bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of N rates and harvest dates on the efficiency of 15N-labelled fertilizer on early harvested potatoes (Solanum tuberosum L.)
Authors: Tran T. Sen , Giroux M.
Published: April 2011

The efficiency of 15N-labelled fertilizer on early harvested potaotes (Solanum tuberosum L., 'Norland') was studied in field experiments on two soil series (Saint-Damase loamy sand and Soulanges sandy loam) during a 2-yr period. The 15NH415NO3 fertilizer was band applied at 0 and 140 kg N ha−1 in 1985 and 0, 70, 140 kg ha−1 in 1986 and four harvests were made during the growing season. The foliage was in full canopy development at 65 or 75 d and its dry matter yield increased significantly with the application of fertilizer-N. At this time about 70% of the total N uptake was in the foliage. From this peak, foliage N decreased gradually with time to about 28% at 95 or 100 d as N was transferred to the tubers. The N concentration in tubers was nearly constant during the growing season. As tuber dry matter increased at each successive harvest, N uptake increased proportionally. Between the first two harvest dates, from 65 to 75 d, the average rates of N accumulation in tubers were 2.1 and 4.5 kg N ha−1 d−1 for the control and N fertilized plot, respectively. The root dry matter and N concentration increased with fertilizer-N and were generally lowest on the final harvest day. Marketable tuber yield responded to N fertilization on the severely N-deficient fields in 1985. But in 1986, the 140 kg N ha−1 treatment delayed the growth of marketable tubers. The percentage of N derived from fertilizer (Ndff) was also very high in 1985 fields and was at a maximum at 65 d (64–69%) with the 140 kg N ha−1 treatment. These values were lower for the same treatments in 1986 fields (39%) because of the larger amounts of available N in soils. The maximum coefficient of utilization (ICU) of labelled fertilizer N was 72–76% in 1985 and 63–68% in 1986. At the final harvest, about 36–50% of the applied fertilizer-N was found in the tubers. Key words: Nitrogen fertilization, 15N-labelled fertilizer, N use efficiency, harvest periods, potato
Effects of two crop rotations on seasonal runoff and soil loss in the Peace River region
Authors: Vliet L. J. P. Van , Hall J. W.
Published: April 2011

Four erosion plots were monitored from 1983 to 1989 (6 yr) to evaluate the effects of two crop rotations and their constituent crops on runoff and soil loss under natural precipitation near Fort St. John in the Peace River region of British Columbia. Rotation 1 consisted of two cycles of summerfallow — canola (Brassica rapa)-barley (Hordeum vulgare L.), and Rotation 2 included summerfallow — canola-barley-barley underseed to red fescue (Festuca rubra L.)-fescue-fescue. Rainfall and snowmelt runoff were collected and sampled throughout the year to determine seasonal runoff and soil losses. Over the 6 yr, the cumulative runoff and soil losses were consistently greater under Rotation 1 than under Rotation 2. There was a greater than fourfold difference in total soil loss, and 33–35% more total runoff. Rainfall-induced runoff and soil losses were significantly higher for Rotation 1 than for Rotation 2. Snowmelt runoff accounted for 90 and 96% of the total annual runoff and for 39 and 80% of the total annual soil loss from Rotations 1 and 2, respectively. Two large rainfall events during 1983 and 1987, each causing a soil loss in excess of 2000 kg ha−1, accounted for between 85 and 91% of the 6-yr total rainfall-induced erosion from Rotation 1. No differences in runoff or soil loss were detected among crops but the comparisons were insensitive because of high residual variation. Key words: Runoff, soil loss, erosion plots, crop rotations
Spatial and temporal fluctuation in biomass, nitrogen mineralizing reactions and mineral nitrogen in a soil cropped to barley
Authors: Burton D. L. , McGill W. B.
Published: April 2011

We compared changes in components of the N-mineralization cascade ranging from the very specific, such as a deaminase, to the highly integrated, such as biomass in a Black Chernozemic seeded to barley (Hordeum vulgare L.) under field conditions at Edmonton. Changes in enzyme content were related to soil [Formula: see text] to determine if the microbial environment changed sufficiently to exert feedback control on N mineralizing reactions and thereby to be detected. Histidase and protease were chosen as model systems for depolymerization and deamination respectively because information exists on their control in pure culture studies, on histidine content and control of histidase in soil, and assay procedures are available for soils. We observed an inverse relationship of labile histidase activity with [Formula: see text] in soils with high [Formula: see text] content and low [Formula: see text] ratio. This relationship provides indirect evidence for [Formula: see text] control of histidase content, but emphasizes that it is only one element of a complex control mechanism. Conversely, enzyme content was not rate limiting to net N mineralization, or sensitive to common control mechanisms. Biomass-C, an integrative measure of substrate supply, potential biological activity and enzymatic activity, describes net mineral-N production better than do indices of any single step. Regular spatial variability is exhibited by [Formula: see text] (and [Formula: see text]). [Formula: see text] is a product of mineralization; a substrate for immobilization, nitrification, plant uptake, and other reactions; and may also be a regulator of activity, or synthesis, of some enzymes. It is intriguing that none of the variables that influence mineral N, such as enzyme activity, biomass, or respiration, varied spatially in a statistically identifiable manner, yet [Formula: see text] did. Key words: Nitrogen mineralization, enzyme content, biomass, protease, histidase, ammonium regulation
Effects of inoculation method and size of Rhizobium meliloti population in the soil on nodulation of alfalfa
Authors: Rice Wendell A. , Olsen Perry E.
Published: April 2011

Field experiments were conducted with alfalfa (Medicago sativa L. ’Peace’) planted on a Black Solod (Landry CL) with pH 5.8 in 3 consecutive years. The same experiment was conducted at two adjacent sites in each year. The population of Rhizobium meliloti in the soil was modified at one site by applying and incorporating a suspension of an indigenous isolate to increase the size to 105 g−1. The other site was on unamended soil with a normal indigenous population of less than 102 g−1. Granular inoculant was applied with the seed or below the seed, or, granular or liquid inoculant was applied beside the row after stand establishment. The soil-placed inoculant treatments were compared with an uninoculated control and a standard seed-applied inoculation treatment. All inoculants were prepared with Rhizobium meliloti NRG-61 which had been selected for low-pH tolerance. Root weight, shoot weight, nodule weight, nodule numbers and strain occupancy of nodules were measured in September of the establishment year and again the following June. Granular inoculant applied with or below the seed resulted in greater nodule weights, nodule numbers and percent nodule occupancy at both sites. Granular inoculant applied with or below the seed was more effective at the site with the normal indigenous population of R. meliloti than at the site with the modified population. When granular inoculants were applied, nodule weights were lower on the site with the modified indigenous population than on the soil with the normal indigenous population. Granular inoculants resulted in significant yield increases over the standard seed-applied inoculant only at the site with the normal indigenous population. There were no substantial differences between the sites in the proportion of nodules occupied by the inoculant strain. These results show that strain occupancy measurements do not necessarily reflect the beneficial effect of inoculation. Key words: Enzyme-linked immunosorbent assay (ELISA), granular inoculant, Rhizobium inoculant, seed inoculant, soil inoculant
Pouvoir fixateur vis-à-vis des ions phosphate de sols tropicaux à argile 1:1
Authors: Frossard E. , Brossard M. , Feller C. , Rouiller J.
Published: April 2011

This study was aimed to clarify the influence of secondary mineral constituents (iron and aluminium oxides, kaolinite) and organic matter on the determination of the phosphate-fixing capacity (PFIX) of well-drained low-activity clay soils. This study was done on soil samples (0–2 mm) and on their particle size fractions. The phosphate-fixing capacity, estimated by an isotopic exchange method, was highly related to the total iron content of the soils. The phosphate-fixing capacity of the particle size fractions was related to their mineralogical composition, and to the organisation of their constituents. H2O2 strongly increased the phosphate-fixing capacity of the soils and of their particle size fractions. Two hypotheses were proposed to explain this. Either H2O2 caused the formation in vitro of amorphous constituents with a high phosphate fixing capacity; or the destruction of organic matter by H2O2 caused the apparition of new surfaces previously masked by organo-mineral aggregation and/or caused the apparition on surfaces of fixation sites previously occupied by organic compounds. Key words: Phosphate-fixing capacity, low-activity clay soils, particle size fractionation, mineralogy, organic matter, H2O2 effect
Effect of tillage practices and hay straw on ammonia volatilization from nitrogen fertilizer solutions
Authors: Al-Kanani T. , MacKenzie A. F.
Published: April 2011

Urea (U) fertilizer solutions applied on soil surface lose nitrogen through ammonia (NH3) volatilization, and such losses may be influenced by tillage practices and by the presence of crop residues. Ammonia measurements in corn (Zea mays L.) fields were initiated and continued for 9 d in July 1988 and 1989 to assess the effects of three tillage practices used in corn production (conventional, CT; reduced, RT; and zero tillage, ZT) and urea-ammonium nitrate (UAN) formulations on the volatilization of NH3 from UAN solutions. The UAN formulations were 33% U — 67% ammonium nitrate (AN) and 50% U — 50% AN. These UAN formulations indicate proportion, as percentage, of total N derived from U and AN, respectively. The experiments were conducted on two agricultural soils of Quebec [Macdonald sandy loam (Humic Gleysol), and St. Benoit sandy loam (Eutric Brunisol)]. Cumulative NH3 losses over 9 d ranged from 0.8 to 9.5% of applied N. On both soils, NH3 losses from 50–50 UAN were higher than the 33–67 UAN by 13.5, 14.6 and 23.9% on CT, RT, and ZT, respectively. Reduced NH3 loss with CT was attributed in part to lower crop residues than with ZT treatments. In a separate experiment to evaluate the effect of plant residues on NH3 loss, chopped timothy hay (Phleum pratense L.) was used to provide a greater surface cover and a uniform spreading of residues. Hay straw surface-applied to a conventionally tilled St. Benoit soil had to reach a threshold level somewhere between 750 and 1500 kg ha−1 to increase N losses compared to no added hay treatment. Key words: UAN solution, ammonia volatilization, tillage, hay straw
Prediction of available potassium in Ontario soils by electro-ultrafiltration and chemical extraction
Authors: Liu Liangxue , Bates T. E. , Tran T. S.
Published: April 2011

The extractions of soil K by electroultrafiltration (EUF) and by chemical methods were compared as predictors of plant-available K for greenhouse-grown alfalfa on 38 Ontario soils. The relation of soil properties to the amount of K extracted by EUF fractions was also examined. The contents of silt and clay were negatively correlated with EUF-K at 50 V and 22 °C and positively correlated with EUF-K at 400 V and 80 °C. Soil pH and organic matter were not significantly correlated with the amounts of K extracted in the EUF-K fractions. The EUF extraction of K was influenced by the presence of carbonate or high exchangeable calcium in soils. Similar correlations were obtained between K uptake and K extracted by chemical methods and the sum of EUF-K fractions. When used along with other soil properties, EUF-K fractions and K extracted by chemical methods predicted availability of soil K with roughly equal ability. The model using the sum of K extracted by EUF at 50, 200 and 400 V is the simplest one and contains three variables, K, K2 and Ca2. The use of EUF is limited due to cost of equipment and time required for analysis, unless a number of nutrients can be accurately determined on one extract. Among the chemical methods, equations developed using three nonacidic extradants, NaCl, ABDTPA and NH4OAc explained more variation in K uptake than two acidic extractants, Mehlich 3 and 0.1 M HNO3. The NaCl model, ABDTPA model and NH4OAc model contained the same variables and had similar R2 values (0.88–0.91). Key words: Available K, chemical methods, electro-ultrafiltration, EUF-K fractions, K uptake
Influence of soil texture on protozoa-induced mineralization of bacterial carbon and nitrogen
Authors: Rutherford P. M. , Juma N. G.
Published: April 2011

Texture affects pore space, bacterial and protozoan populations and their activity in soil. The objective of this study was to test the hypothesis that protozoa grazing on bacteria increase the mineralization of bacterial C and N more in coarse-textured soils than in fine-textured soils. The microcosm experiment consisted of samples from three sterilized Orthic Black Chernozemic soils (SiC, CL and SL) inoculated with Pseudomonos bacteria, two treatments (with and without protozoa), and five sampling dates. The Pseudomonas population was labelled in situ by adding glucose- 14C and KNO3-15N (day 0). A species of Acanthamoeba was added to the microcosms on Day 2. On Day 4 bacterial numbers in all three soils were approximately 3 × 109 g−1 soil. The greatest reduction of bacteria due to protozoan grazing occurred between day 4 and day 7. All soils showed increased CO2-14C evolution and NH4-15N mineralization due to protozoan grazing but the mineralization rate of labelled N in the SL soil was much greater than in the fine-textured soils. The effect of texture on protozoan grazing was not as marked between day 12 and day 37 as earlier in the incubation. Protozoan-induced effects were transient in the soils studied and were most apparent in the coarse-textured soil. Key words: 14C, 15N, N mineralization-immobilization, bacteria, organic matter, Typic Cryoboroll, porosity, protozoa
A comparison of four resin extractions and 32P isotopic exchange for the assessment of plant-available P
Authors: Tran T. Sen , Simard R. R. , Fardeau J. C.
Published: April 2011

Resin extraction procedures are widely used to simulate nutrient uptake by plant roots. The objective of this study was to compare an anion exchange resin in three forms: F, Cl and HCO3, and a mixed anionic-cationic exchange resin in H-OH form to a 32P isotopic exchange method in their ability to extract soil P, and to predict plant-available P for oat (Avena sativa L.) grown in the glasshouse. Thirty-four soils varying widely in chemical and physical properties, and in P contents, were extracted for 24 h at a soil-to-solution ratio of 1:80 with 1 g resin. Increasingly higher P quantities were obtained by isotopic exchange after 1 min (E1 7.61 mg kg−1), Cl-resin (27.3 mg kg−1), HCO3-resin (40.5 mg kg−1), F-resin (75.1 mg kg−1) and H-OH resin (130 mg kg−1). The Cl and HCO3 resins extracted a constant ratio of E1-P in strongly acidic and weakly acidic to neutral soils; this was not the case for the other resins. The pH values of the resin-soil-solution system were related to the natural logarithm of the amount of rapidly exchangeable Ca. The Cl and HCO3 resins best predicted P uptake and relative yield of oat growing on 34 soils. These two methods were superior to chemical methods in evaluating soil P status and fertilizer response of oats. The relationships between the amount of soil P desorbed by the HCO3 and F resins and by plant uptake were improved when the P buffering capacity (MBC) was included in the multiple regression equation. The P intensity factor was most important for the H-OH and Cl resins. In general, desorption of soil P with exchange resins improves, compared to chemical extradants, the evaluation of the P-supplying power of soils. Key words: 32P, anion exchange resin, available P, extraction method
Cleaning soil profiles with a forced-air jet and describing soil morphological features
Authors: Veer C. , Wang C.
Published: April 2011

A forced-air jet technique was compared with the conventional method for cleaning the exposure of soils and facilitating the description of macro-pores, roots and structure in horizontal and vertical soil surfaces under field conditions. The forced-air technique prevents clogging of pores and enhances the exposure of soil morphological features. As a result, soil description as well as pore and root counts are much improved. Key words: Soil description, biopore counts, root counts
Effect of crop rotations on microbial biomass, specific respiratory activity and mineralizable nitrogen in a Black Chernozemic soil
Authors: Campbell C. A. , Biederbeck V. O. , Moulin A. P. , Bowren K. E. , Townley-Smith L. , Janzen H. H.
Published: April 2011

The effects of crop rotations, fertilization, cropping frequency, green manuring, and inclusion of grass-legume hay crops in predominantly spring wheat (Triticum aestivum L.) rotations, on some biochemical characteristics of a fine-textured Orthic Black Chernozemic soil were determined at Melfort, Saskatchewan. Thirty-one years after establishment of this experiment, soil samples were taken from the upper 7.5 and the 7.5- to 15-cm layers in mid-September, 2 wk after cereal harvest and 2 mo after hay harvest and plow-down. Results showed that fertilizer had no effect on the total amount of CO2-C respired, microbial biomass C (BC), and the specific respiratory activity (ratio of CO2-C/BC), but it decreased microbial biomass N (BN), widened BC/BN ratio, and increased the initial potential rate of N mineralization (Nok). The BN was inversely related to straw yields of the most recent crop grown on these plots. When a legume-grass hay crop was underseeded into wheat grown on stubble in a 6-yr rotation, the young growing forage crop decreased BC but increased CO2-C, BN and CO2-C/BC. Reducing fallow frequency in monoculture wheat systems increased CO2-C/BC and Nok. Sweet clover [Melilotus officinalis (L.)] green manure did not increase yields of the subsequent wheat crop, consequently, this treatment did not influence soil biochemical characteristics. The BC appeared to be less sensitive to crop management effects than BN or CO2-C/BC. The BC/BN ratio was wider for systems that received more fertilizer, those that were being fallowed and for the lower soil depths, indicating a possible change in microbial ecology in these situations. This aspect may require further research. In contrast to our earlier conclusions for this fertile Black Chernozemic soil, our results indicate that there are several soil biochemical characteristics that allow identification of short- and long-term treatment effects on soil organic matter. Key words: N mineralization, microbial biomass, C respiration, legumes, fertilization
Relationships between soil chemical properties and sulfate sorption kinetics in Podzolic soils from Quebec
Authors: Courchesne François
Published: April 2011

The relationships between the slope of three kinetic equations (Elovich, first-order and parabolic diffusion) and commonly measured soil chemical properties were investigated. Twenty-six horizons covering a variety of vegetation types, parent materials and topographic positions were sampled in 18 soil profiles of southern Quebec. A miscible displacement technique in which soils were leached with a 250 μmol SO4 L−1 solution (pH = 4.40) was used to determine time-dependent sulfate sorption. The sum of crystalline plus amorphous inorganic Fe (dithionite-pyrophosphate extraction) was the soil property most closely related to the slope parameters of the Elovich (r = 0.797) and of the parabolic (r = 0.808) equations. Amorphous Al (r = − 0.546) and soil pH measured in CaCl2 (r = − 0.588) were most strongly correlated to ln − k′a. Organic carbon was not directly related to sulfate sorption as an individual variable but it improved the multiple regression equations used to estimate 1/β and K0 for the 26 horizons. The Elovich equation was found to give the best representation (average R2 = 0.978) of sulfate sorption kinetics. Good results were also obtained using the first-order equation (average r2 = 0.976) although a marked deviation of experimental data from linearity was observed at high surface coverage. The relatively close relationship between predicted and calculated values confirmed the potential of equations based upon commonly measured soil properties to estimate the slope parameter of kinetic equations describing sulfate sorption by Podzolic soils. Key words: Podzols, sulfate, sorption, kinetics, sesquioxides
Degradation of savanna soils and reduction of water available for the vegetation: the case of northern Cameroon Vertisols
Authors: Seiny-Boukar L. , Floret C. , Pontanier R.
Published: April 2011

The purpose of this study was to characterize and quantify the degradation of Vertisols of savannas in Northern Cameroon. The work was carried out in a region with mean annual rainfall of 800 mm. It is a climate with 9 months theoretical drought and one raining season. The area is heavily populated and farmers use fallow to rejuvenate the soil. The post-cultural savannas (fallows) are subjected to fire, intensive grazing and cutting of fire wood. Three soil types at different stages of degradation were subjected to a study of their soil moisture regime including quantification of runoff during a three-year period. Physico-chemical characteristics are discussed, as well as variations in water reserves as a function of stages of degradation. Maximum wetting front varied from 30 to 80 cm. The most degraded soil lacked plant available moisture for 10 months as compared to 5 months for the least degraded. A model is presented of the dynamic relationships that may exist among the stages of degradation of these Vertisols. Key words: Savanna, Vertisol, water regime, degradation, soil dynamics
Relationship between color value and nitrogen in forest mineral soils
Authors: Qian H. , Klinka K. , Lavkulich L. M.
Published: April 2011

To assess the extent to which moist color value of forest mineral soils supports their differentiation according to concentrations of mineralizable and total N, 239 samples of 0–30-cm mineral-soil layers were examined for the relationship between nitrogen measures and selected categorical climatic and soil variables. The best regression models, using soil color value (SCV), climate, soil moisture and soil texture as categorical variables, explained nearly 70% of the variation in both mineralizable and total N, with climate accounting for most of the variation. The results provided support for the present usage of SCV in estimating mineralizable and total N in forest soils but suggested improvements for the development of a more effective estimation procedure. Key words: Forest soil color, soil nitrogen, climate, soil moisture, soil texture, regression analysis
Oxidation of elemental sulphur and acidulation of calcareous orchard soils in southern British Columbia
Authors: Neilsen D. , Hogue E. J. , Hoyt P. B. , Drought B. G.
Published: April 2011

The capacity of soils to oxidize S was measured by incubation with finely divided elemental S in 13 calcareous orchard soils from the southern interior of British Columbia. Sulphur oxidation rates ranged from 3.4 to 26 μg S cm−2 d−1. The magnitude of pH decrease in response to added S varied inversely with initial CaCO3 content (r = − 0.58, P = 0.04) and silt content (r = − 0.64, P = 0.02) and directly with sand content (r = 0.64, P = 0.02). Incubation studies with one calcareous orchard soil indicated that finely divided S was more effective over time than other acidulants (FeSO4, Al2 (SO4)3 and H2SO4). A field study was carried out on the same soil. Finely divided and bentonitic granulated S were applied at 4.5 t ha−1 on the grass surface or incorporated to a depth of 15 cm. Incorporated fine S was oxidized to a much greater extent during a 2-yr period than was incorporated grandulated S. However, when surface applied, they were oxidized equally but slowly. Key words: S incubation, acidulating materials, S oxidation, soil pH, electrical conductivity
Organic matter characteristics and water-stable aggregation of a sandy loam soil after 9 years of wood-residue applications
Authors: N'dayegamiye A. , Angers D. A.
Published: April 2011

The long-term effects of wood-residue applications on soil properties are not well documented. This study was undertaken to characterize the organic matter and aggregation of a sandy loam after 9 yr of biennial application of wood residues (tree clippings) at rates of 25, 50 and 100 Mg ha−1 with and without nitrogen fertilization. Carbon (C) and nitrogen (N) contents of the whole soil were determined as well as the C content of the density fractions and of the fractions soluble and insoluble to Na4P2O7. In comparison with the control, the whole-soil C content was 16–24% higher following application of wood residues alone and 16–37% higher for application of wood residues supplemented with nitrogen. The treatments had no effect on soil water-stable macroaggregation (> 250 μm). Wood-residue applications had no effect on the humic material (soluble in Na4P2O7) but favored the humin-C content (the fractions insoluble in Na4P2O7) by 25–60% relative to the control. The light-fraction organic matter was on average 68% larger, and the heavy fraction 17% larger, in the treated soils than in the control. On average, 80% of the differences in total organic C induced by residue application could be attributed to differences in the humin and heavy fractions. The long-term effect of wood-residue applications to the soil was, therefore, reflected in an accumulation of the more stable organic matter present as heavy and humin fractions. In addition, the differences in the light fractions suggested a short-term effect of wood-residue applications.Key words: Light and heavy fractions, wood residues, organic C, water-stable aggregates, humic acids, humins
Overwinter changes in Olsen phosphorus in a 24-year crop rotation study in southwestern Saskatchewan
Authors: Campbell C. A. , Zentner R. P.
Published: April 2011

In the Canadian prairie, producers generally sample soils in the autumn for nutrient analyses, whereas calibration of crop responses has been made based on soils sampled in the spring prior to seeding. A recent report suggests that available phosphorus (P) in soil increases between autumn and spring. At Swift Current, Saskatchewan, we have monitored bicarbonate-extractable P (Olsen P) every autumn and spring for the past 24 years, in four cropping systems: continuous wheat (Cont W), fallow-wheat (F-W), and two fallow-wheat-wheat (F-W-W) rotations. The first three systems received nitrogen (N) and P each crop year, with one F-W-W rotation receiving only N. These data were analyzed to test the authenticity of the aforementioned observations. We found that although there were some apparent overwinter increases in Olsen P there were also some decreases. Further, because of the considerable variability in Olsen P, relatively few of the overwinter changes were significant (P = 0.10). Efforts to correlate the changes in Olsen P to overwinter temperature or precipitation were unsuccessful. We concluded that Saskatchewan soil testing laboratories need not make adjustments to P fertilizer recommendations to account for changes in overwinter soil test P levels. Key words: Soil testing, bicarbonate-extractable P, crop rotations, available P
A clamp-column method to obtain particle size separates
Authors: Sheppard S. C. , Evenden W. G.
Published: April 2011

A method to obtain relatively large portions of particle size separates from soil is described. The method was designed to minimize dilution of the soil with dispersant solution, to use simple materials and operations, and to allow fractionation of a single soil sample into a broad range of size classes. These are advantages over elutriation or batch sedimentation methods, and are important when obtaining size separates for studies of contaminant behaviour, erodable soil materials and other related topics. The method is ideally suited to study of contaminant concentrations on soil particle size separates. Key words: Sedimentation, size fractionation, clay, silt, sand, contaminants
Soil properties associated with alfalfa winter survival at Kamloops, British Columbia
Authors: Ryswyk A. L. van , Stout D. G. , Roddan B. H. , Hogue E. J. , Hall J. W.
Published: April 2011

Alfalfa (Medicago sativa L.) survival at Kamloops Agriculture Canada Research Station decreased following the 1985–1986 cold event, when survival varied along a soil gradient. Survival was positively related to the soil's potential available soil-water storage capacity, which may have contributed to a temporary buffering of soil-temperature decline. However, this relationship was not observed following the 1988–1989 cold event, when the air-temperature drop was greater following a prolonged mild period. Key words: Medicago sativa, low-temperature injury, cold hardiness, available water storage capacity, extractable soil potassium
The distribution of selected soil properties in relation to landscape morphology in forested Gray Luvisol soils
Authors: Donald Richard G. , Anderson Darwin W. , Stewart John W. B.
Published: April 2011

Properties of Gray Luvisol soils were examined in relation to landscape position in a boreal setting in Saskatchewan. The thickness of the organic, Ae and Bt horizons, the pH of the Ae, depth to carbonates and the percent clay in the Bt horizon were determined on samples taken from 80 profiles on a 70 × 56-m grid. At each sample location the landform element was described as one of eight elements based on the gradient, profile curvature and plan curvature. The results show that the distribution of soil properties varied as a function of landscape morphology and moisture regime. In general, the pH of the Ae horizons was higher, and the thickness of Ae and organic horizons were greater in convergent areas. In lower footslope soils, a shallow carbonate-rich water table led to a moderately alkaline pH in the Ae horizons and restricted profile development, presumably due to restricted vertical leaching. The ratio of Ae to Bt horizon thickness was greatest on upper slopes, decreasing in lower footslope soils and in convergent areas. The Bt horizons of lower footslope soils contained more clay than Bt horizons of upper slope soils, possibly as the result of the lateral redistribution of soluble and suspended constituents from divergent to convergent areas of the landscape. Keywords: Geomorphology, Luvisol, horizon development, soil depth, soil pH, illuviation
Effect of tillage and fertilization on inorganic and organic soil phosphorus
Authors: O'Halloran I. P.
Published: April 2011

This study was conducted to evaluate the impact of tillage and fertilization practices on soil organic carbon (organic-C) and the distribution of phosphorus between inorganic (Pi) and organic (Po) pools in a clay and sandy loam soil under a continuous corn (Zea mays L.) production system. Tillage treatments were established in the fall of 1981. The soils for this study were sampled (0- to 10-cm and 10- to 20-cm) in June 1988. Treatments consisted of three types of tillage: (i) conventional (CT): fall moldboard ploughing with two spring diskings; (ii) reduced (RT): with either fall chisel ploughing (1981–1986) or no fall tillage (1987) followed by one spring disking, and (iii) no-till (NT); and two types of fertilization (i) inorganic (I): 170 kg N ha−1. 80 kg P2O5, ha−1, 75 kg K2O ha−1, and (ii) organic fertilizer (O): dairy manure applied to give 170 kg N ha−1 plus 80 kg P2O5, ha−1 from inorganic P fertilizer. Even though a lime application was made in the fall of 1985, soil pH was significantly lower in the I fertilizer treatments. Reduction of tillage intensity resulted in a lower pH in the surface layer of the sandy loam soil. Tillage did not affect soil organic-C, or total soil Po (soil-Po) in either soil. Compared with the I fertilizer treatment, the O fertilizer treatment resulted in increased levels of soil organic-C and soil-Po only in the sandy loam soil. Labile levels of Po in the soil were not affected by treatments. Increased soil-Po levels possibly resulted from an increase in stable Po complexes. Moderately labile Po levels were not affected by treatments in the clay soil. In the sandy loam soil, O fertilization decreased moderately labile Po levels in the surface layer of the NT treatment, and increased this P fraction in the 10- to 20-cm soil layer of the RT and CT treatments. In the surface layer of both soils, labile levels of Pi were greater for the O fertilization treatment (approximately 40 and 47% higher for the clay and sandy loam, respectively), and were lower under CT. Increased labile Pi levels were associated with the O fertilizer treatment in the 10- to 20-cm depth increment in the sandy loam soil only, suggesting a greater downward movement of P with manure applications. Key words: Conventional tillage, zero-tilled, no-till, reduced tillage, manure, P fractionation
Influence of incubating monocalcium phosphate with liquid hog manure on inorganic phosphorus, organic phosphorus and phosphorus availability in two Quebec soils
Authors: O'Halloran I. P. , Sigrist A.
Published: April 2011

The effects of incubating monocalcium phosphate monohydrate (MCPM) with liquid hog manure (LHM) on P availability and uptake by Italian ryegrass (Lolium multiflorum Lam.) were evaluated in a 99-d growth chamber experiment. Liquid hog manure with (0.738 g P kg−1 fresh LHM) or without MCPM was aerated for a 21-d period at 24 °C. The soils used in this experiment were an Ormstown silty clay loam (Orthic Humic Podzol), and a Ste. Rosalie clay loam (Humic Podzol). Five treatments were applied to each soil: (i) control with no LHM or MCPM additions, (ii) MCPM, (iii) LHM incubated without MCPM, (iv) LHM incubated with MCPM, and (v) the separate applications of MCPM and LHM incubated without MCPM. Rates of MCPM and LHM applications were 513 kg P2O5 ha−1 and 32 t ha−1, respectively. Incubating LHM with MCPM resulted in a loss of 6% of the total manure-N during the 3-wk incubation period, compared with a 67% loss from the unamended LHM. Additions of both MCPM and LHM had the same effect on shoot-P contents and soil P fractions regardless of whether the materials had been incubated together or added to the soil separately. When compared with adding MCPM only, LHM-MCPM mixtures resulted in greater ryegrass shoot-P contents for plants growing on the Ste. Rosalie soil. However, this increase was approximately equal to the response to LHM additions, and thus presumably not due to improved MCPM P availability. Additions of both LHM and MCPM did not affect soil inorganic P forms compared with the lone addition of MCPM, but sodium hydroxide extractable organic P and sodium bicarbonate extractable organic P tended to be higher when just MCPM was added. Key words: P fractionation, liquid hog manure, manure-fertilizer mixtures, monocalcium phosphate, P uptake
Estimation of snowmelt runoff in the Peace River region using a soil moisture budget
Authors: Hayhoe H. N. , Pelletier R. G. , Vliet L. J. P. van
Published: April 2011

Rainfall and snowmelt runoff on soil frozen below the surface are recognized as important factors contributing to soil loss in Canada. The risk of rain on frozen soil has been quantified, and the amount of snowmelt on frozen soil has been estimated. This study extends such research to derive a climate-based model to estimate winter and spring runoff. This could result in a more accurate erosion prediction for areas where snowmelt is a major source for runoff. Selected components of the Water Erosion Prediction Project (WEPP) model and the versatile soil moisture budget (VB) were tested on observed data for two study sites in the Peace River region. The version of the WEPP model available to us estimated snow depth, soil frost depth and frequency of freeze–thaw cycles. However, the results did not adequately match observed data. The VB was modified in this study to improve the estimate of potential winter and spring runoff, and it was shown that incorporating observations of snow depth improved the estimate of the time and amount of snowmelt runoff. The modified runoff model was validated with data collected in the Peace River area of northern Alberta and British Columbia and with published data from the Prairies. Key words: Snowmelt, runoff, soil moisture budget
Changes in soil properties following forest invasion of Black soils of the Aspen Parkland
Authors: Fuller L. G. , Anderson D. W.
Published: April 2011

The objective of this study was to document the effect of forest invasion on Black soils of the Aspen Parkland in Saskatchewan. A prairie-forest transition zone less than 100-m wide was studied in an upland landscape (LM) with a strong eluvial regime and a lowland landscape (WQ) where strong leaching was restricted to depressional areas. A direct count of grass opal along each transect provided evidence that forest vegetation had invaded prairie as similar amounts of grass opal occurred under forest and prairie. Soil morphology and horizon development could be related to microrelief and to site productivity as inferred from grass opal content along the transects. Forest invasion affected soils differently in the two landscapes. At LM, forest invasion was accompanied by losses of clay and organic materials as soils were progressively transformed into leached and more acidic Luvisolic soils. Eluvial and illuvial development occurring under forest were most pronounced in microdepressions and concave portions of the transect. At WQ, leached acidic soils occurred only in a depression. Forested soils outside the depression maintained high levels of organic matter and high base status comparable to adjacent prairie soils. Alteration of Black soils following migration of forest vegetation onto prairie depends on large scale physiographical effects as well as smaller scale microrelief effects. This study indicates landscape control of water movement plays a vital role in soil development and regulation of ecosystem processes. Thus, the relationship among water, soil and landscape must be considered in environmental research and environmental impact studies. Key words: Prairie-forest transition, forest invasion, Aspen Parkland, biogenic opal, soil-landscape relationships
Transport of herbicides and nutrients in surface runoff from corn cropland in southern Ontario
Authors: Bowman B. T. , Wall G. J. , King D. J.
Published: April 2011

The risk of surface-water contamination by herbicides is greatest following application to cropland when the active ingredients are at the maximum concentration and the soil is the most vulnerable to erosion following cultivation. This study determined the magnitude of surface runoff losses of herbicide and nutrients at, and subsequent to, application. The first of three weekly 10-min, 2.6-cm rainfalls were simulated on triplicated 1-m plots (a set) on which corn had been planted and the herbicide (metolachlor/atrazine, 1.5:1.0) and fertilizer (28% N at 123 kg ha−1) had just been applied. Identical simulations were applied to two other adjacent plot sets (protected from rainfall) 1 and 2 wk following herbicide application. Runoff (natural, simulated) was monitored for soil, nutrient and herbicide losses. Concentrations of total phosphorus in surface runoff water and nitrate N in field-filtered samples were not significantly influenced by the time of the rainfall simulation but exceeded provincial water-quality objectives. Atrazine and metolachlor runoff losses were greatest from simulated rainfall (about 5% loss) immediately following application. Subsequent simulated rainfall usually resulted in < 1% herbicide runoff losses. Herbicide concentrations in all plot runoff samples exceeded provincial drinking-water quality objectives. Since herbicide surface transport is primarily in the solution phase (not via association with soil particles), water-management conservation technologies are the key to retaining these chemicals on cropland. Key words: Herbicide, runoff, rainfall simulation, partitioning, water quality
Increased proportion of active soil N in Breton loam under cropping systems with forages and green manures
Authors: Wani S. P. , McGill W. B. , Haugen-Kozyra K. L. , Juma N. G.
Published: April 2011

Total soil N and N mineralization rate partially characterize the influence of various cropping systems on the growth of sequent crops in a rotation. The objectives of this study were to (1) quantify the relationship among cropping system, total N and mineralizable N; and (2) compare amount of N mineralized under controlled laboratory conditions with plant N uptake under greenhouse conditions. Three cropping systems that have been in operation between 9 and 60 yr on a Gray Luvisol (Breton loam) were selected. They included: (1) an agro-ecological (AER) 8-yr rotation involving fababeans as green manure (AER1 sampled after the first fababean crop and AER2 sampled after 3 yr of continuous forage); (2) continuous grain system (CG), with fertilizer N at 90 kg ha−1 yr−1; initiated in 1980 and considered established in 1981; (3) a classicial Breton rotation (CBR) involving a long-term (ca. 1930) 5-yr rotation with forages and cereals and no return of crop residues (CBR1 fertilized with P-K-S and CBR2 unfertilized). We caution that not all phases of each rotation were sampled; our conclusions pertain to N-mineralization potential in soil samples immediately preceding barley as sequent crop in each rotation. The rate of N mineralization declined with time, but it remained greater than zero after 20 wk of incubation in all soils. Mineral-N accumulation at 20 wk followed the order AER1 > AER2 > > CBR1 > CBR2 = CG. Mineralizable soil N, following one cycle of the AER rotation, was almost double that following 60 yr of the CBR rotation. Data for mineral-N accumulation under laboratory conditions were described best by a single-component exponential model. Legume-based rotations were associated with increased total soil N and a greater proportional increase in active N than in total soil N. Active N was least in soil under the CG system. The incubation-extraction procedure resulted in higher estimates of mineralizable N than did the plant-uptake method; however, the ranking of N-supplying power of soils was the same. Key words: Cropping systems, Gray Luvisol, N mineralization, soil quality, Typic Cryoboralf
Dynamics of 15N in two soil–plant systems following incorporation of 10% bloom and full bloom field pea
Authors: Jans-Hammermeister D. C. , McGill W. B. , Jensen T. L.
Published: April 2011

The distribution and dynamics of 15N following green manuring of 15N-labelled 10% bloom and full bloom field pea (Pisum sativum ’Sirius’) were investigated in the soil mineral N, microbial N and non-microbial organic N (NMO-N) fractions and in a subsequent barley crop at two contrasting field sites in central Alberta: one on a Chernozemic (Dark Brown) soil near Provost and the other on a Luvisolic (Gray Luvisol) soil near Rimbey. Soils and plants were sampled four times during a 1-yr period. The 10% bloom and full bloom pea shoots were similar in dry matter production and N and C content. More N was, however, released from the younger pea residues directly following soil incorporation, which we attributed to a larger proportion of labile components. Barley yield, N content and 15N recovery in the grain were not influenced by legume bloom stage at incorporation, although significantly more 15N was recovered in the barley straw and roots of the full bloom treatment. Incorporation of full bloom legumes resulted in closer synchrony between the appearance of legume-derived mineral 15N and early N demand by the barley crop. The decay rate constants for the recalcitrant fraction of the legume residues were not significantly influenced by bloom stage or site over the time intervals of our observations and are, thus, consistent with the theory that decomposition of the recalcitrant fraction of plant residues can be described by a single exponential equation. Key words:15N, legume green manuring, Pisum sativum, decomposition
SHORT COMMUNICATION: Exchange of 15N among plants in controlled environment studies
Authors: Janzen H. H. , Gilbertson C.
Published: April 2011

Barley receiving unlabelled nitrogen fertilizer was grown among treatments receiving Ca(15NO3)2 fertilizer (5 atom %) in a growth cabinet with high air exchange and in a greenhouse. In both environments, the unlabelled plants and soil were significantly enriched with 15N, apparently, in part, by foliar exchange of atmospheric ammonia. This exchange may warrant consideration in the selection of appropriate controls for 15N calculations. Key words:15N, ammonia, atmospheric exchange
SHORT COMMUNICATION: Influence of soil temperature and moisture on water-soluble phenolic compounds in manured soil
Authors: Paul J. W. , Covert J. A. , Beauchamp E. G.
Published: April 2011

Water-soluble phenolic compounds were measured in fresh and decomposed animal manures. Following manure addition to soil, less than 50% of the water-soluble phenolic compounds were recovered within 1 h. The concentration of phenolic compounds decreased more slowly with decreasing temperatures to 4 °C and increasing soil moisture content during a 14-d incubation. The results suggest that water-soluble phenolic compounds were both adsorbed onto soil particles and decomposed by microorganisms. Key words: Animal manure, phenolic compounds, compost
Activité phosphatasique de quelques sols tropicaux à argile 1: 1. Répartition dans les fractions granulométriques
Authors: Feller C. , Frossard E. , Brassard M.
Published: April 2011

The objectives of this work were: (i) to study the acid monophosphoesterase activity (pH 6.5) of the surface horizons of low-activity tropical clay soils (West Africa, West Indies, Brazil), cultivated or uncultivated, with widely different textures and organic matter (OM) contents, (ii) to measure the phosphatase activity (Pase) in the organic and organo-mineral soil fractions obtained by particle size fractionation. Pase was most significantly correlated to the soil OM content and to a lesser extent to the texture and total P content. Therefore, any modification in soil management resulting in important changes in soil OM contents, leads to important variations in phosphatase activity: Pase decreases after clearing of the native vegetation and continuous cultivation, Pase increase when grass-fallows or meadows succeed to annual cropping. The Pase of all the size fractions (20–2000 μm, 2–20 μm and 0–2 μm) was controled by their OM content. However, the "potential Pase" defined as the ratio Pase/C was higher in the 20- to 2000-μm and 0- to 2-μm fractions than in the 2–20 μm ones This is attributed to a higher Pase renewal by root restitutions in the plant debris fraction (20–2000 μm) and by microbial activity and microbial metabolites in the organo-clay fraction (0–2 μm). More than 50% of the soil total Pase was associated with fractions coarser than 2 μm. Most of the changes in Pase (75–100%) associated with the cultivation were ascribed to these fractions. This illustrate the probably important role of the fractions coarser than 2 μm in the phosphorus dynamics in these soils. Key words: Phosphomonoesterase, organic matter, particle size fractionation, low-activity tropical clay soils