bluuebunny/crossref_metadata_2025 huggingface dataset:
Populations and functional diversity of bacteria associated with barley, wheat and canola roots
Authors: Lupwayi N. Z. , Clayton G. W. , Hanson K. G. , Rice W. A. , Biederbeck V. O.
Published: April 2011

We investigated the effects of field pea (Pisum sativum)-based crop rotations on endophytic bacteria in roots and surrounding soil of cereal and oilseed crops. Barley (Hordeum vulgare), wheat (Triticum aestivum) and canola (Brassica rapa) were each grown (a) following peas inoculated with Rhizobium leguminosarum bv. viceae, (b) following uninoculated peas or (c) in monoculture. At flagleaf (cereal) or flowering (canola) growth stage, populations of soil-extract agar (SEA)-culturable bacteria ranged from log10 7.12 to log10 7.82 cells g-1 soil dry weight in the bulk soil, log10 7.15 to log10 8.12 cells g-1 soil in the rhizosphere, log10 7.77 to log10 10.39 cells g-1 root dry matter (DM) on the rhizoplane, and log10 5.56 to log10 7.63 cells g-1 root DM in root interiors (endophytic bacteria). Differences between treatments in populations and functional diversity of bacteria depended on where the bacteria were sampled in the continuum from bulk soil to root interiors. This affected correlations with crop N and yield because these crop parameters were lowest in monoculture. Thus, populations of endophytic bacteria and functional diversity of rhizospheric bacteria were negatively correlated with crop N accumulation and yields. However, the diversities of endophytic and bulk soil bacteria were positively correlated with crop N and yields. Key words: Community-level physiological profile, crop rotation, substrates, endophytic bacteria, microbial functional diversity, rhizosphere
Response of forage grass to sulphur applications on coastal British Columbia soils
Authors: Kowalenko C. G.
Published: April 2011

Little is known about the S requirement of coastal British Columbia soils. Spring gypsum applications increased yield in two and decreased yield in one of six forage grass rate-of-application field trials. Yield effects did not occur at every cut. At the sites where yield depression was observed, the effect primarily occurred at the intermediate rates and S concentration increased with increased rate of application. Luxury uptake of S (increased S concentrations without a yield effect) showed residual effects occurred into the third season after application, despite the abundant winter precipitation common in the area. Yields were affected in a form × rate × time trial, but not at every cut. Powdered elemental S was available to plants sooner than Agri-Sul (an elemental S fertilizer), but neither as quickly as gypsum. Four of five traditional soil test S extractants were significantly correlated with first-cut uptake of S in the control treatment, with the bicarbonate extraction having the highest coefficient (r2= 0.29). The smaller amount of sulphate in calcium chloride compared to the other extractants showed soil adsorption. Soil S tests are required to manage S for optimum yield without accelerated soil acidification. Key words: S fertilizer forms, S rates, gypsum, elemental S fertilizer, Agri-Sul, plant S uptake, soil S tests
Evaluation of LEACHMN under dryland conditions. I. Simulation of water and solute transport
Authors: Akinremi O. O. , Jame Y. W. , Campbell C. A. , Zentner R. P. , Chang C. , de Jong R.
Published: April 2011

The ability to simulate the dynamics of soil nitrogen under field conditions will aid our understanding of the nitrogen cycle. Our objective was to test the water and solute components of LEACHMN using data obtained from a field lysimeter study conducted on a medium-textured soil in southwestern Saskatchewan, Canada. Our preliminary evaluation of LEACHMN showed that the retentivity and conductivity functions used in this model were not appropriate for our soil as the original model permitted water transmission through the soil profile too rapidly. We, therefore, incorporated the van Genuchten retentivity function into LEACHMN and used the same soil water retention data to generate the van Genuchten parameters. The modified model was able to reproduce changes in water and chloride concentration after minimal calibration. Overall, the value of 0.45 used for the pan coefficient for soil under fallow and 12 mm used for dispersivity produced a realistic estimation of changes in water and chloride within the soil in the 2 yr of the field experiment. The model reproduced soil water redistribution in a fallow system. There was a tendency to under-estimate soil water content during dry periods, mainly as a result of the model’s tendency to over-estimate evaporation. While the centre of mass of chloride was correctly estimated, the model under-estimated the maximum depth of chloride penetration due to a slight tendency to over-estimate evaporation. Based on our statistical and graphical evaluation of LEACHMN, the modified model is adequate for our subsequent nitrate leaching study. Key words: LEACHMN, lysimeter, dryland, water, chloride, nitrate
Nitrate leaching from residual fertilizer N after spring thaw in two corn agro-ecosystems
Authors: Zhang T. Q. , MacKenzie A. F. , Liang B. C.
Published: April 2011

Water samples at zero tension were collected using an open-ended lysimeter and analyzed for NO3−-N from a Chicot sandy clay loam and a Ste. Rosalie clay soil under continuous corn (Zea mays L.) in 1993 and 1994, shortly after spring thaw. There was negligible leaching of NO3−-N at previous fertilizer N rates of 0 and 170 kg ha-1 in both soils. However, NO3−-N concentrations of the leachates from soils receiving 285 and 400 kg N ha-1 yr-1 varied from 1.4 to 80 mg L-1, depending on the initial levels of soil residual NO3−-N and the supply of percolation water. When the initial levels of soil NO3−-N were relatively high and percolation of water was relatively slow in 1993, NO3−-N concentrations of the leachates ranged from 20 to 80 mg L-1. Nitrite-N concentrations were from 1.4 to 15.6 mg L-1 when the initial levels of soil residual NO3−-N were relatively low and percolation was relatively fast in 1994. The occasional higher NO3−-N concentrations in the leachate from the previous higher N applications indicated a potential for contaminating surface and ground waters as a result of NO3−-N leaching in the early spring. Key words: Residual N, nitrate-N leaching, soil solution, continuous corn, N fertilization
Decomposition of crop residues under conventional and zero tillage
Authors: Lupwayi N. Z. , Clayton G. W. , O’Donovan J. T. , Harker K. N. , Turkington T. K. , Rice W. A.
Published: April 2011

Field experiments were conducted to determine decomposition patterns of red clover (Trifolium pratense), field pea (Pisum sativum), canola (Brassica rapa) and wheat (Triticum aestivum) residues under zero and conventional tillage. Crop residue amounts produced in 2 trial years ranged from 1.6 t ha-1 for monoculture wheat to 6.05 t ha-1 for peas, and tillage had no effect. The extent of dry matter (DM) decomposition was usually less under zero than under conventional tillage, e.g., 31 to 41% of canola DM decomposed under zero tillage while 41 to 50% decomposed under conventional tillage in 12 mo. Corresponding percentages for other residues under zero and conventional tillage, respectively, were: 65 and 75% for clover, 43 and 45 to 55% for pea, and 27 and 40% for wheat. The rate and extent of DM decomposition were positively correlated with N and P concentrations, and negatively correlated with C/N, C/P, lignin/P and lignin/K ratios. These decomposition patterns have implications for nutrient release and soil cover. Rapid decomposition is not necessarily desirable because the nutrients released are subject to losses in soil. Key words: Biological soil quality, crop residue quality, crop rotation
Emergence, survival and growth of selected plant species in petroleum-impacted flare pit soils
Authors: Rutherford P. M. , Dickinson S. J. , Arocena J. M.
Published: April 2011

One of the prerequisites to phytoremediation of hydrocarbon-contaminated soils is that plants be able to germinate and become established in the presence of contaminants. This 5-wk growth chamber study examined the tolerance of five grasses and one legume to petroleum hydrocarbons (PHCs) and associated salts in three weathered, fine-textured, flare pit soils obtained from NE British Columbia. Plant tolerance to these soils was measured by percent seedling emergence (PSE), percent seedling survival (PSS) and 5-wk dry shoot biomass; a non-contaminated control soil was included in the study. The contaminated soils showed a wide range in total PHC concentrations (Soil A: 0.1 %, Soil B: 1.8 %, Soil C: 16 % PHC by mass) and in the recently established Canadian Council of Ministers of the Environment (CCME) PHC Tier 1 fractions 1–4. Electrical conductivity in contaminated soils ranged from 3.00 (Soil B) to 5.16 (Soil A) dS m-1. Medicago sativa (alfalfa, cv. Peace) was sensitive (low PSS, PSE and shoot biomass) to high salinity of Soil A but flourished in Soil B, a soil with F3 a nd F4 (gravimetric) concentrations that exceeded CCME PHC Tier 1 Eco Contact standards for agricultural, residential and parkland soils. When considering the combined effects of PHC and salts, Bromus inermis (smooth brome, cv. Carlton) was the grass most tolerant of contaminants in the weathered industrial soils. Compared to other plants, it consistently produced relatively high PSS, PSE and shoot biomass. Soil C was slightly hydrophobic and all plants showed reduced shoot biomass compared to other soils; however, average shoot biomass for Bromus inermis was almost twice as great as any other plant species growing in this soil. More research on the properties and remediation of historic flare pit soils is warranted. Key words: Hydrocarbons, phytoremediation, soil contamination, soil remediation, CCME, soil toxicity
Near-infrared spectroscopy for soil water determination in small soil volumes
Authors: Bullock P. R. , Li X. , Leonardi L.
Published: April 2011

Critical soil water levels for soil microscale processes are difficult to determine because of variability in large soil volumes and lack of techniques for logging soil water contents in small soil volumes. This study tested nearinfrared (NIR) spectroscopy for soil water content determination. Five soil horizons with a range in soil texture, soil organic carbon, carbonates, pH and horizon depth, were tested at air-dry, field capacity and 0.1 MPa tension water content. Volumetric soil water content, determined using the standard method of oven-drying and soil bulk density, was compared to NIR absorbance in various combinations and wavelengths. The NIR spectra obtained with the probe in direct contact with the soil gave better results than when the probe was separated from the soil with a glass slide. The most reliable validation results were obtained using a multivariate partial least squares regression of the full spectrum with an r2 of 0.95 and RMSE of prediction of 6.4%. Smoothing and derivatives of the spectra did not improve the validation results. The relationships for absorbance at single wavelength segments, ratios, differences and area under the curve around the 1940 nm peak were good (r2 values near 0.85 ) but poorer than the results using the full spectra. The high correlation coefficients obtained with the wide variety of soils utilized in this study suggest that NIR absorbance is a practical method for determining volumetric soil water content for small soil volumes. Key words: Near-infrared spectroscopy, soil water, Near-infrared absorbance
Assessment of long-term fate of metals in soils: Inferences from analogues
Authors: Sheppard S. C. (Steve)
Published: April 2011

The assessment of the health and environmental impacts of metal contamination in soils is complicated, and in different ways than is the assessment of many other contaminants. One of the foremost problems is that the metals are often relatively immobile, so that it is necessary to verify predictions of mobility and impact far into the future. One approach is to seek analogue information: information from studies that may not have set out to measure attributes related to metal behaviour, but that none the less provide useful insights. One example would be the information on the mobility of natural clays and pedogenic metals such as iron and aluminum in soils. It is well accepted that clay particles will move downward in soils; what is less commonly inferred is that any contaminants associated with the clays will also move downward. For mobility of some metals, this may be a dominant process. Similarly, bioturbation has proven to markedly outpace leaching for many metals. This paper considers analogues related to cesium from bomb-fallout and Chernobyl, other natural radionuclide inputs to the soil, soil pedogenesis, pollen and non-metal industrialage inputs, ancient metal works, and soil fertility management. Related to biological transfers and toxicity, it considers analogy among elements an d among biota, and analogy to ecotoxicology of metals to freshwater biota. Where possible, limiting values for parameters of assessment models have been derived. Key words: Terrestrial, leaching, mobility, ecotoxicity, assessment
Mineralogical and geochemical studies of hardened subsurface layers in soils of the Azufres and Atecuaro volcanic calderas, southwestern Mexico
Authors: Ostrooumov Mikhail , Garduño Monroy Victor Hugo , Servenay Alise
Published: April 2011

Free silica and halloysite-bearing hardened subsurface layers in the ash fall deposits of the Azufres and Atecuaro volcanic calderas (Michoacan State, southwestern Mexico), known as “tepetates”, have been characterized by chemical analysis, X-ray diffraction (XRD), Raman and Infrared spectrometry, optical (OM) and scanning (SEM) microscopy with energy dispersive X-ray analysis (EDXRA). Chemical analysis of these weathered and hardened formations shows the oxidation of Fe2+, enrichment of Al, Fe3+ and Ti, loss of Si, Na, Ca, K, Mg, and formation of minerals with hydroxyls groups. Tepetates are characterized by elevated SiO2/Al2O3 molar ratios (4.86–8.82) that show part of the SiO2 has crystallized in free siliceous phases. X-ray analysis reveals hydrated (1.0 nm) and dehydrated halloysite (0.7 nm), sanidine, plagioclases, cristobalite, and tridymite. Raman and infrared spectra confirm the presence of these mineral phases and show that the structural transformations occur in opal neoformations. SEM shows a compact matrix with a skeleton of different phenocrysts (aluminosilicates, ferromagnesian minerals and various crystalline silica phases) and the presence of non-crystalline silica (volcanic glass and opal with different degrees of crystallinity). The tepetates form by interaction of two processes: volcanic ash fall then subsequent weathering under variable climatic conditions. These indurated horizons are partly or totally cemented by the diagenetic secondary minerals: non-crystalline silica with variable crystal chemical characteristics and clay minerals. Key words: Ash fall, tepetates, volcanic soil, mineralogy, geochemistry
Effectiveness of using vegetation index to delineate zones of different soil and crop grain production characteristics
Authors: Basnyat Prakash , McConkey Brian G. , Selles Fernando , Meinert L. Brett
Published: April 2011

Cost-effective methods to map differences in productivity across fields have potential application for site-specific management of fertilizer and pesticides. In this study, zones were delineated for a field with hummocky topography in southwestern Saskatchewan by clustering the normalized difference vegetation index (NDVI) derived from Landsat TM information. Zones uniqueness were confirmed if zones differed in grain yield. Two different zones were delineated in the field. These zones had significant (P < 0.05) differences in soil factors related to productivity: average solum depth, spring soil nitrogen (N), phosphorus (P), and spring soil moisture. Over 4 yr, the two zones also had different spring wheat (Triticum aestivum L.) grain yield and protein content. The yield response to N-P fertilizer blend within each zone was different with no significant response to N-P fertilizer in the zone with higher NDVI values versus a significant response to N-P in the zone with lower NDVI. The results indicate a potential economic advantage to reducing fertilizer application to the zone without fertilizer response. Further, the residual soil NO3-N in the zone without fertilizer response was positively correlated with N application in the previous year. Therefore, there is a potential environmental benefit to reducing fertilizer application to that zone to decrease residual NO3-N, which can leach and contaminate ground water or can be denitrified to the greenhouse gas, N2O. Hence, this relatively simple and low-cost method of zone delineation has potential practical application to realize economic and environmental benefits from site-specific management of fertilizer.
Quantification of organic carbon pools for Austria’s agricultural soils using a soil information system
Authors: Gerzabek M. H. , Strebl F. , Tulipan M. , Schwarz S.
Published: April 2011

Within the framework of the project “Austrian Carbon Balance Model”, we estimated soil organic carbon (OC) content for the agricultural land of Austria. The basic chemical and physical data were obtained from the national electronic soil information system BORIS (Boden Rechnergestütztes Informtions System). The latter data were obtained through soil surveys performed over the past 10 yr. The BORIS data were corrected for soil gravel content, bulk densities and differences in chemical analytical methods used for soil OC. Our estimation also showed the following ranking for soil OC content (0–50 cm) under different land use systems: vineyards (57.6 t C ha-1) ~ cropland (59.5 t C ha-1) < orchards/gardenland (78 t C ha-1) ~ intensive grassland (81 t C ha-1) < extensive grassland (119 t C ha-1). Although the main portion of soil carbon is stored in topsoils (0–20 cm) in all land-use classes, deeper soil layers (20–50 cm) contribute significantly to the overall inventory (between 18. 2 and 27.2 t C ha-1), but appear to be less influenced by land use. A total OC storage in Austria’s agricultural soils of 284 Mt was estimated. A west-east gradient of OC storage in agricultural soils of different Federal Provinces was observed. Under Austrian conditions, extensively used grassland plays an important role for OC-storage. Wide C:N ratios in these soils suggest accumulation of poorly humified organic material and slow OC turnover. Key words: Carbon sequestration, soil organic matter, soil humus, soil nitrogen content, C:N ratio
Using pH-dependent CEC to determine lime requirement
Authors: Lemire Edouard , Taillon Kate M , Hendershot William H.
Published: April 2011

Controlling soil pH is important to ensure good crop yield. This study was conducted to determine whether the accuracy of the existing Shoemaker-McLean-Pratt (SMP) pH-buffer method could be improved by using the pH-dependent cation exchange capacity curve (CECpd). Soil pH, SMP and CECpd measurements were performed on 18 acid surface horizon soil samples, with textures from sandy loam to clay loam. These soils were incubated with three levels of calcium carbonate for 12 wk, after which the soil pH and the effective cation exchange capacity (CECe) were measured. The correlation coefficient (R2) for the CECpd and CECe curves was 0.96. The main factor affecting the slope of the curves is the soil organic matter content. The increase of CECe in the soil was also found to be directly proportional to the amount of lime applied, regardless of the type of soil. By using the slope of the Qv versus pH curve for each soil and the relationship between CECe and lime application, we were able to determine the lime required to raise the soil pH in water to 6.5. As an alternative to the current practice of using the SMP buffer, we propose that it should be possible to estimate the pH-dependent CEC curve from measurable soil properties (e.g., organic matter) and to estimate the lime requirement as the difference in CECpd between the existing and desired pH values. Once the slope of the Qv/pH relationship has been determined or estimated for a soil, the only measurement necessary for calculating lime requirement in subsequent years would be the soil pH. The proposed method would provide lime requirement estimates while decreasing the annual cost of soil analysis. Key words: Lime requirement, cation exchange capacity, Non-Ideal Competitive Adsorption, soil properties, organic matter, Fe oxides
The magnetic susceptibility of soils in Kohgilouye, Iran
Authors: Owliaie H. R. , Heck R. J. , Abtahi A.
Published: April 2011

Soil magnetic susceptibility (MS) and Fe were examined for several soils on calcareous parent material, reflecting key climatic conditions and drainage classes in southwestern Iran (Kohgilouye Province). Alfisols, in the eastern and northern parts, contained more pedogenic (citrate dithionite extractable) Fe (up to 60 g kg-1 on a minerogenic basis; 70 % of total Fe, as determined by lithium tetraborate fusion) and poorly crystalline Fe (up to 6 g kg-1 ammonium oxalate extractable) than the Inceptisols in the southern parts. Soil MS (χlf) ranged from 5 to 120 × 10–8 m3 kg-1, with A horizons exhibiting greater values than B horizons, and Alfisols higher than other soils. Pedogenic enhancement of χlf corresponded with preferential leaching of diamagnetics (primarily carbonates), as well as weathering of primary paramagnetics and neoformation of antiferromagnetics. Frequency dependence of MS (χfd), indicating ultrafine superparamagnetics, followed trends similar to χlf. Sequential heating of well-drained samples, from 25 to 500°C, resulted in enhancement of Χ (average of 21%), a ttributed to the conversion of antiferromagnetics to ferrimagnetics; between 500 and 700°C, Χ typically decreased (average of 15%). The Χfd of well-drained soils increased by an average of 5.3 percentiles by 700°C. Gleysolic soils exhibited less weathering (<51% of total Fe), higher proportions of poorly crystalline Fe (>0.15), lower Χlf (<25 × 10–8 m3 kg-1) and Χfd (<2%), as well as greater average enhancements of Χlf (265% at 500°C) and Χfd (8.4 percentiles at 700°C) on heating. Key words: Calcareous, iron oxides, citrate dithionite, ammonium oxalate, frequency dependence, thermal enhancement
Nutrient supply from organic amendments applied to unvegetated soil, lettuce and orchardgrass
Authors: Hammermeister A. M. , Astatkie T. , Jeliazkova E. A. , Warman P. R. , Martin R. C.
Published: April 2011

Organic sources of nutrients are increasingly being used in horticultural and certified organic production. The nutrient-supplying potentials of poultry manure compost (PM), feather meal (FM), alfalfa meal (AA) and vermicastings (VC) and an unamended control were measured in a growth room experiment. The amendments were applied at rates equivalent to 200, 400 and 800 kg total N ha-1 to a soil of low fertility. Nitrogen supply rates and concentrations were measured over 6 mo in unvegetated pots using PRS™ probes and KCl extraction, respectively. Biomass of lettuce (Lactuca sativa L.) and orchardgrass (Dactylis glomerata L.) and N uptake of orchardgrass were measured. Repeated measures analysis revealed significant amendment × rate × time interaction effects for N supply rate and concentration. Of total N applied, available N was 50 to 70% in the FM and PM treatments, 10 to 40% in the AA treatments, and 10% in the VC treatments. High rates of FM and PM were toxic to lettuce but produced good orchard grass yields. VC was safe for lettuce but low N availability limited long-term orchardgrass growth. Higher application rates did not result in corresponding increases in nutrient supply. Consideration should be given to balancing the ratio of available nutrients in amendments with plant requirements. Key words: Apparent nitrogen recovery, plant N uptake, feather meal, alfalfa meal, vermicastings, poultry manure compost
Soil chemical changes following manure application on irrigated alfalfa and rainfed timothy in southern Alberta
Authors: Olson Barry M. , Papworth Lawrence W.
Published: April 2011

In areas within Alberta where suitable cultivated land is not available, or for convenience, the use of forage land is an alternative for manure application. However, there is limited research on the effects of manure on forage land in the province. The objective of this 5-yr study was to determine the effects of manure on soil chemical properties of forage land. Cattle (Bos taurus L.) and hog (Sus scrofa L.) manures were applied at five rates on irrigated alfalfa ( Medicago sativa L.) and on rainfed timothy(Phleum pratense L.) sites. Treatments were replicated four times and arranged in a randomized complete block design. Soil samples (0 to 15, 15 to 30, 30 to 60, 60 to 90, 90 to 120, and 120 to 150 cm) were collected each spring prior to manure application. Manure application on forage land significantly affected soil chemical properties such as increases in NO3-N, PO4-P, K, Na, and electrical conductivity. There was also evidence of accumulation and some downward movement of NO3-N, Na, and K below 15 cm. The higher manure application rates used in this study (>31 Mg ha-1 cattle manure and >42 Mg ha-1 hog manure; wet weight) are not sustainable in terms of potential environmental risk, such as leaching of NO3-N to groundwater, loss of P in runoff water, and increased soil salinity. Appropriate application rates should be based on crop nutrient requirements and management practices that include regular manure and soil testing. Key words: Alfalfa, timothy, manure, hog, cattle, soil nutrients, electrical conductivity
Quantification of soil volumes in the Eg & Bt-horizon of an Albeluvisol using image analysis
Authors: Montagne David , Cousin Isabelle , Le Forestier Lydie , Daroussi Joël , Cornu Sophie
Published: April 2011

In this study, we provide a strategy to quantify the effects on soil evolution of driving forces such as human activities or global change. This strategy was developed for situations in which soil evolution resulted in the formation of a complex juxtaposition of soil volumes with distinct properties including soil colours. It is based on image analysis. Our approach proceeds in two steps: (1) to find the minimum sample size over which the soil anisotropy can be neglected and (2) to define a Representative Elementary Volume (REV) of that sample. This approach was developed on the Eg & Bt horizon of a drained Albeluvisol in which three decimetric soil monoliths were sampled at 60, 110 and 210 cm from a drain. The monoliths were sliced into 1.5-cm horizontal layers. Each slice was photographed and studied by image analysis. At the monolith scale, there was neither lateral nor vertical anisotropy. The sampled monoliths were larger than the REV allowing quantification of the different soil volumes constituting this particular horizon. We quantified significant evolutions of the abundance of the different soil volumes characterized by their colour as a function of the distance to the drain. Such a quantification of the effects on soil evolution of human activities or global change equally applies for Podzols, Calcisols or Gleysols for which pedogenesis also resulted in contrasted soil colour evolutions. Key words: Soil change, pedogenesis quantification, artificial drainage, image analysis, Albeluvisol, representative elementary volume
The traction effect of lateral roots of Gavan (Astragalus raddei) on soil reinforcement in Northwest Iran (rangelands of the Shanjan area of Shabestar)
Authors: Bibalani Ghassem Habibi , Golshani Abolfazl Aghajanzadeh , Najafian Kamal Aldin
Published: April 2011

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Response of the Illinois Soil Nitrogen Test to liquid and composted dairy manure applications in a corn agroecosystem
Authors: Klapwyk J H , Ketterings Q M , Godwin G S , Wang D.
Published: April 2011

Dairy manure is important for corn (Zea mays L.) production in New York. Optimizing corn yield while minimizing environmental loss with manure nutrients is often a challenge. A potential tool for improving N management is the Illinois Soil Nitrogen Test (ISNT), which estimates amino sugar N, a pool of potentially mineralizable N for corn uptake. The objectives of this study were to determine (1) the short-term effects of manure applications on ISNT-N, and (2) the longer-term impacts of annual additions of composted and liquid dairy manure on ISNT-N. A 6-wk incubation study showed that NH4-N from manure temporarily (< 2 wk) increased ISNT results. A 4-yr field study was conducted with annual spring applications of two rates of composted dairy manure (45 and 77 Mg ha-1) and two liquid dairy manure rates (63.5 and 180 kL ha-1). Results showed that ISNT-N slightly decreased over time in check plots (no manure or fertilizer additions) and that increases in ISNT-N over time in compost and liquid manure amended plots were consistent with changes in N credits currently given to manures in New York. Our results suggest that the ISNT accounts for N in previously applied compost and manure amendments, but that samples should not be taken within 2-wk following manure addition. Key words: Amino sugar, compost, Illinois Soil Nitrogen Test, nitrogen, manure, nutrient management
Effect of nitrogen fertilization and topography on soft red winter wheat yield and protein content in two Ontario landscapes
Authors: Denys Christopher J , O’Halloran Ivan P , Lauzon John D
Published: April 2011

Identification of suitable management units for the variable application of fertilizer N is an essential component of a site-specific N management program. Topography and/or soil N test results are examples of two parameters that could potentially delineate N management units for improved grain yield or protein concentration. Field studies were conducted on soft red winter wheat (Triticum aestivum L.) to examine the effects of mineral soil N, soil organic carbon (SOC), and N fertilization on grain yields and protein concentrations in two variable landscapes in southwestern Ontario, Canada. Six N rates (0 to 145 kg N ha-1) were applied to plots (3 × 400 m long), arranged in a randomized complete split block design with four replicates. Sampling on a 3 × 20 m grid indicated slope position affected soil nitrate (NO3-N) and SOC levels at site 1, but not at site 2. The range of spatial correlation for NO3-N was 11.5 m at both sites and for SOC was 16.0 m and 32.4 m at site 1 and 2, respectively. Yields decreased and protein concentrations increased while moving upslope at both sites. Yield response to applied fertilizer N was characterized using a quadratic model. The most economic rate of N (MERN) for site 1 was 105 kg ha-1, and did not vary with topography. At site 2, yield response to applied fertilizer N varied with topography and MERN increased while moving downslope (91, 104, 120 kg N ha-1 for upper, mid, and lower, respectively). Protein concentration responses to applied N were fitted to cubic models, and the nature of the response to applied N did not vary with slope position. Based simply on grain yield, the potential to use topography and/or mineral N in the soil to identify management units for variable application of N was limited at these two sites; however, variably applying N may reduce the risk of exceeding the protein limits for export markets on the upper slope positions without sacrificing yield. Key words: Site-specific crop management, nitrogen application, N fertilizer, variogram, topography
Application of the forest ecosystem model EFIMOD 2 to jack pine along the Boreal Forest Transect Case Study
Authors: Shaw Cindy , Chertov Oleg , Komarov Alexander , Bhatti Jagtar , Nadporozhskaya Marina , Apps Michael , Bykhovets Sergey , Mikhailov Alexey
Published: April 2011

Sustainability of forest ecosystems and climate change are two critical issues for boreal forest ecosystems in Canada that require an understanding of the links and balance between productivity, soil processes and their interaction with natural and anth ropogenic disturbances. Forest ecosystem models can be used to understand and predict boreal forest ecosystem dynamics. EFIMOD 2 is an individual tree model of the forest-soil ecosystem capable of modelling nitrogen feedback to productivity in response to changes in soil moisture and temperature. It has been successfully applied in Europe, but has not been calibrated for any forest ecosystem in Canada. The objective of this study was to parameterize and validate EFIMOD 2 for jack pine in Canada. Simulated and measured results agreed for changes in tree biomass carbon and soil carbon and nitrogen with increasing stand age and across a climatic gradient from the southern to northern limits of the boreal forest. Preliminary results from scenario testing indicate that EFIMOD 2 can be successfully applied to predict the impacts of forest management practices and climate change in the absence of natural disturbances on jack pine in the boreal forest of Canada. Model development is underway to represent the effects of natural disturbances. Key words: EFIMOD 2, forest soil, carbon, nitrogen, model, jack pine
Monitoring soil organic carbon stock changes in agricultural landscapes: Issues and a proposed approach
Authors: VandenBygaart A J
Published: April 2011

The distribution of soil organic carbon (SOC) in the landscape is governed by multiple factors and processes occurring at multiple scales. Thus, an understanding of landscape processes and pedology should aid in designing approaches to study SOC stock changes. Numerous factors affect distribution of SOC in the landscape at varying spatial and temporal scales. Each of these is summarized to set the stage for outlining a proposed approach to monitoring SOC in the agricultural landscape. Many tools are used to assess the variability of soil properties at varying spatial scales. Pedological knowledge and interpretation of landscape processes can be used to understand the spatial distribution of SOC in the landscape. I show that semi-variograms and the minimum detectable difference may be of limited value in deriving a universal approach to assess SOC change. Issues to be considered or resolved before initiating a monitoring system include depth of sampling and influence of management, compositing and sub-sampling, changes in bulk density, landscape effects and SOC dynamics. After considering these issues, I propose an approach to monitor SOC stock change in agroecosystems, acknowledging that any methodology likely cannot be strictly and universally applicable. The approach considers issues such as location, plot layout, and experimental and statistical design. Such an approach, derived from a landscape and pedology perspective, may make the measurement and verification of SOC at varying scales a less daunting task. Key words: Soil organic carbon change, landscape, pedology, experimental design
Long-term solute redistribution in relation to landscape m orphology and soil distribution in a variable glacial till landscape
Authors: Whetter D A , Bullock P R , Eilers R G
Published: April 2011

Landscape delineation based on soilslope associations with similar patterns of solute redistribution would allow for better agro-environmental land management. Long-term redistribution of solutes was examined in relation to topographic variables and static soil properties in a glacial till landscape near Miniota, Manitoba. Static soil properties that were the best predictors of solute redistribution included CO3, Ahor, Solum and OrgC. Temporal variability overshadowed the influence of topographic variables and static soil properties on dynamic solute redistribution within the crop rooting zone (i.e., 120 cm). Topographic variables (relative elevation, topographic index, contributing area) and static soil properties (A horizon depth, solum depth, A horizon organic carbon) were correlated to SO42- and NO3− redistribution. An unexpected result was that more statistically significant relationships were found between these parameters and solute redistribution below 120cm rather than within the root zone. Very low NO3− concentrations were found in the rooting zone at most sample positions, indicating that crop demand during recent growing seasons matched or exceeded supply. Accumulations of NO3− below the rooting zone indicated that deep percolation of NO3− has been an important process over the longer term throughout the upper and mid slope positions of this landscape. A lack of NO3− accumulation in one lower-toe position and the depression indicated that excess NO3− in these profiles may have been leached into the groundwater and/or removed via denitrification or simply may not have accumulated. There appears to be utility in using static soil properties and topographic variables as indicators of dynamic processes of solute redistribution, however, a priori knowledge of soil-landscape relationships and an understanding of associated pedogenic processes and hydrologic regimes are required to achieve sensible results. Key words: solute redistribution; soil properties; topography; landscape; nitrate, sulfate; chloride
Kinetics and mechanisms of monoammonium phosphate-induced potassium release from selected potassium-bearing minerals
Authors: Zhou J M , Huang P M
Published: April 2011

A high concentration of phosphate in the immediate vicinity of the phosphate fertilizer zone of soil could induce K release from K-bearing minerals to soil solution. In this study, the kinetics of K release by monoammonium phosphate (NH4H2PO4) from biotite, muscovite, and microcline were investigated. The results indicate that K release from all of these minerals was promoted by 1 M NH4H2PO4 (pH 4.0). The release of K from these minerals can be described by the zero-order rate equation. The rate coefficients of K released from the minerals (2–5 µm) in 1 M NH4H2PO4 solution ranged from 0.20 to 2.09 mg kg-1 h-1 at 25°C and from 1.22 to 9.00 mg kg-1 h-1 at 45°C, respectively. The amount of K release from the same mineral samples in 1 M NH4Cl solution (pH 4.0) at 25°C was not detectable and was too low to be determined accurately at 45°C. The dfferences in the rate of NH4H2PO4-induced K release from the different minerals were explained by the chemical composition, crystal structure, and the crystallization sequence of the minerals. The activation energies of the phosphate-induced K release from these minerals ranged from 37 to 72 kJ mol-1 and the pre-exponential factor values (Arrhenius equation) ranged from 1.2 × 106 to 7.2 × 1011 mg kg-1 h-1. The examination of the phosphate-reacted minerals shows the formation of crystalline NH4-taranakite in the muscovite and microcline systems and noncrystalline products in the biotite system. The absence of the formation of crystalline NH4-taranakite in the biotite system is attributed to the Fe perturbation. These data indicate that the major mechanism of NH4H2PO4-induced K release from the K-bearing minerals was the combined effect of phosphate and protons on the alteration of minerals. Therefore, the K-supplying rate of soils in the immediate vicinity of fertilizer zones may be enhanced through phosphate fertilization. Key words: Potassium release, kinetics and mechanisms, phosphates, potassium-bearing primary minerals
Comparing in situ methods for measuring nitrogen mineralization under mock precipitation regimes
Authors: Isaac M E , Timmer V R
Published: April 2011

Measurement of soil nitrogen mineralization rates is frequently conducted in situ using a variety of methods, and often producing inconsistent estimates. We conducted a pot experiment to compare rates generated from three different in situ methods (buried bag, covered core, and resin core) under three mock precipitation regimes. Resin core incubations generated the most variable nitrogen mineralization values (9.33–0.09 µg g-1 28 d-1) presumably due to fluctuating soil moisture conditions inherent in the design. Key words: Nitrogen mineralization, in situ incubations, precipitation
Effect of artificially eroded Dark Brown Chernozemic soil and subsequent amendments on the milling and baking quality of wheat under dryland conditions
Authors: Dormaar J. F. , Lukow O. M. , Lindwall C. W. , Kozub G. C.
Published: April 2011

A field was artificially eroded by levelling in 1957. It was continuously cropped to barley for 7 yr. Subsequently, the field was cropped to a wheat-fallow rotation up to but not including 1986. Two major restoring productivity experiments were conducted over that time period. After 30 yr and 19 crops, a third experiment was established to determine the effect of artificial soil erosion and four restorative amendments on 13 wheat quality characteristics. Year, erosion level, and amendment all had significant effects on many wheat quality parameters. Erosion decreased overall quality, mainly by decreasing protein content which in turn affected other quality characteristics. Applications of manure, fertilizer, and straw + fertilizer increased protein content and related characteristics substantially compared to the check. Since high-quality bread wheat is central to its worldwide demand, prevention of soil erosion is essential. Conversely, eroded soil can be ameliorated with amendments but at a cost of the amendment and its application.

Keywords: Soil erosion, topsoil loss, wheat quality, soil moisture, fertility amendment
Seasonal denitrification rates under corn (Zea mays L.) in two Quebec soils
Authors: Liang B. C. , MacKenzie A. F.
Published: April 2011

Nitrogen losses in soil through denitrification are important due to reduced agronomic effectiveness and environmental concerns with nitrous oxide emissions. Knowledge of denitrification may allow for management procedures to reduce these losses. Field experiments were conducted in 1991 and 1992 to investigate N fertilizer effects on denitrification under corn (Zea mays L.) on two soils of contrasting texture in southwestern Quebec. Soil core incubation with C2H2 was used to assess denitrification rates. Total calculated denitrification rate from April to November in 1991 and 1992 varied from 4 to 41 kg N ha−1 on a Chicot sandy clay loam and from 29 to 53 kg N ha−1 on a Ste. Rosalie clay. Denitrification rates increased linearly with increasing fertilizer N rates only in the Ste. Rosalie clay in 1991. Denitrification in the Ste. Rosalie soil was positively related to temperature and NO3− levels in April and May, moisture content from August to November, and temperature in October and November. Denitrification in the Chicot soil was positively related to soil moisture content and NO3− levels in April and May, and soil moisture content in June. Reducing soil NO3− concentrations in April and May could decrease denitrification rate in both Chicot and Ste. Rosalie soils.

Key words: Denitrification, fertilizer N, temperature, moisture content
Fractionnement de la fertilisation azotée d'appoint à la suite de l'incorporation au sol de bois raméaux fragmentés: modifications de certaines propriétés biologiques et chimiques d'un sol cultivé en pomme de terre
Authors: Tremblay J. , Beauchamp C. J.
Published: April 2011

A field experiment was conducted in 1992 and 1993 in a potato crop (Solanum tuberosum L.). Biological and chemical soil properties were investigated following incorporation of chipped ramial wood (chipped fine branchwood) combined with split applications of supplementary N fertilizer. Fungal populations showed a a temporary increase following incorporation of low C/N chipped wood, whereas bacteria and actinomycete populations remained unchanged. Chipped ramial wood did not induce development of common scab or rhizoctonia on tubers. Soil total carbon (C) and water-holding capacity increased with inputs of chipped wood but C/N ratio and pH were not affected. Only available P content decreased following incorporation of chipped wood, likely due to immobilization by microorganisms. Splitting supplementary N fertilizer showed little effect on soil chemical properties, but it reduced the incidence of common scab on tubers in 1992. Soil amendment with chipped ramial wood in combination with split N applications improved biological activity and caused a short-term increase of total C. Key words: Chipped ramial wood, Chipped fine branchwood, split N fertilization, fungal populations, microbial biomass, immobilization, phosphorus
Statistical analysis and presentation in CJSS Vol. 75
Authors: Hall John W.
Published: April 2011

not available
Review and performance of four models to assess the fate of radionuclides and heavy metals in surface soil
Authors: Sheppard M. I. , Elrick D. E. , Peterson S. R.
Published: April 2011

The nuclear industry uses computer models to calculate and assess the impact of its present and future releases to the environment, both from operating reactors and from existing licensed and planned waste management facilities. We review four soil models varying in complexity that could be useful for environmental impact assessment. The goal of this comparison is to direct the combined use of these models in order to preserve simplicity, yet increase the rigor of Canadian environmental assessment calculations involving soil transport pathways. The four models chosen are: the Soil Chemical Exchange and Migration of Radionuclides (SCEMR1) model; the Baes and Sharp/Preclosure PREAC soil model, both used in Canada's nuclear fuel waste management program; the Convection-Dispersion Equation (CDE) model, commonly used in contaminant transport applications; and the Canadian Standards Association (CSA) derived release limit model used for normal operations at nuclear facilities. We discuss how each model operates, its timestep and depth increment options and the limitations of each of the models. Major model assumptions are discussed and the performance of these models is compared quantitatively for a scenario involving surface deposition or irrigation. A sensitivity analysis of the CDE model illustrates the influence of the important model parameters: the amount of infiltrating water, V; the hydrodynamic dispersion coefficient, D; and the soil retention or partition coefficient, Kd. The important parameters in the other models are also identified. This work shows we need tested, robust, mechanistic unsaturated soil models with easily understood and measurable inputs, including data for the sensitive or important model parameters for Canada's priority contaminants. Soil scientists need to assist industry and its regulators by recommending a selection of models and supporting them with the provision of validation data to ensure high-quality environmental risk assessments are carried out in Canada.

Key words: Soil transport models, environmental impact assessments, model structure, complexity and performance, radionuclides 137Cs, 90Sr, 129I