bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of surface manure application timing on ammonia volatilization
Authors: Gordon R. , Jamieson R. , Rodd V. , Patterson G. , Harz T.
Published: April 2011

The purpose of this study was to evaluate the influence of timing of application on ammonia (NH3) volatilization from surface-applied dairy manure. Field trials were conducted over a 2-yr period (1994 and 1995) at the Agriculture and Agri-Food Canada Research Farm in Nappan, Nova Scotia. A total of eight trials were performed in an attempt to characterize what effect the timing of application (morning vs. late afternoon/early evening) has on NH3 volatilization losses. Ammonia losses were also related to several meteorological parameters. The total percentage of NH3 volatilized in the 10 h following field spreading ranged from as low as < 2% to approximately 66%. Late-day spreading typically resulted in at least a 30% reduction in overall NH3 flux densities, primarily due to substantial reductions in NH3 losses occurring within the first 10 h after manure application. The positive benefits of late-day manure spreading were more pronounced during warm, dry weather conditions. Significant (P < 0.05) positive linear correlations were observed between NH3 volatilization in the 10 h following spreading and solar radiation (r2 = 0.56), wind speed (r2 = 0.53), temperature (r2 = 0.34) and vapour pressure deficit (r2 = 0.53). Results from this study have indicated that late day manure spreading practices can substantially reduce NH3 volatilization. Key words: Slurry, ammonia volatilization, dairy, manure application, timing
Optimal time and placement of nitrogen fertilizer with direct and conventionally seeded winter wheat
Authors: McKenzie R. H. , Middleton A. B. , Zhang M.
Published: April 2011

Direct seeding of winter wheat ( Triticum aestivum L.) has rapidly become an accepted practice in the Chinook region of the southwestern Canadian prairies. Continuously cropped Chernozemic soils are frequently N deficient. To determine best N fertilizer management practices, we examined conventional versus direct seeding to establish winter wheat and to determine the effects of banded and seed-placed N fertilizer treatments in the fall versus broadcast N in the s pring. The research was conducted using two experiments. The first experiment compared band placement of N fertilizer in soil that was conventionally cultivated and seeded, to direct seeding with seed placement of fertilizer using 10% and 50% seedbed utilizations. The second experiment determined optimal time of N application (i.e., fall/spring split vs. spring only) for direct seeded winter wheat. Direct seeding proved to be successful for germination and emergence of winter wheat and was either as good as or superior to conventionally tilled and seeded treatments. Nitrogen fertilizer was successfully applied in the fall without increased risk of winterkill and application at the time of seeding was generally equal or superior to spring broadcast N. Based on these results, producers could either apply all N fertilizer at the time of seeding or use a split application strategy by applying a portion of N in the fall, and in the spring apply the remaining N required, based on soil test N and spring soil moist re conditions. Key Words: Winter wheat, ammonium nitrate, urea, nitrogen fertilizer placement, direct seeding, conventional seeding
Availability of nitrogen in solid manure amendments with different C:N ratios
Authors: Qian P. , Schoenau J. J.
Published: April 2011

Manures behave differently as sources of available N due to differences in the amounts and forms of N in the manure. The C:N ratio is an important factor affecting the rate of mineralization and release of available N from manures in which the majority of N is contained in organic forms. In order to ascertain the effect of manure C:N ratio on N mineralization in manure-amended soils, 13 solid manures with a large range in C:N ratio were applied to two Saskatchewan soils (Haverhill sandy loam and Blaine Lake clay loam) at 100 mg N kg-1 along with control (no manure) treatments. A growth chamber experiment was conducted to evaluate the relationship between manure C:N ratio and canola yield and N uptake, and a laboratory incubation was conducted to measure how the addition of manures with different C:N ratios affected the pattern of N release in the soils as measured by supply rates to anion exchange membrane (PRSTM) probes placed directly in the soil. Canola (Brassica napus var. Sprint) was grown under the same environmental conditions to maturity, and yield and nutrient contents were determined. A significant increase in canola yield and N uptake was observed over the control in both soils only when amended with poultry manure (C:N 7.6) or a pelletized form of hog manure that was supplemented with fertilizer N (C:N 6.6). A significant negative correlation was found between cattle manure organic C:N ratio and N mineralization. Overall, the manures showed limited release of available N over the short-term (67 d) when the organic C:N ratio was in the range of 13–15 and tended to decrease N availability in the short-term if the organic C:N ratio was over 15. The C:N ratio appears to be a useful parameter to measure when attempting to predict the effects of solid manure amendments on short-term N availability. Key words: Nitrogen availability, mineralization, manure, C:N ratio, anion exchange membrane
Concentrations of K, Ca and Mg in maize colonized by arbuscular mycorrhizal fungi under field conditions
Authors: Liu A. , Hamel C. , Elmi A. , Costa C. , Ma B. , Smith D L
Published: April 2011

Little attention has been paid to the effect of arbuscular mycorrhizal (AM) fungi on the uptake of nutrients that move mainly by mass flow. The objective of this study was to assess the possible contribution of indigenous AM fungi to the K, Ca and Mg nutrition of maize (Zea mays L.) as influenced by soil P levels and its impact on plant dry mass. The field experiment had a split plot design with four replicates. Treatments included soil fumigation status (fumigation and non-fumigation) and three levels of P fertilization (0, 60 and 120 kg P2O5 ha-1) in a loamy sand soil in 1997 and a fine sandy loam soil in 1998. Soil fumigati on with Basamid® was used to suppress indigenous AM fungi. Plants were sampled at four different growth stages (6-leaf stage, 10-leaf stage, tasseling and silking). Soil fumigation decreased shoot dry weight, but P fertilization increased shoot dry weight at most sampling times. When no P fertilizer was added, fumigation in the loamy sand soil reduced shoot K and Ca concentrations while, in contrast, in the fine sandy loam soil only Mg concentration was reduced by soil fumigation. The concentration of K in maize shoots was positively correlated (P < 0.05) with extraradicular hyphal length in both soils. The correlation between the abundance of extraradicular hyphae and the concentrations of Ca and Mg in maize shoots was significant only for soils where available Ca or Mg was relatively low. Arbuscular mycorrhizal fungi could increase corn biomass production and K, Ca and Mg uptake in soil low in these elements and low in P. These results indicate that the contribution of mycorrhizae to maize K, Ca and Mg nutrition can be significant in a field situation and that the extent of this contribution depends on the availability of these nutrients and of P in soils. Key words: Arbuscular mycorrhizal fungi, soil fumigation, extraradicular hyphae, uptake of K, Ca, and Mg, soil P levels, maize
Trace metal extractability in soils and uptake by bromegrass 20 years after sewage sludge application
Authors: McBride M B , Evans L J
Published: April 2011

The long-term potential for sewage sludge amendments to alter forage trace metal concentrations was determined on bromegrass, which received no sludge application for 20 yr following annual application during 1973-1980 on a no-till randomized-plot experimental site. In addition, soils were analyzed for trace metals, both total and extractable (using hot 0.01 M CaCl2), by axial-view inductively coupled plasma spectrometry. For Cu, Ni, Zn and Cd, extractability from the soil (by CaCl2) as well as plant tissue concentrations were relatively low considering the high loadings of these particular metals, a fact attributable to the near-neutral pH and high organic matter content of these calcareous soils. However, total and extractable soil Mo remained elevated in the sewage-sludge-amended plots above the levels measured in the fertilized control plots some 20 yr after the last sewage sludge application. Mo bioaccumulated in the bromegrass more than the other trace metals investigated at this site. The Cu:Mo ratio in the forage, a measure of potential to induce Cu deficiency in grazing ruminants, was substantially depressed by most of the sewage sludge treatments. Comparison of the 2000 and 1980 bromegrass analyses suggests an increase in the long-term plant availability of Mo in soils amended with high-Fe and high-Al sludges. Conversely, there was a long-term decrease in Mo availability on the high-Ca sludge treatment, consistent with evidence that much of the Mo has been lost from the topsoil since sludge application. For Cu, Ni and Zn, plant availability appears to have decreased between 1980 and 2000, attributable in part to a calculated loss of substantial fractions of these metals from the topsoil. Bromegrass concentrations of Cu, Ni, Zn, Cd and Mo were strongly correlated to CaCl2-extractable and total metals in the soils, indicating the utility of 0.01 M CaCl2 in predicting plant availability. The chemical differences in the three sludge types applied at the site (high-Ca, high-Al, high-Fe) had little long-term impact on the extractability and phytoavailability of most trace metals remaining in the topsoil. Key words: Biosolids, molybdenum, copper, forage, cadmium, heavy metals
Soil bulk density effects on soil microbial populations and enzyme activities during the growth of maize (Zea mays L.) planted in large pots under field exposure
Authors: Li C. H. , Ma B. L. , Zhang T. Q.
Published: April 2011

Soil compaction associated with inappropriate maneuvering of field equipment, and/or modern cropping system negatively affect soil physical properties, and thus, may limit microbial activities and biochemical processes, which are important to nutrient bioavailability. An experiment was carried out using the pot-culture technique to determine the effect of bulk density on soil microbial populations and enzyme activities in an Eutric Cambisol sandy loam soil (United Nations’ classification) planted with maize (Zea mays L.) in the Experimental Farm of Henan Agricultural University, Henan, China (34°49′N, 113°40′E). Numbers of bacteria, fungi, and actinomycetes and the enzyme activities of invertase, polyphenol oxidase, catalase, urease, protease, and phosphatase were determined at various stages during the plant growing season. Microbial numbers were negatively and linearly related to soil bulk density. With increases in soil bulk density from 1.00 to 1.60 Mg m-3, total numbers of bacteria, fungi and actinomycetes declined by 26-39%. The strongest correlations between the soil microbial population and bulk density occurred at the plant growth stages of the 6 fully expanded leaf (V6) and anthesis (R1), with R2 > 0.90 (P< 0.01) for all three microorganism categories. Increasing soil bulk density was related quadratically to the activities of soil invertase and polyphenol oxidase, protease and catalase. It appears that the greatest activities of most soil enzymes occurred at a bulk density of 1.0 to 1.3 Mg m-3, which are optimum for most field crops. The plant growth stages also had an important impact on soil enzyme activities and microbial populations, with strong positive associations between soil microorganisms and enzyme activities with crop growth. Key words: Maize, soil enzymes, microbial population, soil compaction, bulk density, Zea mays
Short-term stability of soil test phosphorus in agricultural fields
Authors: Lamb J A , Rehm G W
Published: April 2011

The spatial and temporal stability of soil test values is important to the use of soil testing for site-specific soil fertility management. A study was conducted to evaluate the spatial and temporal stability of soil test phosphorus (P). Five sites ranging in size from 3.7 to 4.4 ha were soil sampled in the same locations in a 18.3 × 18.3-m grid either three or four times over a 2-yr period. Bray 1-P values were similar or decreased over time, while Olsen-P values at two of five sites decreased. One site showed no pattern and two sites had cyclic patterns where the spring sample values were greater than the fall. The spatial pattern of soil test values during a 2 yr rotation for Bray 1-P and Olsen-P was very stable. The changes in distribution in soil test P categories over a 2-yr period resulted in a shift to lower soil test categories. The decreases in soil test P were probably caused by plant P uptake in combination with no application of P fertilizer during the study. Key words: Soil test phosphorus, spatial stability, pH, temporal stability
Possible role of aluminum in stabilizing organic matter in particle size fractions of Chernozemic and solonetizic soils
Authors: Curtin D.
Published: April 2011

Although phyllosilicate clays, with their large surface areas, are often considered to play the leading role in stabilizing soil organic matter against microbial attack, several studies have suggested recently that oxides of Al and Fe may stabilize organic matter in some soils. The distribution of organic C and oxides in clay (< 0.2 and 0.2–2 mm) and silt fractions (2–5, 5–20, and 20–50 mm) of four Saskatchewan soils (organic C ranged from 21 to 46 g kg-1) was examined to differentiate the contributions of oxides and specific surface to organic matter retention. Carbon concentrations in the particle size fractions (separated following ultrasonic dispersion of the soils) tended to be highest in the fine silt and coarse clay fractions, not in the fine clay as would be expected if specific surface was the sole factor governing organic matter content. When data for the four soils were pooled there was a strong relationship between organic C (y) in the size fractions and Al (x) extracted by dithionite-citrate-bicarbonate [y = 33.9 x0,5 - 7.3; R2 = 0.90***], suggesting a role for A1 in determining the C storage capacity of the size fractions. The C: A1 ratio increased from an average of 12:1 in clay-sized material to 28:1 in coarse silt. Because it had less A1 per unit mass of C, organic matter in the silt separates may be more weakly bonded to mineral material than is clay-associated organic matter. This may imply that organic matter bound to silt is less stable, and thus susceptible to mineralization, than is organic matter residing in the clay fraction. Key words: Organic matter stabilization, particle size separates, extractable A1 and Fe
The effects of a crude oil spill on microbiological indices of soil biological quality
Authors: Timmerman M. D. , Fuller L. G. , Burton D. L.
Published: April 2011

The effects of a crude oil spill and remediation on the biological quality of an agricultural soil were examined based on three microbiological indices: microbial biomass carbon (MBC), dehydrogenase activity (DHA) and microbial metabolic diversity (MMD). The soils in both contaminated and uncontaminated plots were clay loam Gleyed Rego Black Chernozems developed from lacustrine materials overlying till. The four remedial treatments consisted of: meadow bromegrass (Bromus biebersteinii. Rohman and Schult), alfalfa (Medicago sativa L. ‘Algonquin’), fallow with wheat straw incorporation (SF) and unamended fallow (UFSP). An unamended fallow on adjacent uncontaminated land served as a control (UFCON). The spill had a statistically significant, negative effect on MBC and MMD (P = 0.01 and 0.05, respectively). Although a negative effect on DHA was not significant (P = 0.05), the results show evident trends. The forage treatments were, overall, significantly more effective than the SF treatment in restoring soil biological quality in hydrocarbon contaminated soil to control levels. Based on overall trends only, bromegrass had the greatest effect on soil biological quality relative to the UFSP, followed by alfalfa. The incorporation of wheat straw did not significantly affect any of the examined microbial indices. Key words: Crude oil contamination, soil microbial biomass, dehydrogenase activity, microbial metabolic diversity, soil biological quality
Peat oxidation in an abandoned cutover peatland
Authors: Waddington J M , McNeil P.
Published: April 2011

Drained and cutover peatlands represent a persistent source of atmospheric CO2. Contemporary, intermediate, and long-term rates of peat oxidation were measured in an abandoned cutover peatland to estimate the mass of lost in order to determine if the oxidation rate has changed with time since abandonment. Contemporary rates were measured six times per week at 25 locations within the peatland using a portable infrared gas analyser and an enclosure system. Mean daily peat oxidation was 7.7 g CO2 m-2 d-1 or 4.8 mm yr-1. Intermediate (2-13 yr) oxidation rates were estimated using dendrochronological techniques. Over 325 birch (Betula spp.) shrubs, an invasive group of species in abandoned cutover peatlands, were removed from the peatland after measuring the distance to the existing peat surface from the collar of the trunk. Dating the birches permitted the determination of the rate of peat oxidation and erosion since the establishment of individuals. Long-term oxidation (19 yr) was estimated with over 10 000 measurements on exposed stable tree stumps. The mean intermediate and long-term oxidation rates were 6.2 ± 2.9 mm yr-1 and 5.7 ± 1.1 mm yr-1, respectively. These results suggest that peat oxidation rates remain high even after two decades of post-extraction abandonment. Since oxidation is an irreversible process, these results carry important implications for restoration work as well as for the determination of the long-term source of atmospheric CO2. Key words: Peatland, organic soil, oxidation, carbon dioxide, dendrochronology, peat extraction
Production of annual crops on the Canadian prairies: Trends during 1976–1998
Authors: Campbell C. A. , Zentner R. P. , Gameda S. , Blomert B. , Wall D. D.
Published: April 2011

Statistics on annual crop production for the Canadian prairies, Canada’s largest agricultural region, were summarized by crop, soil zone, and province for the period 1976-1998. A brief discussion, demonstrating how these data can be used by agronomists and policy analysts to derive other information of interest to society (e.g., how much raw material is available for ethanol or strawboard production, or for C storage in soils), was presented. The results show that land seeded to cereals has remained fairly constant, but there has been a sharp decrease in the summerfallow area, with the rate of decrease on the Canadian prairies being 1.26% yr-1 in the Brown soil zone, 7.5% yr-1 in the Dark Brown, and 14.3% yr-1 in the combined Black, Gray and Dark Gray soil zones. The rate of decline in summerfallow area was greater in Saskatchewan than in Alberta, and Manitoba (Black soils only) for unknown reasons. The decline in summerfallow area was accompanied by a steady increase in oilseed crops, especially canola (Brassica napus L.) and, since 1987, in pulse crops, especially lentil (Lens culinaris Medikus) and dry pea (Pisum satiuum L.). Key Words: Seeded area, summerfallow, oilseeds, pulses, cereals
Testing the DNDC model using N2O emissions at two experimental sites in Canada
Authors: Smith W N , Desjardins R L , Grant B. , Li C. , Lemke R. , Rochette P. , Corre M D , Pennock D.
Published: April 2011

Measured data from two experimental sites in Canada were used to test the ability of the DeNitrification and DeComposition model (DNDC) to predict N2O emissions from agricultural soils. The two sites, one from eastern Canada, and one from western Canada, provided a variety of crops, management practices, soils, and climates for testing the model. At the site in eastern Canada, the magnitude of total seasonal N2O flux from the seven treatments was accurately predicted with a slight average over-prediction (ARE) of 3% and a coefficient of variation of 41%. Nitrous oxide emissions based on International Panel for Climate Change (IPCC) methodology had a relative error of 62% for the seven treatments. The DNDC estimates of total yearly emissions of N2O from the field site in western Canada showed an underestimation of 8% for the footslope landscape position and an overestimation of 46% for the shoulder position. The data input for the DNDC model were not of sufficient detail to characterize the moisture difference between the landscape positions. The estimates from IPCC guidelines showed an underestimation of 54% for the footslope and an overestimation of 161% for the shoulder. The results indicate that the DNDC model was more accurate than IPCC methodology at estimating N2O emissions at both sites. Key words: Nitrous oxide, DNDC, soil model, greenhouse gas, testing
Bioavailability of heavy metals in soils amended with sewage sludge
Authors: Morera M T , Echeverría J. , Garrido J.
Published: April 2011

The recycling of sewage sludge to agricultural land results in the slow accumulation of potentially toxic heavy metals in soils. A greenhouse experiment was conducted to determine the bioavailability of Cu, Ni, Pb and Zn applied to soils in urban anaerobically stabilized sewage sludge. The soils were Lithic Haplumbrept (Lh), Calcixerollic Xerochrept (Cx1 and Cx2) and Paralithic Xerorthent (Px). Sunflower plants (Helianthus annuus L) were grown in the soils following amendment with the sludge. The addition of sewage sludge markedly increased the average dry weight of the plants in the soils that had lower yields without sludge addition (Lh, Cx2, and Px). The acid pH of the Lh soil favoured the bioavailability of Zn from sewage sludge. The bioavailability of Cu was greater in the alkaline soils than in the acidic soil (Lh), which can be attributed to the high organic matter content of the Lh soil which complexes Cu and impairs its uptake by the plants. The concentration of metals in the plants increased with the sewage sludge dose. The effect of the soil type on the metal concentration in plants was greater that the effect of the dose. Key words: Soils, sewage sludge, heavy metals, bioavailability, sunflower
Effect of tillage and crop rotations on the light fraction organic carbon and carbon mineralization in Chernozemic soils of Saskatchewan
Authors: Liang B. C. , McConkey B. G. , Schoenau J. , Curtin D. , Campbell C. A. , Moulin A. P. , Lafond G. P. , Brandt S. A. , Wang H.
Published: April 2011

Light fraction of soil organic C (LFOC) represents a major portion of labile soil organic C (SOC) and is a key attribute of soil quality. Soil respiration (Cmin) is an important index depicting the potential activity of the labile SOC. Six field experiments, varying in duration (8 to 25 yr), in location (Brown, Dark Brown and Black Chernozemic soil zones of Saskatchewan) and soil texture, were conducted to evaluate the impact of tillage and crop rotations on crop production and soil quality. We sampled the 0-7.5-cm depth of soil in these experiments to determine the treatment effects on LFOC, the proportion of LFOC in the SOC (LFOC/SOC) and Cmin. Increasing the frequency of summer fallow in cropping systems decreased the LFOC in all soil zones; it also decreased the proportion of LFOC in SOC and Cmin. Tillage had little impact on LFOC in the Brown and Dark Brown Chernozemic soil zones, although it significantly decreased LFOC in the Black Chernozemic soil zone. Thus, crop rotation had a greater impact on LFOC than tillage. Tillage did not influence Cmin in any soil zone. Because adoption of no-till management increased SOC in all soil zones, we concluded that LFOC was not a sensitive indicator of the impact of tillage on this soil quality attribute for these Chernozemic soils in Saskatchewan. We also found that LFOC/SOC is directly proportional to sand content. This relationship may assist us in partitioning SOC pools with differing turnover times when modeling SOC dynamics. Key words: Soil organic C, light fraction organic C, tillage, crop rotations, texture, mineralizable C
Amelioration of degraded soils under red pine plantations on the Oak Ridges Moraine, Ontario
Authors: McPherson T S , Timmer V R
Published: April 2011

Soil degradation and subsequent amelioration were studied on soil chronosequences of old-growth forest, abandoned fields, and young and mature conifer plantations on the Oak Ridges Moraine, an environmentally vulnerable landform near Toronto threatened by encroaching urban development. The chronosequences reflect a history of pre-settlement deforestation, exploitive pioneer agriculture and ensuing land abandonment that led to soil fallowing and/or wind erosion in the 1920s followed by soil stabilization after extensive planting with red pine (Pinus resinosa Ait.). Key pedogenic processes were identified and rates and magnitude of soil recovery were quantified in terms of morphological, physical and chemical characteristics of soil profiles. Soil degradation generally involved reduced fertility with profile simplification (haploidization) on non-eroded fallowed fields, and topsoil loss by wind erosion (deflation) on more exposed eroded fields. After reforestation, soil restoration was characterized by cessation of erosion, accelerated horizon development and differentiation, reduced soil bulk density, and increased fertility and acidification of the soil. Chronofunctions revealed substantial recovery in soil organic C, total N, available P, and exchangeable K, Ca and Mg status within 75 yr of initial reforestation on non-deflated, fallowed sites. In contrast, estimated recovery of these parameters on severely deflated sites was delayed far beyond plantation maturity. Key words: Oak Ridges Moraine, plantation (red pine), ecosystem restoration, deflation, soil degradation
Organic carbon storage and stable isotope composition of soils along a grassland to forest environmental gradient in Saskatchewan
Authors: Landi A. , Anderson D. W. , Mermut A. R.
Published: April 2011

Limited information is available about soil organic carbon accumulation rates and stable isotope composition in the boreal region of the Canadian prairies. The objectives of the study were to document soil development, measure carbon storage and accumulation rates, and determine the 13C/12C ratio of organic matter in native prairie soils in the major soil-climatic zones of Saskatchewan. The mean thickness of the Ah horizon increases from 5 cm in the Brown Chernozems to 14 cm in Black Chernozems, and this horizon is absent in Gray Luvisols. The thickness and degree of development of B horizons increase from Brown to Gray soils. Total organic C storage to 1.2 m depth in Brown, Dark Brown, Black Chernozems, and Gray Luvisols is 9.08, 11.72, 14.88, 9.63 kg C m-2, respectively. The long-term mean annual accumulation rates of organic C for Brown, Dark Brown, Black, and Gray soils are 0.57, 0.90, 1.18, and 0.84 g m-2 yr-1, respectively. For a Rego Black Chernozem the rate is 1.83 g m-2 yr-1. All these values are higher than those reported for temperate grasslands in the United States of America. The ỏ13C values of organic C (an average of all profiles in each soil zone to 1.2-m depth) range from -22.9 ‰ for Dry Brown soils, -24.3‰ for Brown soils, -24.8‰ for Dark Brown soils, -25.3‰ for Black soils, and -26.8‰ for Gray soils. The relative contribution of C4 plants to soil organic C decreases from the warm semiarid grassland to the moist Boreal region, where C4 plants have not influenced organic C at all. Considering the net primary production (NPP) estimated for the soil zones, average aboveground carbon sequestration is estimated to be about 0.46% of NPP. These data provides a realistic assessment of C balances in native prairie soils of Saskatchewan. Key words: Rate of carbon accumulation, stable isotope of soil carbon, soil zones of Saskatchewan, grassland soils, forest soils, Rego Black Chernozem soils
Comparison of conservation with conventional tillage for potato production in Atlantic Canada: crop productivity, soil physical properties and weed control
Authors: Carter M R , Holmstrom D. , Sanderson J B , Ivany J. , DeHaan R.
Published: April 2011

Conservation tillage (CT) for potato crop land has been increasing in Atlantic Canada, but producers are concerned that fields managed in this way may be wet, slow to warm in spring, have increased debris at harvest, exhibit higher soil compaction and result in reduced yield. The objective of this study was to compare the effects of four tillage practices on potato yield, soil properties and weed growth over a 3-yr period. The four tillage practices were: (1 ) conventional autumn mouldboard plowing followed by spring secondary tillage; (2) spring mouldboard plowing followed by secondary tillage; (3) autumn chisel plowing followed by spring secondary tillage; and (4) spring CT. Tillage practices significantly affected soil water content (at both the 0- to 15-cm and 15- to 30-cm soil depths) with CT generally showing a greater soil water content prior to spring tillage in comparison to the other treatments. Soil temperature (at the 2- to 5-cm soil depth) prior to spring tillage was not influenced by tillage differences. Conservation tillage increased soil compaction at the 10- to 30-cm soil depth, but not to a level considered detrimental to root growth. Tillage treatments had no effect on amount of soil clods and plant debris passing over the harvester. Potato yield (range of 43 to 51 Mg ha-1) and quality were not adversely influenced by tillage practices. There were few treatment effects on individual weed species or groupings of annual, perennial and total weeds. Overall, CT can be a viable management alternative to conventional tillage because this practice does not negatively affect field management, potato yield, or soil quality. Key words: Conservation tillage, residue management, potato, soil temperature, soil moisture, tillage methods
Crop rotation and soil N amendment effects on maize production in eastern Canada
Authors: Ma B. L. , Ying J. , Dwyer L. M. , Gregorich E. G. , Morrison M. J.
Published: April 2011

Relying less on fertilizer N and more on crop residual and biological N2 fixation by legume crops has been suggested as an effective way to meet the challenge of maximizing economic return while minimizing environmental pollution. A field study was conducted on a Brandon loam soil (Orthic Humic Gleysol) to determine the effects of crop rotation and N amendments on grain yield, crop growth, N uptake and use efficiency (NUE) of maize ( Zea mays L.) and fertilizer replacement values of legume. The rotations included maize in annual rotation with soybean [Glycine max (L.) Merrill], alfalfa ( Medicago sativa L.) or continuous maize. The soil N amendments included no amendment, NH4NO3 at 100 kg N ha-1, stockpiled or rotted dairy manure at 50 Mg ha-1 (wet weight). Averaged across 4 yr, increases in maize grain yield, total plant N uptake, and NUE ranged from 13 to 35% in the maize-soybean and maize-alfalfa rotations compared to continuous maize monoculture. During the study, total dry matter production was 15 to 35% higher and crop growth rate was 13 to 23% higher for maize following alfalfa than for continuous maize monoculture. The effect of legumes on the subsequent growth of maize (i.e., total dry matter production a n d crop growth rate) was most apparent during the grain filling period. Total maize dry matter production was similar up to silking stage for all three rotation systems; however, the difference in total dry matter between maize monoculture and maize in rotation with legume continued to increase after this stage so that the greatest differences were observed at physiological maturity. Grain yield was 19% higher in the 100 kg N ha-1 treatment and 23% higher in the repeated manure amendment than in the unfertilized treatment. Fertilizer N replacement values were on average, 68 kg ha-1 for soybean and 133 kg ha-1 for alfalfa. Our results indicate that maize in annual rotation with legume crops could increase the maize yields by as much as 20% and reduce the amount of chemical fertilizer N by as much as 180 kg N ha-1. The effect of legume preceding crop on maize dry matter production and N uptake is expressed mostly in the later stages of crop growth in this mid- to short-growing- season region. Key words: Rotation, Zea mays, dry matter accumulation, crop growth rate, manure, nitrogen use efficiency
Spatial variability of trace metals in Podzols of northern forest ecosystems: Sampling implications
Authors: MacDonald J. D. , Hendershot W. H.
Published: April 2011

The concentrations of metals in soils are spatially heterogeneous and soil sampling carried out when studying metals in forest ecosystems is often inadequate. We examined the spatial variability of Cd, Cu, Mn, Ni, Pb and Zn in northern forest ecosystems on a transect with distance from two point source emitters with the goal of providing basic information about the distribution and variability of metals in these soils. Samples were taken under six sampling points at four depths from three experimental sites on each of the two transects. Soils were analysed for acid digestible metals, pH and organic carbon content. Standard deviation, coefficients of variation, mean and medians were analysed for each horizon of each site. It was observed that Cu and Mn variability is higher in closer proximity to the point source while the variability of Zn increased with decreasing soil pH. In Sudbury, emitted metals Ni and Cu accumulate together in soils, whereas in Rouyn-Noranda, with the exception of Cd and Zn, metal concentrations were not related in forest floors. Observations suggest that physical factors influencing where metals are deposited as well as the inherent variability in soil chemical characteristics, and the distance from the point source can all act together to result in high variability in soil metal concentrations in a single forest site. Sampling in the interest of relating vegetation metal concentrations or response to soil metals should be carried out on an individual plant basis with multiple samples taken for each individual. Soil samples taken at intervals of 1 to 1.7 m will provide relative error in estimating soil concentrations of 10% or 20%, respectively. Key words: Spatial variability, trace metals, podzolic soils, smelter emissions
Soil properties and lodgepole pine growth on rehabilitated landings in northeastern British Columbia
Authors: Bulmer C. E. , Krzic M.
Published: April 2011

We determined post-establishment tree growth and soil properties on rehabilitated log landings and forest plantation sites with medium texture in northeastern British Columbia. Six years after rehabilitation treatments were applied, 60% of rehabilitated landing plots had more than 1000 stems ha-1, while 17% had fewer than 600 stems ha-1. The average height of undamaged lodgepole pine trees on rehabilitated landings was consistently lower than for trees of the same age on plantations. Surface (0–7 cm) and subsurface (10–17 cm) soil bulk densities were higher for rehabilitated landings than for adjacent plantations. Rehabilitated landing and plantation soils had similar values of total and aeration porosity. Plantation soils had higher available water storage capacity (AWSC) than rehabilitated soils. Soil mechanical resistance after landing rehabilitation was often higher than for plantation soils at the same depth. Soils on both rehabilitated landings and plantations showed an increase in mechanical resistance from June to September 2001. With the exception of June 2001, soil mechanical resistance after landing rehabilitation was often higher than 2500 kPa. For surface mineral soils, there were no differences in total C, N, or cation exchange capacity (CEC) between rehabilitated landings and plantations. Rehabilitated landing soils had significantly higher total C and N at 10–17 cm depth than plantation soils, which coincided with higher clay content for the landing subsoils. Key words: Forest soil rehabilitation, soil degradation, soil productivity, soil conservation
Designing field studies in soil science
Authors: Pennock D. J.
Published: April 2011

Field research in soil science ranges from modal profile descriptions in support of soil survey to elaborate manipulative experimental designs. All of these field approaches make a valuable contribution to soil science, but researchers who do not use either classical manipulative experimental or geostatistical designs have little guidance (or encouragement) available to them. Well-designed field research of any type requires a clear definition of the research question; a thorough review of the literature to establish the state of knowledge; definition of the population under study and the elements that comprise it; and choice of appropriate scales for sampling support, spacing, and study extent based on an understanding of the underlying processes. For studies where hypothesis testing is appropriate, the hypotheses should be based on sound biological or physical reasoning, and sufficient replicates should be taken to ensure a reliable test. The major challenge in field research design is the development of landscape-scale research designs to examine complex interactions among hydrological, climatic, chemical, and biological processes at scales relevant for environmental management. Key words: Research design, landscape-scale , soil genesis, pattern studies, hypothesis testing, spatial statistics, sampling, cesium
Spatial variability of barley (Hordeum vulgare) and corn (Zea mays L.) yields, yield response to fertilizer N and soil N test levels
Authors: O’Halloran I. P. , von Bertoldi A. P. , Peterson S.
Published: April 2011

Identification of management units for the variable application of fertilizer N is a critical component for the implementation of a site-specific N management program. Field studies were conducted to examine the spatial variability of soil nitrate levels, spring barley (Hordeum vulgare) and corn (Zea mays L.) yields and yield responses to fertilizer N applications on two sites in southwestern Ontario, Canada. Soil sampling on a 3 × 10 m grid indicated that soil NO3-N test values had a log-normal distribution and varied considerably at both sites with CVs exceeding 57% on the untransformed data. Ranges of spatial correlation varied from 20 to 95 m with 30 to 80% of the total variance of the ln-transformed data existing as either random or unsampled variance, and these parameters were not temporally stable. Although NO3-N tended to increase at lower slope positions in two of the 3 site-years, considerable within-slope variability of soil NO3-N levels was also observed. Spatial variations in soil N test levels, crop yields and crop yield responses to applied fertilizer N were not strongly related to one another indicating that it would be unlikely that either soil N test level or yield would adequately delineate management zones for the variable application of N fertilizer at these sites. Key words: Variogram, topography, site-specific crop management
Influence of crop rotation and conservation tillage practices on the severity of soil-borne potato diseases in temperate humid agriculture
Authors: Peters R. D. , Sturz A. V. , Carter M. R. , Sanderson J. B.
Published: April 2011

A field trial was established in 1994 in Prince Edward Island, Canada, to determine the effects of 2- and 3-year crop rotations, with either conventional or minimum tillage treatments, on the severity of potato diseases caused by soil-borne pathogens. The 2-yr rotation consisted of spring barley and potato (cv. Russet Burbank) and the 3-yr rotation was barley (undersown with red clover), red clover and potato. In the potato years only, the main plots were split to examine conventional and minimum tillage (sub-plot) treatments. Potato diseases were assessed during the period 2000–2002, 6–8 yr after the initial establishment of the field trial. In each year of the study, potato plants grown in 3-yr rotations developed significantly (P = 0.05) lower levels of stem and stolon canker and black scurf (Rhizoctonia solani) compared with those from 2-yr rotations. Overall, rotation duration (not tillage type) was the main factor contributing to reduction of disease caused by R. solani. The severity of silver scurf (Helminthosporium solani) was significantly (P = 0.05) lower in tubers from plots managed in 3-yr rotations under minimum tillage practices in 2000, significantly higher in plots managed with minimum tillage in 2001, and unaffected by treatment in 2002. The severity of dry rot (Fusarium spp.) was significantly (P = 0.05) lower in tubers from plots managed with 3-yr rotations under minimum tillage practices in 2000, but was unaffected by either tillage regime in 2001 and 2002. The severity of common scab (Strep tomyces scabiei) was low and not influenced by tillage or rotation in any year of study. In summary, a 3-yr crop rotation combined with minimum tillage reduced potato diseases caused by R. solani and did not affect disease caused by other soil-borne pathogens. From a crop health perspective, there appear to be no constraints to the use of minimum tillage practices in association with 3-yr rotations in potato production in regions of temperate humid agriculture. Key words: Crop rotation, minimum tillage, potato, Solanum tuberosum, soil-borne pathogens, Rhizoctonia solani
Relation of yield of corn (Zea mays L.) to nitrogen in shoot and soil during the early-season following manure application to field plots
Authors: McGonigle Terence P. , Beauchamp Eric G.
Published: April 2011

We investigated corn grain yield responses to early-season soil mineral N and plant N content following application of a variety of manures in Eastern Canada. Liquid cattle, liquid swine, straw-bedded poultry, wood-bedded poultry, and solid cattle manures were each applied at 100, 200, and 300 kg N ha-1 prior to planting corn in a field experiment repeated 3 consecutive years. Additional treatments were urea applied at 50, 100, and 150 kg N ha-1, and liquid cattle and solid cattle manures at 200 kg N ha-1 with bedding amendments added to the field before manure spreading. Control plots received no manure, no urea, and no bedding amendment. Part of the ammonium-N applied in manures and a portion of that added as urea was volatilized or immobilized shortly after application and was not recovered as soil mineral N at planting. Across all treatments, soil mineral N in the top 30 cm on Jun. 10 in each year gave a better relationship to corn grain yield than soil mineral N measured at planting or on Jul. 10. Inclusion of data for plant N content on Jun. 10 or Jul. 10 did not improve the regressions. With remarkable consistency across all manure types, across manure rates, and over the three years, similar values for soil mineral N on Jun. 10 in plots given manure at planting had yields typically 0.5-1.0 t ha-1 greater than those in plots given urea at planting. This result indicates that mineralization of N from manure after the time of sidedress N and undetected as soil mineral N on Jun. 10 can contribute to yield increases of corn. Recent manure history should be considered when using soil tests for mineral N that are taken 3-4 wk after planting to calculate sidedress N fertilization. Key words: Sidedress, soil test, slurry, solid, cattle, swine, poultry
An improved disc infiltrometer method for calculating soil hydraulic properties
Authors: Renduo Zhang Xuzhang Xue, , Gui Shengxiang
Published: April 2011

The disc infiltrometer has been established as a field device for in situ measurements of unsaturated infiltration under tensions. Several methods have been developed for calculating hydraulic properties based on infiltration data from the disc infiltrometer. The method by Zhang (1998) has the advantage in using infiltrometer data measured in a relatively short time period to estimate soil hydraulic properties. In this study, we improved this method by replacing the piecewise linear approximation of hydraulic conductivity function (K(h )), which results in overestimated macroscopic capillary length, with the exponential form of K(h). An efficient and accurate iteration procedure was introduced to solve the highly nonlinear equations of the improved method. An experiment was conducted in a large field to measure infiltration processes at various locations with different sizes of disc infiitrometers under different tensions. Based on the infiltration data, the improved method and three other methods in the literature were utilized to estimate soil hydraulic conductivities at different tensions and macroscopic capillary length. Compared with the three methods, the proposed method provided more accurate and stable estimations of the hydraulic conductivity and macroscopic capillary length, using infiltration data collected at short experiment periods within 20 min. Key words: Soil hydraulic conductivity, disc infiltrometer, infiltration rate
Mobility of copper from sulphate and chelate fertilizers in soils
Authors: Flaten P. L. , Karamanos R. E. , Walley F. L.
Published: April 2011

Copper is a nutrient known for its lack of mobility in soils. This phenomenon affects fertilizer product and placement options when attempting to correct Cu deficiencies. A column experiment was designed to directly compare the mobility of Cu sulphate (CuSO4 5H2O) and a chelated Cu fertilizer (CuEDTA) in five soils with different levels of organic matter (2 to 108 g kg-1 organic C) and clay (4.1 to 34.9%). The movement of Cu, supplied as Cu sulphate and CuEDTA, through a 10- cm column of soil was examined during a 10-d period by monitoring the Cu concentration in leachate following daily additions of 2 cm deionized water and subsequently assaying the soil columns, in 1-cm increments, for DTPA-extractable Cu (DTPACu). Copper sulphate was virtually non-mobile in all soils with at least 20 g kg-1 organic C and 10% clay. However, in a soil with 2 g kg-1 organic C and 4% clay, Cu sulphate moved as much as 7 cm. The restricted mobility of Cu sulphate in all but one soil in this study suggests that in most western Canadian Prairie soils, having relatively high levels of organic matter and clay, Cu supplied as Cu sulphate should be regarded as immobile from an agronomic perspective. In contrast, a portion (2 to 46%) of the CuEDTA moved through the entire 10 cm column of all soils within 3 d, i.e., following three daily additions of 2 cm of water. The enhanced mobility of the chelated Cu is of agronomic significance in that it suggests that this Cu source is more likely to move into the root zone without incorporation and provide adequate feeding sites for a crop when placed in or near the seedrow. Key words: Cu mobility, Cu sulphate, Cu chelate, soil texture, organic matter, leachate
Surface application of cement kiln dust and lime to forages: Effect on soil pH
Authors: Rodd A. V. , MacLeod J. A. , Warman P. R. , McRae K. B.
Published: April 2011

This 2-yr field trial on forage plots compared the relative effectiveness of surface applications of cement kiln dust (CKD) to lime for raising soil pH. Seven soil treatments, in four blocks, were established at four low pH sites, which were: (1) a check plot; (2) lime at the recommended application (L), based on soil test for each site; (3) lime at 1.5 × L; (4) CKD at L; (5 ) CKD at 1.5 ( L; (6) CKD at an equivalent to lime basis; and (7) CKD applied at 1.5 times the equivalent to lime basis, where equivalence was based on CKD’s apparent neutralizing value equal to 75% that of lime. Soil pH was determined before applications and was monitored afterwards for two growing seasons. Two months after surface application, the CKD increased soil pH more than lime, despite its apparent neutralizing value being only 75% that of lime. Effects were greater closer to the soil surface and trends persisted through the following year. The CKD appears to be a quick-acting lime substitute due to its fineness (more than 99% passed through 100-mesh compared with 58% of lime). Key words: Forage, lime, cement kiln dust, pH