Orthic Podzol Research Articles

Increased nitrogen leaching under piles of slash— a consequence of modern forest harvesting techniques

Piles of logging residues (slash‐piles) are a consequence of modem logging techniques. The piles cover 10 to 15% of a clear‐felled area. The effect of slash‐piles on nitrogen leaching was estimated by collecting precipitation1 and percolating water below slash‐piles and below the O, E and B horizons of an Orthic Podzol during two growing seasons. Open funnels were used for precipitation, PVC troughs for water leaving the pile and filled‐in zero tension lysimeters for percolating soil water. Exchangeable ammonium and nitrate of humus samples were analysed. The increased nitrogen leaching from the soil below slash‐piles was probably caused by an increased mineralization of the humus layer and a reduced nitrogen uptake by roots.

COMPARISON OF ALUMINUM SPECIATION IN SOIL SOLUTIONS EXTRACTED BY BATCH AND COLUMN METHODS

Soil solutions from an Orthic Ferro-Humic Podzol and a Typic Humisol were extracted using a soil to solution ratio of 1:10 by the batch and column procedures. The aluminum speciation in the extracts was determined by measuring three forms of dissolved aluminum (uncomplexed monomeric, total monomeric and total reactive). The two methods of extraction gave different results. For most of the mineral horizons and the moderately to well-decomposed organic horizons the batch method tended to extract more dissolved aluminum, particularly in uncomplexed monomeric form. The greatest differences between the two methods were for the lowest bulk density materials, the L and F horizons of the Podzol and the Of of the Humisol. The variations were due to channelling in the column and the inability of the shaker to assure good mixing between the soil and solution. It is concluded that the batch method is best suited for routine laboratory analyses. Key words: Soil solution chemistry, Podzols, Humisols

SHORT-RANGE SOIL VARIABILITY AND CLASSIFICATION OF PODZOLIC PEDONS ALONG A TRANSECT IN THE LAURENTIAN HIGHLANDS

Pedons were described, sampled and classified at 5-m intervals along a 130-m transect in an area typical of the southern Laurentian Highlands in order to assess short-range soil variability. Orthic Ferro-Humic Podzol was the dominant subgroup (25 of 27 sites). Differences in depth to bedrock and in soil water regime resulted in four soil families; bedrock was exposed at one site. At 21 of the 27 sites, however, the pedons were classified in one family: Orthic Ferro-Humic Podzol, coarse loamy, cold, humid. Differences in thicknesses and sequences of horizons resulted in a total of at least nine soil series. At scales of 1:20 000 or somewhat smaller, the soils of map units in the area would be most appropriately indicated as slope phases (10–40% slopes) of families. The dominant family would be the one indicated above with inclusions of shallow to extremely shallow phases and bedrock outcrops. Key words: Soil variability, Podzolic soils, classification of pedons

Clay mineralogical comparisons of weathering profiles associated with spruce and birch stands

Abstract As a pilot study of clay-mineral speciation due to vegetational differences, the distribution of clay minerals was studied in two soil profiles with 65-year-old stands of spruce and birch within Tönnersjöheden Experimental Forest. Dystric cambisols and orthic podzols were developed on till parent material. Principal minerals were quartz, potassium feldspars and plagioclases originating from metamorphic Proterozoic bedrock. Minor minerals were phylIosilicates and amphiboles. In the clay fraction of the till, the young soil profiles were characterized by smectite with accessory kaolinite in A2-horizon, vermiculite in B-horizon and chlorite in C-horizon. Weathering, detrital inheritance, transformations and neoformations of smectite and kaolonite are discussed.

INCREASE IN NEUTRAL SALT EXTRACTABLE CATION EXCHANGE CAPACITY OF SOME ACID SOILS AS AFFECTED BY CaSO4 APPLICATIONS

The equilibration of acid soils, a Sombric Ferro-Humic Podzol (CSSC-2) from British Columbia, an Orthic Ferro-Humic Podzol (CSSC-19) from Quebec and two horizons of a Dystric Brunisol (SSD-330, SSD-331) from British Columbia, with CaSO4 solution demonstrated that SO4 ions reacted with components of these soils. These reactions increased soil pH, ion activity product (Al)(OH)3 and neutral salt extractable exchangeable cations. The increase in pH and ionic activity product (Al)(OH)3 were noticeable on a single equilibration; however, increase in neutral salt extractable cations was only observed after subsequent equilibrations. After three equilibrations, the sums of NaCl extractable cations were 6.56, 11.99, 5.62 and 4.31 meq/100 g for soil samples CSSC-2, CSSC-19, SSD-330 and SSD-331, respectively. The corresponding values for the unequilibrated soils were 5.20, 7.49, 4.30 and 2.50 meq/100 g. On further equilibration there was no increase in total extractable cations for sample CSSC-2; however, for the other three samples there were increases which became progressively smaller. The reaction of SO4 ions with aluminum hydroxy clay complexes seems to be the mechanism for the increase of negative sites. Key words: Cation exchange capacity, CaSO4, acid soils

ACTIVITE BIOLOGIQUE DANS LES SOLS DE SIX ECOSYSTEMES FORESTIERS DU QUEBEC MERIDIONAL

Dynamics of woody material degradation were studied in the soils of six forest ecosystems of meridional Quebec. This comparative study was performed measuring weight losses of wood samples, buried for long periods of time in the different horizons of each soil studied. In all cases, degradation was much faster close to the soil surface; thus a more or less marked decreasing vertical gradient was observed in the activity for most of the soils studied. The lengths of time necessary for half decomposition (50%) were calculated for the samples buried in each station. For the hardwood forests, values of about 1.7, 2.8 and 2.3 yr were obtained for half decomposition in the Melanic Brunisol, the Sombric Brunisol and the Dystric Brunisol, respectively. A value of 4.6 yr was calculated for the Minimal Humo-Ferric Podzol of the mixed forest to reach half decomposition. Similarly about 35 and more than 40 yr would be necessary for half decomposition of the samples in the Orthic Ferro-Humic Podzol and the Ortstein Ferro-Humic Podzol of the two coniferous forests, respectively. The influence of major environmental factors, such as climate, soil and vegetation on the dynamics of microbial and faunal soil communities is discussed.

VARIATIONS OF pH WITH ANNUAL CUMULATIVE PRECIPITATION IN ACID FOREST SOILS

Colorimetric soil pH measurements made systematically across Belcarra Mountain in the rain-forest of British Columbia over the 4-yr period 1975 to 1978 showed summer (June or July) values to increase somewhat with total cumulative precipitation (previous November to July). After dry winters, lower pH values in both A and B horizons were recorded, the increase in acidification being so marked on the sandy Podzols as compared to the less light-textured Brunisols that the normal increase in pH down the profile was reversed. The causes of such variations are discussed along with their significance when characterizing Orthic Humo-Ferric Podzols of the region.

GENESE D’UN HORIZON PROFOND FAIBLEMENT CIMENTE DANS UN PODZOL SABLEUX DES BASSES TERRES DU QUEBEC

An Orthic Humo-Ferric Podzol formed on a sandy deposit in the St. Lawrence lowlands exhibited a weakly cemented horizon at depth. Weathering of minerals was active mainly in the upper Ae horizon and released large amounts of iron, aluminum and silica. These elements migrated down the profile as organo-metallic complexes and accumulated as concretions in the podzolic B-horizons but also in the cemented horizon at depth. Micromorphological analysis showed that this latter horizon had a chlamydic/plectic assemblage. A comparison was made with other horizons found at depth in various profiles and differing from this one by their macro- and micromorphological, physical and chemical properties. The relative content of the various constituents of the cement was calculated. The sum of organic matter plus free sesquioxides ranged from 7 to 85%. There are apparent similarities in the formation of ortstein and duric horizons. The results serve to establish the concept of "ortstein-duric horizon-fragic horizon" intergrades in weakly cemented horizons found at depth in many Quebec soils.

The Growth Response of Young Jack Pine to Nitrogen and Phosphorus

N as urea at rates of 0 and 100 kg/ha and P as triple superphosphate at 0, 200, and 400 kg/ha were applied to 5-year-old jack pine growing in a well-drained, sandy, orthic humo-ferric podzol. The urea was broadcast, but two types of application were made for the P: it was either broadcast or placed in the soil about each tree. One half of each plot received herbicide treatment. Tree measurements and foliage sampling were made later in the year of treatment and also during the next year. Fertilizer treatments increased the needle weight of foliage produced in the treatment year but did not affect height. Simazine–paraquat herbicide reduced height growth the year after treatment. From the changes in nutrient concentrations it is argued that K is a most likely limiting nutrient.

GENETIC HISTORY OF TWO WELL-DRAINED SUBALPINE SOILS FORMED ON COMPLEX PARENT MATERIALS

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.

Properties of Some Common Newfoundland Forest Soils and their Relation to Forest Growth

The morphological, physical, and chemical properties of nine, important, broadly defined Newfoundland forest soil types are described in this paper. The soils of the Avalon Peninsula are generally stonier, more compacted, and richer in silt and clay than those of western Newfoundland. Gleysols and gleyed podzols are the common soils on the Avalon Peninsula whereas orthic and peaty podzols are the common soils in western Newfoundland. In both sample areas the growth of balsam fir and black spruce stands is best on brunisols and poorest on gleysols and deep peats. Only a very small proportion of the total nutrient supply in the various soils is in an available form, but amounts are considered adequate to maintain the nutrient cycle and its associated forest growth at their present levels more or less indefinitely, provided there is no severe disturbance involving the permanent removal of some of the available nutrients. To achieve lasting increases in forest productivity it will be necessary to increase the rate of nutrient cycling by appropriate cultural treatments.

The Pedogenic Significance of Volcanic Ash Layers in the Soils of an East Slopes (Alberta) Watershed Basin

Evaluation of analytical data for a soil described in the field as an Orthic Humo-Ferric Podzol revealed the presence of a paleo-Eutric Brunisol in the lower portion of the solum. A layer of volcanic ash overlying this Brunisolic solum served as a stratigraphic marker for separating the two sola. The IIBfh and IIIBf horizons of the Orthic Humo-Ferric Podzol soil, as described in the field, met the classification requirements for podzolic B horizons. However, the depth to which processes of podzolization appeared active barely included the layer of volcanic ash, comprising the IIIBf horizon of the pedon. The development of the pronounced IVBm horizon was ascribed to paleogenesis.

SIGNIFICANT PARTICLE SIZE VARIATION AND WEATHERING IN ORTHIC PODZOL PROFILES1

SummaryPhysical analyses of 15 Orthic Podzols of south‐eastern Quebec, Canada, showed that the extent of the breakdown of the gravel, sand, and silt and the accumulation of clay was dependent on the porosity of the parent material and the type of rocks in the gravel. There was no clay accumulation in the B horizon when the results were expressed on a percentage weight per unit volume basis. The sand was fractionated into five grades. The specific gravity of the gravel was smaller than that of any sand fraction and that of the sand increased towards the finer fractions. The specific gravity of the gravel also increased down the profile; that of the sand did not. These changes were also related to the type of parent material.A value for each horizon, calculated as follows: image was used as an index of weathering to show the degree of weathering intensity.

TENEURS ELEVEES DE FER LIBRE ET IDENTIFICATION TAXONOMIQUE DE CERTAINS SOLS DU QUEBEC CONTENANT DE LA MAGNETITE

Free iron determined after extraction by acid ammonium oxalate was found to be abnormally high in various horizons of two Quebec soils containing magnetite, namely: an Orthic Humic Podzol (Pikauba series) and an Orthic Regosol (Malbaie series). When magnetite was removed, prior to the analysis, truer values for free amorphous sesquioxides of iron and aluminum were obtained and could serve to distinguish Podzolic from other classes of soils. The calculated pH-dependent cation exchange capacities were not affected by the presence of magnetite in soils. This last criterion, together with pH in CaCl2, exchangeable aluminum and degree of base saturation, can well serve as a substitute for differentiating Spodic B horizons from other horizons as used in the Canadian taxonomic classification of soils.

EFFECT OF DOLOMITIC LIMESTONE TREATMENTS ON YIELD, QUALITY AND CATION CONTENT OF FLUE-CURED TOBACCO

The addition of dolomitic limestone at 0.56, 1.12, 1.68, 2.24 and 2.80 metric tons/ha to three Orthic Podzol soil series improved the value per plot and quality of Virginia-type flue-cured tobacco. Applications above 5.04 metric tons/ha reduced dollar value per plot and above 3.36 metric tons dolomitic limestone/ha reduced quality. Calcium, magnesium and potassium content varied with seasons and locations during the three-year test period, but increasing rates of dolomitic limestone generally increased magnesium percentages and reduced calcium and potassium percentages in cured leaf tissue. Ca/Mg ratios ranging from 3.2:1 to 2.2:1 and K/Ca + Mg ratios from 0.63:1 to 1.02:1 were found to be associated with highest yield and quality.

CLAY ILLUVIATION IN SOME ORTHIC PODZOLS OF EASTERN CANADA

The Arago, Barney, and Holmesville soils, Podzols from Quebec, Nova Scotia, and New Brunswick, respectively, each had friable Bfh horizons with moderate granular structure, and with organic matter and free Fe2O3 contents greater than the Ae and C horizons. The Arago and Holmesville had thin Bhft horizons containing over 10% organic matter and 5% free iron oxides. The C horizons of these two soils had some features characteristic of fragipans.The B horizons of the three soils had a high "pH-dependent charge component" in the C.E.C. values. The "permanent charge component" was similar throughout the Arago profile except for the Bhft horizon where clay accumulation had occurred.Translocation of clay from the Ae to the upper B horizons was indicated by the twofold increase in clay content and the relative enrichment of fine clay in the B horizons. Removal of free iron affected the clay contents differently in the different: horizons but the maximum clay content in the upper B horizons remained. The definitions of Orthic Podzols, Textural Podzols, and t horizons should be re-examined.

PROPERTIES AND GENESIS OF THREE MEMBERS OF THE UPLANDS CATENA

Field measurements were recorded of water table, Eh, moisture, and temperature for three members of the Uplands catena throughout 2 years. Samples of the Orthic Podzol (Uplands), Gleyed Orthic Podzol (Rubicon), and Orthic Gleysol (St. Samuel) were analyzed.High Eh values (above 600 mv) and a water table below 4 ft prevailed at the Uplands site. The soil had well-developed Ae and Bfh horizons. High Eh values prevailed at the downslope Rubicon site except for a few weeks each spring when the water table was at the surface. The soil had strongly developed Ae, Bhf, and Bfhg horizons. The water table remained at or near the surface at the depressional St. Samuel site. The Eh values in the upper 2 ft fluctuated appreciably; below this depth, they remained low (0 ± 150 mv). The brownish Bfg horizon was high in free iron oxide but low in organic matter and in free aluminum. Oxidation of ferrous iron from the underlying reduced-zone apparently contributed toward the development of this horizon.Montmorillonite is the dominant phyllosilicate in the Ae horizons and chloritized vermiculite in the B horizons of both Podzols. In St. Samuel, the dominant phyllosilicates are vermiculite in the Aejg horizon, and montmorillonite and mixed-layer material in the Bfg horizon.Morphological, chemical, and mineralogical properties of three members of the Uplands catena are related closely to redox conditions.

The Characterization of Carbohydrate Constituents from Different Soil Profiles

Orthic Podzol, Podzol with Permafrost, Orthic Gray Wooded, Dark Brown Solodized Solonetz and Orthic Black profiles were studied for the carbohydrate constituents. The samples were hydrolyzed and the resulting sugars were determined using paper and column chromatography. The soil hydrolyzates were usually analyzed for galactose, glucose, mannose, arabinose, xylose, ribose, fucose and rhamnose. Largest amounts of sugars (mg. per g. of organic matter) were found in the top layers of Orthic Podzol and Orthic Gray Wooded profiles and the lowest amount in the Orthic Black profile. The total content of sugars decreased considerably with depth in Orthic Podzol, Orthic Gray Wooded and Orthic Black profiles but there was little change with depths in the Dark Brown Solodized Solonetz and in the Podzol with Permafrost. In general glucose was dominant in all horizons and it constituted 42 to 54% of the total sugars in the organic horizon of the podzolic soils. The other sugars decreased in the following order: galactose, mannose, arabinose, xylose, rhamnose and fucose-ribose. Four to seven high Rf sugars were found in selected samples analyzed; they made up 6 to 13% of the total sugars.