bluuebunny/crossref_metadata_2025 huggingface dataset:
Denitrification following herbicide application to a grass sward
Authors: Tenuta Mario , Beauchamp Eric G.
Published: April 2011

The application of the herbicide Roundup (glyphosate), and subsequent death of a predominately bromegrass (Bromus inermis Leyss.) and blue grass (Poa pratensis L.) sward, resulted in a 20- to 30-fold increase in denitrification rate 14 and 49 d after application compared to herbicide-untreated and fallowed soil treatments. The regulation of denitrification by O2, carbon and NO3− availabilities was assessed by measurement of various soil variables. The regulation of denitrification by C and NO3− availabilities was further studied in a laboratory experiment in which denitrification was measured following NO3− and glucose-C addition to soil from the field treatments. Elevated denitrification in the herbicide-treated soil was attributed to increased soil moisture and NO3− contents resulting from the death of vegetation. The death of the grass sward did not increase available C to denitrifiers, whereas the absence of vegetation in the fallowed soil 1 yr following herbicide application reduced available C. This study indicates that herbicide application to a grass sward increases denitrification and hence may contribute to greater nitrous oxide emission and N loss from soil. Key words: Denitrification, herbicide, plants, nitrate, regulation, soil moisture
Fluoride sorption and mineral stability in an Alberta soil interacting with phosphogypsum leachate
Authors: Luther S. M. , Poulsen L. , Dudas M. J. , Rutherford P. M.
Published: April 2011

A by-product of phosphate fertilizer production is phosphogypsum (PG). Relatively high F concentrations occur in the solid phase and in the highly acidic process water (PW) that initially fills its pores. The present research addresses the fate of F and the effects on mineral stability as phosphogypsum leachate (PGL) interacts with calcareous (Ck) soil and non-calcareous (Bt) soil. In a sequential batch equilibration, soils were exposed to fresh PGL during 30 d-long extractions. Major ions, pH and electrical conductivity (EC) were monitored. At 28 d, F concentration decreased from 31 mg L−1 in the PGL to 11 mg L−1 in the Bt-PGL mixture and 22 mg L−1 in the Ck-PGL mixture. Saturation indices (SIs) for fluorite ranged from 2.1 to −3.6. Extracts were closer to saturation with fluorite than with the other F minerals studied. Using alternative geochemical constants, fluorapatite was predicted to be stable in Bt-PGL extracts. The day 28 Bt-PGL extract was also near equilibrium with alunite, basaluminite, jurbanite, gypsum, amorphous silica, and quartz. Of the phyllosilicates in the soil-PGL mixtures at day 28, only kaolinite was predicted to be stable in only the Bt-PGL mixture. The potential for clay mineral instability and accelerated dissolution in F-rich PGL needs to be considered m the design of PG repositories. Key words: Fluoride, phosphogypsum, waste management, leachates, geochemical modeling, mineral stability
Effect of soil base saturation and endomycorrhization on growth and nutrient status of sugar maple seedlings
Authors: Ouimet Rock , Camiré Claude , Furlan Valentin
Published: April 2011

Nutrient imbalances of declining sugar maple (Acer saccharum Marsh.) stands in southeastern Quebec have been associated partly with high soil exchangeable acidity and low base saturation on. A greenhouse experiment was set up to determine how growth and nutrient status of sugar maple seedlings can be influenced by soil acidification and the presence of an endomycorrhizal fungus. The experiment consisted of five levels of soil base saturation (from 12 to 50%) and two levels of soil inoculation by an endomycorrhizal fungus (inoculated and control) in a complete factorial arrangement Sugar maple seedlings were grown for 3 mo in the treated soil substrates. Seedling shoot elongation rate, growth [dry matter (TDM) mass, stem diameter, and total leaf area], and K, Ca and Mg concentrations in foliage and roots decreased with soil acidification with base saturation used as an indicator of the soil-acidification status. Foliar K and Ca level reached values below critical thresholds when soil base saturation was reduced to 12%. Under the experimental conditions, seedling growth was not significantly affected by endomycorrhization, except for root DM mass, which was reduced by 24% compared with the control treatment. For mycorrhizal seedlings, foliar Al concentration increased linearly from 113 mg kg−1 to 210 mg kg−1 with the reduction of soil base saturation from 50% to 12%, while, for non-mycorrhizal seedlings, foliar Al concentration remained at a high level (195 mg kg−1) independently of the soil acidification level. Sugar maple seedling growth was not related to accumulation of Al in foliage. The results of this experiment support the hypothesis that a causal relationship exists between the level of soil base saturation and the growth decrease and associated nutrient disorders observed in declining sugar maple stands in Quebec. Key words:Acer saccharum, nutrient status, seedling growth, soil base saturation, endomycorrhizae
A conceptual model for nutrient availability in the mineral soil-root system
Authors: Gobran George R. , Clegg Stephen
Published: April 2011

We propose a conceptual model based on our results from rhizospheric studies of a Norway spruce stand growing on a nutrient poor Podzol in Southwest Sweden. We assume that dynamic linkages exist between three soil fractions: bulk soil, rhizosphere (Rhizo) and soil root interface (SRI). The soil fractions were characterized by organic matter content, electrical conductivity, pH, and soluble and exchangeable cations. Analyses showed great differences among the three soil fractions, especially the properties of the SRI. Cation exchange capacity and base saturation were higher in the rhizosphere and SRI than in the bulk soil. We attribute this to accumulation of organic matter (OM) in the rhizosphere and SRI. Moreover, the rhizosphere and SRI fractions had lower pH and higher titratable acidity than the bulk soil. Any possible negative effects of Al to the roots could be offset by accumulated organic matter and base cations (BC). The calcium-aluminum balance followed a consistent trend: bulk < rhizo < SRI. The results suggest that soil around the roots exhibits a different chemical composition than that of the root-free (bulk) soil, indicating more favorable conditions for roots. We suggest that trees growing on nutrient-poor acid soils invest their energy around roots to create a favorable microenvironment for both roots and microorganisms. Our results suggest that existing models which attempt to connect tree growth to soil acidification need modification. Such modification would include horizontal variation (bulk soil, rhizo and SRI) besides the vertical ones normally emphasized. It is possible that the conceptual model may enable a better understanding and description of naturally existing relationships between soil and plants under normal and stressed conditions. Key words: Conceptual model, organic matter, rhizosphere, soil root interface, acidification and growth models, Norway spruce
Influence of the time and rate of liquid-manure application on yield and nitrogen utilization of silage corn in south coastal British Columbia
Authors: Zebarth B. J. , Paul J. W. , Schmidt O. , McDougall R.
Published: April 2011

Manure-N availability must be known in order to design application practices that maximize the nutrient value of the manure while minimizing adverse environmental impacts. This study determined the effect of time and rate of liquid manure application on silage corn yield and N utilization, and residual soil nitrate at harvest, in south coastal British Columbia. Liquid dairy or liquid hog manure was applied at target rates of 0, 175, 350 or 525 kg N ha−1, with or without addition of 100 kg N ha−1 as inorganic fertilizer, at two sites in each of 2 yr. Time of liquid-dairy-manure application was also tested at two sites in each of 2 yr with N-application treatments of: 600 kg N ha−1 as manure applied in spring; 600 kg N ha−1 as manure applied in fall; 300 kg N ha−1 as manure applied in each of spring and fall; 200 kg N ha−1 applied as inorganic fertilizer in spring; 300 kg N ha−1 as manure plus 100 kg N ha−1 as inorganic fertilizer applied in spring; and a control that received no applied N. Fall-applied manure did not increase corn yield or N uptake in the following growing season. At all sites, maximum yield was attained using manure only. Selection of proper spring application rates for manure and inorganic fertilizer were found to be equally important in minimizing residual soil nitrate at harvest. Apparent recovery of applied N in the crop ranged from 0 to 33% for manure and from 18 to 93% for inorganic fertilizer. Key words: N recovery, manure management
Micronutrient concentrations of commercially grown vegetables and of soils in the Lower Fraser Valley of British Columbia
Authors: Pieri L. A. De , Buckley W. T. , Kowalenko C. G.
Published: April 2011

Zinc (Zn), copper (Cu) and molybdenum (Mo) concentrations of potatoes, cabbage, cauliflower, carrot, turnip, corn and lettuce grown commercially in three important agricultural regions of the Lower Fraser Valley of British Columbia were surveyed. Zinc and Cu concentrations in the edible portions of the various vegetables were within and frequently at the lower range of concentrations reported for corresponding vegetables grown in other non-contaminated areas of the world. It was concluded that there is more concern about low levels than about toxic Zn and Cu concentrations for vegetables grown in the Lower Fraser Valley. Molybdenum concentrations tended to be greater than those reported elsewhere in the world. Instances of high concentrations were quite site specific. At one location, the concentrations of Zn, Cu and Mo in potato tubers were considerably higher than in potatoes at other locations but it was not possible to determine whether this was due to the cultivar grown, the characteristics of the soil or management practices. The concentrations of the three metals in non-edible parts of the vegetables frequently varied more than the part normally consumed showing that extrapolation of the survey data to other types of vegetables regarding human nutrition quality must be made with caution. There were few correlations between concentrations of the elements in plants and in the corresponding soils, limiting extrapolation to other locations by soil analyses. A comparison of adjacent sites showed greater total soil Cu and Mo, and extractable P and K, concentrations under cultivated than under virgin conditions. Key words: Copper, zinc, molybdenum, survey
Interpretation of autumn soil tests for hazelnut
Authors: Kowalenko C. G.
Published: April 2011

The suitability of soil-test analyses for fertilizer recommendations for hazelnuts was assessed by detailed examinations of correlations with corresponding leaf-tissue concentrations in an orchard survey study. Correlations were examined only where optimum leaf-tissue nutrient concentrations had previously been established (i.e. N, P, K, S, Mg and Ca). Soil nitrate concentrations tended to increase substantially and relatively consistently in orchards where leaf N concentrations were greater than the optimum range, showing that soil and leaf analyses can be used for fertilizer recommendations for conservation and environmental as well as production considerations. Since most of the trees of the orchards in the study had P that was at or above adequate amounts, only limited conclusions could be made for soil P tests. Data from this survey and other literature showed that hazelnut trees can obtain adequate P from soils that have relatively low Bray-1 extractable P. Ammonium acetate extraction provides a reasonably good estimate of the K and Mg that are available to hazelnuts, and, for both nutrients, K and Mg fertilizer should be recommended for hazelnut (compared with many other crops) when soil-test analyses are relatively high. Ammonium acetate extracted considerable Ca from the soil and the amount extracted was not correlated with the concentration of Ca measured in the leaves. Calcium chloride (which extracts only unadsorbed sulphate) was a relatively poor extractant for available S because of the occurrence of sulphate adsorption in these soils. A surface 15-cm soil sample was adequate for most of the nutrients measured, but supplementation with subsurface analyses would improve nitrate, and possibly subsurface S should be included in the development of a soil test for S Soil testing is necessary to determine whether nutrients are building up in the soil. Also, only soil testing can be used for analysis-based recommendations prior to tree planting. Key words: Hazelnuts, Corylus avellana, filbert, nitrogen, phosphorus, potassium
Soil moisture modelling — conception and evolution of the VSMB
Authors: Baier Wolfgang , Robertson Geo. W.
Published: April 2011

The Versatile Soil Moisture Budget (VSMB), including the background leading to its development in the "early days" meaning around 30 yr ago, is described. National and international efforts before that time created a healthy climate for the development of agrometeorology in Canada and the pioneering work in soil moisture and crop-weather modelling.Events in the early days leading to a concerted endeavour of soil moisture modelling included: (i) a small group of highly qualified professionals from different disciplines, as well as support staff, had been established under the guidance of a team leader at the then Plant Research Institute (PRI); ii) a Canada wide crop-weather study had produced daily climatological and crop data at nine Canada Department of Agriculture establishments over 10 yr (1953–1962); iii) a computer became available to PRI staff (IBM 1620 with 16K); and (v) several sub-models providing the necessary input to the soil moisture model were at various stages of development (e.g. the "latent" evaporation and the biometeorological time scale sub-models).This paper presents an overview of the development of the VSMB using standard climatological data for generating daily soil moisture estimates under crops. Its concept, design and widespread applications in Canada and abroad are discussed. A more detailed analysis is left to the other presentations at this Symposium. Key words: Soil moisture, modelling, applications
Evaluation of a cultivar-sensitive soil water model for the potato crop
Authors: Gordon R. , Brown D. M. , Dixon M. A.
Published: April 2011

A modified version of the irrigation scheduling model SimISP (Simulating Irrigation Scheduling in Potatoes) was evaluated in terms of its ability to simulate the potato crop root zone soil water content through the growing season. The model uses daily radiation, temperature, humidity, windspeed, precipitation and seasonal crop and soil parameter inputs to estimate evaporation, transpiration, canopy expansion and dry matter accumulation. Recent cultivar-specific characteristics incorporated into the model allow for more precise simulations between cultivars.Simulations were conducted for rainfed, irrigated and artificial shelter-imposed stress conditions during four growing seasons on two soil types in Colchester County, Nova Scotia. Generally strong agreement between simulations and field measured (TDR) available soil water content in the top 15 cm of the soil profile was achieved with an average error within ± 4.7 mm and a relative error within ± 0.26. Larger errors were obtained for the 15- to 30-cm soil layer with average errors within ± 7.3 mm and the relative error within ± 0.52. Differences between model simulations and field measurements indicate the need for an improved root growth sub-model that is soil water sensitive and more precise estimates of soil water recharge after rain. Key words:Solanum tuberosum L., SimISP, simulation model
Point specific measurement and monitoring of soil water content with an emphasis on TDR
Authors: Topp G. C. , Hayhoe H. N. , Watt M.
Published: April 2011

During the past decade, a number of developments have improved the possibilities for real-time, in situ monitoring of soil water content, providing potential for much improved testing and validation of soil water models Brief reviews of the principles and procedures are presented for the gravimetric and gamma ray attenuation methods. A summary of the developments of time-domain reflectometry (TDR) demonstrates its high capability for continuous monitoring of soil water content. Portable dielectric probes (PDP) and capacitance instruments also use the high dielectric constant of water as an indicator of soil water content. Commercially available TDR instruments offer a choice of options that allow this method to be fitted to a variety of specific measurement requirements. The ease of use and portability of TDR instruments and the flexibility of design for the TDR probes has made possible the rapid measurement of surface and near surface water contents on a field scale. Multiplexers and data loggers now allow the efficient monitoring of water content to record both spatial and temporal patterns not previously detectable. Fine resolution and analyses within the electric field of a TDR probe has allowed us to measure and record the diurnal patterns of water uptake from, and its release to, relatively dry sod adjacent to growing corn roots Water distribution calculations show that the water measured as moving in and out of roots daily is sufficient to hydrate and stabilize the sheaths of soil that surround the root growing in dry soil. Key words: Soil water content, TDR, root uptake, root exudation, field measurement, water balance
Defining a realistic control for the chloroform fumigation-incubation method using microscopic counting and 14C-substrates
Authors: Horwath William R. , Paul Eldor A. , Harris David , Norton Jeannette , Jagger Leslie , Horton Kenneth A.
Published: April 2011

Chloroform fumigation-incubation (CFI) has made possible the extensive characterization of soil microbial biomass carbon (C) (MBC). Defining the non-microbial C mineralized in soils following fumigation remains the major limitation of CFI. The mineralization of non-microbial C during CFI was examined by adding 14C-maize to soil before incubation. The decomposition of the 14C-maize during a 10-d incubation after fumigation was 22.5% that in non-fumigated control soils. Re-inoculation of the fumigated soil raised 14C-maize decomposition to 77% that of the unfumigated control. A method was developed which varies the proportion of mineralized C from the unfumigated soil (UFC) that is subtracted in calculating CFI biomasss C. The proportion subtracted (P) varies according to a linear function of the ratio of C mineralized in the fumigated (FC) and unfumigated samples (FC/UFC) with two parameters K1 and K2 (P = K1FC/UFC) + K2). These parameters were estimated by regression of CFI biomass C, calculated according to the equation MBC = (FC − PUFC)/0.41, against that derived by direct microscopy in a series of California soils. Parameter values which gave the best estimate of microscopic biomass from the fumigation data were K1 = 0.29 and K2 = 0.23 (R2 = 0.87). Substituting these parameter values, the equation can be simplified to MBC = 1.73FC − 0.56UFC. The equation was applied to other CFI data to determine its effect on the measurement of MBC. The use of this approach corrected data that were previously difficult to interpret and helped to reveal temporal trends and changes in MBC associated with soil depth. Key words: Chloroform fumigation-incubation, soil microbial biomass, microscopically estimated biomass, carbon, control, 14C
Solution, exchangeable and clay-fixed ammonium in south coast British Columbia soils
Authors: Kowalenko C. G. , Yu S.
Published: April 2011

Solution, exchangeable and clay-fixed ammonium were measured in a variety of south coast British Columbia soils in the laboratory using extraction, equilibration and leaching procedures, and with and without ammonium amendments in order to evaluate the relative significance of adsorption and fixation processes on nitrogen behavior. Non-amended soils contained from 59 to 224 g N g−1 of fixed ammonium and these amounts were correlated with clay (positive) and sand (negative) contents. The amount of native fixed ammonium in the soils was influenced by management history. Recovery of ammonium added to eight selected samples by a small volume of solution followed by air drying was the same with 1 and 2 M KCl extractions, but less was extracted by 0.1 M KCl and even less by water. This showed that both 1 and 2 M KCl had sufficient K+ to displace the NH4+ present (inherent and added) on the exchange sites without an apparent effect on fixed ammonium. Up to 68% of the ammonium added was not extracted by 2 M KCl and assumed to have been fixed in the clay lattice. The proportion of the added ammonium that was adsorbed onto the exchange sites was linear up to 200 μg N g−1 application, but the amount fixed by the clays was linear to only about 100 μg N g−1 application rate. Data from studies where soil columns were leached with NH4NO3 provided only limited information on the relative importance of exchange versus fixation processes to the adsorption of ammonium. Leaching columns with a limited number of batches of NH4NO3 followed by water (short cycle) were useful for comparing the ability of different soils to adsorb and retain ammonium, but the relative importance of exchange versus fixation could not be determined. In the 18 samples of this study, the amount of NH4+ adsorbed ranged from 84 to 25% during short cycle column leachings. Different patterns of adsorption occurred among the four soil samples that were leached with a large number of batches of ammonium (long cycle), but it could not be determined whether or not these patterns were related to differences in proportions of fixation relative to exchange. Measurements showed that ammonium was fixed in the soils during the long cycle leachings but that the amounts of fixed ammonium measured were influenced by air drying the sample before analysis. Several studies with and without toluene additions showed that microbial activity must be controlled during these measurements. It was concluded that south coastal soils contained significant amounts of fixed ammonium and can fix additional ammonium. The amount of ammonium in the clay fixed pool and the potential to fix added ammonium was different in relation to the soil type, their previous management, and wetting and drying cycles. The biological significance of fixed ammonium and the fixation process must not be discounted in any nitrogen studies of these soils for proper interpretation of data. Key words: Ammonium fixation, equilibration, column leaching, microbial/enzyme inhibition, extractant concentration
Chemical fractionation of soil boron: I. Method development
Authors: Hou J. , Evans L. J. , Spiers G. A.
Published: April 2011

A chemical fractionation scheme for soil boron was investigated by measuring the amounts of B extracted from minerals and synthetic soils amended with B. The scheme fractionated B into five fractions — readily soluble (solution plus non-specifically adsorbed), specifically adsorbed, oxide bound, organically bound and residual. These five fractions were extracted by 0.01 M CaCl2, 0.05 M KH2PO4, 0.2 M acidic NH4-oxalate, 0.02 M HNO3-30% H2O2, and 1:4:5 HNO3-HF-HCl, respectively. The methodology was tested on goethite and clay mica and three synthetic soils containing mixtures of goethite, clay mica, humic acid, calcite, and quartz sand and amended with three levels of B. Specifically adsorbed and oxide bound B were significantly correlated with the content of goethite in the synthetic soils, while residual B was significantly correlated with the content of clay mica. The recovery of extracted B, estimated as the percentage of total fractions over total B content in minerals and synthetic soils, ranged from 85 to 104%, with a mean of 97%. The overall results obtained with the fractionation scheme were deemed satisfactory as to sensitivity and precision for B fractionation. Key words: Boron, soil fractionation, sequential extraction
Fertilizer responses of dry bean in southern Alberta
Authors: McKenzie R. H. , Middleton A. B. , Seward K. W. , Gaudiel R. , Wildschut C. , Bremer E.
Published: April 2011

Previous reports suggest that the response of dry bean to N fertilizer is often dependent on bean cultivar. In addition to N, commercial producers of dry bean in southern Alberta frequently apply P, K and Zn, even though soil test levels of these nutrients are often high. To evaluate the fertilizer responses of commercial dry bean cultivars in southern Alberta, three experiments were conducted. In the first experiment, the response of GN 1140 great northern bean, NW-63 small red bean, Othello pinto bean, and Viva pink bean to N fertilizer rates and rhizobia inoculation was determined at three sites each year from 1994 through 1996. The second experiment was conducted at the same sites to determine the response of these cultivars to P and K fertilizer. The third experiment was conducted at the same sites in 1995 and 1996 to determine the response of the same four cultivars and OAC Seaforth navy bean to soil-applied and foliar Zn application. The four cultivars responded similarly to N in the first experiment. Seed yields ranged from 81 to 100% of maximum yields when available N levels (fertilizer-N plus nitrate-N to 30 cm just prior to seeding) were less than 80 kg N ha–1, but were always greater than 90% of maximum yields when available N levels were greater than 80 kg N ha–1. Rhizobia inoculation did not significantly increase seed yields or reduce the response to N fertilizer, although early-season plant growth was frequently improved by inoculation. Seed yield was only increased by application of P fertilizer at one site and by application of K fertilizer at one site, while application of Zn did not increase seed yield at any of the sites. The critical soil test levels for responses to P, K or Zn were consistent with levels reported for other crops or regions, but further validation of these levels is required due to the lack of sites with low nutrient availability. Key words: Phaseolus vulgaris, fertilizer nitrogen, phosphorus, zinc, Rhizobium leguminosarum biovar phaseoli, rhizobia inoculation
Potassium management for carrots in Prince Edward Island
Authors: Sanderson Kevin R. , Sanderson J. Brian
Published: April 2011

Nine field studies were conducted over a 3-yr period to determine the response of carrot (Daucus carota L.) to soilapplied K on sandy to loamy sand Orthic Podzol soils in Prince Edward Island (PEI), Canada. Mid-season soil K levels ranged from 34 to 103 µg g-1, and sites were classified as L– (very low), L (low) and M (medium) (Mehlich 3 extractable) according to the PEI Soil and Feed Testing Laboratory. Cultivars used were Imperator-type and the crops were managed to conform to local growing practices. Treatments consisted of preplant broadcast applied muriate of potash (KCl) at 0, 75, 150, 225 or 300 kg K ha-1. When no K was applied, total carrot yields on the L–, L and M soil K ratings were 70, 90 and 98% of the maximum yield, respectively. To achieve 95% of the maximum yield, 150, 75 and 0 kg K ha-1 were required on the L–, L and M soils, respectively. Increasing rates of applied K linearly increased the K content of carrot petioles and soil samples taken at harvest. Potassium content in the carrot roots increased linearly with the rate of applied K, but parallel line analyses indicated that separate K response lines were required for each K soil test rating. Rates of 300, 150 and 75 kg K ha-1 were required to increase root K content to above the published standard of 27 mg g-1 (DM basis) on the L–, L, and M soil K sites, respectively. Key words: Carrot, potassium, soil K rating, nutrient content, yield
Genetic variability of principal isoflavones in red clover
Authors: Papadopoulos Yousef A , Tsao R. , McRae K. B. , Mellish A. E. , Fillmore S. A. E.
Published: April 2011

Isoflavones, known for their health benefits, are abundant in red clover (Trifolium pratense L.). Total isoflavone concentrations can be 30 times that of soybean, indicating that red clover is a good source of nutraceutical and functional food ingredients. In this study, tissue samples of 13 red clover cultivars were taken at two growth stages (late-bud stage and late-flowering stage) to determine the concentration of individual isoflavones using HPLC. Individual isoflavone concentrations and total isoflavone concentration differed significantly according to red clover cultivar. We found significant genetic variability for total isoflavone concentration and individual isoflavone concentrations; these differences were not related to ploidy level (diploid vs. tetraploid). Broad-sense heritability (H = genetic variance/total variance) ranged from 0 to 83% and was influenced by isoflavone type and sampling date. The results of this study suggest that there is significant genetic variability for isoflavone concentrations among currently available red clover cultivars. Key words: Trifolium pratense L., biochanin A, formononetin, growing stages, broad-sense heritability
Incorporation de résidus organiques dans un substrat tourbeux pour la production d'impatiens et de géraniums
Authors: Gauthier Fabienne , Gagnon Serge , Dansereau Blanche
Published: April 2011

During winter 1994 and spring-summer 1994, seedlings of Impatiens wallerana 'Accent Coral' and Pelargonium × hortorum 'Orbit Hot Pink' were grown in a commercial substrate (PRO-MIX 'BX') or in one of 24 substrates composed of perlite (35% by volume), peat moss and of six organic residues (composted water-treated sludge, forestry compost, fresh or composted used peat extracted by biofilter during treatment of municipal water, and fresh or composted paper sludge). The purpose of the study was to determine the maximal proportion of these residues to be incorporated into a peat substrate to obtain quality plants. Growth parameters (growth index, top dry weight, and visual quality) generally decreased with increasing proportion (5, 10, 25 or 40% per volume). During the winter experiment, growth of control plants was superior to growth of plants grown in substrates composed of residues. An incorporated proportion of 25% per volume was shown to be maximal for the production of impatiens and geraniums. Key words: Impatiens wallerana, Pelargonium × hortorum, water treated sludge, composted wastes, peat moss, subirrigation
Restoring organic matter in a cultivated, semiarid soil using crested wheatgrass
Authors: Curtin D. , Selles F. , Wang H. , Zentner R. P. , Campbell C. A.
Published: April 2011

Planting of cultivated land with perennial forages may increase C sequestration in soil organic matter and contribute to atmospheric CO2 mitigation strategies. However, little is known of the effectiveness of introduced grasses in restoring organic C in cultivated soils of the Canadian prairies. Our objective was to evaluate the C sequestration potential of crested wheatgrass (CWG) (Agropyron cristatum L. Gaertn.), a widely introduced, early-season grass. In 1995 and 1996, we measured soil CO2 fluxes, C inputs in plant material and total soil C under CWG and a fallow-wheat (Triticum aestivum L.)-wheat rotation (F-W-W). These were two of the treatments in a replicated crop rotation experiment initiated in 1987 in southwestern Saskatchewan on a medium-textured soil that had previously been under long-term wheat production. Average to above-average growing season (1 May to 31 July) precipitation in 1995–1996 resulted in annual inputs of C in wheat residues of 3000–4500 kg ha−1. Growth of CWG, which was hayed and removed, was relatively poor in both years, but especially in 1995 when dry matter yield was only 1300 kg ha−1. For the 1988–1996 period, there was a strong correlation (R2 = 0.81; P < 0.001) between CWG yield and precipitation received in May, showing the importance of early spring rains determining CWG yield and C inputs to the soil. Carbon inputs under CWG (1200 kg ha−1 in 1995 and 2400 kg ha−1 in 1996) were less than under wheat but CO2-C emissions were similar under CWG and wheat. Soil C measurements in fall 1996 confirmed that CWG did not gain C relative to the F-W-W rotation. Although failure of CWG soil to store more C than cultivated soil may be partly because weather conditions during the experiment were more favourable for wheat than CWG, our results cast doubt on the ability of CWG to restore C stocks in prairie soils degraded by long-term cropping. Key words: Carbon sequestation, carbon dioxide emissions, wheat, crested wheatgrass, fallow
Spatial dependence of soil organic carbon mass and its relationship to soil series and topography
Authors: Bergstrom D W , Monreal C M , St. Jacques E.
Published: April 2011

Concern about the global increase in atmospheric CO2 has focussed attention on C sequestration in soil and the influence of management practices on soil organic C (OC) stocks. Evaluation of management practices is required at scales comparable to farm management units, which encompass heterogeneous soils and different landforms. The objectives of this study were to describe the spatial dependence of soil OC mass in two adjacent fields with contrasting tillage practices on Black Chernozemic soils using geostatistics and relate it to topographic features and soil series. Mass of OC was measured for a surface layer, the A horizon and solum. The spatial dependence of OC mass was at a scale commensurate with topographic variation. Spatial analysis generally corroborated description of the sampling site by soil series, which represented differences in drainage as influenced by slope-position and redistribution of water across the landscape. Soil series alone or grouped by drainage class, therefore, provided a framework by which to stratify the site for evaluation of effects of tillage practice on OC mass and extrapolation of results to comparable sites within the same landscape. Key words: Carbon sequestration, drainage class, scale, soil series, topography
Mixed papermill residues affect yield, nutritive value and nutrient use of a grass-alfalfa sward
Authors: Arafoui M A , Simard R R , Belanger G. , Laverdiere M R , Chabot R.
Published: April 2011

Mixed papermill residues (MPR) can improve soil quality, but their impact on forage yield and quality is not well documented. Three MPRwere applied to mixed grass-alfalfa (Medicago sativa L.) sward in 1997 and 1998 at near 100, 200 and 400 kg N ha-1 and were compared to calcic ammonium nitrate (CAN) at 0, 50, 100 and 200 kg N ha-1 on a Bedford clay loam (Humic Gleysol). The MPR and CAN induced a significant linear increase in forage DM yield and relative yield (RY). The sward response to MPR addition in 1997 was related to the MPR C:NH4+ ratio. MPR and CAN increased the forage NDF concentration in 1998, but there was no effect in 1997. Nitrogen concentration in forage tissues was increased by MPR and CANinputs in 1997, but was decreased in 1998. In all treatments, NO3− tended to accumulate in forage tissues when the N nutrition index (INN) exceeded the optimum level. Forage nutritive value from the MPR was comparable to CAN.The results of this study suggest that MPR can be an efficient N source for grass-alfalfa swards on fine-textured soils. Key words: Acid detergent fiber, forage, grass, Medicago sativa L., mineral fertilizer, neutral detergent fiber, papermill residues
Soil water drying and recharge rates as affected by tillage under continuous barley and barley-canola cropping systems in northwestern Canada
Authors: Azooz R H , Arshad M A
Published: April 2011

In areas of the northwestern Canadian Prairies, barley and canola are grown in a short growing season with high rainfall variability. Excessively dry soil in conventional tillage (CT) in dry periods and excessively wet soil in no-tillage (NT) in wet periods could cause a significant decrease in crop production by influencing the availability of soil water. The effects of CT, NT and NT with a 7.5-cm residue-free strip on the planting rows (NTR) on soil water drying (–dW/dt) and recharge (dW/dt) rates were studied in 1992 and 1993 during wet and dry periods to evaluate the impact of NTR, NT and CT systems on soil moisture condition. The soils, Donnelly silt loam and Donnelly sandy loam (both Gray Luvisol) were selected and soil water content by depth was measured by time domain reflectometry. Water retained at 6 matric potentials from –5 to –160 kPa were observed. In the field study, –dW/dt was significantly greater in CT than in NT in the silt loam for the 0- to 30-cm layer during the first 34 d after planting in 1992. The 0- to 30-cm soil layer in CT and NTR dried faster than in NT during a period immediately following heavy rainfall in the silt loam in 1993. The drying coefficient (–Kd ) was significantly greater in CT and NTR than in NT in the silt loam soil in 1993 and in the sandy loam soil in 1992 in the top 30-cm depth. The recharge coefficient (Kr) was significantly greater in NT and NTR than in CT for the silt loam soil. The NTR system increased the –dW/dt by 1.2 × 10-2 to 12.1 × 10-2 cm d-1 in 1992 and 1993 in the silt loam soil and by 10.2 × 10-2 cm d-1 in 1993 in the sandy loam soil as compared with NT. The dW/dt was 8.1 × 10-2 cm d-1 greater in NTR in 1992 and 1993 in the silt loam soil and was 1.9 × 10-2 greater in NTR in 1992 than in CT in the sandy loam soil. The laboratory study indicated that NT soils retained more water than the CT soils. The NTR practice maintained better soil moisture conditions for crop growth than CT in dry periods than NT in wet periods. Compared with NT, the NTR avoided prolonged near-saturated soil conditions with increased soil drying rate under extremely wet soil. Key words: Water drying, water recharge, water depletion, wet and drying periods, hydraulic properties, soil capacity to retain water
Ammonia volatilization and soil nitrogen dynamics following fall application of pig slurry on canola crop residues
Authors: Rochette Philippe , Chantigny Martin H , Angers Denis A , Bertrand Normand , Côté Denis
Published: April 2011

Land application of liquid manures is a major source of atmospheric ammonia. The presence of crop residues on the soil surface usually increases emissions by retarding slurry infiltration, whereas incorporation of slurry into soil reduces emissions. Our objective was to quantify the relative reduction in NH3 volatilization resulting from the soil incorporation of pig slurry (PS) applied on canola (Brassica napus) residues under fall conditions in Quebec, Canada. Pig slurry was applied at 7.4 L m–2 on six plots covered by canola crop residues. Slurry and residues were incorporated in the top 5 cm of soil (INCORP) in half of the plots, while the other half were left untouched (SURF). Ammonia volatilization was measured following application for 10 d using wind tunnels. Soil NH4+ and NO3− contents, pH, moisture and temperature were also monitored to explain variations in NH3 fluxes. Soil NH4+-N in the surface soil was lower than expected shortly after slurry application, maybe as a result of fixation by clays or interception by crop residues. The volatilization of NH3 was higher (P < 0.05) on SURF plots than on INCORP plots in 20 of the 26 measuring periods, with total NH3 losses being five times greater in the former. Cumulated emissions during the first 11 h accounted for the 60 and 53% of total NH3 emissions for the SURF and INCORP plots, respectively. Our results confirm that a large fraction of the NH3 volatilization from slurry application on canola residues can be greatly reduced if the slurry and crop residues are incorporated into the soil immediately after slurry application. Despite significant reduction (80%) of NH3 volatilization in INCORP compared with SURF plots, no difference was found in soil mineral N between treatments, suggesting that other processes such as N mineralization or denitrification were more active in INCORP plots. Key Words: Ammonium, nitrate, nitrogen cycle, organic amendments
Ca-Mg ratios for evaluating pedogenesis in the piedmont province of the southeastern United States of America
Authors: Shaw J N , West L T , Hajek B F
Published: April 2011

The nature of parent materials strongly influences soil development in the southeastern US Piedmont. In this region, most parent materials (saprolite) form from metamorphic and igneous felsic and mafic rocks. Although most soils in felsic terrains are acid and kaolinitic, soils formed from mafic parent materials range from kaolinitic Ultisols to Alfisols with smectite. Because it is sometimes difficult in soils developed in mixed terrains to determine parent material influence, exchangeable Ca/Mg ratios were used to elucidate soil-parent material relationships. Establishment of Ca/Mg signatures diagnostic of soil-parent material suites could facilitate soil mapping activities and forest fertilization regimes. Characterization data collected as part of the National Cooperative Soil Survey (mainly Georgia and Alabama) were evaluated, and soils were grouped by parent material type. The Ca/Mg ratios did not prove to be diagnostic for separating parent materials; however, significant depth trends existed. In most of the groupings, Ca/Mg ratios decreased with depth in the solum, which was most likely due to selective retention of Ca2+ and the effects of bio-cycling. The ratio either increased below the solum (mafic soils), or continued to decrease (felsic soils). Thus, these ratios are useful for identifying solum depth in some of these soils. The (Ca + K)/Mg ratios were more diagnostic with regard to parent material. These data suggest soils possessing ratios of (Ca + K)/Mg < 2 within the solum (excluding surface horizons) have been significantly influenced by mafic parent materials. Key words: Piedmont, Ca-Mg ratios, Ultisols, Alfisols, pedogenesis
Long-term nitrogen, phosphorus and potassium fertilization of cassava influences soil chemical properties in North Vietnam
Authors: Nguyen Hung , Schoenau J J , Van Rees K. C.J. , Nguyen Dang , Qian P.
Published: April 2011

The long-term effects of yearly fertilizer applications on soil chemical properties and nutrient availability are not well documented for cassava (Manihot esculenta) production in Vietnam. In 1990, research plots were established (randomized complete block design) with 12 treatments to test effects of different rates of N, P and K on soil properties in Acrisols (FAO-UNESCO Soil Classification) at Thai Nguyen University, North Vietnam. In June 1998, composite soil samples (0- to 10-cm and 10- to 20-cm depth) were collected from each plot. Nine years of N application significantly reduced the labile pools of soil inorganic P, total soil P and soil extractable K and Mg. Total soil N was only slightly increased in the 10- to 30-cm depth. Long-term applications of P significantly increased soil inorganic P fractions, but reduced concentrations and supply rates of nitrate and K. Moreover, 9 yr of K application significantly increased soil organic C (two depths), soil total N (10-30 cm) and soil extractable K in the 0- to 10-cm depth. Generally, the results show that long-term applications of mineral fertilizers in a ratio of N:P2O5:K2O of 2:1:2 (at the rates of 80 N:40 P2O5:80 K2O or 160 N:80 P2O5:160 K2O) are effective in maintaining the total content and availability of applied nutrients, but when applied alone are associated with decreases in other nutrients. Key words: Nitrogen, phosphorus, potassium fertilizers, cassava, ion exchange resin, soil properties
Soil science on the Canadian prairies - Peering into the future from a century ago
Authors: Janzen H H
Published: April 2011

Now, as a new century begins, may be a good time to reflect on the future of Soil Science on the Canadian prairies. One way to do that is to step back about one hundred years, to the turn of the previous century when our grassland soils were first cultivated. What questions perplexed scientists then? And how did they look for answers? My objective is to listen for our forebears’ thoughts in their writings, now largely buried. From this historical vantage may emerge insights, not only into where our science has been, but also into where it might yet go. Key words: Soil organic matter, crop rotation, grassland soils, history
Comparison of N fertilizer, source-separated municipal solid waste compost and semi-solid beef manure on the nutrient concentration in boot-stage barley and wheat tissue
Authors: Rodd A. V. , Warman P. R. , Hicklenton P. , Webb K.
Published: April 2011

Composting of source-separated municipal solid waste (SSMSW) is an option currently used to divert refuse from landfills. There is interest in using this material to alleviate soil constraints. Since many livestock producers ensile their cereals, after harvesting at boot-stage, the purpose of this project was to determine the effect that SSMSW compost and semi-solid beef manure, with and without supplemental N fertilizer, would have on the concent ration of minerals in this feed.

The addition of N fertilizer increased the concentration of N, K, Ca, Mg, Mn, Cu, and Zn in boot-stage tissue of barley in 1996 and wheat in 1997, but only increased the concentration of B in wheat tissue. Cereal boot-stage N, K, and Mn concentrations were higher in the manure than compost-amended plots. However, boot-stage Mg and Cu concentrations tended to be higher in the compost-amended plots. As manure addition increased, the concentration of N and K in barley and wheat , Ca and Cu in wheat, and Mn in barley increased. As the rate of compost addition increased, the concentration of Mg in barley and wheat decreased, while that of Cu in barley increased. Even though the SSMSW compost was applied at higher than normal agronomic rates, tissue Cu and Zn concentrations were not at levels considered to be harmful to plants or livestock. Key Words: Barley, wheat, boot-stage, compost, fertilizer, mineral concentrations, municipal solid waste manure
Mean residence times and characteristics of humic substances extracted from a Taiwan soil
Authors: Wang M C , Chang S H
Published: April 2011

Humic substances are well known for their long-term persistence in soil environments. The relationship between the mean residence times (MRT) and characteristics of humic substances extracted from a soil with highorganic matter (OM) content in Taiwan was investigated. The MRTs of the soil organic matter (SOM) and its humic substances extracted from the soil samples taken from three depths (0–20, 40–60, and 70–150 cm) of a soil profile were determined by 14C-dating procedures. Moreover, the humic substances were subjected to elemental analysis and investigation by electron spin resonance (ESR), Fourier transform infrared (FTIR), and solid-state 13C nuclear magnetic resonance (13C NMR) spectroscopies. The ranges of the MRT of fulvic acids (FA) (MW < 1000), FA (MW > 1000), humic acid (HA) (MW > 1000), and humins (MW > 1000) were 143 ± 110 to 1740 ± 60, 213 ± 120 to 1690 ± 200, 253 ± 60 to 2200 ± 40, and 293 ± 40 to 2173 ± 70 yr, respectively. The higher standard deviations of the means of determined MRTs of FA (MW < 1000) and FAs (MW > 1000) may be due to their lability. Further, the MRTs of the FAs (MW < 1000), FAs (MW > 1000), HAs (MW > 1000), and humins (MW > 1000) increased with increasing soil profile depth, indicating the slow biological and chemical degradations of humic substances in the deeper layers. The elemental composition and spectroscopic properties of FTIR, 13C NMR, and ESR of humic substances did not change significantly with their MRTs. The MRTs in the range observed in this study were apparently long enough to render humic substances a high degree of chemical stability. Key words: Humic substances, mean residence times, ESR, FTIR, 13C NMR, humin