closely linked. Drainage followed irrigation anywhere from a day to many days, stretching at times into weeks or months. By far the largest drainages, however, occurred during the irrigation season. Irrigation amounts provided most of the water for return flows with summer or winter precipitation contributing little to the drainage. At the higher irrigation levels the return flow quantities and calculated water use quantities clearly indicate that sprinkler design flow quantities are too high for the area and that improvements in irrigation efficiencies are possible. Key words: Drainage, irrigation, lysimeters, water use, apple trees

Description: A calcium-bound phosphate (PCa) chronofunction from a Vancouver Island soil chronosequence was compared mathematically with a chronofunction produced by leaching parent materials from the soil chronosequence with 0.3 M acetic acid for up to 24 wk in modified soxhlet extractors. The equivalent of approximately 13 yr of PCa weathering in the surface 10 cm of the chronosequence soils was achieved by one week of leaching in the soxhlets. After 24 wk of soxhlet leaching, the parent material samples lost approximately 20% of their original 220 g weight and resembled Ae horizon samples from the soil chronosequence. Equations derived from the change in elemental composition of the soxhlet-leached parent material samples were used with the elemental composition of the top 10 cm of the youngest soil (127 yr) in the chronosequence to predict the elemental composition of the top 10 cm of the oldest soil in the chronosequence (550 yr). The predictive equations were useful for elements such as Ca, Na, K, Al, Si and PCa, whereas the amount of Mg and Fe remaining in the soil chronosequence was overestimated, due to the inability of the acetic acid solution to attack ferro-magnesian minerals. An equation relating the weight of soil residues to soxhlet leaching time predicted that the chronosequence soils would experience a lowering landscape rate of 0.05 mm yr−1. The soxhlet leaching and field-time calibration technique described is considered by the authors to be useful for other applications, such as predicting loss of soil buffering constituents due to acid rain or predicting rates of release of elements from contaminated soils. Key words: Soil chronofunctions, soil chronosequence, soxhlet weathering, leaching

Description: Podzols formed in high-rainfall areas of south coastal B.C. often have layers of highly organic material at depth in the profile, and in many cases, “pipes” of similar material angling down through the profile. These materials have a greasy feel, few discernible mineral grains, occasional remnants of wood structure and a cellular nature. The horizontal layers, termed "root mats", range in thickness from 1 cm to 〉 30 cm, and are overlain by coarse-textured material of low organic matter content. Chemically this material is similar to surficial H horizons with respect to C:N and N:S ratios, but closely resembles Podzolic B horizons with respect to Fe content and humus fraction ratios. In contrast oxalate-extractable Al values are remarkably high, sometimes exceeding 10%. The majority of the root mats can be classified as organic (〉 17% organic C), either as H or O horizons. Those containing 〈 17% C meet the criteria for Bhf horizons. Key words: Root mat, root channel, oxalate-extractable Al, organic horizons

Description: Chemical and biological properties were evaluated in 1987 on an acidic silty loam soil following a long-term field study established in 1978 and cultivated with silage corn. Treatments included a control, solid cattle manure (20, 40 and 60 Mg ha−1 FYM) and pig slurry (60, 120 m3 ha−1 SLU) applied every 2 yr and annually, respectively. No fertilizer was applied. The results of this study have shown that neither treatment significantly affected soil pH values, total-N contents and C:N ratios compared to the control. The cation exchange capacity (CEC) of the soil was significantly higher with FYM treatment than with control or SLU application. The highest rates of FYM and SLU have also increased (P 

Description: The evolution of carbon dioxide and methane was measured from laboratory columns packed with surface (0–30 cm) materials representing a fen, a bog and a swamp and with varying water tables and treated with water containing 10 mg L−1 dissolved organic carbon. Carbon dioxide evolution increased in a linear relationship as the water table was lowered, ranging from 0.3–0.5 g CO2 m−2 d−1 to 6.6–9.4 g CO2 m−2 d−1 for the water table at 10 cm above and 70 cm below the peat surface, respectively. Methane evolution decreased in a logarithmic relationship as the water table was lowered. The fen showed the highest rates of methane flux (28 mg CH4 m−2 d−1 when inundated) and the bog the lowest (0.7 mg CH4 m−2 d−1 when inundated). These differences appeared to be related to the acidity of the soils and their microbial characteristics. Molar ratios of carbon dioxide:methane evolution increased from 4 to 173 under inundated conditions to 〉 2500 when the water table was at a depth of 70 cm. Key words: Methane, carbon dioxide, water table, organic soils, peatlands

Description: Soil phosphorus transformations and losses were measured in three profiles representative of an environmental gradient covering a grassland to forest transition: a Calcareous Brown, an Orthic Black and an Orthic Gray Luvisol. A sequential extraction procedure was used to measure the different forms of both inorganic (Pi) and organic (Po) phosphorus present in soil horizons. The mobilities of phosphate anions and of some selected (Po) compounds (glucose 6-phosphate, choline phosphate and adenosine triphosphate) were estimated through isotopic dilution kinetic experiments, and indicated that all the tested Po compounds had a higher mobility than phosphate anions in B horizons; also, Po was predominant over Pi in the water extracts from these soils. A mass-balance approach (Pedogenic Index) which incorporates depth-bulk density parameters in measuring the composition of soil horizons was used to calculate losses of Pt and apatite-P (HCl-Pi). Both grassland soils behaved similarly; they lost 500–550 kg P ha−1 (20%) of their original Pt and 30% of the initial HCl-Pi fraction was either transformed to various other forms of P or lost from the solum. Losses of Pt (3020 kg P ha−1: 41 %)and of HCl-Pi (70%) were much higher in the Gray Luvisol. Since losses of Pt could not be due to leaching of phosphate anions through the profile, the importance of Po in P leaching should be considered along with surface runoff in determining the fate of P in these soils. Key words: Pedogenic index, P mass balance, P fractionation, organic P leaching, P mobility

Description: Farmers in Saskatchewan have recently begun intercropping pea with nonlegumes in order to reduce lodging of the pea crop and thus improve harvesting operations. The response of pea and lentil to intercropping and N application was determined at five locations throughout Saskatchewan in 1987. At each site one of the following combinations was tested: lentil and flax, pea and rape, pea and yellow mustard or pea and oats. All treatments received 10, 30 or 50 kg N ha−1 as urea. Nitrogen-15 microplots were included to measure N2-fixation and percent fertilizer use efficiency (% FUE). Intercropping reduced lodging and improved harvesting conditions of pea and lentil. An increase in the land equivalent ratio (LER) due to intercropping was observed at two sites where growing conditions were poorer than at the other three sites. At the other sites intercropping systems had a similar or intermediate % FUE to that of the monocropped legume and non-legume. Percent N derived from N2-fixation (% Ndfa) ranged from 4.6 to 87.6, depending on site, level of N application and cropping system. Intercropped legumes had a significantly higher % Ndfa than monocropped legumes at two sites. Nitrogen fertilization reduced the % Ndfa of monocropped legumes at two sites but never affected the % Ndfa of intercropped legumes. Total N2 fixed was almost always less in intercropped than in monocropped systems, although only significantly at two sites. No significant lower values for atom % 15N of intercropped non-legumes as compared with monocropped non-legumes were observed, indicating that transfer of N from the legume to the non-legume was minimal. Key words: Intercropping, monocropping, flax, lentil, rape, pea, yellow mustard, oat

Description: A close relationship between organic-carbon content and bulk density was utilized to develop equations for predicting the bulk densities of inorganic soils around the Gulf of Alaska; for example[Formula: see text]where Db is the bulk density (Mg m−3) of fine-earth and OC is the organic carbon content (g kg−1). Adding discrete variables for soil texture (three classes):[Formula: see text]where A is 2.24 for loamy sands, 1.86 for sandy loams, and 1.73 for silt loams. Most of the samples used in developing these equations were from B and C horizons, but they appear to be applicable to other horizons too. They are not valid for (1) horizons with very low organic carbon content (C  2 mm) were considered in computing the bulk densities of whole soil horizons, because rock fragments are generally much denser than the bulk fine-earth. Key words: Clod samples, Podzolic soils, Spodosols, organic matter

Description: Nine different manures were evaluated to determine their ability to supply carbon to denitrifying bacteria in waterlogged soil. Manure slurries (anaerobically decomposed) and stacked or composted manures (aerobically decomposed) were included in this study. Water-soluble C concentration was considerably higher in the slurries than in the stacked or composted manures. Volatile fatty acids (VFA, including acetate, propionate, and butyrate) were significant components of water-soluble C in the slurries. Concentrations of VFA ranged from 5.9 to 26.1 g kg−1 in the slurries. Nitrous oxide production (denitrification) and CO2 evolution in manure-amended soil was closely related to both water-soluble C and VFA concentrations in the manures. In a second experiment, acetate, propionate, and butyrate appeared to be equally effective C sources for denitrifiers in soil amended with dairy cattle slurry. Nitrous oxide production was better correlated with VFA disappearance than with water-soluble C disappearance. Volatile fatty acids were produced during decomposition of solid poultry manure in soil under anaerobic conditions. These VFA were produced from readily available C substrates by fermentative bacteria and accumulated after NO3− had disappeared through denitrification. Denitrification in manure-amended soil depends on the source of manure and the kind and extent of decomposition that occurred in the manure. Key words: Slurry, water soluble carbon, volatile fatty acids

Description: A growth room pot experiment was conducted to relate differences in the aggregating ability of several grasses and legumes to root development and the frequency of VA mycorrhiza fungi. Forages with the most extensive root development within 80 d resulted in the greatest improvements in aggregation. Although the frequency of VA mycorrhiza varied between forages, it was not associated with improvements in aggregation. Key words: Soil structural deterioration, soil degradation, VA mycorrhiza, roots, grasses, legumes

Description: The persistence of the herbicides cyanazine, metribuzin, and atrazine was studied at different controlled temperature and moisture contents in Regina Heavy Clay soil. Degradation of the herbicides approximated first-order kinetics at temperatures in the range 5–30 °C and at moistures of above 20%. The breakdown of cyanazine was faster than metribuzin, which, in turn, was more rapid than atrazine. The breakdown of the three herbicides under field conditions, following June applications of 1.0 kg ha−1, was measured. Over 90% of the applied cyanazine had dissipated within 56 d, while the metribuzin and atrazine were more persistent, with approximately 30% of the initial treatment remaining at the end of the growing season. In all cases, there was no leaching of the chemicals below 10 cm. The laboratory data were used in conjunction with meteorological records in a computer program to simulate the dissipation pattern for the herbicides. There was good agreement between the observed and predicted residue levels for cyanazine, and a reasonable agreement for atrazine. For metribuzin, the model underestimated the rate of loss. Key words: Herbicides, atrazine, cyanazine, metribuzin, predicted field persistence

Description: Soil biomass C, N and P were determined for a native forest site, an unmined deforested site and an age-series of adjacent coal mine spoils (5, 10, 12, 16 and 20 yr). Biomass C ranged from 209 to 867 μg g−1 soil, biomass N from 20 to 75 μg g−1 soil and biomass P from 7 to 29 μg g−1 soil. Biomass C, N and P were linearly related to each other. Biomass C was also related to the root biomass. Biomass N with a mean C:N ratio of 11.8 accounted for 2.2–4.2% of the total soil N and was positively related to the mineral N of soil. Biomass C:P ratio ranged from 27.6 to 31.0%. The biomass P was significantly related to the bicarbonate soluble soil Pi. Soil microbial biomass was characterized by a mean C:N:P ratio of 29:3:1. Soil microbial C, N and P were positively related with the age of mine spoils, the values for the youngest spoil (5 yr old) being about four times lower compared to native forest soil. Total soil N was also positively related with age of spoil. The data suggest that microbial biomass can be taken as a functional index of soil redevelopment. Key words: Surface coal mining, soil microbial biomass C, biomass N, biomass P, mine spoil

Description: Evaporite mineralogy, soil solution and groundwater chemistry of a saline seep from southern Alberta were investigated using chemical and mineralogical techniques, and simulations with a geochemical model (SOLMNEQ), to determine the nature of the salinity. The shallow groundwater and soil solution were dominated by Na and SO4. Although simulations with the geochemical model predicted that many evaporite minerals could theoretically precipitate below the water table and in the soil, gypsum, bassanite, and calcite were the only evaporite minerals identified. Medium to coarse, silt-size, bassanite crystals and medium, sand-size, bassanite and gypsum crystals were observed in the upper (0–30 cm) and lower (〉 88 cm) profile, respectively. Calcite was indentified in all horizons. This mineral sequence cannot be explained by the Hardie-Eugster model of closed-basin brine evolution. The common-ion effect involving calcite dissolution and gypsum and/or bassanite precipitation, however, was probably an important mechanism controlling the mineral sequence observed here. Evidence of slight dissolution of bassanite crystals was observed in the surface horizon, whereas evidence of strong dissolution of bassanite and gypsum crystals was observed in the lower profile and below the water table. The results of this study suggested that gypsum and bassanite may be a major source of Ca and SO4 in the groundwater and soil solution. Key words: Saline seep, groundwater chemistry, soluble salts, evaporite mineralogy

Description: not available

Description: A soil sample, from an accretionary environment, high in 137Cs activity, was fractionated into exchangeable cations, organic-rich material, and sand, silt, and clay separates to determine the partitioning of 137Cs activity. Most of the 137Cs activity was associated with separates containing organic matter. About 21% of the 137Cs activity consisted of exchangeable cesium while 51% of the activity was associated with organic-rich silt to sand-size separates. Results of this study have relevance to the use of this radionuclide for estimating soil erosion. Key words: Fallout cesium, soil separates, clays, organic matter, humic material

Description: Plans are presented for the construction of a probe for measuring depth to water surface in water wells. The probe utilizes a battery-powered audible buzzer and a light-emitting diode. The probe is cheap, simple to construct, and durable enough for extended field use in forest and peatland hydrology studies. Key words: Water wells, depth probe, electronic circuitry, audible buzzer, peatland, hydrology

Description: Detailed soil profile descriptions were made to assess the residual effect of compaction and tillage treatments applied 10 yr ago on a Ste-Rosalie clay. The treatments applied consisted of five passes at a contact pressure of 61.8 kPa with no tillage, 15 passes of 61.8 kPa with chiselling, moldboard plowing, no tillage, subsoiling, and a control. The results were analyzed using nonparametric statistics. The untilled plots that received 15 wheel passes showed mottling that was more abundant and closer to the surface than the other plots while the subsoiled plots had a finer, less abundant and deeper mottling than the other plots. Peds in the Ae horizon were finer in the subsoiled and chiselled plots and coarser in the untilled plots and conventionally tilled plots that received 15 vehicle passes. It appears from this work that the effect of compaction is very persistent in clay soil and that subsoiling followed by reduced traffic can have a long-term effect on soil structure. Key words: Compaction, tillage, profile descriptions, clay soil

Description: The conversion of undissolved acidic functional groups into dissolved carboxylate anions has been monitored during potentiometric titration of a Typic Mesisol Peat at 25 °C. The analytical chemical calculations of total acid functional groups and of H+ dissociation equilibrium functions take the dissolution process into account. With 0.05 g of sample suspended in 20 mL of 0.1 N NaCl, the molarity of carboxylate anions in the external solution ranged from 4.3 × 10−4 M at 1 mL g−1 0.1 N NaOH, to 1.5 × 10−3 M at 6 mL g−1 0.1 N NaOH. The corresponding amounts of undissolved carboxyl groups were 5.2 × 10−4 and 1.0 × 10−4 mol g−1. Differential acid constants (KGA) for the undissolved carboxyls were 7.6 × 10−4 (σ 1.4 × 10−4) for αG  0.026 (0.026 – 0.60). A substantial increase in productivity was achieved by means of an automatic titrator and a microcomputer with spreadsheet software. Types of data production and processing that were previously labor intensive have now become much more practical. Key words: Organic soils, organic matter solubility, organic soil carboxyls, organic soil ion exchange, organic soil titration, pH dependent solubility

Description: Dinitrogen fixation with field bean (Phaseolus vulgaris L. 'GN1140') and pea (Pisum sativum L. 'Trapper') over the growing season under field conditions was determined using 15N isotope dilution methods. Levels of N2 fixation were low during the early part of the growing season for both bean and pea, and increased later in the growing season. At physiological maturity, GN1140 fixed over 91 kg N ha−1, contributing between 60 and 90% of the N in the bean plants. Pea fixed 117 kg N ha−1, which constituted a maximum of 57% of the pea plant N. More N was contained in the bean and pea pods than was fixed over the growing season. Key words: Bean (field), pea, Phaseolus vulgaris, Pisum sativum, 15N dilution

Description: Two years of field experiments and one growth chamber experiment were conducted to determine the role of VA mycorrhizae in P and Zn absorption as well as the P-Zn interaction. The pattern of development of vesicular-arbuscular mycorrhizae (VAM) in the early growth stages of maize (Zea mays L.) plants in southern Ontario, Canada was investigated. The field experiments consisted of three fertility treatments, recommended phosphorus (RP), high phosphorus (HP) and HP plus zinc (HPZn). The RP and HP soils were used in the growth chamber experiment and Zn fertilizer was added to both RP and HP soils to have treatments of RP, HP, RPZn and HPZn. Benomyl was used in the second year of the field experiment and in the growth chamber experiment to reduce mycorrhizal infection. In the field experiment in 1987, 20% of the roots were colonized by VAM in the RP soil just 3 wk after sowing. At 40 d after sowing, about 50% of roots were infected. The HP treatment significantly reduced VAM infection intensity compared to the RP treatment. The addition of 40 kg Zn ha−1 to the HP soil had little effect on mycorrhizal infection intensity in either field or growth chamber experiments. However, Zn fertilization increased mycorrhizal infection in the RP treatment in the growth chamber experiment. Treatment with benomyl significantly decreased mycorrhizal infection, shoot dry weight, P concentration and P inflow in the RP soil, suggesting the fungal relationship is important for P absorption in this soil. There was no conclusive evidence that mycorrhizae are important for P absorption in the HP soil. Although HP treatment decreased VAM infection greatly in both field and growth chamber experiments, it did not affect the absorption of Zn. Benomyl did not affect the shoot Zn concentration in either field or growth chamber experiments, suggesting that mycorrhizae are not important in the absorption of Zn on this soil. Key words: VAM infection development, maize, P, Zn, benomyl

Description: The soil macropore system was analyzed with the help of image analysis, comparing images from computed-tomography (CT) scanning with images obtained from thin sections. The images obtained with the two methods were analyzed with an image analyzer (IBAS 2000) for various pore characteristics. Macroporosity measurements obtained with CT scanning were comparable with those obtained with thin section. Computed-tomography scanning of soil cores which had been impregnated with styrene resin revealed a decreased level of soil macroporosity, in particular of planar macroporosity, as compared to nonimpregnated soil cores. CT scanning provided a useful method in characterizing a compacted soil layer. Through three-dimensional analysis of the CT scans, boundaries of compacted soil layers could be identified to the nearest 1 mm. The advantages of this method are that it is nondestructive, and fast, images can be made at 1-mm intervals, and it has the capability for three-dimensional images. However, resolution is limited to pores larger than 750 μm. Key words: Soil porosity, image analysis, thin sections, CT scanning

Description: Three soils from Prince Edward Island (a loam, a fine sandy loam, and a sandy loam) were tested under a laboratory rainfall simulator to examine the effects of frequency of freezing and thawing, winter rye cover, incorporated cereal residue, and subsoil compaction on runoff volume and sediment loss. Wooden soil boxes were subjected to simulated rain (i) at the end of a 10-d freezing period, and (ii) at the end of the 5th 24-h freezing period of a 10-d alternating freeze-thaw cycle (freeze/thaw). Where the soil was continuously frozen for 10 d, there was 178% greater sediment loss and 160% greater runoff than with daily freeze/thaw over the same period, but there was no difference in sediment concentration. Incorporated cereal residue decreased sediment loss to 50% and runoff to 77% of that from bare soil. Winter rye cover decreased sediment loss to 73% of that from bare soil. Simulated soil compaction caused a 45% increase in sediment loss. The loam soil showed 16.5% greater loss of fine sediment fractions

Description: A theoretical model of the effect of small amounts of water on the threshold shear velocity of sand grains has been tested in wind-tunnel studies. The model is based upon the capillary forces developed at interparticle contacts surrounded by isolated wedges of water. These forces (Fc) are inversely proportional to moisture tension (P) and directly proportional to the geometric properties of the contacts (G). Given[Formula: see text]the cohesion of the material decreases with increasing moisture tension and particle angularity. The incorporation of this capillary force model into Bagnold's threshold model for dry particles gave a general relation which indicated that the threshold shear velocity of wet particles increases as the square root of the inverse of moisture tension. Laboratory measurement of the soil moisture characteristic curve of any sand therefore provides a simple, though indirect indication, of its susceptibility to entrainment by wind under low moisture conditions. Most sands appear to be exceedingly resistant to wind erosion at moisture tensions below 10 MPa or at gravimetric moisture contents above approximately 0.2%. Further work is needed to determine if this potentially practical relationship also applies to more complex agricultural soils. Key words: Aeolian, moisture tension, threshold shear velocity

Description: The effects of pipeline construction on agricultural soil quality ratings were evaluated for the A and B horizons of Orthic Dark Brown Chernozem and Dark Brown Solonetz soils at three sites in Central Alberta 1 wk after construction. At each site, samples of the Ap horizon from the spoil side, trench, and work side portions of a pipeline right-of-way were compared to a sample of the Ap horizon from an adjacent area unaffected by pipeline construction. Spoil material below replaced topsoil on the trench was compared to a sample of an undisturbed B horizon. Regardless of soil type or land use, construction had no effect on the Ap horizon on the work side. This was due to optimum weather conditions during construction; low rainfall resulted in lack of soil rutting and minimal soil mixing. For both soil types under cultivation, construction increased soluble salt concentrations in the Ap horizons on the spoil side due to mixing of topsoil and spoil materials. There were few effects on the Ap horizon on the spoil side in pasture land, due to trench only topsoil stripping and easy spoil removal from a well-developed sod layer. Both the Ap and spoil from the trench in the Dark Brown Solonetz had increased salt concentrations, while there were few changes in the Dark Brown Chernozem. Mixing of topsoil and spoil material, and bringing salt-enriched material to the spoil surface are thought to be reponsible for the increase. For both soils and land uses, soil effects due to construction were reflected in the Ap horizon of the trench and spoil side by changes in pH, electrical conductivity, soluble salts and bulk density. Even with the increases in the soil properties monitored, the results indicated that regardless of soil type or land use, pipeline construction did not significantly affect the agricultural soil quality of the A and B horizons. Key words: Pipeline construction, solonetz, chernozem, work side, trench, spoil side

Description: The rate of hydrolysis of DCPD to OCP in solutions of different pH values, calcium concentrations and temperatures was studied. Rates of hydrolysis were very slow at pH 6.0, relatively rapid and similar at pH 7.0 and 8.0, much slower at 10 °C than at 20 or 30 °C, and only slightly increased by increasing calcium concentration. Key words: Dicalcium phosphate dihydrate, hydrolysis, pH, temperature, calcium concentration

Description: Determination of volumetric soil water content (θ) using time domain reflectometry (TDR) is well established. A commercially available instrument (IRAMS) (the IRAMS (Instrument for Reflectometry Analysis of Moisture in Soils) is a trademark registered by Foundation Instruments Inc. of Ottawa) is now available which incorporates computer software, thus providing direct readouts of θ. A field study of the operation of the IRAMS showed that it operates consistently and repeatedly. The IRAMS values were higher but related linearly to those obtained using a TDR cable tester and manual calculations of travel times. A linear correction of the IRAMS readings is proposed and possible causes are suggested for the observed deviations from expected values. Key words: Time domain, reflectometry, soil water content, field

Description: Six soils within and adjacent to two willow-ring depressions in hummocky moraine of the Dark Brown soil zone were monitored for seasonal changes in water table levels, redox status, and soil temperature to evaluate color citeria for identifying saturated and reduced soils of the Gleysolic order. Soils in the center of the willow-ring depressions had water table levels close to the soil surface, Ept values of  400 mV, and were covered by hydrophytic vegetation. Three of the depressional soils had matrix chromas of 1 in the Ae and/or Bt (Btj) horizons, with prominent rusty mottles, and met the color criteria of Humic Luvic Gleysols. The fourth depressional soil had matrix chromas of 1 in the Btj horizon, but no mottles were present within 50 cm of the soil surface, and met the color criteria of an Orthic Humic Gleysol. Two nondepressional soils, on lower slope positions just outside the willow-ring depressions, exhibited water table levels generally below 1.5 m, had an Ept of 〉 400 mV, and lacked hydrophytic vegetation. Of these, one soil had matrix chromas of 2 and prominent rusty mottles within 50 cm of the soil surface and met the color criteria of a Rego Humic Gleysol. The other had mottles of low chroma within 1 m of the surface and met the color criteria of a Gleyed Rego Dark Brown. Based on this study, the color criteria are adequate for depressional soils but are inadequate for the classification of soils beyond the willow-ring. Key words: Water table level, redox potential, soil temperature, morphological criteria, gleying

Description: Adaptation of conservation tillage systems for corn (Zea mays L.) production on the poorly drained soils of southwestern Ontario is limited by excess soil moisture early in the growing season. Ridge-tillage appears capable of reducing early-season soil moisture in these soils. A study was conducted to evaluate the effect of corn residue management in a ridge-tillage system in comparison with fall-mouldboard-plow and zero-tillage on early season soil moisture and temperature of a Brookston clay loam (Orthic Humic Gleysol). Ridge-tillage resulted in lower early-season soil moisture and higher temperatures within the seed zone than zero-tillage but they were comparable to those from mouldboard-plow tillage despite the fact that ridging caused a significant increase in surface residue. Chopping corn stalks in the fall contributed to lower early season moisture and higher temperature within the ridge. Key words: Till-plant, residue management, corn, soybean, Zea mays L., Glycine max L.

Description: Soil losses from agricultural land in the Lake Simcoe–Couchiching Basin between 1800 and 1981 are estimated with the universal soil loss equation (USLE). Existing methods and data are used to estimate and combine the six USLE factors with one exception. A new method that is consistent with the USLE slope definitions was developed and used to estimate the topographic factor. The results of the present study add to earlier erosion assessments because they describe the erosion hazard throughout the basin from the first days of forest clearance and agricultural settlement to the present. In particular, they indicate that soil loss rates on agricultural land have gone almost full circle from high to low and back to high rates in the past 130 yr. This result indicates the need to continue our search for permanent and more viable systems of land use. Key words: Soil erosion, potential soil loss, regional assessment

Description: The migration of the long-lived nuclide 129I in the biosphere may be changed if the nuclide passes through an organic soil (organic soils often occur in topographical depressions where groundwater generally enters the biosphere). The reactivity of I and, hence, its transportability may be altered in organic soils by processes in which microorganisms participate. The aim of this study, therefore, was to test for microbial participation in these processes. Twelve samples of nine organic soils, varying widely in degree of humification and in parent vegetation, were used in this study and were collected mainly on the Precambrian Shield of Ontario. Experiments were conducted using glucose, thymol, and γ radiation (60Co) to stimulate or suppress microbial activity in the soils. The presence of glucose generally increased I− removal from solution whereas thymol depressed removal. Gamma irradiation of the soils decreased I− removal from solution in all samples, but 100 kGy terminated I− removal in only one sample. If the removal of I− from solution after exposing the soils to 100 kGy of γ radiation is termed nonbiological, the biological removal of I− from solution exceeded the non-biological in all samples but one. The natural I content of the soils was directly related to both the biologically and the nonbiologically mediated processes of I− removal from solution. We conclude that microorganisms play an important role in the processes of I− removal from solution in organic soils of the Precambrian Shield of Ontario. Key words: Nuclear fuel waste, 129I, groundwater, microorganisms, enzymes, mobility

Description: A growth chamber experiment was conducted to assess the Mn and Cu nutrition of canola (Brassica napus L. 'Westar') and whether S nutrition has an impact on the Mn and Cu nutrition of this crop. Three rates of Mn (0, 25, and 50 mg kg−1), three of Cu (0, 5, and 10 mg kg−1) and three rates of S (10, 20, and 30 mg kg−1) were applied in all combinations to canola grown on an organic soil. High Mn:Cu ratios (〉 15) led to Cu deficiency, which, at 10 and 20 mg S kg−1, was alleviated by Cu additions. The Mn-induced Cu deficiency was self-corrected at the 30 mg S kg−1 application rate. This was attributed to the alleviation of a Cu × Mo antagonistic effect through addition of S. Key words: Canola, available soil Mn and Cu, Mn × Cu × S interaction, S × Mo interaction, Cu × Mo interaction

Description: Vertical saturated hydraulic conductivity, as an important soil characteristic, should be part of the information displayed on soil survey maps. As rigorous measurement techniques are relatively slow and cumbersome, a rapid procedure for estimating vertical saturated hydraulic conductivity of soils using soil morphology was tested for Prairie conditions. Morphological estimates of vertical saturated hydraulic conductivity were compared to field measurements using an air entry permeameter for 36 sites representing 25 soil series. Eighty-three percent of the estimated values were within one saturated hydraulic conductivity class of the mean measured value. It was concluded that morphological observations are sufficiently accurate to allow field characterization of pedons. In Alberta, in Chernozemic areas, management procedures do not appear to modify strongly the saturated hydraulic conductivity. This in turn allows useful predictions of saturated hydraulic conductivity to be related to soil series concepts and therefore allows extrapolation to manageable tracts of land using map unit concepts. Key words: Saturated hydraulic conductivity, soil morphology, Alberta, estimating

Description: A highly weathered, clayey soil was sampled 14 yr after a Pinus radiata stand was broadcast fertilized with 0, 50 and 200 kg P ha−1 as ordinary superphosphate. Incremental loadings of oxalate and citrate anions from 10 to 100 μmol of anion g−1 soil were evaluated for increased soluble, reactive P (SRP) and soluble, nonreactive (SNP) P. Sorption isotherms were compared to evaluate the effect of the previous fertilization on P sorption by the soil material sampled, and also to measure SNP displacement by orthophosphate-P. A portion of the SNP pool was more readily released than SRP and orthophosphate displaced a significant amount of SNP. After 14 yr the effect of fertilization was still obvious in the sampled soil material. Much of the organic anion-soluble P was in the SRP form. Key words: Citrate, organic P, orthophosphate, oxalate, Pinus radiata, residual P

Description: Greenhouse and field experiments were conducted to evaluate the effect of inoculation with a phosphate-solubilizing isolate of Penicillium bilaji on the yield and phosphate uptake by canola (Brassica napus L.). Under greenhouse conditions, P. bilaji inoculation did not affect canola pod or straw dry matter production, but did increase straw and pod P concentrations resulting from increased P uptake over uninoculated treatments. Addition of P at 20 mg kg−1 soil as Florida rock phosphate plus inoculation with P. bilaji resulted in P uptake by canola nearly equivalent to that resulting from the addition of monoammonium phosphate (MAP) alone at the same rate of P. Addition of Florida rock phosphate alone had much less effect on plant P uptake. Addition of P. bilaji generally increased dry matter yields and P uptake by canola in two field sites. Penicillium bilaji appears to be able to increase the uptake of P from sources unavailable for plant uptake; P uptake by control plants inoculated with P. bilaji absorbed as much P as that absorbed by uninoculated plants receiving MAP. Key words: Penicillium bilaji, Brassica napus, fertilizer efficiency, rock phosphate, monoammonium phosphate

Description: Maize (Zea mays L.) was grown outdoors hydroponically and in soil to compare yields in the two systems and to determine the extent to which soil temperature and plant nutrition limit yield of soil-grown plants. The hydroponic system consisted of 22.5-L plastic pails filled with "Turface" to which nutrient solution was added at least twice daily. In all 3 yr dry-matter accumulation throughout the growing season was greater on the hydroponic system than in well-fertilized, irrigated sandy-loam soil when planting pattern and density were the same. Maximum aboveground dry matter and grain dry matter on the hydroponic system were 25.8 and 12.2 Mg ha−1, respectively. It is apparent that there is a soil-based constraint that limits aboveground dry-matter production to 75–85% of the potential with the aboveground environment in the region. Grain yield appears to be limited to a lesser extent. To determine the effect of root-medium temperature, growth in pails buried in the soil was compared to that in soil and in pails placed on the soil surface. Although the temperature of the buried pails was consistently lower than that in the aboveground pails and in the soil, dry matter accumulation was similar to that in the aboveground pails indicating that soil temperature was not a cause of the lower yield of the soil-grown plants. There was no evidence that plants growing on the highly fertilized soil were nutrient limited at any growth stage. Other studies have indicated that transient water stress on soil-grown plants will not explain the difference in growth on the two systems. Key words: Maize, hydroponics, soil limitations, soil temperature, nutrition

Description: not available

Description: Four minerals, thuringite, hornblende, biotite and magnetite, in which Fe2+ content represents 91, 83, 78 and 33% of the total Fe content, respectively, were treated with 0 plasma to evaluate the effect of this oxidizing agent on the valence state of the iron. X-ray diffraction analysis and Mössbauer spectroscopy indicated that these minerals were not affected by the treatment within the detection limits of the instruments. The method is thereby acceptable for the decomposition of organic matter in soils; the dry environment inherent in the 0 plasma treatment cannot transport cations susceptible to substitution for those present in the interlayer space. Key words: XRD patterns, Mössbauer spectra, hornblende, thuringite, biotite, magnetite

Description: Sampling of soil 9 yr after a high-rate urea application showed a significant increase in total N content and a decrease of the C:N ratio in the Bhf horizon. This change corresponded to a gain of 368 kg of N ha−1 in the 3-cm thick, sampled portion of this horizon. The changes in N status were accompanied by a general darkening of the soil. It is assumed that both fertilizer N and indigenous forest floor N were translocated to the B Horizon after the treatment. Key words: Forest fertilization, nitrogen, nutrient cycling, urea

Description: Average percentages of soil material 〉 0.84 mm diameter estimated from wind erodibility groups (WEG) are commonly employed in the appraisal of the wind erodibility of soils. Soil samples taken after seeding from four areas of Alberta were sieved on a Modified Rapid Rotary Sieve. Agreement between the sieving data and estimates of material 〉 0.84 mm made using the WEG was poor (r = 0.33). Samples from soil textural groups generally had twice as much material 〉 0.84 mm than predicted by the WEG. Using 350 soil samples the relationship between soil aggregates 〉 0.84 mm and (1) field estimated soil properties, and (2) soil management was investigated by multiple regression analysis. Aggregation was strongly dependent on soil texture (r = 0.67) with coarser-textured soils having fewer aggregates 〉 0.84 mm and thereby being more erodible. Increasing quantities of soil carbonates (up to 10%) increased soil erodibility. Preseeding tillage decreased erodibility. Conversely, postseeding packing operations increased erodibility except when a rodweeder was used. Type of seeding implement, rotations, and type of crop seeded (oilseeds versus grains) had no statistically significant effect on aggregation. The coefficient of multiple determination (R2) for the final model was 0.61. Results were corroborated by previous experimental findings and confirmed that the WEG are not accurate for Canadian Prairie soils. The study demonstrated that although soil texture and carbonate content played an important role, tillage had a considerable effect on soil erodibility. Key words: Wind erosion, soil erodibility, WEG, aggregation, soil management

Description: The effects of three forms of nitrogen on flue-cured tobacco production were observed for 5 yr. Significant effects were obtained for yield, quality, gross return and total nitrogen. No significant differences were found for maturity, total alkaloids or reducing sugars. The data showed that the use of a fertilizer containing 75% nitrogen in the form of [Formula: see text] or urea and 25% as [Formula: see text] produces a tobacco with acceptable agronomic and chemical characteristics. Key words: Flue-cured tobacco, nitrogen forms, nitrogen sources, nitrate [Formula: see text], ammonium [Formula: see text], urea

Description: During 5 yr, the seasonal distribution of N, P, K, Ca, and Mg and changes in soil pH in soil fertilized for flue-cured tobacco were investigated. Soil samples were taken periodically during the growing season at three depths. There was no movement of N, P, K, Ca, or Mg below 20 cm from the point of fertilizer application when the total rainfall during the 7 wk after transplanting tobacco was less than 180 mm and was fairly evenly distributed in amounts of 25 mm or less. When showers were concentrated over a shorter period and were more abundant, there was some leaching of N, K, Ca, and Mg. Rainfall conditions which were favorable for leaching of N had no influence on the movement of P. Key words: Flue-cured tobacco, nitrogen (NO3), phosphorus, potassium, calcium, magnesium, pH.

Description: This study was conducted to determine which of eight different extractants best described the K-supplying capacities of nine southern Ontario soils. The total amount of K extracted by eight crops of alfalfa grown in the greenhouse was related to soil K by regression techniques. The following procedures extracted increasingly higher average amounts of soil K: water; electro-ultrafiltration (EUF) at 20 °C (EUF-K-20) (37 μg K g−1); EUF at 80 °C (EUF-K-80) (83 μg K g−1); 2M NaCl (89 μg K g−1); 1M NH4OAc (131 μg K g−1); 0.1 M HNO3 (163 μg K g−1); seven sequential 7-min extractions with boiling 1 M HNO3 (Mactotal) (940 μg K g−1); and 0.2 M sodium tetra-phenyl boron (NaTPhB) (3248 μg K g−1). Of the eight extractants tested, the amount of K removed by EUF was the most closely associated to total K uptake; a multiple regression model with the logarithm of EUF-K-20 and the logarithm of EUF-K-80 as independent variables explained 97% of the total variation in K uptake. The K extracted by 2 M NaCl and by 0.1 M HNO3 also explained more variation in total K uptake (r2 = 0.86, and 0.92, respectively) than did 1 M NH4OAc (r2 = 0.61), which is currently used in the Ontario soil test program. The other extractants did not offer an improvement over NH4OAc, with the exception of the most soluble fraction of Mactotal (StepK). Extraction of soil K with electro-ultrafiltration may offer a more precise estimation of the K supplying capacities of southern Ontario soils than the currently used extractant. Key words: Electro-ultrafiltration, nonexchangeable K, ammonium acetate, soil test

Description: The adsorption and desorption of 14C-fluridone (1-methyl-3-phenyl-5-[3-(trifluoromethyl) phenyl]-4(1 H)-pyridinone) were investigated at 1:1 and 1:5 soil:water ratios at solution concentrations ranging from 11.9 to 1190 ng mL−1, simulating herbicide concentrations under field conditions from recommended rates of application. Freundlich adsorption isotherms were developed for a sandy loam, sandy clay loam and silty clay soil. At 1:1 soil:water ratio, as initial herbicide concentration in the system increased 20 fold, the soil solution concentration at adsorption equilibrium increased by 86, 87 and 76 times for the sandy loam, silty clay and sandy clay loam, respectively. The mean equilibrium concentrations at adsorption were 1.8, 9.5 and 3.4 times higher than those at desorption for the sandy loam, silty clay and sandy clay loam, respectively. For each soil type, the adsorption coefficient (K) values were higher at 1:1 compared to 1:5 soil:water ratio. Slope constants (1/n) for the isotherms indicated that the intensity of adsorption was affected by soil:water ratio. Key words: Herbicide, fluridone, adsorption, desorption, soil:solution ratio, isotherm

Description: Field experiments were conducted in Prince Edward Island (P.E.I.) to determine the effects of Zn (zinc sulfate) applied to the soil; applied as a foliar spray; and the effects of chelated Zn applied as a foliar spray on Zn concentration of alfalfa (Medicago sativa L.), ryegrass (Lolium multiflorum Lam.), wheat (Triticum aestivum L.), and barley (Hordeum vulgare L.). Plant tissue Zn levels as low as 12 mg kg−1 in forages, 14 mg kg−1 in cereal boot stage tissue and 19 mg kg−1 in cereal grain were not related to Zn deficiency. Tissue Zn levels as high as 123 mg kg−1 in barley boot stage tissue and 153 mg kg−1 in alfalfa did not result in yield reduction or any Zn toxicity symptoms. Cereal and forage yields were not affected by Zn treatments. In most cases, soil and foliar Zn applications were effective in increasing the Zn concentration in forages and cereals. Should a Zn deficiency be suspected (either from the crop or animal nutrition viewpoint) Zn could be applied to the soil at 20 kg ha−1 or as a foliar spray at 0.5 to 1.0 kg ha−1 to overcome the problem in this region (and in other areas with similar soil and climatic conditions). Key words: Plant Zn, soil and foliar applied Zn, Zn chelate and zinc sulfate, podzol soils

Description: Effects of environmental variables on denitrification in acid (pH 4.0–5.5), infertile soils of lowbush blueberry (Vaccinium angustifolium Ait.) stands were investigated under laboratory conditions. All soils produced N2O when nitrate was added and samples were waterlogged and incubated for 2 d at temperatures of 20 °C or greater. No N2O production occurred at temperatures of 15 °C or lower. Nitrous oxide was the main gas evolved at the natural pH levels of these soils. Mercuric chloride inhibited nitrous oxide evolution. Raising soil pH resulted in increased rates of denitrification, and in more conversion of nitrous oxide to dinitrogen. Soil taken from a site that had been fertilized repeatedly exhibited higher rates of N2O evolution than did soil from a site that had never been fertilized. N2O production from waterlogged samples without added nitrate was positively correlated with percent organic matter and nitrate concentration of soils at the time of sampling. In a field experiment, more N2O was produced by samples from fertilized plots than by those from unfertilized plots, but absolute values from both types of plots were low. Key words: Nitrous oxide, pH, nitrate, moisture

Description: The half-life of metribuzin applied to a bare soil surface was calculated to be 3–7 d over four field tests. An artificial cover erected after application or a shallow incorporation increased the half-life of metribuzin approximately 2.5- to 3-fold. Leaching out of the 0- to 5-cm-deep sampling zone could not account for loss of metribuzin. It was concluded that metribuzin persistence may be affected by volatility and/or photodecomposition losses under field conditions, especially shortly after application. Key words: Metribuzin half-life, volatility, photodecomposition, row width

Description: According to Emerson's model of the soil aggregate, a large soure of physical weakness exists at the surface of sand particles within the aggregate, particularly when wet. The aim of this study was to simulate sand particles with glass beads and to test the hypothesis that a bed of glass beads can resist large compressive forces in water when a polymer is bonded to the bead surfaces using chemicals and conditions that produce hydrolytically stable, covalent bonding. Because carboxyl and amine functional groups can react to form the amide bond and silanes can bond to a silanol surface (e.g., sand or glass), polyacrylic acid (PAA: FW ≈ 50 000), amines, and silanes were used to test the hypothesis for glass beads (53-μm mean diameter). The pressure at which the bed surface of the glass beads (when water-saturated) was penetrated with a flat probe (radius = 1.37 mm) served as an index of strength imparted by various chemicals when these were introduced into the system individually and in various combinations. A dramatic increase in the strength of the bed surface occurred only when all the theoretical requirements were met for both covalent bonding between the polymer and the silane and silanol coupling between the silane and the glass surface. We conclude that the hypothesis is confirmed for a simple system of glass beads and that large increases in the efficiency of soil conditioners may be potentially realized in soil aggregates if the weak links between inorganic particulates (sand, silt, and clay particles) and organic polymeric materials (natural or synthetic) are augmented with, or replaced by, strong and water-resistant links. Key words: Soil structure, soil conditioners, polymers, coupling agents, soil aggregates

Description: Ligands such as complexing organic acids play a significant role in the dynamics of release of plant nutrients in soils. The objective of this work was to study the dynamics of slowly exchangeable K and Mg release from 12 Quebec soils by ten successive extractions with 5 × 10−4 M citric acid, over a period of 1800 h, and by a single extraction with boiling 1.0 M HNO3. All soils were characterized by a mixed clay mineralogical composition with swelling minerals as major components. The kinetics of slowly exchangeable K and Mg cumulative release were described using two forms of the Elovich, the parabolic diffusion, power function, and first and zero order equations. Comparisons of r and SE values showed that the extended form of the Elovich equation best fitted K and Mg release to citric acid. The amount and rate of K release by the citric acid procedure were highly correlated to the amounts of slowly exchangeable HNO3-extractable and rapidly exchangeable NH4OAc-extractable K and to the coarse clay content of the soils. The amount of Mg released to citric acid was proportional to the unbuffered cation exchange capacity of the soils. The results indicated that the citric acid procedure was a time saving alternative to the study of the kinetics of slowly exchangeable K and Mg release from soils. Key words: Nonexchangeable K, citric acid, nonexchangeable Mg, podzolic soils, kinetics

Description: Seven major parent materials from the Athabasca oil sands area were investigated for detailed mineralogy and chemistry. The clay mineral species identified and quantified were mica, smectite, kaolinite, chlorite and vermiculite. The fine (50–250 μm) sand mineralogical suite was dominated by quartz, with lesser amounts of Na-, K-, and Ca-feldspars, and minor amounts of individual heavy mineral species. Electronoptical examination indicated that the feldspar grains in the parent materials have undergone extensive preglacial weathering. Regional mean levels of all analyzed elements (Al, Ca, Fe, K, Mg, Na, Mn, P, Cr, Co, Cu, Ni, Pb, Sr, V, and Zn), with the exception of Ca, are related to textural variability. The variability of Ca levels within the study area is related to the occurrence of calcareous parent materials. The highest levels of all major, minor, and trace elements were associated with either the Legend unit derived largely from Cretaceous bedrock or with the modern sediments of the Athabasca delta. Key words: Soil parent materials, clay mineralogy, trace element levels, sand mineralogy, feldspar morphology

Description: Acid rain and N fertilizers both contribute to soil acidity, but no method has been available to compare their relative impacts. A simple model (SOLACID) is presented to assess quantitatively the acidifying effects of precipitation and N fertilizers on agricultural soils. Acid rain has been treated as a dilute solution of NH4NO3, (NH4)2SO4 and associated acids. Soil and plant pathways are considered for [Formula: see text], [Formula: see text]and [Formula: see text] by way of leaching, gaseous losses from microbial reduction, plant uptake and removal, and organic immobilization and mineralization. Leaching of [Formula: see text] was the factor to which the model was most sensitive. A relationship between base saturation and base cation leaching is described. Field data reported from 21 treatments at six experimental sites were used to test the model, which provided reliable estimates of final pH (r2 = 0.92**) and of changes in base saturation (r2 = 0.86**). Compared with previously published methods, the model provided the best estimates of lime requirements as computed from field measurements (r2 = 0.87**). Key words: Ammonia, sulfate, leaching, nitrification

Description: Organic matter, Fe and Al were determined in dithionite-citrate-bicarbonate (d), oxalate (o), pyrophosphate (p) and tetraborate (t) extracts from Quebec Podzolic B horizons in order to evaluate the ability of these reagents to extract the organo-metallic complexes as well as inorganic oxides and hydroxides, and to verify the appropriateness of soil classification criteria. Dithionite solubilized most of the Fe whereas oxalate extracted most of the Al compounds; the ability of the same reagents to extract Al and Fe, respectively, was directly related to the amount of organo-metallic complexes. Pyrophosphate extracted not only complexes but also inorganic compounds while tetraborate extracted mainly complexes. Organic matter extraction by dithionite, oxalate and tetraborate was enhanced by a high fulvic acid content; it was highest in the Bh and lowest in the Bf horizons. Organic matter, Fe and Al extraction by tetraborate was reduced in the presence of a large Fe-inorganic compounds content. These results indicated that extracting ability of the reagents depends on the nature of the B horizons, except for Fe extraction by dithionite and Al extraction by oxalate. Consequently, Fe and Al extraction by pyrophosphate or tetraborate is not appropriate for classification purposes. Differentiation of Bh horizons from other Podzolic B horizons was possible by using the total organic C to Fed + Alo ratio, because the ratio was 〉 3 for Bh horizons and

Description: Net mineralization of sulfur (S) and nitrogen (N) and nitrification in an F(Oe) horizon were examined over a 16-wk period (May to September) with (a) buried bags, (b) lysimeters and (c) closed flasks at 10, 20 or 30 °C. The amount of [Formula: see text] plus [Formula: see text] extracted from soil held at 33 kPa tension over 16 wk, when extrapolated to the mass of soil in the field, was 30 kg ha−1 N and 9 kg ha−1[Formula: see text] at constant 20 °C in the flasks, and 33 kg ha−1 N and 4 kg ha−1[Formula: see text] in buried bags (mean daily temperature 15.2 °C). On the basis of lysimeter data there was a net release of only 8 kg ha−1 N and a net retention of 3 kg ha−1[Formula: see text] under field conditions, with fluctuating temperature and moisture and actively absorbing roots. Nitrate recovered from the three types of experiment was equivalent to 18, 36, and 4 kg ha−1 N, respectively. Mineralization appeared to be particularly sensitive to temporal changes in average daily temperatures in the field. The late-summer peak in mean daily forest-floor temperature triggered a shift from net mineralization to net immobilization of N. Key words: Soil temperature, forest floor, sulfate, ammonium, nitrate

Description: This study was undertaken to determine the effect of tillage and fertilizer on soil structure in fields under corn production in Quebec. Three types of tillage (moldboard, chisel and zero-till) and two types of fertilizer (manure and inorganic fertilizer) were applied yearly for 6 yr on a clay and a sandy loam soil. Macroaggregation was obtained after dry and wet sieving and microaggregation after sonification. Soil geometric mean diameter and aggregate stability were increased after manure applications and still further by zero-till. The amount of aggregates in each size fraction was affected differently by the fertilizer and tillage treatments. The fraction of organic matter binding the  250-μm units played a greater role in soil aggregation than total soil organic matter content. Key words: Aggregation, manure, organic matter, soil pH, reduced tillage

Description: In a previous study, the mean weight diameter of water-stable aggregates of a clay soil was increased by up to 50% after two growing seasons under barley and alfalfa compared to fallow or corn. The objective of the present study was to determine whether rapid changes in water-stable aggregation under different crops were related to changes in soil carbohydrate content. Compared to fallow or corn, cropping to barley and alfalfa for 2 yr did not affect the soil C and N contents but significantly increased carbohydrate content by up to 25%. The correlation (r = 0.63, P = 0.001) between aggregate mean weight diameter and carbohydrate content suggested that at least part of the change in water-stable aggregation was related to carbohydrates. Treatment of the soil with sodium periodate prior to wet-sieving confirmed the partial involvement of carbohydrates in the stabilization of aggregates by crops. The remainder of the crop effect on aggregation was removed by sodium tetraborate which suggests that more-humified, though ill-defined, organic substances were also involved. Key words: Carbohydrates, aggregate stability, barley, alfalfa, corn, periodate

Description: Relationships between bulk density (BD) and loss on ignition (LOI) for forest floor, shallow mineral soil (0–25 cm depth), and peat were described by exponential functions. The data were collected in forests across the North Central US. For forest floor, predicted BD, BDp = 0.073 + 2.369 exp(− 0.073 LOI), R2 = 0.75, (BDp in Mg m−3 and LOI in percent dry wt), and for surface mineral soil, BDp = 0.669 + 0.941 exp(− 0.240 LOI), R2 = 0.95. For peat, BDp = 0.043X + 4.258 exp(− 0.047 LOI), R2 = 0.89, where X is a dummy variable with a value of 0 for surface peat (0–25 cm depth) and 1 for subsurface peat (25–175 cm). Key words: Bulk density, loss-on-ignition

Description: Soft white wheat was grown on a clay loam soil for 2 yr with a wide range of soil nitrate (SN) (70–280 kg ha−1) and fertilizer nitrogen (FN) (0–400 kg ha−1) treatments The field experiment was designed to determine the slopes of the yield response curves to FN (δy/δFN) and to SN (δy/δSN), to determine how the ratio of (δy/δSN)/(δy/δFN), or marginal rate of substitution, is affected by FN, SN, and depth of SN and to determine if refinements to the current FN recommendations for irrigated soft white wheat are required. The δy/δFN values in both years were high at low levels of FN and SN but declined as FN and SN increased. The δy/δSN in 1985 when most SN was situated in the 0- to 30-cm soil layer was initially high (26.0) at low levels of SN but rapidly declined as SN increased. The δy/δSN in 1986, when most SN was situated in the 30- to 120-cm soil layer, was intially low (6.0) but increased as SN increased. Since the δy/δFN and δy/δSN values were sensitive to changes in FN and SN as well as the depth of SN the MRS values were variable in both years. The δy/δSN increased as SN increased when SN was situated in the 30- to 120-cm soil layer so there was only a small effect of depth of SN on FN recommendations. The FN at maximum profit occurred at a greater combined amount of SN and FN for the higher SN levels in both years. This preliminary field study suggested that fertilizer N recommendations could be improved by using an equation for predicting FN that considers a variable yield response to FN and SN, an interactive effect of FN and SN on yield, and an effect of depth of SN on yield. Key words: Soil nitrate, fertilizer nitrogen, soft white wheat, soil test N