ALBERT

Description: 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

Description: Concern has been expressed that reduced tillage systems may lead to excess soil compaction, negatively impacting on crop growth. The objectives of this study were to determine the effects of tillage systems zero (ZT), minimum (MT) and conventional tillage (CT) and crop rotations on soil bulk density and penetration resistance after 4 yr on an Indian Head heavy clay soil, in southeastern Saskatchewan. Moisture content was similar among tillage systems, except for slight differences in the lower soil depths with crop rotation. Penetration resistance and bulk density of a heavy clay soil were increased in the surface 10 cm of the soil by ZT as compared to CT management. However, in the deeper soil zones, tillage system did not consistently influence either bulk density or penetration resistance. Inclusion of peas in the crop rotation had a moderating effect on bulk density and penetration resistance, while inclusion of flax in a continuous rotation increased bulk density and penetration resistance in the surface soil profile. At the 30- to 45-cm depth, ZT had a lower bulk density than CT or MT in the rotation which included fallow, possibly because the tillage operations associated with the cultivated fallow led to compaction in the deeper soil zone. Penetration resistance was great enough in the deeper soil zone in all tillage systems to restrict rooting, but difference due to tillage treatment or cropping rotation was not sufficient to markedly influence crop production. Key words: Penetration resistance, bulk density, crop rotation, tillage

Description: not available

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Description: Atomic absorption spectrophotometric measurements of Al in plant digests and neutral salt extracts of soils were studied. Using a new lamp (Westinghouse design) and 5 × scale expansion, 1.0 ± 0.08 ppm Al was measured. Lanthanum (2000 ppm) suppressed enhancements from Na, K, Sr, Fe and a mixture of a large number of constituents. The measurements in plant digests were independent of dilution, gave complete recovery of added Al and showed excellent agreement with the 8-quinolinolate colorimetric values. Similarly, there was complete recovery from soil extracts, but the measurements by atomic absorption were larger than by 8-quinolinolate or Aluminon. It was concluded that the new lamp provides adequate sensitivity, stability and freedom from interferences so that atomic absorption can be used for routine measurements of Al in plant digests and neutral salt extracts of soils.

Description: Five vegetation treatments were established in 1.2 m × 1.2 m plots in 1990: (1) bare mineral soil, (2) Epilobium angustifolium, (3) Rubus spectobilis, (4) Alnus rubra and (5) a mixture of all three species. Soil temperatures were measured at 10-cm depths in three replicates of each treatment during the early summer of 1991. Mean, maximum and minimum temperatures always exhibited the same rank order of treatments — bare 〉 Epilobium 〉 Rubus 〉 mixture 〉 Alnus — but the latter four treatments were not readily distinguishable. A data-adjustment procedure based on Fourier analysis was conducted and its utility discussed for use in the separation of treatment effects where observations exhibit a detectable diurnal cycle. Using this method, the soil thermal regime of the Epilobium treatment was demonstrated to be statistically distinct from that of the bare plots and from those of the other vegetation treatments. Key words: Fourier analysis, diurnal pattern, soil temperature, vegetation effects, microclimate

Description: Copper, in the form of Cu-polyflavonoid, was applied at 50 or 100 ppm to surface samples of nine Wisconsin soils varying from 0.8 to 12.5% organic matter. The effects on yield and on plant uptake of Cu, Zn and Mn were evaluated using oats (Avena sativa L. cv. Lodi). Complexed Cu additions increased extractable Cu, had little effect on extractable Zn, but also increased extractable Mn. Complexed Cu decreased plant uptake of Zn, but increased uptake of Mn. Interactive effects of organic matter, clay, available phosphorus and Zn appeared to occur with respect to plant yield and Cu, Zn, and Mn uptake.

Description: In a soil incubation experiment with different rates of Zn, the amounts of Zn extracted with 0.005 M DTPA, 1 M MgCl2, and 0.01 M CaCl2 increased with an increase in the organic matter content of a neutral sandy loam soil and with alfalfa added as an organic amendment. Addition of muck and peat increased the amount of Zn exchanged with 1 M MgCl2 but decreased the amount soluble in 0.01 M CaCl2, whereas addition of clay increased the amount of exchangeable Zn but decreased the amounts in the DTPA and 0.01 M CaCl2 extracts. Liming of an acid sandy loam soil (pH 4.9) to about the neutral point reduced the amounts of extractable Zn markedly. A pretreatment of the soils with phosphate almost invariably increased the amounts of extractable Zn. In a corresponding pot experiment, the highest rate of Zn (250 ppm) reduced the yield of corn slightly, prevented the growth of lettuce, and reduced the yield of alfalfa markedly when these crops were grown successively in the acid soil. The concentration of Zn reached levels of 792 ppm in the corn and 702 ppm in the alfalfa. Addition of 50 ppm Zn to the acid soil restricted the growth of lettuce and increased the concentration of Zn to 523 ppm. Despite discrepancies, the concentrations of Zn in the plants as influenced by soil organic matter, organic amendments and liming were usually in accord with the amounts of Zn extracted from the soils. But the P pretreatment tended to decrease the concentration of Zn in corn and lettuce. The mean weight concentrations of Zn in the three species were correlated significantly with the amounts of Zn extracted with 0.005 M DTPA (r = +0.73), 1 M MgCl2 (r = +0.93) and 0.01 M CaCl2 (r = +0.90).

Description: The results of two studies are reported: (1) a comparison of colorimetric and atomic absorption measurements of Fe and Al in dithionite, oxalate, and pyrophosphate extracts of soils; and (2) a comparison among nine Canadian laboratories of measurements of dithionite-, oxalate-, and pyrophosphate-extractable Fe and Al in six soils. Colorimetric and atomic absorption analyses gave the same measurements of Fe and Al in dithionite, oxalate, and pyrophosphate extracts of soils. Data reported by six Canadian laboratories showed close agreement; data reported by three laboratories showed poor agreement, indicating a need for reference soil samples containing known amounts of extractable Fe and Al to standardize laboratory procedures. Atomic absorption analysis of the extracts is much more rapid than colorimetric analysis and details of the atomic absorption methods are appended.

Description: We used a simple empirical model to predict denitrification rates from measurements of bulk soil properties. Boundary analysis was used to define relationships between denitrification rate and each of air-filled porosity, respiration rate and mineralizable-C content. The ratio of measured denitrifying enzyme activity to the maximum measured value was used to account for variation in amounts of enzymes and numbers of denitrifiers in soil. Nitrate content had little effect on denitrification rate and was excluded from the model. Because the model did not account for microscale variability, it did not accurately predict rates in individual soil cores. Nevertheless, population means and distributions of predicted and measured values were similar. The seasonal patterns of mean values of predicted and measured denitrification rates were also similar over the second half of the sampling period, which extended from May to November. The model did not account for appreciable denitrification on three dates in May. This discrepancy indicated that environmental regulation of denitrification may not be uniform over the season. The model was not sufficiently sensitive to factors influencing episodic events. Key words: Denitrification rate, model, boundary line

Description: Inorganic phosphorus (P) is generally believed to be relatively immobile in Chernozemic soils. However, available P (e.g., Olsen-P) has been found at depth in some soils and this has been postulated to be either the result of leaching or of transportation by plant roots. Lagumes, in particular, are believed to be involved in the latter mechanism. A long-term (34-yr) crop rotation study conducted on a heavy clay, thin Black Chernozemic soil at Indian Head, Saskatchewan, was sampled to a depth of 4.5 m in May and September 1991, to determine the influence of fertilization, cropping frequency, legume green manure and legume-grass hay crops on Olsen-P distribution in the soil profile. The results indicated that Olsen-P may indeed leach in Chernozemic soils, especially when fallow-containing cropping systems are fertilized. It also appeared that deep-rooted legumes, such as sweetclover Melilotus officinalis L.) green manure and alfalfa-bromegrass (Medicago sativa L. — Bromus inermis Leyss) hay crops do increase Olsen-P in the subsoil, possibly through root decomposition in situ. Key words: Rotations, bicarbonate-soluble Pi, legumes, green manure, fertilizers

Description: The effects of cultivation on the net mineralization of carbon and nitrogen in a lacustrine Brown clay (Sceptre) and two Orthic Black soils on glacial till (Oxbow) were assessed with the aid of fractionation and radiocarbon dating techniques. Fractionation of the soil organic matter of comparative virgin and cultivated soils by acid hydrolysis and peptization in dilute NaOH showed that the distribution of carbon and nitrogen among fractions of these soils was similar. There was no measurable alteration in the mean residence time (MRT) of the soil during the first 15 to 20 yr of cultivation, during which time the Sceptre soil had lost 19% of its carbon and the Oxbow, 35%. However, the MRT increased from 250 yr before present (BP) to 710 years BP after 60 yr of cultivation of the Oxbow soil. The losses for nitrogen were 10% lower than for carbon in the Oxbow soil due to the recycling of nitrogen in the soil. The rate of loss of carbon from the Oxbow soil during the cultivation period was simulated by expressing it as the sum of two first order reactions using fractionation and carbon dating data as the variables.

Description: 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

Description: Wood Mountain loam was wetted with water or (NH4)2SO4 solution to provide a factorial combination among three moisture and three NH4-N levels. Samples in polyethylene bags were incubated at 2.5-cm depths in fallow, and in an incubator that simulated the diurnal patterns of temperature fluctuation recorded in the field. During the growing season, treatments were sampled regularly for moisture, NO3− and exchangeable NH4-N. Similar determinations were made on in situ samples taken in fallow Wood Mountain loam. The incubator simulated the effects of growing season temperatures on soil N transformations satisfactorily. Pronounced increases or decreases in temperature led to flushes in N mineralization. However, in the 1972 growing season, temperature was suboptimal and temperature changes were generally small. Consequently, when a stepwise multiple regression technique was used to analyze the data, neither ammonification nor nitrification showed a quantitative relationship to temperature. Comparison of the nitrification occurring in laboratory-incubated soils with that occurring in situ led to the conclusion that 70 to 90% of the NO3-N produced in surface soil resulted from wetting and drying. Estimates of potentially ammonifiable soil N(No) and its rate of mineralization (k) were derived from cumulative ammonification by assuming that the laws of first-order kinetics were applicable. In the 10, 15, and 20% moisture treatments the average No was 27, 41, and 82 ppm, respectively. Under the conditions of this study, the time required to mineralize half of No was about 7 wk.

Description: An understanding of the mineralization factors in contrasting cultivated soils is necessary for accurate predictions of plant-available N. The objective of this work was to determine the N-mineralization potential and mathematical models that can properly describe the dynamics of the mineralization process in 20 meadow soils from Quebec. The mineralization was monitored over 55.4 wk in a laboratory incubation at 20 °C with intermittent leaching. The cumulative mineralization curves in most soils were characterized by definite lags or a sigmoidal pattern and near-linear release with time after 20 wk. The data were best described by the Gompertz equation; first-order models were inadequate. The total amount of mineralizable N and the potential mineralization rate were very closely correlated with the total amounts of C or N (r 〉 0.73; P 

Description: Acadia or dykeland soils have produced forages successfully for centuries. The formation of barren areas within very productive forage stands has been noted recently in some land-formed fields, indicating either poor germination or poor growing conditions. A survey was undertaken in 1988 to determine the differences in soil attributes between barren and productive areas, namely: topographical position, resistance to penetration, bulk density, pH, plant-available P2O5, -K2O, Ca, and Mg, salt content (as measured by conductivity and sodium adsorption ratio), and exchangeable and soluble Ca, Mg, K and Na. Barren areas had greater: plant-available P2O5, resistance to penetration (the differential ranged from 480 to 1440 kPa), bulk density (in the top 15 cm), salt and sodium content than the productive ones. The exchangeable and soluble Na:Mg and Na:Ca ratios were higher on barren areas than on productive areas. Organic matter content was lower on barren than on productive areas. Values for topographic position, pH, particle size classes and plant-available K2O, Ca, and Mg were similar between the productivity areas. The results of this survey indicate that the formation of barren areas appears to be mainly due to accumulation of excess salts, especially sodium. Reasons for salt accumulation in these areas are discussed. Key words: Acadia soils, dykeland, salt, sodium, organic matter, resistance to penetration

Description: Field studies were conducted on a Landry clay-loam soil (Black Solod) to evaluate the effects of green manuring Tangier flatpea (Lathyrus tingitanus 'Tinga'), lentil (Lens culinaris 'Indianhead') and alfalfa (Medicago sativa 'Moapa') on subsequent barley (Hordeum vulgare 'Galt') crops. Each trial consisted of separate legume phases planted in 1984, 1985 and 1986 and barley phases in each of the subsequent years. The flatpea and lentil were incorporated (green manured) in late July or in late August to early September. The alfalfa was incorporated in late August to early September. The 3-yr mean dry matter (DM) yields of lentil and Tangier flatpea varied from 1047 to 2308 kg ha−1, with considerable variability from year to year. Alfalfa, used as an annual legume, produced 812 kg DM ha−1. Dinitrogen fixation by the annual legumes, as assayed by acetylene reduction was 16 kg N ha−1 or less. Soil moisture measurements following the legumes showed 2–3 cm less water in the profile to a depth of 120 cm following alfalfa and late-incorporated Tangier flatpea than following summerfallow and early-incorporated lentil and Tangier flatpea. Ammonium-N levels in the soil were similar following the various legume green-manure treatments. Nitrate-N levels following the legumes were variable, but the levels of nitrate-N in the plots following legume incorporation generally followed the order: fallow 〉 early incorporation 〉 late incorporation. The grain and N yield of barley following early-incorporated lentil and flatpea were equal to or only slightly less than the yield following fallow, suggesting that annual legumes have a good potential as green-manure crops in place of fallow in Black Solod soils of the Peace River region. Key words: Legume plow-down, soil conservation, dinitrogen fixation, soil moisture, nitrate-N

Description: Possible sources of SO4 in soil, drift and bedrock at two saline sites in southern Alberta were investigated using sulfur and oxygen isotope analyses. Slight differences (0.6–5.2 per mil) between δ34S values of SO4 and insoluble S in the geologic material were attributed to kinetic fractionation during oxidation of organic S. Negative δ18O values of SO4 in the shallow (6 m) bedrock indicated sulfate reduction. The exact source of SO4 could not be determined in this preliminary study. The isotope approach, however, shows promise and warrants more detailed study. Key words: Salinization, sulfates, sulfur isotopes, oxygen isotopes

Description: A survey of efflorescent crusts and associated surface soils in central and southern Alberta was conducted to determine evaporite mineralogy and elemental composition. X-ray powder diffraction indicates that efflorescence mineralogies are dominated by sodium sulfate minerals, such as thenardite and mirabilite. Sodium magnesium sulfate minerals such as konyaite and bloedite are also frequently present, with eugsterite, halite and thermonatrite among other evaporites identified. The content of selected elements in the salt crusts and surface soils was determined using instrumental neutron activation analysis. Trace-element concentrations from site to site were extremely variable. However, comparisons with elemental abundances previously reported for till and soils indicate that there is generally no mean accumulation of trace elements in salt-affected soils. Exceptions are Br and Cl, which show enrichment in soils infused with soluble salts. Key words: Salinity, trace elements, evaporites, mineralogy

Description: The distribution of selenium (Se) in 54 Canadian soil profiles was examined according to horizon in the profile, and to soil properties. Apart from the organic surface layers, the Podzolic B horizons had the highest Se values (0.52 ppm), and so displayed a marked accumulation. The Luvisolic and Gleysolic B horizons also showed some accumulation. The Se content of parent materials was generally low (0.10 ppm). Simple correlation analyses of the combined data (irrespective of horizon) indicated that Se distribution was closely associated with both organic carbon and NH4-oxalate extractable Fe and Al. When the data were arranged according to genetic groupings, this association remained true only for Podzolic B horizons. Multiple regression analyses revealed that the predominant factors involved in the Se distribution were the Se content of parent materials, and the organic carbon content of the upper horizons, in that order, except for Podzolic soils. Clay had little or no influence on the Se distribution. In spite of the relationship of Se to parent materials, the contribution by atmospheric contaminants to the Se enrichment of soils could remain important.

Description: Soil respiration during the growing season was calculated from CO2 profiles in a heavy clay soil under native grass and on cultivated plots. Soil respiration of the native grass plots was correlated with moisture content and temperature of the surface soil. However, the correlation accounted for only ⅓ of the observed variation in soil respiration and could not explain the large difference between two growing seasons. Addition of mineral N decreased soil respiration and irrigation increased it. Total soil respiration on the cultivated plots was higher than on the native grassland. On the wheat plots, soil respiration was significantly correlated with soil moisture but not with temperature; the reverse was true for the fallowed plots. Soil respiration between 1 May and 1 September on the native grassland was highly correlated with rainfall and the number of days with rain in excess of 5 mm. It was concluded that the number of wetting and drying cycles in the soil was mainly responsible for the annual variation in soil respiration. From comparison with data on shoot production, it appears that soil respiration exceeds net production in wet years and that the opposite is true in dry years.

Description: A simple power-function equation was developed to relate changes in soil 137Cs with time to an average annual soil-loss rate. The equation accounts for tillage dilution of the concentration of 137Cs in the surface plow layer and for enrichment in the eroding soil. The predictions from the relationship were similar to values for a more complicated model and to measured values given in previous studies. Key words: Erosion rate, prediction, cesium-137

Description: Potassium mine refinery dust at rates from 1.12 to 11.2 ton/ha (½ to 5 ton per, acre) was applied to a Dark Brown Chernozemic silt loam and to a Black Chernozemic loam. Under dryland farming conditions, no significant effects on yields of cereal grains have been recorded. After 5 years there is no indication that any K has moved deeper than 46 cm (18 inches). The chlorides have been removed from the surface soil and about 50% have leached to below 213 cm (7 ft). The K replaced some of the exchangeable Ca and Mg which were subsequently leached to lower depths. Much of the added K is now in the exchangeable form; some may have become fixed in the clay lattice.

Description: The impact of cultural practices on soil aggregate characteristics which determine the susceptibility of the soil to wind and water erosion was studied at two long-term (〉 30-yr) crop rotation sites on Black Chernozemic soils at Indian Head and Melfort, Saskatchewan. Surface soil (top 5 cm) taken in spring and fall, 1991, was air-dried and sieved by rotary sieve to measure aggregate size distribution. The water-stability of soil aggregates (1–2 mm) was determined after: (i) slow wetting, and (ii) fast wetting. Both rotation studies employed conventional tillage management until 1990 when the Indian Head experiment was converted to zero-tillage. Summerfallowing increased the wind-erodible (

Description: 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

Description: Much forested land in the wetter zones of northern Vancouver Island is characterized by thick humus layers, with two distinct ecosystem phases: the younger "HA" phase arising from disturbance is productive after clearcutting, but in the old-growth "CH" phase, seedlings suffer growth check after 5–8 yr, with reinvasion of the ericaceous shrub salal (Gaultheria shallon Pursh.). We used solid-state 13C nuclear magnetic resonance (NMR) spectroscopy and CuO oxidation to examine whether chemical differences in the humus might be associated with difference in forest productivity after clearcutting. NMR spectra of woody horizons, which were similar for CH and HA sites, were dominated by signals from lignin of decomposed wood. Non-woody humus types were typical of forest litter layers, and were dominated by signals in the O-alkyl region. The differences between CH and HA sites were: (i) higher tannin content in the CH sites, most likely from salal inputs and (ii) higher ratio of carbohydrate to lignin C, indicating less effective decomposition in CH sites. Oxidation with CuO also showed more advanced decomposition in the non-woody horizons of HA than of CH sites. Less effective decomposition possibly due in part to tannin accumulation could contribute to the lower forest productivity on salal-dominated CH sites in this region. Key words: 13C NMR, CuO oxidation, decomposition, humus, tannin, salal

Description: Development of Typic Haplorthods in a heathland area in Denmark responded over a short period of time (decades) to changes of vegetation. Part of the heath, Hjelm Hede, was left undisturbed and was invaded by trees, mainly oak and a few aspen and conifers. Another part of the heath was planted with Norway and Sitka spruce 60–70 yr ago. The soils under heath, oak and spruce were studied. Major differences were found, some visible in the field and others detectable in the laboratory. Under oak, relative to heath, horizon boundaries were less distinct, pH increased in the top horizons, organic carbon and C/N ratio decreased, and iron and aluminum contents in the upper B horizons decreased. Compared with the original heath podzol, the soil under spruce had a lower pH in the O, E and upper B horizons, higher organic carbon content and C/N ratio in the top horizons, increased cementation, and a placic horizon. However the pyrophosphate-extractable iron and aluminum content was significantly lower than in any of the other soils. The soil under oak showed "depodzolization" features, whereas the soil under spruce was increasingly podzolized, though the podzolization mechanism might be different from that under heath. Analyses of phenolic compounds in the soil water were consistent with these conclusions. The three main components of substituted benzoic acids were gallic acid, protocatechuic acid and coumaric acid, which are all strongly complexing agents believed to take part in the podzolization process. Generally, the highest concentrations were found under spruce and the lowest under oak.Key words: Vegetation-induced soil changes, Spodosols, phenolic compounds

Description: The concentration, contents, and distribution of nutrients, metals, and soil materials were quantified at the Howland Integrated Forest Study (HIFS) site in eastern Maine. The site is a mature, low-elevation spruce-fir forest on Podzolic soils developed from dense basal till. Standard morphologically based soil sampling and quantitative soil pits were both used to characterize the soil component of this ecosystem. Vertical trends in nutrient concentrations at the site were largely governed by the distribution of organic matter. Standard morphological soil sampling techniques tended to overestimate soil pools of labile cationic nutrients and C, and underestimate trace metals and P, as a result of underestimations of coarse fragment content. These discrepancies can be critical if extrapolations for nutrients, metals, and C are made using existing databases to regional or global scales.Key words: Forest soils, spruce-fir, quantitative pits, sample size

Description: Methane oxidation by soils is an important sink for this greenhouse gas. When tested at 50 mg L−1, the herbicide bromoxynil, the insecticide methomyl, and the nitrification inhibitor nitrapyrin inhibited methane oxidation by soil slurries. The results suggest that these chemicals might decrease methane oxidation by agricultural soils. Key words: Soil methane oxidation, inhibition, agrochemicals

Description: Mixtures of ammonium nitrate and ammonium polyphosphate fertilizers were used to drip fertigate Summerland McIntosh apple trees (Malus domestica Borkh.) grown on M.9 rootstocks in gravelly sandy loam. Levels of N corresponding to 25 and 50% of the recommended broadcast rate (23.5 and 47.0 g tree−1, respectively) and three levels of P (0, 17.5 and 35.0 g tree−1) were applied in a factorial randomized complete block design. Soil acidification began within 1 yr in a zone extending approximately 60 cm vertically and horizontally from the drip source. Acidification was most severe at 20–30 cm directly beneath the emitter where the soil pH decreased from 5.8 to 4.5 after 1 yr and to 3.7 after three seasons of fertigation. Rate and magnitude of pH decline were equal for both rates of N and acidification was not enhanced by the simultaneous addition of P. Calcium, Mg and K were leached to the periphery of the acidified zone. The rapid displacement of K may be of concern, particularly when NH4 forms of N are drip-fertigated in coarse-textured soils with marginal K levels. Key words: Fertigation, soil acidification, cation leaching, nitrogen fertilizer

Description: To better understand environmental regulation of denitrification, we examined relationships between denitrification rate and six determinant soil properties: moisture content, air-filled porosity, NO3− content, respiration rate, mineralizable-C concentration and denitrifying enzyme activity (DEA). Soil cores were collected on 27 sampling dates over a growing season at a site seeded to barley (Hordeum vulgare). Denitrification rate was measured using a static core technique and acetylene blockage. Moisture content and air-filled porosity and, to a lesser extent, mineralizable-C concentration and respiration rate were more strongly related to denitrification rate than was DEA. Denitrification rate was unrelated to NO3− content. On most sampling dates, mean denitrification rate increased substantially only below an air-filled porosity of 0.3. Moreover, the distribution of individual measurements of denitrification rate was less skewed at lower air-filled porosities. Approximately 60% of variation in mean values of denitrification rate for each sampling date could be accounted for by measurements of bulk soil properties, of which moisture content and air-filled porosity were most important. Measurements of bulk soil properties did not account for nil values of denitrification rate at low air-filled porosities or for small-scale spatial variability. Such measurements were better indicators of temporal variation — that is, when denitrification occurred — than of actual rates. Key words: Denitrification, air-filled porosity, denitrifying enzyme activity

Description: A study was made of the effects of temperature and different microorganisms, or mixtures of microorganisms, on the changes in the nitrogenous constituents of mixed forest litters (mixed pine, oak, maple) during decomposition periods of up to 4 yr at 1, 4, 10, and 27 C. The percentage of total-N in the decomposing materials increased with time, the increase being related to loss in weight of sample. The percentage of amino-N/total-N was higher with the soil-extract-treated leaf mixture than with the fungi-inoculated material; it increased to a maximum at some intermediate period, then decreased, and was highest with the 930 day 27 C material. Most of the individual amino acids increased in amount up to 930 days; then decreased, the amounts being, in general, higher with higher temperatures. Much of this increase was related to loss in weight of sample, but there appeared to be some net synthesis of amino acid. Lysine and, to a lesser extent, histidine were exceptions to this generalization. The amounts of hexosamines increased with decomposition: with the soil-extract-treated materials the increase of galactosamine was relatively greater than that of glucosamine, but little or no galactosamine was found in any of the fungi-inoculated materials. The amino acid ratios, i.e., the proportion of one relative to another, did not change in any consistent fashion, except for lysine. With the fungi-inoculated material, autoclaving reduced the amount of lysine to less than one-half and a ninhydrin-reacting material appeared before arginine on the amino acid chromatograms; its amount was not changed during decomposition. It may be similar to lysine derivatives found in acid hydrolyzates of heated milk.

Description: Three tillage treatments were evaluated over a 4-yr period for their effects on runoff and soil loss under natural precipitation on a Donnelly silt loam soil (Solonetzic Gray Luvisol) near Dawson Creek in the Peace River region of British Columbia. Conventional-tilled (CT) plots (spring or fall cultivation) received twice the amount of tillage as the reduced-tilled (RT) plots, while the zero-tilled (ZT) plots were only disturbed at seeding once a year. The plots were seeded to barley (Hordeum vulgare L.). Rainfall and snowmelt runoff were collected throughout the year to determine seasonal runoff and soil losses. The effects of the tillage treatments on runoff and soil loss depended on the season (whether caused by rainfall or snowmelt) and the crop year. Mean snowmelt runoff was ZT 〉 CT 〉 RT. Conventional tillage had significantly higher rainfall runoff and soil loss from snowmelt than the other two tillage treatments, with no significant differences between RT and ZT. Mean rainfall-induced soil loss was significantly different for each tillage treatment, with CT 〉 RT 〉 ZT. Soil losses from snowmelt were low, less than 30% of those from rainfall, since snowfall was 45% below normal. Soil losses from rainfall were consistently higher than from snowmelt for each tillage treatment in each of the four crop years and provided over 75% of the 4-yr total annual soil loss. Tillage effects were more pronounced in years with low runoff and soil loss than in years with high runoff and soil loss. Zero tillage and RT are effective in reducing average annual soil losses by 81 and 53%, respectively, of those observed under conventional tillage. Key words: Runoff, soil loss, erosion plots, seasons, tillage

Description: Growth chamber and laboratory studies of four selected soils differing in C:N:S ratios and the percentage of total S present as HI-reducible S in the soil organic matter showed that: (1) the yield response of alfalfa to applied S occurred when the 0.01 M CaCl2-extractable soil SO4—S was less than 3.3 μg/g, (2) mineralization of soil organic S was unaffected by the addition of 25 μg S/g to the soils, and (3) the amount of S mineralized was not directly related to the quantity of total S, HI-S or the percentage of total S present as Hi-reducible S. It was noted that the largest amount of S mineralized occurred from the soil with the lowest C:N:S ratios.

Description: 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

Description: 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

Description: 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

Description: Field studies were conducted on Prince Edward Island (PEI) at two locations over a period of 2 years on the effect of soil and foliar applied Co on Co concentration in forages and cereals. Application of Co did not affect crop yields, although the yields varied considerably from location to location (data not reported). The Co concentration in cereal grain ranged from 10 to 25 μg kg−1 in the control plots. With foliar-applied Co, maximum Co concentrations in wheat, barley and oat grain were 101, 70 and 29 μg kg−1, respectively, in the three crops. In forages, large increases in Co were found in the first cut using foliar sprays but in the second cut the Co increases were small and significant only in one-half of the cuts. Soil applications of Co at 150 g ha−1 were ineffective in raising the grain Co but in forages Co was significantly increased in about one-third of the cuts. The mean Co concentration in forages and cereals from various fields in PEI ranged from 13 to 28 μg kg−1; such levels are considered deficient for livestock. In the case of suspected Co deficiency, 60 and 100 g Co ha−1 applied as a foliar spray to forages and cereals, respectively, should raise the feed crop Co concentration in the sufficiency range for livestock. Key words: Cobalt, wheat, barley, oats, alfalfa, timothy

Description: 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

Description: The effect of timing of application on the recovery of fertilizer N applied to irrigated soft white wheat (Triticum aestivum L.) was investigated in a 3-yr field study and a 1-yr lysimeter study using 15N-labelled urea and ammonium nitrate. Fertilizer N treatments consisted of a check and 90 kg ha−1 applied as preplant N, postplant N or combinations. Under a controlled watering regime in the lysimeter experiment, timing of N application had no effect on plant growth parameters. In the field studies, although grain yield was not affected by N timing, grain N concentration increased from 17.9 to 19.6 g kg−1 as the proportion of postplant N was increased from 0 to 100%. Plant N uptake was greater when all of the N was applied postplant than preplant (means = 124.5 and 114.2 kg ha−1, respectively) in the field studies. Plant recovery of fertilizer N (FNR) by the difference method was greater when all of the fertilizer N was applied postplant (43.7%) man preplant (28.6%) in the field experiments. With a negative apparent added N interaction (ANI), the FNR was less by the difference method than by the 15N method. However, with a positive ANI, FNR was less by the 15N method than by the difference method. There was a greater difference between methods as the proportion of N applied as postplant N increased. Key words: Fertilizer N timing, irrigation, soft white wheat, nitrogation, fertilizer N recovery

Description: The effect of hexazinone (applied as Velpar L.) on carbon dioxide (CO2) evolution, nitrogen (N), phosphorus (P), and sulfur (S) mineralization in a surface organic layer (L–H horizons) of a forest soil was followed during a 150-d laboratory incubation. Hexazinone was applied at recommended field rates equivalent to 2 and 4 kg a.i. ha−1 and at a higher rate, 8 kg a.i. ha−1. A bioassay determined that hexazinone at 4 and 8 kg a.i. ha−1 affected the root and shoot biomass of oats for up to 63 d after application. Hexazinone had no effect on CO2 evolution, ammonification, nitrification or net S mineralization in the L–H horizons. An increase in extractable P was found in the hexazinone-treated soils at the end of the incubation. Hexazinone applied at recommended field rates of 2 and 4 kg a.i. ha−1 would have little direct impact on nutrient-cycling processes in the L–H horizons of mixed-wood cutovers. Key words: Hexazinone, carbon dioxide evolution, nitrogen, phosphorus, sulfur, forest soils

Description: 137Cs in the soil was used to estimate soil erosion at two National Soil Conservation Program benchmark sites in the province of Quebec (sites 15-QU and 16-QU). The 137Cs baseline in an uneroded forest area was approximately 3100 Bq m−2. The 137Cs content at site 15-QU ranged from 1072 Bq m−2 to 6389 Bq m−2, while at site 16-QU it ranged from 663 Bq m−2 to 5444 Bq m−2. Computed net erosion over the past 30 yr at site 15-QU varied from a loss of 9.65 kg m−2 yr−1 to a gain of 10.88 kg m−2 yr−1 and at site 16-QU from a loss of 6.38 kg m−2 yr−1 to a gain of 1.73 kg m−2 yr−1. The average net erosion rates were 2.43 kg m−2 yr−1 at site 15-QU and 1.29 kg m−2 yr−1 at site 16-QU. Soil samples collected on a grid pattern indicated that 90% and 83% of the area at sites 15-QU and 16-QU, respectively, was subjected to net soil loss. A comparison of total 137Cs movement from eroded areas to depositional areas showed that 24.2% of 137Cs was lost from site 15-QU, while about 17.6% of 137Cs was lost from site 16-QU. Mapping of 137Cs content and calculated soil loss and deposition showed that soil erosion was closely related to topography.Under similar slope conditions, the soil erosion rates were 27–68% higher at site 15-QU than at site 16-QU. Higher tillage frequency and use of silage corn were the suggested reasons for the higher soil erosion rates at site 15-QU compared with site 16-QU, which had been used for hay and small grains. Key words: 137Cs, erosion, deposition, soil conservation

Description: 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

Description: The use of inter-row ground covers has been suggested to reduce soil degradation in raspberry (Rubus idaeus L.) production. The effect after 6 yr of consistent inter-row management of ground covers or roto-tillage in raspberry on soil wet aggregate stability (WAS), bulk density, organic C and total N, and mineralizable nitrogen in the Fraser Valley of British Columbia was studied. Management treatments included no cover crop or cover crops of barley (Hordeum vulgare L.), sheep's fescue (Festuca ovina L.), perennial ryegrass (Lolium perenne L.), and white clover (Trifolium repens L.). A general pattern of perennial grasses 〉 legume and barley 〉 control was observed for soil WAS. Some quantitative and qualitative differences in the organic component of the soil profile to 30 cm were detected among management treatments. The differences were not statistically strong because the changes were small relative to the large pool present, but were relatively consistent overall. The white clover treatment tended to have more organic carbon, particularly in the subsurface, than the other treatments. The four treatments that included inter-row vegetation tended to have a greater amount of total and mineralizable N than the clean-tilled control. Crop vigour, as indicated by cane diameter, was reduced by the perennial grasses, but the inter-row management had only limited effects on berry yield. White clover appears to provide the best compromise between improving soil quality and minimizing competition with the berry crop. Key words: Wet aggregate stability, barley, sheep's fescue, perennial ryegrass, white clover

Description: Producers in western Canada have applied phosphorus (P) fertilizer to annual crops for many years. This has increased soil available P and gradually decreased the expected yield response to P fertilization, but yield responses to small amounts of P placed with the seed are still reported regardless of soil available P levels. Controlled growth chamber studies suggest that the P responses should be most apparent during cool, wet springs. This 24-yr field study compared the yields of two fallow–spring wheat–spring wheat (F–W–W) systems, one fertilized with N and P each crop year, and the other fertilized with only N. The study, which was part of a long-term crop rotation experiment, was conducted on an Orthic Brown Chernozemic loam at Swift Current, Saskatchewan. Bicarbonate-extractable P (Olsen P) in the 0- to 15-cm depth in spring of the treatment receiving no P remained relatively constant (about 19 kg ha−1) throughout the study, while P fertilizer application at 6.5 kg ha−1 yr−1 increased extractable soil P by about 0.9 kg ha−1 yr−1. However, this increase in available P has not reduced yield responses to seed-placed P over the years. Regression analysis showed that yield response to P on fallow soil was positively related to temperature between emergence and the three-leaf stage and to precipitation at dough stage, but negatively related to precipitation near seeding time. For wheat grown on stubble, response to P was negatively related to temperature between 10 and 16 June (i.e., about the three- to four-leaf stage) and positively to precipitation received at anthesis stage. We concluded that, although available P in prairie soils has probably increased in recent years, producers can still expect to receive a 10% yield increase when small amounts of P are applied with the seed.Key words: Crop rotations, bicarbonate-extractable P, Olsen P, temperature effects, effect of precipitation

Description: The objective of this study was to compare the effects of three tillage treatments and soil constituents on soil porosity characteristics. The experiment was initiated in the fall of 1987 on a Kamouraska clay (Orthic Humic Gleysol). Moldboard plowing, chisel plowing and no-till were compared during the fourth growing season of a continuous barley (Hordeum vulgare L.) system. Surface soil samples were taken in late May 1991 after seeding and at the beginning of October before primary tillage. Soil porosity was characterized by measuring the total porosity and its textural, structural and shrinkage components. The tillage treatments had no significant effect on total porosity. In May, however, the structural porosity was 25% larger under moldboard plowing than under no-till. On average for the two sampling dates, the interclod porosity was 51% larger under moldboard plowing than under no-till. In addition, this component of the structural porosity increased during the growing season under all treatments. In May, the shrinkage porosity decreased progressively from moldboard plowing to chisel and to no-till whereas the reverse trend was observed in the fall. Textural porosity was positively correlated with clay and organic carbon contents. This study shows that tillage affects mainly the structural porosity and in particular its interclod and shrinkage components. Key words: Tillage, total porosity, structural porosity, textural porosity, shrinkage porosity

Description: One set of 12 lysimeters (75 cm × 15 cm, packed with 70 cm of Plainfield sand) was treated with 14C-labelled metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methyl ethyl)acetamide] in an emulsifiable concentrate (EC) while a second set was treated with a 25% granular (25G) formulation. Atrazine [2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine] was applied to all lysimeters as an internal reference. Duplicate soil cores from each treatment were removed and frozen at 1, 2, 4, 8, 12, and 21 wk following application. All lysimeters received supplementary water throughout the study, simulating 25-yr return storms on days 2 and 9, followed by a simulated irrigation practice thereafter. Soil cores were cut into seven 10-cm segments to obtain persistence data and concentration profiles. No metolachlor and only a few traces of atrazine appeared in the effluent throughout the study. Metolachlor EC disappeared more rapidly than metolachlor 25G, with 50% disappearance times of 2.2 and 4.0 wk, respectively. After 1 and 2 wk, 14.0 and 28.7% more metolachlor 25G than EC, respectively, remained in the top 10-cm layer. No metolachlor was detected below 40 cm in any soil core. Up to 22.3% of applied 14C accumulated in the effluent after 21 wk, with traces appearing in the effluent on day 2, following a 50-mm watering. 14C recovery in the lysimeter systems decreased to 78% after 21 wk, which may be partially ascribed to volatilization losses. Key words: Leaching, degradation, radioisotope, mobility, herbicide

Description: The economics of hauling manure as an amendment for restoring the productivity of artificially eroded wheat cropland was investigated using a simulation model. The model incorporated data on the long-term variability of wheat price, growing season precipitation and manure moisture content, and data from manure application experiments conducted on land where topsoil had been removed in levelling. Results showed that on average over the long term, the value of manure as an amendment for restoring the productivity of slightly eroded wheat cropland ( 80 cm soil lost/removed), hauling distance can be extended approximately 20 km. The disposal market for feedlot manure can be expected to extend to a distance of about 55 km from its source. Results are applicable to the dryland wheat areas of the dark brown soil zone of the Canadian prairies. Key words: Feedlot manure, fertilizer economics, eroded soil, animal wastes

Description: One saline soil in a side-hill seep and another in a closed basin in southern Alberta were investigated using hydrological, chemical and mineralogical techniques to compare the nature of soil salinization. The morphology of the saline Gleyed Regosolic soil in the seep indicated strong upward movement of water and soluble salts. This was evident from the presence of mottles in the soil solum, a shallow water table (≤ 2.69 m), and high EC (2.8–32.5 dS m−1) and SARt (4.8–55.5) values in the shallow groundwater and soil. High soluble Mg/Ca ratios (2.1) in the soil extract of the Ccasa3 horizon and the presence of Mg-calcites (4–5 mol %) indicated restricted leaching at this site. The morphology of the saline Orthic Dark Brown Chernozemic soil in the closed basin reflected slight upward movement of water and soluble salts. This morphology was consistent with a deeper water table (≥ 2.62 m), and lower EC (2.2–10.0 dS m−1) and SARt (2.9–11.3) values in the shallow groundwater and soil. High Mg/Ca ratios (4.8–7.0) in soil extracts of the C horizons, but no Mg-calcites, indicated greater leaching at this site. We estimated that it would take about 77 yr to salinize the soil at the seep via upward groundwater movement, and 6500 yr to salinize the soil at the closed basin. The high tritium content of the shallow groundwater at both sites suggested that downward (closed basin) and lateral (seep) movement of water to the water table was an important factor contributing to shallow water tables and soil salinization. Key words: Salinization, hydrology, chemistry, mineralogy, side-hill seep, closed basin

Description: Greenhouse, field and laboratory studies were conducted to determine if N availability to corn (Zea mays L.) and NO3 leaching were affected by encapsulating conventional granular fertilizer within peat pellets (organo-mineral fertilizers or OMF). In the greenhouse, total N uptake by three 6-wk crops of corn from soil fertilized with NH4NO3 was 9.1% higher than the mean from soils fertilized with OMF made with urea (OMF-urea) or with NH4NO3 (OMF-AN). Total N uptake was 5.1% higher from soils fertilized with OMF-AN than OMF-urea. Differences in total N uptake among the fertilizers were constant across crops. In two field trials, total N uptake was slightly higher (4%) from soil fertilized with commercial NH4NO3 than with OMF-AN. In a laboratory experiment, NO3 from commercial NH4NO3 fertilizer leached more readily from soil than NO3 from OMF-AN. Approximately 95% of the NO3 from commercial NH4NO3 fertilizer leached from 3-cm soil cores in the first 50 mL of leachate whereas only 26% of the NO3 contained in OMF-AN leached. In another trial, NO3 from commercial NH4NO3 fertilizer leached more deeply than NO3 from OMF-AN after application of 2.5 cm irrigation water to soil in 63-cm leaching columns. Virtually no NO3 was retained within the OMF-AN pellet after leaching, suggesting that the retention of NO3 by OMF-AN used in our work is of limited duration. The OMF is an effective source of N to crops and is less prone to NO3 leaching losses than commercial NH4NO3 fertilizer when rain occurs soon after application. More work is required to determine the effect of pellet size and composition on NO3 retention, NO3 leaching losses and crop availability of N. Key words: Nitrate leaching, corn, organo-mineral fertilizers

Description: 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

Description: Placement and interaction of urea and KCl fertilizers for corn production needs to be evaluated to develop rational fertilizer management programs. A field study, involving three rates of urea and KCl with band and broadcast placements, was conducted with corn on two Quebec soils in 1988 and 1989 to determine nutrient interactions on corn (Zea mays L.) dry matter yields, N and P uptake and on soil N and K. In two sites (Chicot 1988 and Ormstown 1989) with dry surface soils, no rainfall for 5 d and significant rainfall after 5 d, broadcast urea resulted in higher dry matter yields and uptake of N than banded urea. In the Chicot 1989 site where urea application was on moist soil and followed by rainfall insufficient to move broadcast urea into the soil, banded urea was more effective than broadcast urea. Banded urea generally resulted in increased inorganic N and fixed [Formula: see text] in soil sampled from within fertilizer bands but lower levels in soil between bands in comparison with broadcast urea. Banding KCl resulted in increased exchangeable K+ in the band. Compared with exchangeable K+, fixed K+ was less affected by placement methods and rates of added N and K. Interactions between rates and placement methods of N and K on dry matter yield, N and K uptake and soil N and K were few and relatively small. Key words: Fertilizer placement, urea, KCl, Zea mays, grain, corn

Description: In this study we investigated the occurrence of arylsulfatase activity in Saskatchewan soils and assessed the relationships between enzyme activity and soil properties. Thirty-nine soils representative of the five soil zones in Saskatchewan, and exhibiting a wide range of physical, chemical, and biological characteristics were studied. Arylsulfatase was detected in all the soils. Enzyme activity ranged from 14 to 770 μg ρ-nitrophenol released g−1 soil h−1. Arylsulfatase activity was highly correlated with levels of organic C (r = 0.73***), total S (r = 0.74***), HI-S (r = 0.60***), and microbial biomass C (MB-C; r = 0.56***). There was a relatively weak positive correlation (r = 0.48**) between arylsulfatase activity and the amount of SO4-S in the soils, indicating that end-product inhibition of the enzyme was not a factor at the low levels of SO4 commonly found in Saskatchewan soils. Key words: Sulfur, HI-reducible S, microbial biomass, organic C

Description: Use of fallout 137Cs for measuring soil erosion rates requires an accurate estimate of the mean areal activity of 137Cs of an uneroded reference site. To study the short-range variability of 137Cs in a forest soil, 16 profiles were sampled in a small area (8 × 8 m). Variability was relatively low (CV = 16%), so that the mean areal activity (3163 Bq m−2) at this reference site was estimated with a relatively low allowable error (

Description: A study was carried out to evaluate the effect of ammonium lignosulphonate (NH4LS) addition on the retention and desorption of P in a clay soil. High rates of NH4LS and diammonium phosphate (DAP) were added in four experiments: (1) simultaneous NH4LS and DAP addition, (2) DAP addition as a pretreatment followed by NH4LS addition, (3) NH4LS addition as a pretreatment followed by DAP addition, and (4) incubation of the soil with NH4LS for 15 d as a pretreatment followed by DAP addition. Both NH4LS and DAP increased Ca dissolution (CaD) when added alone, but DAP decreased CaD in the presence of NH4LS. Simultaneous addition of NH4LS and DAP, or incubation of NH4LS with soil decreased dissolution of Ca. Formation of Ca-P compounds accounted for part of the increases in P retention especially at high rates of P additions. Additions of NH4LS reduced P retention, except when DAP alone was added initially to the soil. This suggests that lignosulphonate competed with phosphate ions for adsorption sites when NH4LS was added either before or simultaneously with DAP. Phosphate desorption increased with increased P retention and was greater with simultaneous additions of NH4LS and DAP. In summary, NH4LS improved the efficiency of P fertilizers through increasing P solubility. Key words: Phosphate precipitation, Ca dissolution, phosphate potential, line potential

Description: Lignosulfonate (LS) has been used as a carrier for micronutrients and has the potential to improve macronutrient fertilizer efficiency, but little is known about the behaviour of LS fertilizer mixtures in soil. A laboratory study was conducted using ammonium lignosulfonate (2.67% wt wt−1) in combination with diammoniumphosphate (DAP), urea (U) and U+DAP incubated in a silty clay loam soil. The experiment monitored CO2 evolution and NH3–N volatilization for 69 d and extractable soil N periodically for 38 d. Addition of LS initially increased CO2 evolution, but only a small proportion (10–22%) of the LS-C was evolved as CO2. Lignosulfonate decreased urea hydrolysis slightly and reduced the proportion of added N volatilized from the LS+U treatment. Lignosulfonate treatments accumulated N in the form of [Formula: see text], suggesting that LS may inhibit nitrification. A larger proportion of added inorganic N was recovered in the LS + fertilizer treatments, indicating that LS may increase fertilizer N availability. Key words: Lignosulfonate, urea, diammonium phosphate, ammonia volatilization, nitrification, fertilizer efficiency

Description: Two well-characterized humic acids (HA), extracted from a volcanic soil and a leonhardite, were used to synthesize insoluble Fe complexes. The complexes were treated at different concentrations and contact times with a siderophore (deferoxamine mesylate) and a mixture of simple organic acids (citric, oxalic, tartaric, and ketoglutaric acids) naturally occurring in root exudates in order to evaluate the capacity of the extracting solutions to desorb Fe from the humic complexes. Results showed that iron can be extracted from the complexes according to the concentrations and pH of the extractants. The mixture of organic acids was generally a better extractant than the siderophore at the high concentration because of lower solution pH. Despite constant differences in solution pH, the extracting capacity of the two extractants was similar at lower concentrations. However, the extent of desorption varied with HA characteristics. Iron appeared to be more easily released from complexes with HA rich in aliphatic carbons than from those with HA rich in aromatic carbons. These findings were attributed to the stereochemical complexity of highly aromatic humic substances that prevents natural chelators to easily reach the Fe complexing sites. Key words: Humic substances, iron, siderophores, organic acids, plant chlorosis

Description: The effect of subsoiling of Solonetzic and of Chernozemic soils was studied over a 5-yr period under dryland conditions and under irrigation, involving 11 farm sites, and 2 soil zones. Subsoiling reduced soil density for up to 3 yr on most of the Solonetzic soils and on one of the Chernozemic soils. Overwinter soil-water recharge in subsoiled Solonetzic soils was increased for up to 3 yr, but not in subsoiled Chernozemic soils. Under irrigated conditions, subsoiling reduced soil salinity and sodicity at one site; however, under dryland conditions soil salinity and sodicity levels remained unaltered. Crop emergence on one of the Solonetzic soils was decreased in the first year after subsoiling because of poor seedbed conditions. Subsoiling increased crop production on Solonetzic soils in the 1st, 2nd, 3rd and in the 4th years, and at one site in the 5th year. Subsoiling did not affect crop production on Chernozemic soils. Increased crop production resulted from increased soil water depletion with depth, and also from greater crop water-use efficiency. Soil loosening by subsoiling, as indicated by decreased soil bulk density of the B horizon lasted up to 3 yr, during which the largest yield increases were measured. The results suggest that subsoiling may have to be repeated every 5 yr or more. Key words: Subsoiling, amelioration, soil water, crop growth

Description: Knowledge of water desorption characteristics of peat substrates is of primary importance in horticulture. However, these characteristics are difficult to measure as they are influenced by sample preparation, particularly when samples are obtained from potted substrates containing growing plants. The aim of this study was to determine the effect of sample preparation on the water desorption characteristics of peat substrates and to propose an alternative method to limit sample disturbance. This study shows that water desorption characteristics of peat substrates obtained using Tempe cells differ from those obtained using pots and a tension table apparatus. However, the latter method is time and resource consuming. An alternative method for routine and rapid determination of water desorption characteristics of undisturbed samples was tested. Measurements of water potential (ψh) in pots were obtained using tensiometers. Volumetric water content (θ) was measured by time domain reflectometry (TDR), a non-destructive in situ method commonly used for mineral soil characterization. The technique measures the apparent dielectric constant of the soil (ka) and empirically relates it to θ. Empirical relationships between θ and ka were derived for three different peat substrates. Using these relationships, water desorption characteristics (θ versus ψh) were derived for three substrates in laboratory experiments and compared to water desorption characteristics obtained using a tension table to establish different ψh and a gravimetric determination of θ. The approach using TDR and tensiometers appears to be reliable, fast and to allow large number of simultaneous water characteristic determinations. Key words: Water characteristics, water release curve, time domain reflectometry, peat sustrates

Description: Crop rotations and tillage practices can modify not only the total amount of organic matter (OM) in soils but also its composition. The objective of this study was to determine the changes in total organic C, microbial biomass C (MBC), carbohydrates and alkaline phosphatase activity induced by 4 yr of different rotation and tillage combinations on a Kamouraska clay in La Pocatière, Quebec. Two rotations (continuous barley (Hordeum vulgare L.) versus a 2-yr barley–red clover (Trifolium pratense L.) rotation) and three tillage treatments (moldboard plowing (MP), chisel plowing (CP) and no-tillage (NT)) were compared in a split-plot design. Total organic C was affected by the tillage treatments but not by the rotations. In the top soil layer (0–7.5 cm), NT and CP treatments had C contents 20% higher than the MP treatment. In the same soil layer, MBC averaged 300 mg C kg−1 in the MP treatment and up to 600 mg C kg−1 in the NT soil. Hot-water-extractable and acid-hydrolyzable carbohydrates were on average 40% greater under reduced tillage than under MP. Both carbohydrate fractions were also slightly larger in the rotation than in the soil under continuous barley. The ratios of MBC and carbohydrate C to total organic C suggested that there was a significant enrichment of the OM in labile forms as tillage intensity was reduced. Alkaline phosphatase activity was 50% higher under NT and 20% higher under CP treatments than under MP treatment and, on average, 15% larger in the rotation than in the continuous barley treatment. Overall, the management-induced differences were slightly greater in the top layer (0–7.5 cm) than in the lower layer of the Ap horizon (7.5–15 cm). All the properties measured were highly correlated with one another. They also showed significant temporal variations that were, in most cases, independent of the treatments. Four years of conservation tillage and, to a lesser extent, rotation with red clover resulted in greater OM in the top soil layer compared with the more intensive systems. This organic matter was enriched in labile forms. Key words: Soil management, soil quality, organic matter, carbohydrates, microbial biomass, phosphatase

Description: About 250,000 acres of soil with fragipan have been mapped in Nova Scotia. The fragipan horizons of two soils (Tormentine and Debert) reported in this paper are typical for the province. They have high bulk densities and low saturated hydraulic conductivity. They are also low in organic carbon and free oxides. They are high in fine sand and silt but low in clay, and the fragments of fragipan are readily slaked in water. Mica, chlorite, vermiculite, and kaolinite were found in the clay fractions of both soils throughout the two profiles. A moderate amount of smectite was found in the clay fractions of the Ae horizon of Debert but not in the Tormentine profile. A significant amount of clay increase in both fine and total clay fraction was found in the Bf horizon of the Tormentine soil and the Bmgj and Btx horizons of the Debert soil, and results from translocation or lessivage. The brittleness and other associated properties of the fragipans were attributed to clay bridges linking coarser particles, which were shown in the scanning electron microscope pictures.

Description: The soil had a thick, dark brown, highly porous Podzolic B horizon with a high content of amorphous Fe, Al- organic matter complex material and a low bulk density, underlain abruptly by a dense, gray fragipan with a bulk density of nearly 2 g/cm3. Mean pore diameters of subhorizons within the Podzolic B ranged from about 25 to 120 μm and those of the fragipan were about 0.5 μm. The marked contrast in porosity was consistent both with hydraulic conductivity values of about 20 cm/h in the Podzolic B and 0.2 cm/h in the fragipan, and with the micromorphology. Strongly oriented argillans in the fragipan indicated some clay translocation. The clay mineralogy indicated weak weathering of phyllosilicates, but appreciable weathering of primary minerals must have occurred to produce the amorphous Fe and Al- rich amorphous material in the Podzolic B. Seepage along the surface of the fragipan, and the absence of roots in this layer indicated the significance of this horizon with respect to plant growth and to the water regime of the soil.

Description: The possibility of nitrates being leached into groundwater supplies from improper use of fertilizers is a concern to society. Two experiments were conducted on a loam soil in the Brown soil zone at Swift Current, Saskatchewan. In the first experiment, continuous wheat (Triticum aestivum L.), grown under various fertilizer-N management systems and with and without cereal trap strips (tall stubble, 0.4–0.6 m) to capture snow and enhance soil-moisture storage, was compared with short stubble cut at the standard height (0.15–0.2 m). Prior to seeding in spring 1991, tall stubble had stored 14.7 ha-cm of soil moisture at 0–1.2-m depth compared with 10.9 ha-cm under short-stubble treatment. Because growing-season precipitation in 1991 was much higher than normal (302 mm from 1 May to 31 My), considerable NO3-N was leached below the rooting zone of wheat (1.2 m), particularly in the tall-stubble treatment. Leaching patterns were as expected in short stubble, with major leaching occurring only at the highest N rate (125 kg ha−1), where yield and N-uptake response had levelled off. However, in tall stubble, the amount of NO3-N leached beyond the root zone under the 0 and 25 kg N ha−1 rates was similar to that under the 125 kg N ha−1 rate. This result was attributed to poor tillering obtained at low N rates, which contributed to lower evapotranspiration, thereby permitting more moisture to be leached and enhancing N mineralization. When we used a leaching model (NLEAP) to simulate our results, it gave lower estimates of NO3 leached and did not reveal the interaction of NO3-N leaching with N rates that was observed under tall stubble. The second experiment measured soil NO3-N distribution to 2.4 m under two fallow–wheat–wheat systems after a 24-yr period. One system received only N, the other, N + P fertilizer. The results corroborated those obtained under tall stubble in the first experiment: the poorly fertilized system had the most NO3-N below the root zone. The results of this study suggest that the key to reducing nitrate leaching is the adoption of proper fertilization practices, since too little fertilization may potentially be as detrimental to groundwater pollution as too much. Key words: Fertilizer N, N uptake, snow management, crop rotations, NO3 leaching

Description: An extraction-fractionation method was developed with which it is possible to isolate 60–67% of the humus of Chernozemic and Luvisolic soils. Two humic acid fractions were obtained: (1) a conventional alkali-pyrophosphate extractable HA-A; (2) a clay-associated HA-B fraction isolated after ultrasonic dispersion, in water, of the residue of the alkali-pyrophosphate extraction. As compared to the HA-A, the HA-B fractions had lower C contents but greater N contents, narrower C:H ratios, higher molecular weights, and less resistance to hydrolysis in 6 N HCl. It was concluded that the HA-B is a weakly humified, potentially labile humic constituent stabilized by adsorption to clay. Spectral measurements on low-ash (

Description: The addition of ammonium salts increased the hydraulic conductivity of samples taken from the Bnt horizon of a Solonetz soil. The improved conductivity was caused by an increase in the salt concentration in the soil solution and by the ammonium adsorbed on the clay particles. Since the dominant clay mineral in this soil type is montmorillonite, purified bentonite was used for comparative studies. Mobility studies of montmorillonite systems indicated that the adsorbed NH4 ions are tightly bound to the clay particles. The size of the NH4-tactoids was found to be larger than that of the Na-tactoids but less than half that of the Ca-tactoids. It was concluded that the beneficial effect of ammonium on water movement in Solonetz soils will be less than that of calcium, but the transformation of the adsorbed ammonium in the field, followed by replacement of sodium by hydrogen, may result in further improvement of these soils.

Description: Conditional stability constants of some metal fulvate complexes have been determined at 25 C using specific ion electrodes. In aqueous 0.1 M NaNO3, solution, the log K values are: 4.86 and 5.08 at pH 3 and 4 for mercury complexes; 3.04 and 3.64 at pH 4.9 and 5.95 for cadmium complexes; and 3.22, 3.72, and 4.35 at pH 3, 4, and 5 for copper complexes. In 0.04 M NaNO3 solution, the log K value for mercury–fulvic acid system is 5.12 at pH 3.1. The order of metal affinity toward fulvic acid Hg 〉 Cu 〉 Cd is in general agreement with the literature for complexing of these metals with similar type donors.

Description: Water contents and bulk densities were measured in a soil pedon with a gamma-ray transmission technique utilizing 137Cs and 241Am. By alternating the sources for each scan down the soil profile, both bulk density and water content were determined in 1-cm increments in the top 10 cm of the pedon. Bulk density decreased to a depth of 6 cm about 30 min after 4 cm of water was ponded on the soil surface. As soon as the water drained from the surface, bulk density values increased and approached pre-irrigation levels. Water content increased rapidly corresponding to the decrease in bulk density. Assuming that the bulk density remains constant during ponding, calculated water contents may be in error by as much as 0.25 gcm−3.

Description: not available

Description: not available

Description: not available

Description: Monocalcium phosphate was broadcast at 0, 50, 100, and 200 kg P/ha to a calcareous soil, very low in NaHCO3-extractable P. Wheat (Triticum aestivum cv. Selkirk) and flax (Linum usitatissimum cv. Marine) were seeded in the 1st yr and barley (Hordeum vulgare cv. Montcalm) and flax were alternated in 3 subsequent yr. Subplot treatments consisted of 0, 5, 10, 20 and 40 kg P/ha applied as monoammonium phosphate with the seed. Wheat and barley responded well to broadcast or seed-drilled P. The latter was the most effective method of application; this was apparent even on plots receiving large amounts of broadcast P. In contrast, flax was not responsive to newly applied P, and yields decreased with application of seed-drilled P in combination with large amounts broadcast. The solubility of P in the untreated soil was between that of octacalcium phosphate (OCP) and hydroxyapatite (HA). The solubility of P in the treated soils was greater than in the untreated soils for the duration of the sampling period (3 yr) and was slightly less than that of OCP for the 50 kg/ha treatments, about that of OCP for the 100 kg P/ha treatment and greater than that of OCP for the 200 kg P/ha treatment. These studies indicate that the reaction product most likely governing the solution concentration of P was OCP.

Description: not available

Description: not available

Description: not available

Description: Two well-drained soils formed in the subalpine zone of the Washington Cascades from the same complex parent material and environment exhibit contrasting morphologies due to the vegetation. One of the soils, presently unforested, exhibits in its morphology the influence of three ash falls and a complex vegetational history. The horizon sequence and properties fit the Lithic Regosol criteria of the Canadian classification system. The second soil, formed on the same parent materials but under forest vegetation, exhibits properties of an orthic Ferro-Humic Podzol. These pedons exemplify the complex nature of soils whose classification has previously been oversimplified as steep, rocky soils or lithosols.

Description: Recent surveys in the Canadian subarctic have shown the wide distribution of cryogenic earth-hummock soils with permafrost. A study of chemical, physical, mineralogical and micromorphological features revealed quite acidic, partially unsaturated surface horizons, large amounts of amorphous sesquioxides and fulvic acids, and fluctuating redox conditions. It appears that the permafrost table and the surface organic layer play a governing role in most pedological processes. It is suggested that the occurrence of fires contributes a cyclical aspect to these processes, which appears to be an integral part of soil development in the subarctic. A consideration of fire history helps to explain many of the physical and environmental variations found in the field.

Description: Greenhouse studies were conducted in which various amounts of phosphorus were added to calcareous and noncalcareous soils, and the iron, manganese, zinc and copper utilization by wheat were determined. Wheat yields were significantly increased by phosphorus fertilization; mean yields on the noncalcareous soils were greater than on the calcareous soils. Plant micro-element concentration and uptake were reduced in many instances when large amounts of phosphorus were applied. Plants grown on the calcareous and noncalcareous soils had similar concentrations of iron, manganese and copper. However, plants grown on the calcareous soils tended to contain lower amounts of zinc than plants grown on the noncalcareous soils. Concentration of micro-elements in soil-water extracts of phosphated soils, particularly for the noncalcareous soils treated with large amounts of phosphorus, tended to be greater than for nonphosphated soils. Yields were usually not affected when phosphorus at 2–100 ppm was added to nutrient solutions. Zinc and copper concentration and uptake were usually greater for plants grown in a 2-ppm phosphorus solution than for plants grown in solutions of higher concentration. In several instances, plant iron concentration and uptake were also reduced by high phosphorus concentration. Manganese uptake appeared not to be affected by phosphorus concentration. Increasing the micro-element concentration of nutrient solutions at various phosphorus concentrations did not affect yields but increased plant micro-element concentration and uptake, indicating that ion antagonism was mainly responsible for the lower utilization of microelements in high phosphorus media.

Description: Properties of soils along the 3% slope were affected both by water table levels and by the nature of the parent sedimentary rock. All of the soils had upper sola of medium to fine texture, due largely to the disintegration of the underlying shaly gravel. Relatively impermeable shaly bedrock at depths of 1–2 m from the surface maintained generally high water tables. Redox potentials, gley colors and mottling were closely associated with proximity to the surface of the water table. Evidence of podzolisation and of clay weathering and translocation were obscured by the release of bases and clay from the disintegrating gravel. Hydraulic conductivities of the surficial layers were generally much lower than those of the gravelly subsoil layers, but the data were highly variable due to soil variability, seasonal changes in soil structure and problems with methodology. The data suggest that surface ridging might be more effective than tiles for draining soils such as these.

Description: Thatcher wheat was grown in tank-type lysimeters over a 7-yr period to determine the effect of fertilizer, two levels of available water and two cropping systems on the yield and nutrient content of grain and on some soil nutrients. Fertilizer did not change the yield of grain materially under natural rainfall. Added water only increased the yield by one-half and three-quarters of continuous wheat and fallow, respectively. Fertilizer with added water nearly doubled the yield of continuous wheat and increased by one-third the yield from the wheat-fallow rotation. The P content of the grain was not affected by fertilization, but was higher in the treatments to which additional water was applied than in those receiving natural rainfall only. It was also higher in continuous wheat than in fallow wheat. There was an interaction between the N and P uptake ratio and the N content of the grain. Fertilizer or additional water or both increased or decreased the N content, depending upon which way the N or P balance was shifted. Surplus available N not utilized by the crop grown with natural rainfall accumulated as nitrates at lower soil depths, particularly under the wheat-fallow system. All the NO3-N produced where supplemental water or water and fertilizer were applied was utilized and none accumulated. The organic N content of the surface soil increased along with a reduced loss in organic C where water and fertilizer were applied, as compared to the other treatments. Fertilizer application resulted in a sharp increase in NaHCO3 soluble P, particularly following the supplemental water plus fertilizer treatments where an excess of P was supplied with the fertilizer over that removed by the crop. There was an increased demand on soil P where water only was applied, and the soluble P content was appreciably reduced.

Description: Brown heart sometimes occurs in rutabagas (Brassica napobrassica Mill.) grown on some southern Ontario soils even though a recommended quantity of B fertilizer has been applied. Fourteen field experiments were conducted on growers' fields over a 4-yr period to determine the cause of this phenomenon. Brown heart occurred when the hot-water-soluble B content of the soil decreased below approximately 1.3 ppm although there were a few exceptions. An application of 4.5 kg B/ha as borax did not completely overcome the brown-heart condition in a majority of the experiments. The B concentration in the third or fourth leaf from the centre of the whorl was not related to brown-heart incidence. However, it was found that a B concentration of less than 18 ppm in the roots was generally associated with brown-heart incidence. Although there was no clear relationship between the Ca/B ratio in the leaf blades and brown-heart incidence, there was an increase in brown-heart incidence as the Ca/B ratio in the roots increased above 170. In three experiments, an application of 224 kg Na/ha as NaCl significantly increased brown-heart incidence, whereas in a fourth experiment there was a significant decrease. There was some evidence that the Na may slightly decrease the B concentration. Also the Ca concentration increased as the Na concentration increased in rutabaga tissues thereby affecting the Ca/B ratio and possibly brown-heart incidence. There was also evidence that, in the root tissues, the Ca/B ratio was inversely related to the K concentration. It was concluded that the effectiveness of B in decreasing brown-heart incidence was related to the Ca concentration in rutabaga plants.

Description: The adsorption of acid and dimethylamine salts of 2,4-D and dicamba was studied on Canadian prairie soils and various other adsorbents, using slurry-type adsorption experiments. The amount of adsorption of both the acid and dimethylamine forms of the two herbicides was minimal. The results were explained on the basis of dissociation of the acidic and dimethylamine salts to the respective anionic forms in the near-neutral prairie soils. This conclusion was supported by (1) the strong adsorption of these herbicides to the anion-exchange resin but not to the cation-exchange resin; (2) the strong adsorption of the 14C-dimethylamine cation to these soils; and (3) the leaching patterns of the 14C-dimethylamine salts of both herbicides from soils and resins. Only the anionic species were eluted from columns containing soils and cation-exchange resin whereas only the 14C-dimethylamine cation eluted from columns containing anion-exchange resin. Both forms of 2,4-D and dicamba were strongly adsorbed to activated charcoal, cellulose triacetate, and peat. There was little or no adsorption of these herbicides to montmorillonite and kaolinitic clays, cellulose powder, or wheat straw.

Description: In a series of 11 surface burns in old fields at two locations in southern Ontario the environmental factors having the greatest effect on fire severity were fuel moisture content, windspeed and fuel energy. Other environmental factors were of less significance. Changes in soil chemistry were restricted to the surface litter and were transitory. Changes at mineral soil depths may have gone undetected because of the highly buffered soils involved. As much as 30% of the loss of nutrients from the biomass during burning was recovered in downwind deposits of fly-ash adjacent to the burned areas. Recovery estimates are considered approximate and minimal but indicate the importance of nutrient losses in fly-ash during low temperature burns.

Description: Ecological studies on soil nematodes, enchytraeids, collembolans and mites in a 1948 Pseudotsuga menziesii plantation at Shawnigan, British Columbia were made from March 1971 to March 1972. The plantation was thinned to 1,900 stems/ha and urea was applied at 0, 224 and 448 kg N/ha just before faunal sampling. Monthly samples were extracted in high-gradient apparatus, Murphy split funnels and simple wet funnels. Fifty-two and 53% of collembolans and mites, respectively, occurred in the top 5.3 cm of the 17.5-cm soil profile studied. The Pearson and Hartley power function test indicated that for intramonth sampling to show statistical significance of treatment, at least 10 samples per treatment would be required for any of the groups under experimental conditions similar to the one reported here. Collembolans and mites exhibited significant downward seasonal distribution, and urea treatment accentuated this phenomenon for all four groups, suggesting that sampling below 6 cm would be required to observe the full impact of urea fertilization on the soil fauna. Except for enchytraeids, seasonal population fluctuation contrasted with the generally observed pattern in temperate regions of spring and fall peaks and showed increases through the spring, culminating in summer and autumn maxima. Urea fertilization increased annual mean population of nematodes by 1.41 and 2.51 times the control for 224 and 448 kg N/ha, respectively, and decreased enchytraeids by 0.52 and 0.28 times the control for the same two fertilizer rates; collembolans and mites were not significantly affected.

Description: A computer program was written to estimate from sequential data the parameters for a Markov chain probability model. The program was applied to the analysis of field workday probabilities at 10 selected locations across Canada. The suitability of the first-order Markov chain model was tested and the locations across Canada were compared as to the probability and conditional probabilities of workdays. These probabilities estimated by the program also provide data which should be of interest in farm machinery selection.

Description: not available

Description: not available

Description: Yield of white beans increased markedly (250, 1,090 and 1,545 kg/ha) when grown in field plots at soil temperatures of 11.6 (T1), 19.7 (T2), and 29.7 C (T3) (20-cm depth 0830 h). This represents a change in yield of 71.1 kg/ha per 1 C change in the seasonal temperature (T2) of the soil from 23 June to 21 August. The number of degree-day units for the soil (〉 5 C) corresponding to these temperatures (20-cm depth) were 268, 602, and 1,004. A decrease in the Soil Moisture Index (SMI) from 0.69 to 0.10 and an increase from 0.69 to 1.00 lowered yield by 35% and 6%, respectively (T2), for the seasonal temperature. Loss in yield from plants infected with bacterial blight (Xanthomonas phaseoli E.F. Sm. Dows.) by spraying the organism onto leaves of 21-day-old seedlings was negligible. However, loss in yield from plants infected by injecting the organism into stems was 9.0, 43 and 52% for plants grown at cool (T1), seasonal (T2), and warm (T3) soil temperatures, respectively. Percent of pods infected by spraying was increased, whereas percent of pods infected by injection was decreased at the higher soil temperatures. In general under cool seasonal temperatures, protein content of the infected and noninfected beans decreased with higher moisture that coincided with only a small change in yield. The protein content, however, remained fairly constant under large yield increases resulting from higher soil tempratures. The data are interpreted in relation to spread of the disease in fields from seedborne infection and subsequent spread of the disease to adjacent healthy plants.

Description: The potential application of a computer soil data file to the study of soil concepts is discussed. This method aids the pedologist to analyze, summarize and correlate large quantities of data. For applied objectives the data file allows the prediction of soil properties for interpretive purposes. The computerized soil data file was used to explore its usefulness in studying the concept of the modal profile, confirmation of definitions of the Podzolic and Gleysolic Great Groups, derivation of equations for estimating soil drainage and cation-exchange capacity, and studying some interrelationships among soil properties. Soil parameters used to define soils at the Order and Great Group levels did trend toward normal distributions for Gleysolic but less for Podzolic soils. The prediction equations for cation-exchange capacity accounted for a higher percentage of the variation than did equations for soil drainage. Many soil property interrelationships were confirmed. The study illustrates some of the weaknesses of using routine soil survey data collected over a 10-yr period.

Description: Soil samples from virgin profiles of Solonetzic and geographically associated Chernozemic series along with Ap horizons of Solonetzic and Chernozemic soils were taken. Soil pH, organic C, oxalate-extractable Al and Fe, inorganic P forms, organic and total P, and extractable P by NH4F + H3SO4 and NaHCO3 methods were determined. On the average, Solonetzic sola had higher contents of oxalate-extractable Al and Fe, Fe-P, and lower levels of Ca-P than do their associated Chernozemic sola. There was not a clear difference in Al-P contents between the sola of the two Orders. Ap samples from Solonetzic soils had twice the amount of NH4F + H2SO4- and NaHCO3-extractable P found in the Chernozemic ones. The higher levels of extractable P in the Solonetzic than in the Chernozemic Ap samples could be explained by the higher contents of Al-P and Fe-P in the former. The high acidity in the upper sola of Solonetzic soils, indicative of intense weathering conditions, apparently has resulted in relatively high contents of oxalate-extractable Al and Fe, and these probably account for the higher levels of Al-P and Fe-P and lower levels of Ca-P in the Solonetzic than in the Chernozemic soils.

Description: Total Zn and seven measures of extractable Zn in horizons of seven soil profiles declined with increasing depth of sampling within the profile. Although not invariabily found, some extractants removed more Zn from the deepest horizons of some profiles than from the horizon sampled immediately above. This distribution pattern was more pronounced for extractable than total Zn. From 27 horizon samples containing an average of 108 ppm total Zn, 2 N MgCl2, DTPA, North Carolina, Morgan, N KCl, acidic NH4Ac, and 0.01 M CaCl2 extractants solubilized an average of 4.14, 3.77, 3.37, 1.99, 1.82, 1.64, and 0.69 ppm Zn, respectively. Extractable Zn values were positively correlated with total Zn, organic matter, percentage clay, and cation-exchange capacity, but inversely related to soil pH, base saturation, and percentage sand. Zinc concentrations in corn and in oats grown on the horizon samples were best correlated with amounts extracted by 2 N MgCl2, acidic NH4Ac, and N KCl. Regressions on extractable Zn and soil pH accounted for as much as 74 and 55% of variations in Zn content of corn and oats, respectively.

Description: not available

Description: The X-ray diffraction (XRD) peak intensities of smectites in Chernozemic and related soils of Western Canada are generally low, in contrast to the high peak intensities of smectites in Podzolic soils of Eastern Canada and those of standard smectite samples. Consequently, X-ray quantitative analysis based on standard smectite samples may underestimate the amount of smectite and overestimate the amount of noncrystalline material in western Canadian soils. This study was undertaken to find the reasons for the weak XRD peak intensities of western soil smectites in terms of their purity and crystallinity. The Tiron dissolution method extracted only small amounts of noncrystalline material from the western soil clays and had little effect on XRD characteristics. The cation exchange capacity (CEC) hysteresis (or pH dependent CEC) between pH 3.5 and 11.0 of the western soil clays was also relatively small which confirmed the absence of significant amounts of noncrystalline material in these soil clays. Observed deviations of XRD positions from true basal spacings indicated that the western soil smectite particles were consistently thinner than the eastern soil smectite and Wyoming montmorillonite particles. Electron microscope observations supported these results. Because the diffraction intensity is proportional to the square of the particle thickness, the thinness of the western soil smectite particles appears to be a major factor in reducing their peak intensities. Thus, to obtain comparable peak intensity data from different soil smectites, particle thickness should be taken into account. Since it is often not practical to measure particle thickness, a procedure for quantifying smectite in soils that avoids this measurement is proposed. Key words: Peak intensity, crystallinity, particle size, particle thickness, Chernozemic smectite, Podzolic smectite

Description: Soils developed from parent materials derived from uppermost Cretaceous and Tertiary sedimentary rocks have been delineated from those which do not contain any of these younger sediments. The present study was initiated to determine the validity of this delineation. Parent materials from six locations in southwestern Saskatchewan were collected to determine their general chemical and physical properties. Clay fractions from each of these six parent materials were then subjected to detailed chemical and mineralogical analyses. The two parent materials containing the greatest amount of post-Bearpaw bedrock sediments (Jones Creek, Scotsguard) were characterized by substantially more organic carbon and less CaCO3. The presence of coal and the absence of carbonates in local bedrocks were considered to be the source of these deviations. In general, fine clays were comprised of 64–69% smectite, 14–21% illite and 10–13% kaolinite and coarse clay contained 32–39% smectite, 25–34% illite and 11–14% kaolinite. An exception was found in two fine clays which had less smectite but 3–6% vermiculite. Total iron content of the fine clays ranged from 7.16 to 8.11% expressed as Fe2O3. However, only a small fraction of this iron was extractable using the CDB technique. There were no substantial differences in surface areas or CECs of the clay fractions. Despite minor differences in the chemistry and mineralogy of these six parent materials, a separation of the soil associations does not appear to be warranted. Key words: Parent materials, uppermost Cretaceous, Tertiary, bedrock, clay mineralogy

Description: Many soil mapping units (MU) have not been adequately sampled to provide a true measure of their variability; therefore, their descriptions must be regarded as incomplete, and valid statistical comparisons cannot be made with other closely related MU. The number of samples required to detect the differences in means of 18 soil properties between Brantford and Beverly Silt Loam MU were calculated and they ranged from 4 at the 80% probability level (10 at the 95% probability level) for organic matter content of the Ap horizon to several thousand for pH of the Ap horizon. Calculation of required sample numbers indicated that sufficient samples had been collected to make valid statistical comparisons between seven of the soil properties. All seven properties were found to be significantly different between the two MU at the 95% probability level. However, only two of the properties, hue and organic matter content of the Ap horizon, had distinctly different modal values between the two MU and neither of these properties is easily measured in the field. Therefore, it was concluded that the 18 soil properties examined were impractical and unreliable criteria for separating the MU in the field. But, the MU separations can be readily and validly made on the basis of landscape position.

Description: not available

Description: Lettuce grown in a pot test using the surface soil layer of three golf course sites contaminated with mercurial fungicides contained up to 317 ng Hg/g as compared with no more than 36 ng Hg in plants grown in corresponding deeper soil layers containing much less Hg. In another experiment with 10 crop species, addition of phenylmercuric acetate to a loam soil at the rate of 5,000 ng Hg/g increased the Hg content of several of the species slightly over that found in the controls. The highest amount found was about 440 ng Hg/g in soybean vines and potato tops. The concentration tended to be lower in the edible portion (fruit, grain or roots) than in the remainder of the plants. In an incubation experiment where phenylmercuric acetate was added to seven soils and two clay-sand mixtures at the rate of 5,000 ng Hg/g, the retention of added Hg against volatilization varied from 41% in a sandy subsoil to 97% in a peat. Addition of flowers of sulfur was effective in preventing volatilization of Hg from the soils, but not from the clay-sand mixtures. Subsequent equilibration of the Hg-treated samples in 0.01 M CaCl2 removed only a minimal amount of Hg from one soil, but removed appreciable amounts from the clay–sand mixtures.

Description: The acid neutralization method and manometric procedures, using several acid-reducing agent combinations, were compared to determine their suitability for carbonate determination in organic soils. The soil–acid reaction observed with the acid neutralization procedure was significantly influenced by the acid concentration and soil type. Mean soil–acid reactions were 0.394 and 0.412 meq/g with the 0.3 and 0.6 M HCl, respectively. Moreover, it ranged from 0.023 to 0.694 meq/g soil for different soil types. The comparison of manometric procedures that were made used different acid-reducing agent combinations of HCl, CCl3COOH, HClO4, and SnCl2, and FeCl2. Of these, the HClO4–SnCl2 combination gave the lowest mean blank reading and standard deviation that remained stable (0.05 ± 0.009 ml). Though the perchloric acid alone is adequate for calcitic determinations, using the SnCl2 reducing agent with longer reaction times is recommended.