bluuebunny/crossref_metadata_2025 huggingface dataset:
ATTEMPTS TO IMPROVE SOLID STATE 13C NMR SPECTRA OF WHOLE MINERAL SOILS
Authors: ARSHAD M. A. , RIPMEESTER J. A. , SCHNITZER M.
Published: March 2010

This study describes a number of different preparation techniques for recording solid state 13C NMR spectra of whole mineral soils. Removal of paramagnetic Fe3+ improves the quality of 13C NMR spectra of whole soils and of particle size fractions. The C:Fe ratio appears to be an important indicator for obtaining satisfactory 13C NMR spectra of whole soils and fractions separated from them. If the C:Fe ratio is >> 1, the quality of the spectrum will be good; if the ratio is > 1, a reasonable spectrum will be obtained, but if the ratio is < 1, the spectrum will be poor. Organic-matter-rich soil and particle size fractions separated by a flotation technique produce well-defined 13C NMR spectra, typical of humic materials. Reduction of C-enriched fractions with sodium dithionite and stannous chloride improves the spectral resolution. The data presented herein show that satisfactory solid state 13C NMR spectra can be run on untreated soil particle size fractions, non-magnetic portions of whole soils, and fractions enriched in soil organic matter by flotation, especially after chemical reduction. Key words: 13C NMR spectroscopy, paramagnetic mineral separation
EFFECTS OF LIME AND GYPSUM ON YIELDS AND NUTRITION OF TWO CULTIVARS OF BRUSSELS SPROUTS
Authors: CUTCLIFFE J. A.
Published: March 2010

Field experiments were carried out at different locations in Prince Edward Island each year for 3 consecutive years to determine the effects of calcific limestone, dolomitic limestone, and gypsum on yields and nutrition of two cultivars of Brussels sprouts (Brassica oleracea var. gemmifera). The soils at the sites selected had initial pH levels of 4.9–5.7. Preplant, broadcast applications of gypsum at 5.5 t ha−1 resulted in yield increases of about 30% at all locations. Analysis of leaf tissue collected when the sprouts began to form indicated that Ca, Mg, Mn and Zn concentrations of approximately 1.4–2.6%, 0.25–0.32%, 88–274 μg g−1 and 26–35 μg g−1, respectively, are within the sufficiency range. The incidence of internal browning was not affected by either the lime or gypsum treatments at the two locations where this disorder occurred. Key words: Lime, gypsum, yield, leaf tissue nutrient concentration, internal browning, Brussels sprouts
EFFECTS OF CROPPING ON MACRO-AGGREGATION OF A MARINE CLAY SOIL
Authors: ANGERS D. A. , MEHUYS G. R.
Published: March 2010

Field and growth chamber experiments were conducted to evaluate the short-term effects of selected crops on macro-aggregation of a Kamouraska clay soil. Under field conditions, the growth of barley (Hordeum vulgare L.) and alfalfa (Medicago sativa L.) for up to 2 yr resulted in increased macro-aggregate size and stability compared to a fallow control and to initial conditions. Under these two crops, the proportion of water-stable aggregates of the 2- to 6-mm fraction increased from 25% in May 1986 to 40% in September 1987 at the expense of the 0.25- to 1.0-mm fraction which decreased from 37% to 19% over the same period. Macro-aggregation after 2 yr was not different in corn (Zea mays L.) and fallow control. Seasonal variations in aggregate stability were significant but small and less important than the effects of cropping treatments. Results of the growth chamber experiment agreed with those obtained under field conditions suggesting that controlled environment experiments can be used to model cropping effects on the aggregation of this soil. Key words: Aggregation, soil structure, clay soil, corn, barley, alfalfa
THE EFFECTS OF SLOPE POSITION AND CROPPING SEQUENCE ON SOIL PHYSICAL PROPERTIES IN PRINCE EDWARD ISLAND
Authors: EDWARDS LINNELL M.
Published: March 2010

Soil physical characteristics were examined at depth intervals of 0–15 and 15–30 cm over three slope positions (top-, mid-, and bottom-slope) for three cropping sequences (hay-barley, cereals-barley, and potato-barley). Hydraulic conductivity was a significant (P ≤ 0.05) 40–50% greater at top-slope than mid- or bottom-slope, and aggregate stability percentage was a significant 6–7% greater at bottom-slope than mid- or top-slope when the soil aggregates were pretreated by freezing and thawing (freeze/thaw). Under the potato-barley sequence shear strength, penetration resistance and bulk density were significantly greater than any other sequence by up to 29, 21 and 15%, respectively; while hydraulic conductivity and maximum penetration depth were, respectively, up to 65 and 28% lower than any other sequences. Under hay-barley, hydraulic conductivity and aggregate stability (freeze/thaw) were, respectively, up to a significant 82 and 10% greater than any other sequence. There was, therefore, significantly more compaction under potato-barley and more soil physical enhancement under hay-barley than other respective sequences. Disease severity was up to 55% greater at bottom-slope than at mid-slope or top-slope for Birka barley, which also showed a significant linear decrease (r2 = 0.89) in yield with increasing shear strength. Yield of Perth barley showed a significant linear increase with increasing soil depth (r2 = 0.92) and clay-silt content (r2 = 0.78). Key words: Aggregate stability (freeze/thaw), crop rotation, penetration resistance, shear strength, barley, potatoes, hay
ADMIXING ORGANIC OVERLAYS AND MINERAL SUBLAYERS OF SHALLOW PEAT SOILS FOR IMPROVING SOIL PRODUCTIVITY
Authors: LÉVESQUE M. , MATHUR S. P. , DINEL H.
Published: March 2010

This growth room and greenhouse study with 13 subsoils and organic overlays was aimed at developing crop choices and strategies for continued land use of shallow organic soils and at refining the criteria used for assessing the long-term agricultural capability of deep organic soils. Soil materials from four geoprovinces in Canada were mixed in various volume/volume proportions to provide 25 different soil media. Root, leafy vegetable and grass crops were grown on each soil. All pots were adequately fertilized and watered. A gyttja-layer of marine-fecal origin that acidifies rapidly on exposure to air was rendered productive on admixing with an adjacent layer rich in Ca-containing molluscan-shells. Generally, all clay, sand and silt sublayers improved on admixing with organic overlays. At the same time, the organic overlays did not become markedly less productive on being mixed with mineral sublayers in 1:1 volume proportions except when the sublayers were clays. Yields decreased when clays formed more than 25% of the mixture by volume, particularly when the crops grown were vegetables. Key words: Peat soils, soil management, soil productivity
COMPARISON OF BARLEY GROWTH IN NATURALLY AND ARTIFICIALLY SALINIZED SOILS
Authors: JANZEN H. H.
Published: March 2010

An experiment was conducted under controlled conditions to compare the growth of barley in naturally and artificially salinized soils. In two Chernozem soils, a Whitney clay loam and a Cavendish sandy loam, the decline in barley yield per unit increase in salinity was the same in naturally and artificially salinized treatments. These findings suggest that artificially salinized soils accurately simulate the effects of naturally saline soils in their effect on barley growth. The results further substantiate previous findings that growth response to salinity appears to be related to the availability of calcium in the soil. Key words: Calcium, salinity, Chernozem
DRYING OF FROZEN SOILS
Authors: JONG E. de , KACHANOSKI R. G.
Published: March 2010

Drying rates of frozen aggregates varied from 2 mg cm−2 h−1 to zero, mainly in response to decreasing water content. Temperature, windspeed and dryness of the air controlled the maximum rate of drying. The variation in drying rate with water content was explained by the balance between ice and water in the pores. Key words: Frozen soils, evaporation, environmental factors
ESTIMATING VERTICAL SATURATED HYDRAULIC CONDUCTIVITY FROM SOIL MORPHOLOGY IN ALBERTA
Authors: COEN G. M. , Wang C.
Published: March 2010

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
CONVERSION OF ELECTROMAGNETIC INDUCTANCE READINGS TO SATURATED PASTE EXTRACT VALUES IN SOILS FOR DIFFERENT TEMPERATURE, TEXTURE, AND MOISTURE CONDITIONS
Authors: McKENZIE R. C. , CHOMISTEK W. , CLARK N. F.
Published: March 2010

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
THE INFLUENCE OF WATER TABLE LEVELS ON METHANE AND CARBON DIOXIDE EMISSIONS FROM PEATLAND SOILS
Authors: MOORE T. R. , KNOWLES R.
Published: March 2010

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
EFFECT OF CARBON CONSTITUENTS IN MANURE ON DENITRIFICATION IN SOIL
Authors: PAUL J. W. , BEAUCHAMP E. G.
Published: March 2010

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
THE EFFECT OF SULPHUR ON MANGANESE AND COPPER NUTRITION OF CANOLA
Authors: KARAMANOS R. E. , HODGE N. , STEWART J. W. B.
Published: March 2010

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
MICROBIAL PARTICIPATION IN IODIDE REMOVAL FROM SOLUTION BY ORGANIC SOILS
Authors: KOCH J. T. , RACHAR D. B. , KAY B. D.
Published: March 2010

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
NINE FORAGES AND THE AGGREGATION OF A CLAY LOAM SOIL
Authors: STONE J. A. , BUTTERY B. R.
Published: March 2010

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
BULK DENSITY EQUATIONS FOR SOUTHERN ALASKA SOILS
Authors: ALEXANDER E. B.
Published: March 2010

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 < 1 g kg−1); (2) organic soils; or (3) disturbed or compacted soils. Coarse fragments (particles > 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
THE EFFECT OF SPRING AND FALL APPLICATION OF N ON YIELD AND QUALITY OF BARLEY (Hordeum vulgare L.) AND RAPESEED (Brassica campestris L.)
Authors: NUTTALL W. F. , BOWREN K. E. , DAWLEY W. K. , MALHI S. S.
Published: March 2010

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
USE OF A SOIL CHRONOSEQUENCE TO CALIBRATE SOXHLET GENERATED CHRONOFUNCTIONS
Authors: SINGLETON G. A. , LAVKULICH L. M.
Published: March 2010

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
EXTRACTION OF POTASSIUM AND SODIUM FROM ACID AND CALCAREOUS SOILS WITH THE KELOWNA MULTIPLE ELEMENT EXTRACTANT
Authors: LIEROP W. VAN , GOUGH N. A.
Published: March 2010

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
EVAPORITE MINERALOGY, AND SOIL SOLUTION AND GROUNDWATER CHEMISTRY OF A SALINE SEEP FROM SOUTHERN ALBERTA
Authors: MILLER J. J. , PAWLUK S. , BEKE G. J.
Published: March 2010

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
COMPARISON OF PARTITION COEFFICIENTS FOR 54Mn AND SOIL-EXTRACTABLE Mn, INCLUDING RELATIONSHIP TO PLANT UPTAKE
Authors: SHEPPARD S. C. , EVENDEN W. G.
Published: March 2010

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 < 0.001) between the Kd for 54Mn and plant Mn concentrations confirmed that this relationship is useful for modelling applications. The sorption of 54Mn was the best single measurement to predict the plant-availability of soil Mn, determined in a previous study. However, in concert with pH and clay content data, the DTPA + NaHCO3-extractable Mn gave the best correlation to plant uptake. Key words: Kd, frequency distribution, radionuclides, soil test, isotopic exchange
EFFECT OF EARLY GROWING SEASON MOISTURE STRESS ON BARLEY UTILIZATION OF BROADCAST-INCORPORATED AND DEEP-BANDED UREA
Authors: HARTMAN M. D. , NYBORG M.
Published: March 2010

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
RESIDUAL EFFECTS OF COMPACTION AND TILLAGE ON THE SOIL PROFILE CHARACTERISTICS OF A CLAY-TEXTURED SOIL
Authors: DUVAL J. , MEHUYS G. R. , RAGHAVAN G. S. V. , GAMEDA S.
Published: March 2010

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
STABILITY OF FE2+-BEARING MINERALS DURING OXIDATION PRETREATMENT FOR SOIL ANALYSIS
Authors: KIMPE C. R. DE , MILES N. , CARSON D.
Published: March 2010

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
CHEMICAL DIFFERENCES IN DARK BROWN CHERNOZEMIC Ap HORIZONS UNDER VARIOUS CONSERVATION TILLAGE SYSTEMS
Authors: DORMAAR J. F. , LINDWALL C. W.
Published: March 2010

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
EFFECT OF TILLAGE REDUCTION AND FERTILIZER ON SOIL MACRO- AND MICROAGGREGATION
Authors: WEILL A. N. , MCKYES E. , KIMPE C. R. DE
Published: March 2010

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 into > 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
ADSORPTION-DESORPTION EQUILIBRIA OF 14C-FLURIDONE AT LOW SOLUTION CONCENTRATIONS AND SOIL:WATER RATIOS
Authors: MALIK N. , DRENNAN D. S. H.
Published: March 2010

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
QUANTIFICATION OF SOIL CALCIUM CARBONATES BY STAINING AND IMAGE ANALYSIS
Authors: BUI E. N. , MERMUT A. R.
Published: March 2010

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
CONTRIBUTION OF N2 FIXATION TO FIELD BEAN AND PEA N UPTAKE OVER THE GROWING SEASON UNDER FIELD CONDITIONS IN SOUTHERN ALBERTA
Authors: KUCEY R. M. N.
Published: March 2010

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
A HIERARCHICAL APPROACH TO THE STUDY OF ORGANIC C, N, P, AND S IN WESTERN CANADIAN SOILS
Authors: ROBERTS T. L. , BETTANY J. R. , STEWART J. W. B.
Published: March 2010

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
THE EFFECT OF ANTECEDENT FREEZE-THAW FREQUENCY ON RUNOFF AND SOIL LOSS FROM FROZEN SOIL WITH AND WITHOUT SUBSOIL COMPACTION AND GROUND COVER
Authors: EDWARDS LINNELL M. , BURNEY J. R.
Published: March 2010

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 <0.075 mm than the fine sandy loam which showed 23.4% greater loss than the sandy loam. Key words: Freeze-thaw, erosion, compaction, winter rye, cereal residue, rainfall simulator, Prince Edward Island soils
EVALUATION OF A MODIFIED RAPID ROTARY SIEVE
Authors: BLACK J. M. W. , CHANASYK D. S.
Published: March 2010

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
THE FATE OF APPLIED NITROGEN IN A FRASER VALLEY SOIL USING 15N IN FIELD MICROPLOTS
Authors: KOWALENKO C. G.
Published: March 2010

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
CHANGES WITH TIME IN SOIL BIOMASS C, N AND P OF MINE SPOILS IN A DRY TROPICAL ENVIRONMENT
Authors: SRIVASTAVA S. C. , JHA A. K. , SINGH J. S.
Published: March 2010

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
WEATHER SENSITIVITY OF WESTERN CANADA WHEAT YIELD, 1900–1988
Authors: WALKER G. K.
Published: March 2010

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
A METHOD OF ESTIMATING YIELD FOR LARGE-SCALE FIELD RESEARCH PROJECTS
Authors: BRYDON JERELEEN , RENNIE D. A.
Published: March 2010

The Innovative Acres field-scale project was designed to compare water-efficient farming systems with the more commonly used crop-fallow farming system in Saskatchewan. This project spanned the period between 1982 and 1987, and tested 40 locations each year. The present study was undertaken at two of these locations, to compare the sampling methodology used by the Innovative Acres (IA) project with a more intensive sampling scheme, and thereby assess the relative validity of productivity estimates developed from the IA sampling method. At both locations, grain yield estimates for the field based upon twelve IA benchmark sites were statistically similar (P > 0.05) to yield estimates from the more intensive sampling scheme (59 samples). Yield estimates from the IA transect more closely approximated the farmers' estimates of grain yield at both locations. Weighted grain yields, based on the distribution of topography along the transects, gave no better estimate of yield than did grouped mean data at both locations. The IA sampling procedure estimated to within 10% of the true mean grain yield, at the 90% probability level. It is concluded that this level of precision allows accurate comparisons to be made between two cropping systems. Key words: Field-scale research, transects, topography