ALBERT

Description: The pine-wood nematode, Bursaphelenchusxylophilus (Steiner and Buhrer), was most commonly extracted from Cerambycidae emerging from nematode-infested pines in Minnesota and Wisconsin during 1981 and 1982. The greatest number of nematodes were extracted from Monochamusscutellatus (Say) and Monochamuscarolinensis (Olivier). Low numbers of B. xylophilus were found in some buprestids but no nematodes were found in the curulionid and scolytid beetles examined. Two species of Cerambycidae, Monochamusmannorator (Kiby.) and M. scutellatus were associated with B. xylophilus from balsam fir in Minnesota. Bursaphelenchusxylophilus from insects associated with balsam fir were morphologically different from insects associated with pine. Dauer larvae of B. xylophilus were concentrated in the thoracic segments of M. scutellatus and Monochamusmutator (Lec.) examined. Bursaphelenchusxylophilus was transmitted to twigs during maturation feeding and to logs during oviposition by M. carolinensis, M. mutator, and M. scutellatus.

Description: Alnusrubra Bong, dominates the first 65 – 80 years of a sere that is initiated naturally on the terraces of the Hoh River. Stands of 14, 24, and 65 years were studied to determine to what extent the Alnus stage enriched the nitrogen inventory of the site. Bare sandbars deposited by the river had a mean of 783 kg/ha nitrogen. Alnus communities caused an increase in the nitrogen inventory so that, by 65 years, total community nitrogen was 4659 kg/ha, soils held 3594 kg/ha N in the upper 45 cm, and Alnus trees held 942 kg/ha N. The nitrogen contents of the soil, Alnus wood, bark, and branches, grasses, total aboveground biomass, total belowground biomass, and sticks less than 1 cm diameter all showed significant increases from 14 to 65 years. The A. rubra stage is an important link in the nutrient inventory between unvegetated, recently deposited sandbars and the climax coniferous forests dominated by Tsugaheterophylla (Raf.) Sarg. and Piceasitchensis (Bong.) Carr.

Description: Root elongation of greenhouse-grown Alaskan taiga tree seedlings increased with increasing root temperature in all six species examined and was most temperature sensitive in warm-adapted aspen (Populustremuloides Michx.). Root elongation was slower in fine than large roots and in black spruce (Piceamariana (Mill.) B.S.P.) was less temperature sensitive in fine than in large roots. Root elongation in the laboratory was slowest in black spruce, which has an inherently slow growth rate, and most rapid in poplar (Populusbalsamifera L.) and aspen, which grow more rapidly. In contrast, field root elongation rates tended to be highest in black spruce from cold wet sites, suggesting that site factors other than soil temperature (e.g., moisture) predominated over genetic differences among species in determining field root elongation rates. The seasonal pattern of root elongation was closely correlated with soil temperature and reached maximum rates in July for all tree species (except aspen medium-sized roots). Most roots of each species were in the top 20 cm of soil. However, root growth penetrated to greater depth in warm compared with cold sites. Root biomass in a 130-year black spruce forest (1230 g/m2) comprised only 15% of total tree biomass. Root biomass of 25-year aspen and 60-year poplar sites (517 and 5385 g/m2, respectively) comprised a greater proportion (57% in poplar) of total tree biomass than in spruce.

Description: The patterns of translocation of carbon in different-age tissues of four common moss species in a black spruce (Piceamariana (Mill.) B.S.P.) dominated forest near Fairbanks, Alaska, were studied by 14C labelling and carbohydrate analysis. A simple, in-vial combustion technique was developed for combustion of small (

Description: The aboveground biomass of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) and annual production over 7 years was studied in relation to thinning and nitrogen fertilization. Biomass yield of both treatments increased during the first 3–4 years then decreased for fertilization but not with thinning. Treatments doubled biomass production of individual trees over the study period when applied separately and quadrupled it when combined. Annual biomass production per unit of foliage (E) increased during the first 3–4 years, but was at or below control level after 7 years. The increased E accounted for 20, 37, and 27% of the stemwood dry matter response to thinning, fertilization and the combined treatments, respectively; the remainder was attributed to an increase in foliage biomass. Thinning, but not fertilization, influenced distribution of radial growth along the stem, increasing growth only below the top one-third of the stem. This pattern was related to crown development.

Description: The history of spruce budworm (Choristoneurafumiferana (Clem.)) outbreaks for the past 200 to 300 years, for nine regions in eastern Canada, indicates that outbreaks have occurred more frequently in the 20th century than previously. Regionally, 21 outbreaks took place in the past 80 years compared with 9 in the preceding 100 years. Earlier infestations were restricted to specific regions, but in the 20th century they have coalesced and increased in size, the outbreaks of 1910, 1940, and 1970 having covered 10, 25, and 55 million ha respectively. Reasons for the increase in frequency, extent, and severity of outbreaks appear mostly attributable to changes caused by man, in the forest ecosystem. Clear-cutting of pulpwood stands, fire protection, and use of pesticides against budworm favor fir–spruce stands, rendering the forest more prone to budworm attack. The manner and degree to which each of these practices has altered forest composition is discussed. In the future, most of these practices are expected to continue and their effects could intensify, especially in regions of recent application. Other practices, including large-scale planting of white spruce, could further increase the susceptibility of forest stands. Forest management, aimed at reducing the occurrence of extensive fir–spruce stands, has been advocated as a long-term solution to the budworm problem. The implementation of this measure at a time when man's actions result in the proliferation of fir presents a most serious challenge to forest managers.

Description: Flooding of soil for 45 days severely inhibited growth of 115-day-old Pinusbanksiana Lamb, and P. resinosa Ait. seedlings, with significant effects apparent within 15 days after initiation of flooding. Both species adapted poorly to flooding of soil but P. banksiana was more adversely affected than P. resinosa as shown by earlier and more drastic reduction of growth in the former species. In both species flooding decreased the rate of height growth, production of secondary needles, dry weight increment, and relative growth rates of various plant parts. Root growth of both species was reduced more than shoot growth. The reduction in dry weight increment of root systems of both species reflected arrested branching and elongation of roots as well as decay of roots, mainly the very small nonwoody roots. Flooding slightly stimulated ethylene production by submerged stems.

Description: The presence of ectomycorrhizal and vesicular–arbuscular (VA) mycorrhizal fungi in soils from five sites in a mixed conifer zone in southwest Oregon, each consisting of a 1- to 1.5-year-old clear-cut adjacent to an undisturbed forest stand, was determined by bioassay with Pseudotsugamenziesii (Mirb.) Franco, Pinusponderosa Dougl. ex P. Laws & C. Laws, and Trifoliumsubterraneum L. 'Mt. Barker' as hosts grown at root zone temperatures ranging from 7.5 to 35 °C. Maximum formation of both ectomycorrhizae and VA mycorrhizae occurred at 18.5–24 °C in soils from all sites, and there were no significant qualitative or quantitative differences between disturbed (clear-cut) or undisturbed (forest) soils. Mycorrhiza formation was moderate even at the lowest temperature tested (7.5 °C) but was greatly reduced or prevented at or above 29.5 °C. Treatment of soil at 35 °C for 1 week did not appear to adversely affect viability of ectomycorrhizal fungus propagules, but young mycorrhizae subjected to the same treatment appeared to be severely injured. Thus the ability of native mycorrhizal fungi to grow at low soil temperatures is especially important as they may contribute to the survival of seedlings outplanted into climatic zones characterized by warm, dry summers following cool, wet winters and springs.

Description: Techniques are described for field and laboratory extraction of small quantities of sugar maple (Acersaccharum Marsh.) xylem sap when pressure in the xylem is less than atmospheric. Accurate estimates of sap sugar concentration can be made with a hand refractometer most of the year. There is, however, appreciable within-tree variation in sap sugar concentration at any given time and within short periods of time.

Description: Copper, nickel, and cobalt solutions were added to a variety of substrates to test the effects of these metals on the germination and radicle elongation of two deciduous and five coniferous woody species native to eastern North America. For species grown on filter paper, germination was little affected by metal concentrations of up to 100 ppm. Filter-paper tests showed that radicle elongation was reduced by 25% at concentrations that ranged from 1 to 5 ppm for Betulapapyrifera Marsh, to as much as 50 to 100 ppm for Pinusstrobus L. Concentrations causing similar effects on mineral and organic soil substrates were, respectively, 10 and 100 times greater than those for filter paper. For all species, toxicity followed the pattern Ni 〉 Cu 〉 Co for filter paper and [Formula: see text] for mineral and organic soils. Deciduous species were more readily damaged by these metals than were coniferous species.

Description: The photosynthetic capacity of different needle age-classes of black spruce (Piceamariana (Mill) B.S.P.) was studied using 14C labelling on whole branches at a site near Fairbanks, Alaska. Black spruce had highest photosynthetic rates in the 1-year-old tissue with the four most current age-classes showing similar high rates before declining with age. Older needles were found to maintain 40% of maximum photosynthetic rates after 13 seasons. Highest level of nitrogen was found in current needles with the first eight age-classes maintaining high levels before declining to 70% of maximum values in the oldest needles. Phosphorus levels were much higher in current tissue with a gradual decline after the 1-year-old tissue to a value of 55% of maximum values in the oldest tissue. Nutrient use efficiency was found to be highest in the 1-year-old tissue and declined with needle age. The loss of nutrient use efficiency may be due to the use of older tissue as aboveground nutrient stores, a decline in the efficiency of the photosynthetic apparatus of the needles, or an increase in the leaf specific weight. Black spruce has adapted to the low nutrient availability with low photosynthetic rates and low nutrient contents. Greater longevity of the needles would maximize the photosynthetic return per unit nitrogen invested in the needles.

Description: Twenty-four specimens of six boreal tree species were excavated: eight Pinusbanksiana Lamb., five Populustremuloides Michx., four Piceaglauca (Moench) Voss, three Piceamariana (Mill.) B.S.P., two Abiesbalsamea (L.) Mills., and two Lara laricina (Du Roi) K. Koch. Root systems were described, and percent biomass determined for above- and below-ground components for half these specimens. Tree ages ranged from 3 to 120 years. Horizontally spreading lateral roots dominated the root systems of all species and occurred within 3– 15 cm of the ground surface. Nutrient and moisture absorption appear to be the principal functions of lateral roots. Maximum vertical root growth occurred near the tree stump as: tap-, heart, sinker, and oblique lateral roots. Vertical root morphology is influenced by site conditions. In addition to providing mechanical support, sinker and taproots may be important adaptations for deep-water utilization on xeric sites. Our data suggest that roots may be important in boreal succession processes through two related mechanisms: (i) nutrient and water deprivation occurring through preemptive growth of tree roots from climax species over roots of serai species, and through interception by mosses; and (ii) niche partitioning occurring below ground between serai and climax, and among climax tree species, by vertical separation of the root systems.

Description: The impact of Hurricane David on the forests of Dominica was measured 40 days after the hurricane struck the island on August 29, 1979, with winds averaging 92 km/h which lasted 10.2 h. Sixteen 0.1-ha plots were studied. They were located on a variety of slope and exposure conditions, representing three life zones and 11 plant associations. Measurements included tree diameter at breast height (dbh), total height, wood volume, and percent canopy closure of stand. Species and damage conditions were noted. The hurricane caused severe damage, particularly to forests on the southern half of the island. Forty-two percent of the standing timber volume in the study areas was damaged at an average intensity of 27 m3/ha. About 5.1 × I06 timber trees were damaged in an area of 246 km2. "Complex" vegetation was more resistant to hurricane damage than "simpler" vegetation. The climax Dacryodesexcelsa Vahl associations suffered the least hurricane damage, while the palm brake suffered the most damage. Only one species (Richeriagrandis Vahl) exhibited significantly higher hurricane damage. Trees in larger diameter classes tended to uproot with more frequency than smaller diameter trees, which tended to snap and break. Regrowth of seedlings and saplings was rapid on wet areas of the damaged sites. We found more species on regenerating plots than on the undisturbed forest plots. The damage caused by Hurricane David is the most extensive reported to date anywhere, and damage to vegetation by hurricanes appears to be more extensive than damage by earthquakes and landslides. Owing to their high frequencies in the Caribbean, hurricanes induce cyclic plant successions.

Description: A probabilistic two-step method of analysis is described that overcomes the problems associated with using a single model to analyze data drawn from a two-state system. The two steps of the analysis are (i) to determine the probability that an observation with given characteristics falls in each of the two states of the system and (ii) to estimate the response of the dependent variable in each of the two states as a function of characteristics of observations. Estimating cull volume in standing trees provides an example. This analysis results in two component models that more closely describe the process of interest than is possible with any single model. Statistically sound approximations to confidence intervals and tests of hypotheses for the parameters of each of the component models may be computed.

Description: A variety of evergreen and deciduous forests in the taiga of interior Alaska were studied over a 5-year period to examine how the chemical quality of forest-floor organic matter affected its rate of decomposition and mineral cycling within and outside the tree vegetation. Litterbag and respiration studies were used to monitor decomposition. Natural forest-floor substrates and others altered by addition of N, P, and K fertilizer and glucose as a carbon source were studied in the laboratory and field for rates of weight loss and O2 consumption. Forest floors differing in C/N ratios, including those deficient in N, were used to measure substrate quality influences on seedling growth, nutrient content, and tannin content. Microbial (bacteria and fungi) biomass was measured across a range of forest types along with pH, base saturation total pool sizes of N and P, and annual mineralization of organic matter per square metre. Under identical moisture and temperature conditions average respiration rates in evergreen forest-floor L, F, and H substrates were 1.8, 2.8, and 2.0 times less than in the corresponding deciduous forest horizons, respectively. Birch L and F horizons had respiration rates 11.5 times higher than the corresponding black spruce layers. Weight losses in birch L, F, and H horizons were 6, 3, and 2 times higher, respectively, than in the corresponding black spruce substrates. Substrates had a quality-dependent decay rate which did not change when they were relocated within or between sites indicating that measured field climatic differences were not as influential on decay rates as substrate quality components. Fungal biomass was significantly correlated with the quantity of organic matter in all sites (n = 15, r = 0.62) but correlations were better for deciduous (n = 9, r = 0.89), and evergreen (n = 6, r = 0.82) forests separately. Strong correlations exist also between grams of organic matter decayed per square metre per year and fungal biomass (n = 13, r = 0.86), and fungal biomass and grams of N and P mineralized per square metre per year (n = 14, r = 0.95) and (n = 11, r = 0.94, respectively). Seedlings on mineral-deficient substrates produced more tannins than the controls, and seedlings on substrates with widening C/N ratios had successively less tissue with lower N content, and proportionally more roots. Nitrogen content of litter fall in increasingly nitrogen-poor forest floors was correspondingly lower. Nitrogen content of litter fall on N rich forest floors and N fertilized forest floors was proportionately higher. Nitrogen withdrawal in leaves at senescence was inversely correlated with grams N mineralized per square metre per year in forest floors. Fertilization did not influence microbial processes in the field, though lab studies indicated a negative influence of NH4, P, and K on microbial respiration. Glucose added in the laboratory and field markedly increased forest-floor microbial respiration. In vitro glucose-induced increases in respiration were not influenced by addition of ammonium nitrate and were significantly depressed by addition of P and K. In the field, fertilization had no effect on either glucose-induced respiration or microbial biomass.

Description: An old, merchantable, low-site class black spruce (Piceamariana (Mill.) B.S.P.) stand growing on a Lithic Humo-Ferric Podzol overlying a granite bedrock, and a younger but merchantable low-site class jack pine (Pinusbanksiana Lamb.) stand growing on a Ferro-Humic Podzol overlying a deep coarse sand near Baie Comeau, P.Q., were analysed for stand biomass and macronutrient contents of both stand and soil. The magnitude of the depletions of macronutrients from the site, in full-tree and tree-length methods of logging, are compared with their available and total quantities in the soil. The range of values from the literature for nutrient inputs are presented and discussed in relation to logging losses. The results suggest that full-tree logging in the dry jack pine stand could cause a severe loss of potentially mineralizable N supply; P, K, and Mg deficiency problems owing to export are not apparent, but a Ca balance problem is apparent. The implication is that full-tree logging should be avoided on such sites.

Description: Seven units (about 2 ha each) of black spruce – feather moss forest were experimentally burned over a range of fuel moisture conditions during the summer of 1978. Surface woody fuels were sparse and the principal carrier fuel was the forest floor (largely mosses and their decomposition products). Forest floors after burning comprised a small-scale mosaic of unburned, scorched, lightly burned, moderately burned, and heavily burned (organic materials entirely consumed) conditions. Percentage of the unit area in the moderately and heavily burned condition ranged from 11.2 to 77.2% and percent decrease in forest-floor thickness varied from 27.4 to 63.1% in the seven units. Forest-floor consumption was most closely correlated with the moisture content of lower moss (01 horizon) and lower duff layers (022 horizon) at the time of burning. For the first 3 years after fire, biomass production was greater on heavily burned than on lightly burned sites (58 vs. 37 g/m2 on an annual basis). Heavily burned sites were completely dominated by the invading species Epilobiumangustifolium L., Ceratodonpurpureus (Hedw.) Brid., and Marchantiapolymorpha L., whereas lightly burned plots were occupied by sprouting species such as Calamagrostiscanadensis (Michx.) Beauv., Vacciniumuliginosum L., and Ledumgroenlandicum Oeder. Soil pH and amounts of total P and available P in the forest floor increased significantly as a result of burning; and in all cases, increases reached a maximum in moderately and heavily burned areas. Total N in the forest floor increased significantly in moderately burned, but decreased slightly in heavily burned areas. Total N and total P showed smaller increases in the surface mineral soil as a result of burning. Supplies of available P in the mineral soil increased almost 4-fold in moderately burned and over 16-fold in heavily burned areas.

Description: Radial stem wood sections of fertilized (at age 14 years) and unfertilized loblolly pine (Pinustaecla L.) trees were analyzed 5 and 9 years after treatment to establish if xylem nitrogen (N) can be used for a diagnostic nitrogen test. The percentage of xylem nitrogen in wood formed since fertilization was greater in fertilized than in unfertilized trees. The 2 years of wood growth near the cambium had a higher percent N than older wood, but differences between treatments were less pronounced than in older wood. Concentrations of N for fertilized and unfertilized trees were nearly constant for 2- to 9-year-old wood indicating that a sampling technique to determine the N status of loblolly pine could be developed by increment coring.

Description: Allometric regressions for estimating red maple (Acerrubrum L.) biomass did not differ by stand age and site index. Significant differences were found only in terms of error variance, not in terms of regression slope or intercept. These trends suggest a single predictive model is valid for regional estimates. More attention should be given to regional sampling procedures and predictive relations that are valid for a wide range of stand and site conditions in developing weight tables and conducting biomass inventories.

Description: Seed size was examined as a possible explanation for variation in the size of containerized loblolly pine (Pinustaeda L.) seedlings. Under laboratory conditions of minimal environmental stress, larger seed were found to germinate more quickly and produce a larger germinant after 28 days of growth. In a similar experiment conducted under greenhouse growing conditions, large seed produced the largest seedlings. Size differences among seedlings in both experiments resulted from differences in the rate of germination unique to each seed size class. Consequently, seedling size and possibly uniformity of growth were considered to be a function of germination patterns which were strongly influenced by seed size and weight.

Description: A 24-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand was treated with various levels and combinations of nitrogen fertilization and thinning. Over a period of 5–9 years after treatments, trees were sampled to determine effects on foliage quantity and sapwood characteristics at different stem heights together with their relationships. Sapwood width remained relatively constant up the stem where heartwood was present, but the number of annual rings it contained decreased with height. The sapwood width at breast height (bh) increased with stem diameter; treatments had little effect on percent sapwood at bh. The ratio of foliage mass to sapwood cross-sectional area changed for different portions of the crown and was lower when based on sapwood area at bh than at base of live crown. Significant linear relationships of foliage mass and area to sapwood area at bh were found, but relationships of foliage to basal area (bh) were just as close for all treatments; treatments significantly affected these relationships with control trees having the lowest regression slopes.

Description: The allocation of biomass and nutrients (N, P, K, Ca, Mg) was measured from August 1976 to September 1978 in a young, second-growth Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stand in the Oregon Coast Range. Tree biomass comprised 78–79% of the total standing crop of organic matter with the remainder allocated as follows: soil organic matter, 17%; forest floor, 4%; and fungi, 2%. Bole biomass accounted for 64–66% of the total tree standing crop; the remainder was apportioned among: nonmycorrhizal roots, 17–18%; branches, 7–8%; mycorrhizae, 6%; and foliage, 4%. Nutrient stocks in aboveground tree components exceeded those in belowground components by one to nine times. For all nutrients except Ca, roots and mycorrhizae contained larger stocks than either the forest floor or fungi; amounts of Ca in the forest floor and in fungi were twice those in roots and mycorrhizae. Return of organic matter to the soil by fine roots and mycorrhizae ranged from 84 to 78% of total tree return. About 73% of total net primary production was invested in growth and maintenance of roots and mycorrhizae. Return of N, P, and K to the soil by mycorrhizae comprised 83–87% of total tree return and 25–51% of Ca and Mg return. Return by mycorrhizae of N, P, and K was four to five times greater than that of roots, nearly equal for Ca, and three times less for Mg.

Description: The root density and depth patterns of four boreal forest age sequences were analyzed for successional trends. Rooting depths increased with age on sandy substrates which supported aspen (Populustremuloides Michx.) and jack pine (Pinusbanksiana Lamb.) communities. Rooting depth did not change in an aspen series on fine-textured substrates or in a black spruce (Piceamariana (Mill.) BSP) series growing on organic substrates. Plant communities growing on mineral soils showed a decrease in near-surface root densities and understory vascular plant cover with increasing age. Maximum rooting was deepest on sandy substrates and shallowest on organic deposits. Roots in all stands were concentrated near the ground surface. In most cases 50% of all roots were located within 15 cm of the forest floor. Root densities in this zone ranged from 11 000 to 30 000 roots m−2 of vertical surface. Densities were approximately 4300 roots m−2 for the overall rooting zone.

Description: Seedlings of six Alaskan taiga tree species and one tall shrub were grown in sand at three phosphate levels. There was a positive correlation between the growth rate of a species at the high-phosphate level in sand culture and its productivity in the natural environment. Poplar (Populusbalsamifera L.), which had highest growth rate under high phosphate, was most sensitive to reduction in phosphate supply, followed by birch (Betulapapyrifera (Reg.) Fern, and Raup) and aspen (Populustremuloides Michx.), whereas growth of conifers (larch (Larixlaricina (Du Roi) K. Koch), white spruce (Piceaglauca (Moench) Voss), and black spruce (P. mariana (Mill.) B.S.P.)) from late successional sites was slow and unaffected by phosphate supply. Similarly, when birch and white spruce seedlings were transplanted into natural forest stands, the maximum growth rate of birch was greater than that of white spruce, but birch growth was curtailed more by unfavorable conditions than was that of white spruce. We conclude that a slow growth rate reduces nutrient requirement and therefore minimizes nutrient stress on infertile sites, whereas a rapid growth enables nutrient-demanding species to dominate fertile sites.

Description: Annual net N mineralization in the 0–10 cm mineral soil zone of nine forest stands on silt–loam soils was measured using a series of insitu soil incubations from April 1980 through April 1981. Differences in soil organic matter (SOM) dynamics among sites were shown with net N mineralization ranging from 0.54 to 2.10 mg N mineralized•g SOM−1•year−1. This variation was not related to percent N in SOM. Net N mineralization varied seasonally with maximum rates in June and very low rates in winter. Nitrification rates were constant from May through September despite fluctuations in soil ammonium pools. Nitrification was greater than 50% of annual net N mineralization at all sites. N uptake by vegetation, as estimated by net N mineralization plus mineral N inputs via precipitation, with minor corrections for mineralization below the incubation depth and for mineral N losses to groundwater, ranged from 40.3 to 119.2 kg N•ha−1•year−1. Annual leaf and needle litter production ranged from 2.12 to 4.17 Mg•ha−1•year−1 and was strongly correlated with N uptake (r = 0.938, P 

Description: Vegetation, forest productivity, and soils of 23 forest stands in the taiga of interior Alaska are described. The stands are arranged on an environmental gradient from an aspen (Populustremuloides Michx.) stand on a dry, steep south-facing bluff, to open black spruce (Piceamariana (Mill.) B.S.P.) stands underlain by permafrost on north-facing slopes. The coldest site is a mixed white spruce (Piceaglauca (Moench) Voss) and black spruce woodland at the treeline. Mesic upland sites are represented by successional stands of paper birch (Betulapapyrifera Marsh.) and aspen, and highly productive stands of white spruce. Several floodplain stands represent the successional sequence from productive balsam poplar (Populusbalsamifera L.) and white spruce to black spruce stands underlain by permafrost on the older terraces. The environmental gradient is described by using two soil factors: soil moisture and annual accumulated soil degree days (SDD), which range from 2217 SDD for the warmest aspen stand to 480 SDD for the coldest permafrost-dominated black spruce site. Soils vary from Alfie Cryochrepts on most of the mesic sites to Histic Pergelic Cryochrepts on the colder sites underlain by permafrost. A typical soil profile is described for each major forest type. A black spruce stand on permafrost has the lowest tree standing crop (15806 g•m−2) and annual productivity (56 g•m−2•year−1) whereas a mature white spruce stand has the largest tree standing crop (24 577 g•m−2) and an annual productivity of 540 g•m−2•year−1, but the successional balsam poplar stand on flood plain alluvium has the highest annual tree increment (952 g•m−2•year−1). The study supports the hypothesis that black spruce is a nutrient poor, unproductive forest type and that its low productivity is primarily the result of low soil temperature and high soil moisture.

Description: The effects of self-pollination in white spruce, Piceaglauca (Moench) Voss, were examined in 20 trees in three populations. The most drastic effect is the increased frequency of empty seeds which averages over 90%, and is 5 to 22 times higher than that from comparable cross-pollinations. The average numbers of embryonic lethal equivalents, although highly variable for individual trees, averaged 8.0, 9.1, and 12.9 for the three populations. Self-pollination also resulted in slightly lower germination and reduced survival. The total number of lethal equivalents affecting seed yield, germination, and survival to age 17 years is estimated as 12.6. The effect of selfing on growth becomes evident at age 2 years and increases to age 17 years when seedlings from self-pollinations averaged 44.5% shorter and 63.7% smaller diameter than seedlings from unrelated matings.

Description: The influence of mechanical and architectural properties of trees on growth rates, mortality rates, and relative probabilities of snapping and uprooting were examined on Barro Colorado Island, Republic of Panama. Of 310 fallen trees, 70% snapped, 25% uprooted, and 5% broke off at ground level. Stepwise discriminant analysis between snapped and uprooted trees indicated that of the variables measured, wood properties were the most important factors determining the type of death in trees. Uprooted trees tended to be larger, shorter for a given stem diameter, and to have denser, stiffer, and stronger wood than snapped trees. There were no significant differences between trees that snapped and trees that uprooted in the extent of buttress development or in the slope of the ground upon which they grew. Trees with low density wood grew faster in stem diameter than those with high density wood but also suffered higher mortality rates. After damage, many of the snapped trees sprouted; small trees sprouted more frequently than large trees. Sprouting is proposed as a means by which weak-wooded fast-growing trees partially compensate for being prone to snapping.

Description: Sprouting of sugar maple (Acersaccharum Marsh.) was investigated in the first growing period following conventional, commercial clear-cutting in the Nashwaak Experimental Watershed Project, in New Brunswick. The number of sprouts and the height of the tallest sprout on 296 stumps from dormant-period cuts were recorded. A regression equation was developed from standing trees in adjacent uncut areas to predict dbh from diameter at stump height. The percentage of stumps which bore sprouts decreased with increasing dbh greater than 15 cm. The relationships between dbh and number of sprouts per stump, and between dbh and height of the tallest sprout per stump were bimodal with frequency peaks occurring at 10 and 65 cm. The number of clumps of sprouts per stump was relatively constant in all dbh classes except for an apparent increase in the 65-cm dbh class.

Description: Dispersal gradients of conidia of Sirococcusclavigignenti-juglandacearum Nair, Kostichka, and Kuntz, the causal agent of butternut canker, were studied in the forest for various rainfall dates. During rain, large numbers of conidia from branch cankers were carried in runoff water down the tree trunks of butternut (Juglanscinerea L.), causing infections that resulted in trunk cankers. Conidia also were dispersed in small droplets or aerosols and disseminated up to 40 m from a cankered tree during rainfall. Concentrations of conidia in the air decreased exponentially with increasing distances from the inoculum source. Dispersal gradients were influenced by stand composition and (or) size of the inoculum source, with steeper gradients associated with a dense forest canopy and a small area source of inoculum. Weather conditions, excluding the necessity for rain, had little influence in altering dispersal gradients within the same stand for different rainfall dates.

Description: Deer browsing and interference from forest weeds, particularly hayscented fern (Dennstaedtiapunctilobula (Michx.) Moore), New York fern (Thelypterisnoveboracensis L.), and short husk grass (Brachyelytrumerectum Schreb.), influence the establishment of Allegheny hardwood reproduction. We determined the independent interference by deer and weeds after a seed cut and a removal cut in a two-cut shelterwood sequence. Weeds, particularly the ferns, caused significant interference with germination, survival, and growth of desirable species following both cuttings. Deer browsing had no direct effect on desirable species because they did not grow enough to emerge from the herbaceous cover. Deer browsing did affect growth ofRubus, yellow and black birch (Betulaalleghaniensis Britt, and Betulalento L.), and pin cherry (Prunuspensylvanica L.) that grew above the herbaceous cover. Browsing of Rubus may be a serious problem in some stands because substantial reduction in fern and grass coverage occurred as the Rubus developed.

Description: Seasonal patterns of biomass, nitrogen (N), and phosphorus (P) were determined for major plant parts of the deciduous shrub Vacciniumuliginosum L. and the evergreen shrub Ledumgroenlandicum Oeder. in a black spruce (Piceamariana (Mill.) B.S.P.) forest in interior Alaska. New growth comprised 52 ± 7% of aboveground biomass in Vaccinium compared with the evergreen Ledum for which a maximum of 38 ± 3% of aboveground biomass was new growth. In Vaccinium the spring decline in leaf N and P concentration was due to dilution by increasing leaf biomass, whereas the autumn decline in N and P concentration was due to retranslocation, at which time 68–72% of leaf N and P was retranslocated from leaves. In contrast, the entire decline in N and P concentration of new growth in Ledum was due to dilution by increasing leaf biomass. Uptake contributed 60–68% of the maximum N and P requirement for aboveground growth of Vaccinium, with the remainder coming from stored reserves. Ledum supported 71–79% of its aboveground nutrient requirement by direct uptake from soil and may have been less dependent upon stored nutrient reserves. Vaccinium and Ledum together comprised only 0.8–2.8% of the standing crop of aboveground vascular biomass and N and P pools at Washington Creek but contributed 16% of vascular aboveground production and 19–24% of the N and P cycled annually by vascular plants. The importance of understory shrubs is due to their small support structure and rapid turnover of biomass and nutrients (34–43% of aboveground pools annually) relative to that of the trees (2–5% annually). Understory shrubs at Washington Creek and in other evergreen forests are much more important in nutrient cycling than their small biomass would suggest.

Description: Content of mercury in organic soil horizons was monitored to ascertain seasonal changes in background levels. L, F, and H horizons were relatively enriched in mercury in early spring. Levels then diminished and reached seasonal low values in August. Content of mercury then increased twofold during September after which levels declined to summer values. F horizons had the highest content of mercury and H horizons had the lowest. Key words: Mercury cycling, mercury dynamics, heavy metal

Description: The sulfur status of rapeseed (Brassica napus and Brassica campestris) plants grown in field studies was assessed using a variety of plant indices; percent sulfur, percent hydriodic acid reducible sulfur (HI-S in plant dry matter), HI-S:total S ratio, and total N:total S ratios. Of these, HI-S:total S determined at the rosette growth stage was the most accurate and consistent index of seed yield. A growth chamber study indicated that the HI-S:total S ratio would not be affected by nitrogen fertilizer application at normal field rates. Key words: Sulfur, deficiency, rapeseed (Brassica spp.), plant analysis

Description: The effects of surface mining for coal on soil respiration (CO2), microbial biomass C, ATP levels, bacterial and actinomycete numbers, bacterial taxa, hyphal lengths, fungal taxa, N2 fixation and decomposition potential were determined for a short-grass prairie site in southern Alberta, Canada. Soil respiration, microbial biomass C, ATP, actinomycete numbers, hyphal lengths and N2-fixing potential were significantly lower in the mined soil particularly when compared to the undisturbed topsoil. Bacterial numbers were, however, greater in the mined soil than in the unmined soil. The bacteria isolated from the undisturbed soil were dominated by Bacillus spp., coryneforms and non-pigmented Gram-negative rods, while those from the disturbed soil belonged mainly to the coryneform group. Mining also caused the fungal community to shift from one dominated by Chrysosporium-Pseudogymnoascus and sterile dark organisms to one dominated by Alternaria spp., Cladosporium spp., sterile dark forms and yeasts. Decomposition of filter paper, 24 mo after their placement in the field, was significantly faster on the disturbed site than on the undisturbed site. Key words: Surface mining, microbiology, prairie soil

Description: A field study was conducted to measure the effect of soil salinity on barley grown under irrigated conditions in Alberta. Salinity was measured by the saturated paste extract, 1:2 soil-to-water extract, vertical probe and horizontal surface array methods. Correlation coefficients were determined between salinity measurements and the yield of barley to establish the suitability of these methods for predicting the growth of barley. Nineteen fields over 2 yr were monitored and soil salinity and the yield of barley were determined at a number of sites in each field. All methods of measuring salinity were significantly correlated (P = 0.01) with the yield of barley. At an EC of 7.8, yields of barley were reduced by 50%. Sodium concentration and sodium adsorption ratio were closely correlated with yield of barley and with saturated-paste-extract salinity. Soil moisture and pH were not as effective as salinity and sodium measurements in predicting the yield of barley. The saturated-paste-extract salinity was more closely correlated with the 1:2 soil-to-water extract than with the vertical probe or the horizontal surface array. The latter three methods were effective for rapid determination of the yield reductions which would occur on saline soils. No difference in tolerance to salinity was found between Klages (two-row) and Galt (six-row) cultivars of barley. Key words: Salinity tolerance of barley, methods of measuring salinity, vertical probe EC, horizontal array EC, saturated paste EC, 1:2 soil-to-water extract EC

Description: This paper considers the productivity and nutrient cycling in examples of the major forest types in interior Alaska. These ecosystem properties are examined from the standpoint of the control exerted over them by soil temperature and forest-floor chemistry. We conclude that black spruce Piceamariana (Mill.) B.S.P. occupies the coldest, wettest sites which support tree growth in interior Alaska. Average seasonal heat sums (1132 ± 32 degree days (DD)) for all other forest types were significantly higher than those encountered for black spruce (640 ± 40 DD). In addition, black spruce ecosystems display the highest average seasonal forest-floor and mineral-soil moisture contents. Forest-floor chemistry interacts with soil temperature in black spruce to produce the most decay-resistant organic matter. In black spruce the material is characterized by the highest lignin content and widest C/N (44) and C/P (404) ratios. Across the range of forest types examined in this study, soil temperature is strongly related to net annual aboveground tree production and the annual tree requirement for N, P, K, Ca, and Mg. Forest floor C/N and C/P ratios are strongly related to annual tree N and P requirement and the C/N ratio to annual tree production. In all cases these controls act to produce, in black spruce, the smallest accumulation of tree biomass, standing crop of elements, annual production, and element requirement in aboveground tree components.

Description: The distribution of NO3-N in the soil, and N uptake by the crop during the first 12 yr of a long-term rotation study at Swift Current, Saskatchewan were studied. A considerable amount of NO3-N appeared to be leached beyond the rooting zone of the cereal crop in years of above average precipitation and also in some relatively dry years with heavy spring rains. Thus, leaching of NO3-N seemed to occur even under continuous wheat rotations. At all times there was considerable NO3-N situated at the 60- to 120-cm depth. In wet years N uptake by the plants reduced the amount of NO3-N located in the subsoil, but in dry years the amount of NO3-N in the subsoil remained higher throughout the growing season. The latter could result in groundwater pollution, especially if such a soil was fallowed the next year. Fall rye (Secale cereale L.) made more efficient use of mineral N than spring-sown crops. In dry years more NO3-N persisted in the root zone of N-fertilized wheat than in the root zone of unfertilized wheat, but in wet and average years there was little difference due to N application. The average rate of net NO3-N production in fallow land from spring thaw to freeze-up (166 days) was 107 kg∙ha−1. Values ranged from about 60 to 175 kg∙ha−1 with the lowest values being obtained during very dry or very wet years. The quantity of N mineralized (kg∙ha−1) between spring thaw and freeze-up was related to precipitation (mm) by the equation Nmin = 29.0 + 0.20 precipitation for the 0- to 60-cm depth (R2 = 0.65*). Key words: Nitrate leaching, N uptake, crop rotations, N mineralization rate

Description: Functional relationships between soil water content and water suction were examined and related to textural and organic carbon content data. Soil water retention curves between 5 and 10 000 kPa were determined on disturbed samples of 18 soils representing various soil Great Groups in the Canadian prairies. The best fit was obtained with a two-straight-line regression model. Correlation and regression analysis showed that texture was the main soil property influencing the shape and position of the water retention curve. Organic matter influenced primarily the water content at which a break in the curve occurred. Soil zone and cultivation history had little effect on water retention. Key words: Water retention, texture, organic matter, two-straight-line regression

Description: Field investigations between 1970 and 1980 revealed frequent carry-over residues of atrazine (2-chloro-4-ethylamino-6-isopropylamino-s-triazine) and its major metabolite, N-de-ethyl atrazine (2-chloro-4-amino-6-isopropylamino-s-triazine) in soils and many were associated with visible crop damage. Susceptible crops in rotation with corn appeared to tolerate a carry-over of 0.1 mg/kg Σ-atrazine (atrazine plus metabolite) under field conditions. Where the carry-over residues were above 0.1 mg/kg the severity of injury appeared to be related to the amount of residue, the soil type, the crop species, and the weather conditions. A growth cabinet experiment was designed to study the response of five susceptible crop species to simulated carry-over levels of atrazine between 0.05 and 0.70 mg/kg active ingredient added to a sandy loam, a loam and an organic loam soil, that contained 1.0, 3.5 and 10% organic matter (OM), respectively. Additions of as little as 0.10 mg/kg atrazine to soils with 1.0 and 3.5% OM caused visible injury to develop on the foliage of all five crop species. Alfalfa (Medicago sativa L.) appeared to be the most sensitive crop species, being affected by atrazine at 0.05 mg/kg. On soils with 10% OM the phytotoxic effects of atrazine were considerably reduced and all five crops tolerated residue levels up to 0.70 mg/kg without serious injury. Key words: Atrazine, N-de-ethyl atrazine, residue, crops, field, growth chamber

Description: Soils ranging in texture from loamy sand to clay that had been tilled annually for at least 35 yr were compared with adjacent unfilled soils. Properties considered important to plant growth were measured: water-stable aggregate size distributions, bulk density (BD), organic carbon (OC), penetrometer resistance (PR), oxygen diffusion rates (ODR), pH, hydraulic conductivity (Kaep), air-filled porosity (AFP), total porosity (TP), degree of air occupation of pores (AFP/TP) and soil moisture desorption curves. AFP, AFP/TP, ODR, BD, Kaep and soil moisture desorption curves suggested that the tilled sites in all soil types had become compacted below 10-cm depth relative to the undisturbed sites. OC, PR, BD and aggregate size distributions were strongly influenced by soil textural differences. OC appeared to increase with cultivation in sandy soils compared with the undisturbed. PR was increased by tillage in the coarse-textured soils, but decreased in the fine-textured soils. Acidity increased under long-term tillage in all soils except the clay. Large degrees of variability of ODR data require further investigation. Rapid in situ techniques for measuring Kaep and AFP are needed, as these parameters appeared to best reflect the effect of long-term tillage on soil physical quality. Key words: Soil structure, soil degradation, soil compaction, soil management, tillage effects

Description: The effect of fertilizer P on the salt tolerance of barley grown on previously summerfallowed land was studied under dryland field conditions. Linear regression equations showed that the yield response to added fertilizer P did not change significantly over the full range of salinity levels experienced. Linear regression equations using mean soil salinity levels to a 60-cm depth equal to or greater than 6 mS∙cm−1 appeared to describe the yield function of barley more realistically than did equations using the entire range of salinity levels. Both fertilized and unfertilized barley yields were not affected by salinity until a level of 4 mS∙cm−1 had been reached. Beyond this point yields were reduced by approximately 9–10% per unit increase in salinity. It was concluded that added fertilizer P did not improve the salt tolerance of barley grown under dryland conditions in Saskatchewan. Key words: Salinity, barley, P fertilizer, salt tolerance, yield

Description: Two field experiments were conducted, each over a 3-yr period, to compare the availability of N from liquid cattle manure (LCM) with that from urea and anhydrous ammonia to corn. Two times of application (preplant vs. sidedress) and two methods of application (surface vs. injection) of LCM were compared with respect to corn grain yield and soil NO3− concentration during two periods of the growing season. The availability of LCM N was approximately one-half that of fertilizer N. Injection of LCM either before planting or as a sidedressing between the corn plant rows resulted in LCM N being approximately 60% as available as fertilizer N. Application of LCM to the soil surface, as a side dressing resulted in LCM N being approximately one-third as available as anhydrous ammonia N. The data were discussed and interpreted on the basis that manure N is made up of two principal fractions, "organic" and ammoniacal N. The organic N fraction, consisting of all the N other than ammonia, becomes only partly available to the crop through mineralization whereas the ammoniacal N fraction is subject to volatilization if not incorporated into the soil immediately. Soil NO3− concentrations in the June-July period showed the surface preplant LCM N availability to be approximately one-half that of preplant applications of urea. Nitrate concentrations during the September-October period suggested that LCM showed no greater levels of NO3− than urea even at twice the rate of N application. Key words: Corn, nitrogen, preplant and sidedress applications, liquid dairy cattle manure

Description: 137Cs from the atmospheric testing of nuclear devices in the 1950s and 1960s was used to estimate soil erosion in eight small basins in hummocky topography. Three basins had not been cultivated since the 1950s and in these 137Cs showed little or no separation according to landscape position. In the cultivated basins, 137Cs increased from the top to the bottom of the slopes reflecting the simultaneous occurrence of soil erosion on the upper slopes and deposition on the lower slopes. The redistribution of 137Cs was least in a cultivated basin where water erosion was minimal. From the 137Cs it was estimated that over the past 20–25 yr the upper slopes in the cultivated basins had lost 20–60 kg soil/m2, whereas the lower slopes had gained 25–80 kg/m2. Some middle-slope positions lost soil, others gained. An attempt to construct 137Cs and soil balances for each of the cultivated basins was only partially successful. The inability to accurately delineate areas of erosion and areas of deposition is probably the major obstacle in calculating accurate balances for the basins. The 137Cs balances did show promise of being able to separate soil losses by wind and water erosion. Key words: Water erosion, wind erosion, 137Cs, deposition, universal soil loss equation

Description: Two shallow mineral overburdens, a deep mineral overburden and a peat overburden from northern Alberta were examined to determine effects of each on the growth of jack pine and slender wheatgrass. Plants were grown in the greenhouse in 30-cm-deep cores in which the overburdens were placed in either 5- or 15-cm-deep layers over oil sand tailings. For comparison with current reclamation practices, cores containing a mixture of sand, peat and deep overburden were also used. The growth of slender wheatgrass was best in the peat and very poor in the deep overburden. Jack pine also grew very poorly in the deep overburden but reasonably well in the other three overburdens. There was extensive root development of both species in the sand layer beneath all four overburden types. Increasing the depth of peat from 5 to 15 cm resulted in a decrease in the growth of both plants whereas increasing the depth of the mineral overburdens had favorable effects. The amount of available P was much higher in sand under the 5-cm layers than sand under the 15-cm layers. Iron and Mn uptake was suppressed with the thick layer of peat. Mixing 15 cm of peat with deep overburden and sand did not affect the growth of slender wheatgrass but reduced shoot production of jack pine. Key words: Reclamation, oil sands, jack pine, slender wheatgrass, plant growth, peat

Description: Soil-landscape relationships were studied in detail at a site comprised of Dark Brown and related soils of the Weyburn Association in central Saskatchewan. Detailed soil observations along transects identified actual soil series and related their distribution to landscape parameters. A slope-profiling approach, involving division of slopes according to angular differences between measured lengths along the transects, revealed that while soil distribution varied in terms of slope position, slope length, slope gradient and sequence, the most significant relationship lies between soil distribution and shape of slopes. Most slopes could be subdivided readily into convex units, concave units, usually short rectilinear units joining them, and depressional units. Such divisions generally coincided with observable soil divisions, corresponding, respectively, with shallow, deep and gleyed soils. The convex units comprised Regosols and Rego, Calcareous and ’shallow Orthic’ Dark Brown Chernozemic soils. The concave units included ’deep Orthic,’ ’AB Orthic’ and Eluviated series. The depressional units were generally composed of Gleyed Orthic or Gleyed Eluviated series. Both field and laboratory analyses confirm that the soils within landscapes form a continuum, but that recognition of the soil groupings suggested provide a practical and feasible field separation in mapping soils. A combination of aerial photos, field examination of soils and an evaluation of slopes and particularly slope changes could be used to recognize and map these broad, landscape-related soil groupings. Key words: Soil association, soil catena, soil series, slope analysis, topography, map units

Description: Colorimetric soil pH measurements made systematically across Burnaby Mountain in well-drained loamy soils of the rainforest of British Columbia over an 8-yr period from 1974 until 1981 showed that acidification of the subsoil increased after two consecutive drier-than-average years. This changing acidity contrasted with the relatively stable acidity of the subsoil in imperfectly drained soils, regardless of changing patterns of precipitation. Key words: pH, forests, loams, precipitation

Description: The effect of fertilizer P, N and N-P combined on barley grain yield and protein content when grown on stubble land ranging widely in surface salinity (0–60 cm depth) was tested. Critical salinity levels were calculated from linear regression equations derived from sampling sites with surface salinity levels [Formula: see text]. Added P did not appear to affect the salt tolerance of barley. Yield increases due to fertilizer N were reduced rapidly as soil salinity levels increased and in one trial appeared to reduce the tolerance of barley to salinity. Calculated salinity levels at 50% and zero yield of N-fertilized barley were lower than for barley not fertilized with N. Calculated salinity levels at zero yield for the control and P treatments were 18.5 and 15.1 mS∙cm−1, respectively. These levels compared favorably with values reported in the literature for barley grown on saline fallowed land. Protein content of barley grain increased with an addition of N and with salinity. The latter fact could be largely explained by a strong positive correlation between soil salinity and soil NO3−-N levels and to a lesser degree by a reduction in yield with increasing salinity. Key words: Salinity, barley, fertilizer effects, yield, protein

Description: Crop yields and soil data were obtained for 5 yr on 12, 1-ha plots of slight to moderately saline Solonetzic soil which had been plowed to a depth of 61 cm. Wheat, durum wheat, oats and flax were grown. Wheat yields range from a decrease of 0.25 t/ha to an increase of 0.74 t/ha. An average increase of 0.34–0.40 t/ha should be expected from deep plowing this type of soil. The surface soil following deep plowing increased in clay, fine clay, pH, CaCO3 and H2O-soluble Ca. It decreased in H2O-soluble Na. Water-soluble Mg remained relatively constant. With moderate fluctuations, these changes have persisted for 5 yr. Key words: Deep plowing, Solonetzic, sodium, calcium carbonate

Description: Two poorly humified peat soils, containing 23 or 1207 ppm (wt/wt) Cu, and two well-humified muck soils with 151 or 1264 ppm Cu, obtained from 3-yr-old field experiments on simulated extravagant applications of Cu for mitigation of organic soil degradation and subsidence, were used in this study. The aim was to determine whether the longevity of Escherichia coli (K12 JE 2517-a nonmotile mutant) cells inoculated into the soils would be affected by the soil Cu concentrations. The rapid spread plate method was used for counting viable cells of the coliform. Both microbially active and bromomethane-sterilized soils were aerobically incubated with the bacterium normally alien to the soils for 48 and 168 h, respectively, with or without further additions of 10 ppm Cu to the soils with the bacterial cells. A pulverized quartz sand was included in the experiments to provide comparison. Unlike the immediate and sustained lethality of Cu revealed in sand suspensions, neither the previously nor the newly added Cu had any negative influence on the survival or proliferation of the added E. coli cells. The results thus showed that the soil Cu had no direct bactericidal or bacteriostatic effect. These data were therefore in accord with earlier suggestions that the Cu mitigates decomposition and resultant subsidence by inactivating degradative and accumulated soil enzymes that contribute substantially to the dissipation of their substrate-rich milieux. Key words: Copper, bacteria, organic soils, subsidence

Description: The kinds and concentrations of the major ion pairs were determined in saturation extracts of 141 soil samples collected from a Solonetzic soil treated with various kinds of tillage combined with surface-applied chemical amendments. The correlations between concentrations of ion pairs and EC and pH of saturation extracts were statistically tested. Sulfate ion pairs NaSO4−, MgSO40 and CaSO40 occurred in relatively high concentrations. The other ion pairs were of low concentrations. Of the total soluble Ca, ion pairs ranged from 20.8% in the Ap horizon to 50.5% in the Csk horizon and Mg was approximately the same. The comparable values for Na were 0.8% and 4.6%, respectively. Ion pairs NaSO4−, KSO4−, MgSO40 and CaSO40 were significantly correlated with EC. Only carbonate ion pairs were significantly correlated with pH. Correcting concentrations of Na, Ca and Mg for ion pairs and activities changed considerably the SAR values in the Bnt1 horizon. Key words: Ion pairs, Solonetzic soils, ion activities

Description: Cemented, fragic and intergrade-cemented horizons of five soil series of Quebec were studied using submicroscopic, micromorphological and chemical processes. The quantities of bonding agents present in the bonding material were expressed as a relative percentage. These bonding agents consist of organic matters, Fe, Al and Si hydroxides assumed to be present as FeO(OH), AlO(OH) and SiO(OH)2, and clays (

Description: The relative abundances of arabinose, xylose, mannose, galactose, glucose, total pentoses, total hexoses and total sugars in 50 soil horizon samples derived from two groups of Canadian peat soil profiles have been correlated with five characteristic soil properties, namely, fiber content, pyrophosphate index, ash content, C:N ratio and cation exchange capacity. The correlation coefficients demonstrated that of the monosaccharides or sugars examined, glucose and total sugar contents correlated best with the five soil properties. The coefficients also showed that sugar analysis is as reliable as the five soil properties for assessing the degree of decomposition of peat. Sugar analysis, therefore, can be used to differentiate peats. Key words: Peat, monosaccharides, soil properties, correlation, decomposition

Description: Five soils along a 300-m transect on the Canadian Shield in Eastern Ontario are investigated. The soils have been formed in a coarse-textured Wisconsin till derived from the local granodiorite bedrock. They are acidic, moderately weathered and generally show morphological evidence of sesquioxide formation, eluviation and illuviation. This is confirmed by the analytical data which also reveal a number of clay mineral weathering transformations. The dominating influence on pedogenesis has been the macroenvironment, although local variations in drainage characteristics have resulted in gleying and some rock fragment disintegration at depth. Key words: Pedogenesis, clay development, granodioritic till

Description: The ability of a phytosociologically based, ecological classification system to explain the variability of soil and physiographic properties is tested. Sixty stands from a research forest in southwestern British Columbia are defined in terms of three categorical levels of the ecosystem taxonomy of V. J. Krajina. The stands belong to 14 associations, eight alliances, and three orders. Using these taxa, nested and one-way analyses of variance are performed on 40 soil and physiographic properties of the included ecosystems. Because the hierarchy tested is unbalanced and the samples are of unequal size, the estimates and significance of the variance components for both analyses are determined by approximation techniques. The results from the one-way analyses show that for mineral soil pH and for most physiographic factors between one-half and two-thirds of the variability can be explained by the classification of the ecosystems into associations. For the other properties and for the alliances and orders, this proportion is typically much lower. The study suggests that for general pedologic and environmental characterization there may be little justification for using the alliance and order categories. Key words: Soil-plant relationships, taxonomy, biogeocoenose, integrated classification

Description: Experiments were conducted on the effect of a hydrophobic layer, a 1:4 mixture of crude oil:soil, on water and salt movement in columns of brine-contaminated and uncontaminated soil. The mixing of oil with soil lowered water retention at low suctions, and increased saturated permeability and water repellency of the mixture. The hydrophobic layer reduced capillary rise, and increased waterholding capacity of the overlying soil. After 6 wk of intermittent leaching the salt content of the soil above and below the hydrophobic layer was lower than in the absence of this layer. The hydrophobic layer prevented resalinization of the overlying soil during a subsequent 4-wk evaporation period. The thickness of the hydrophobic layer (0.5 or 1.0 cm) did not seem important. Key words: Salt movement, hydrophobic layers, redistribution of water and salt

Description: A mathematical-physical model developed in the Netherlands for the simulation on nonsteady flow of water in subsurface-drained soils was tested by comparing its output with data collected in spring from two farmers’ fields in the Lower Fraser Valley of British Columbia. The ultimate objective of the tests was the prediction of soil strength and trafficability. The model was found to be useful for predicting depth to the water table and, to a lesser extent, soil water matric potential in the top 15 cm in fields drained by drains spaced at 30.5 m and 15.2 m. However, there were problems in evaluating input data. One problem was that of obtaining the drainage intensity, which was found to have a great effect on model output. A solution of the modified Glover-Dumm transient-state drainage equation provided a means of obtaining the drainage intensity directly from measured water table recession. A second problem was related to the use in the model of soil water flow parameters obtained from the water flow characteristic measured on undisturbed columns in the laboratory. Key words: Drainage model, matric potential, water table depth, trafficability, drainage intensity

Description: Lignitic material located in a reshaped mine spoil at a depth of 35–53 cm was extremely water-repellent and no root growth was observed in or below this layer. The material is black (10YR 2/1) when dry and is easily identifiable. It is postulated that this layer may influence water movement and nutrient uptake because of the water repellency. Key words: Lignite, reclamation, strip mining, water repellency

Description: Urea and ammonium nitrate were applied at rates of 75, 150 and 300 kg N/ha as either a single application in April or split into three equal increments, one applied in April and the second and third following cuts one and two. The orchardgrass-perennial ryegrass sward responded significantly to applied N in each year; however, the yield produced by the two sources differed in only one of the three years. In that year split applied ammonium nitrate gave 8% higher yields than similarly applied urea. The sources were found to be equivalent when applied in the spring. Split application of the N rates increased total annual dry matter yields in one of the three years regardless of N source. In all three years split application of N shifted forage production from cut one to cuts two and three. Key words: N uptake, split N application, orchardgrass-perennial ryegrass sward

Description: Varying total amounts of water (160 and 320 mm) were infiltrated into 60-cm columns of air-dry saline sodic clay soil. The intervals between irrigation applications were varied from 5 to 20 days. The soil columns were subjected to a potential evaporation rate of 4.8 mm∙day−1 in a growth room. The cumulative evaporation followed a square root of time response, similar to that found by others for non-saline soils of coarser texture. An analytical solution of the Richards’ equation gave satisfactory (± 10%) prediction of cumulative evaporation at the end of the experiment as long as water was added in amounts of 40 mm or more per irrigation. The numerical solution to the Richards’ equation gave satisfactory estimates of evaporation for the latter stages of the experiment, but in the earlier stages it underestimated evaporation because of the too deep distribution of water in the soil given by this model. The neglect of hysteresis was invoked to explain the discrepancy between observed and predicted soil water content profiles. The "versatile soil moisture budget" empirical model also gave satisfactory prediction of evaporation but the successful prediction of water content profiles depended on "field capacity" values measured in situ. Key words: Soil moisture, modelling, water budgets, Richards’ equation

Description: Zn increased shoot dry matter yield of 62-day-old corn grown in the greenhouse on Almasippi loamy fine sand (Gleyed Carbonated Rego Black) containing 0.77 ppm DTPA-extractable Zn whereas corn in the field on the same soil had not responded to Zn. Soil mass or dimensions had little influence upon degree of response to Zn. When no Zn was applied, Zn uptake was not influenced by soil mass, suggesting that the amount of plant-available soil Zn did not increase with increasing soil mass. Results from this study provided little evidence that restricted soil mass, limiting the amount of available soil Zn, was the primary cause of greater response to Zn fertilization in pot as compared to field experiments. Key words: Corn, soil-mass, zinc

Description: Methods currently available for inoculating alfalfa (Medicago sativa L.) seed with Rizobium meliloti were evaluated to determine their ability to produce effective nodulation and to increase forage yield under moderately acid (pH 5.8–5.9) soil conditions. Five inoculation treatments were applied in a field experiment: no inoculant, 5.5 g inoculant/kg seed applied without inoculant sticker, 5.5 g inoculant/kg seed applied with inoculant sitcker, 50.7 g inoculant/kg seed applied with inoculant sticker, and 5.4 g inoculant/kg seed applied with a commerical seed-coating process. Alfalfa yields were not increased relative to the uninoculated control when inoculant was applied without sticker at 5.5 g inoculant/kg seed. However, when the inoculant was applied at 50.7 g/kg seed using a sticking agent alfalfa yields were increased 85% during the first harvest year and 47% in the second harvest year. Lower, but significant yield increases were obtained with 5.5 g inoculant/kg seed applied with a sticking agent and 5.4 g inoculant/kg seed applied with the commerical seed-coating process. In an assay conducted in the greenhouse, double antibiotic (streptomycin, rifampicin) resistant strains of R. meliloti were used to determine the proportion of nodules formed by the inoculant Rhizobium. Between 92 and 100% of the nodules contained antibiotic resistant strains when the inoculant was applied with a sticking agent or with the seed-coating process, while only 38% of the nodules in the treatment without sticker contained antibiotic resistant strains. The results demonstrate the importance of applying inoculants with a sticking agent or in conjunction with seed coating to obtain maximum yields of alfalfa on moderately acid soils. Key words: Acid soil, Rhizobium meliloti, Medicago sativa, inoculation, antibiotic resistant mutants

Description: Frost penetration and soil temperature may determine the winter survival of crops or populations of insects. In this study, several techniques for measuring frost and thaw penetration are compared to a simplified numerical heat flow model in order to assess the range of applicability of the measurement and modelling systems. Two Uplands sand sites, one snow cleared and one with a natural snow cover were instrumented with thermocouples, frost-tubes and time-domain reflectometry to record soil temperature and frost penetration. The numerical model was used to simulate soil temperature and frost using daily maximum and minimum air temperature and snowfall from the nearby weather site. All methods used to measure frost penetration were found to be adequate where large temperature gradients occurred. Temperature-based determinations of the frozen zone have a more limited range of applicability than systems which indicate changes in liquid water content of the soil. The diffusion-based heat flow model provided useful estimates of soil temperature and frost penetration. Key words: Frost penetration, soil temperature modelling, frozen/unfrozen interfaces

Description: The UNIFIED and AASHTO systems are used in engineering to classify soils for specific purposes. To facilitate use of the soil surveys by engineers, it has been customary to interpret soil survey mapping units in terms of these engineering classification systems. The procedure, however, is often difficult to follow and normally time-consuming. When used in combination with pedotechnical setting sheets, interpretation sheets reduce this time element and provide for more effective use of the soil survey information. This paper demonstrates development and application of the interpretation sheets. Key words: Engineering soil classification, pedotechnical interpretations, UNIFIED, AASHTO, soil engineering

Description: In a greenhouse study, two Mesisols, a woody and a sedge peat, were enriched with calcitic agricultural limestone at rates of 0.5–30 t/ha to increase their pH from 3.0 to 5.8. The general fertilization included 50 ppm (20 kg/ha) of Cu (wt/wt). Maximum yields of potatoes were obtained at a soil pH of 3.4–3.6 (4–6 t lime/ha rate) but harvest index of potato tubers (mass of tubers as percent of total dry matter produced) indicated that the 10-t/ha rate would be more suitable. The Cu concentration of potato leaves and tubers did not exceed 16 ppm, and was thus less than phytotoxic level (20 or 30 ppm), even at soil pH lower than 3.4. After further addition of other fertilizers and 25 ppm of Cu, carrots gave maximum yields at the 30-t/ha rate. Copper concentrations in carrot tops and roots were below 16 ppm even at the 10-t-lime/ha rate (soil pH 3.8 or 4.0). Onions, grown after repetition of the fertilization for carrots, gave highest yield, particularly of bulbs, at the 30-t-lime/ha rate but this corresponded to an undesirably high soil pH of 5.7 or 5.8. The Cu concentration in bulbs exceeded 16 ppm only when yields were unacceptably low at the 6-t/ha and lower rates of liming. In all crops, Cu concentrations generally decreased sharply as soil pH rose above 4.0. The Ca:Mg ratio in plants usually increased with liming but, within the range observed here, did not closely parallel increases in yield. Plant concentrations of N, P and K generally decreased with liming at the highest rates (20 or 30 t/ha). Key words: Liming, peat, potatoes, onions, carrots, copper

Description: To assess effects of soil Cu on the yield and nutrition of a crop, onions (Allium cepa ’Autumn Spice’) were grown in field microplots at sites A (peat), B (muck) and C (mucky peat). The surface layers (0–20 cm) of the plots contained four levels of residual fertilizer Cu up to 1200 ppm (wt/wt) at sites A and B and up to 600 ppm at site C. The highest Cu treatment at sites A and B contained about 4–6 times the Cu required for mitigating the excessive decomposition and subsidence of such organic soils. Neither the Cu treatment level nor the total soil Cu concentration influenced crop yields at sites B or C. Crop yield responded positively to the two highest Cu treatment levels at site A where the background level of soil Cu was the lowest among the three sites. The Cu concentrations in the crop at all sites were below the level considered to be phytotoxic (20 ppm). Fe and Zn contents in plants were also not depressed by higher Cu concentrations except for foliar Fe on the highest Cu treatment plots at site A. These plots were intrinsically poorer in Fe than those treated with lesser Cu. Foliar Fe:Cu and Zn:Cu ratios were also lowest, but not below adverse levels, for the highest Cu treatment levels at sites A and B, respectively. Even the highest levels of soil Cu did not reduce N supply for, or N nutrition of, the onion crop, or alter the crop concentrations or uptakes of P, K, Ca, Mg and Mn. Key words: Copper, onions, subsidence, histosol, muck, peat

Description: An aerobic incubation procedure was used to evaluate the susceptibility to mineralization of N and S in five Gleysolic soils and their particle-size fractions (2–50 μm, 1–2 μm, 0.2–1 μm and

Description: The mounting and. preserving of soil profiles is a current practice to keep reference soils for scientific needs, teaching aids and display purposes. Techniques described in the literature (Berger and Muckenhirn 1945; Bushnell 1930; Day 1968; van Baren and Bomer 1979; Hammond 1974) have been proven satisfactory for mineral soils. However, when applied to organic soils, they have failed to minimize changes to the physical (shrinkage) and chemical (oxydation) nature of the soil material. The proposed technique offers an alternative which reduces shrinkage on drying and fixes the physical and morphological features such as color, structure and appearance in their in situ state. Key words: Peat, organic soils, monoliths, polyester mounting

Description: Forty-six soils originally mapped as belonging to the Brookston series were sampled in southern Ontario. Using current taxonomic criteria only 27 of the original group of soils belong to the Brookston Family. This family can now be defined as Orthic Humic Gleysol, fine clayey, illitic, alkaline, strongly calcareous, mild subaquic. Using a multivariate clustering procedure (CLUSTAN) a group of 12 soils was finally allocated to the Brookston series. The confusion between soil map units and taxonomic units and the changing concept of the soil series are largely believed responsible for the wide range in properties of the originally mapped Brookston series. Key words: Soil calssification, multivariate analysis, soil series

Description: A kinetic study, regarding the interactions between OH− ions and soil surfaces, was carried out in order to investigate the nature of the process, and calculate its specific rate. A two-step process took place when initial OH− ion activities were sufficiently high. A first rapid step was always followed by a relatively less rapid step. The two steps were ascribed to the interaction of OH− ions with external and internal soil surfaces, respectively. Experimental data fitted a pseudo-first-order kinetic equation very well over the time period examined, so that the values of the specific rate were calculated at different initial NaOH concentrations. Since a decrease of the specific rate was observed when the initial OH− ion activity was increased a diffusion-controlled mechanism was postulated to regulate the rate of the process. The change of the specific rate as a function of the supporting electrolyte concentration was also investigated. Key words: Deprotonation kinetics, permanent charge, pH-dependent charge, diffuse double layer

Description: The addition of Cu at 2 and 4 kg/ha did not increase the yields of carrots, beets, onions, or rutabagas grown in soils normally used for these crops in Prince Edward Island. Leaf tissue Cu concentrations of these crops were found to be in the range of 6–14 ppm and generally were not affected by the added Cu. Key words: Tissue copper, vegetable yields, podzol soil

Description: Six soil profiles belonging to the Brookston, Lockport, Guelph, Chinguacousy and Haldimand series were sampled in southern Ontario. Illite contents of the clay fractions ranged from 25 to 56% and vermiculite contents ranged from 13 to 53%. The native fixed ammonium content varied from 57 to 367 μg/g and accounted for between 3 and 44% of the total nitrogen, being proportionally less in Ap horizons. Results of simple linear regression analyses demonstrated significant correlations of native fixed ammonium with percentages of clay, illite, illite plus vermiculite and K2O. The amount of ammonium fixed increased with increasing concentration of added ammonium up to the highest rate of application (2000μg NH4+/g soil). Regression analysis indicated that vermiculite was more important in the fixation of added NH4+ than illite. Studies on Ap horizons comparing the amount of NH4+ fixed with the amount of K− fixed for equivalent amounts of added cation showed that K+ was fixed in greater quantities than NH4+. Key words: Native fixed NH4+, NH4+ fixation, clay mineralogy

Description: Soils derived from Pleistocene deposits with an aeolian mantle in the Fraser Lowland of British Columbia and adjacent Washington State are analyzed and compared for classification as Podzols and Spodosols. Data from Canadian and American sources are examined for six groups of soils that correlate across the international boundary. Soils classified as Spodosols meet the criteria for Podzols, but the converse is not true, mainly because the pyrophosphate-extractable Fe + Al is less than half of the dithionite-citrate-extractable Fe + Al. The Canadian classification is Humo-Ferric Podzols. The presence of amorphous material in this area is recognized and expressed in U.S. soil taxonomy as Andic intergrades of Xerochrepts. Evidence of amorphous material in the aeolian mantle of these soils is a smeary feel when rubbed wet, and the following other characteristics (with the common ranges in the upper 60 cm): low bulk density (850–1150 kg/m3), high 1.5-MPa water-to-clay ratio (0.95–3.33), high cation exchange capacity (130–400 meq/100 g clay), high pH in sodium fluoride (10.0–11.1), and low percent base saturation (9–46%). The soils have 1–21% glass or glassy aggregates in the upper 60 cm and a trace to 6% below 60 cm. Key words: Podzolization, NaF pH, bulk density, Andic Xerochrepts, Pleistocene deposits, Whatcom County.

Description: The objective of this study was to evaluate changes in soil bulk density associated with construction of a 500-kV transmission right-of-way (ROW) across a peatland in northwestern Minnesota. Immediately before (1979), and for 2 yr following construction (1980, 1981), bulk density of the organic soil within the ROW and in undisturbed control areas was monitored. Soils were primarily Typic Mesisols (Borohemists), with some Mesic Fibrisols (Sphagnofibrists). Monitoring was carried out in five vegetation types, ranging from graminoid fen to treed bog. Soil bulk density was determined in 25-cm increments to 1 m. There were no significant differences in density between the ROW and the control before construction. When data for the 2 yr following construction were combined, results showed significantly higher density in the surface of the ROW than in the surface of the controls. Absolute differences were small, however. The density in the ROW was 5% higher and that in the controls 5% lower than the overall mean of 0.052 g∙cm−3. Largest differences were in a vegetation type with a fibric surface, the treed fen, where, in 1981, the surface in the control had a bulk density of 0.033 g∙cm3, and in the ROW, 0.049 g∙cm−3. Because of high hydraulic conductivity at both densities, any present restriction of water flow across the peatland is unlikely. Key words: Transmission lines, water flow, histosols, Minnesota

Description: Three field trials were conducted to determine if and how response of corn (Zea mays L.) to applied N changes during continuous production. Nitrogen was broadcast at rates of 0, 56, 112, 168, 224 and 336 kg/ha each year for 10 yr. Rates of N in excess of 168 kg/ha significantly reduced emergence at the Fox site; no effect occurred elsewhere. Applied N had no effect upon seedling weight, decreased the interval from seeding to silking, and increased grain and stover yields at all sites. The most profitable rates of N for grain production throughout the study were 85 and 110 kg/ha at the Conestogo and Fox sites, respectively. At the Chinguacousy site, there was a significant year by N rate interaction with grain yield declining by 5600 kg/ha over 10 yr in the 0-kg-N/ha treatment. A model developed by multiple regression analysis (R2 = 0.71) for this site predicted that the most profitable rates of N application were 38, 178, and 213 kg/ha in years 1, 5, and 10, respectively. Applied N decreased ear moisture content at harvest and increased lodging at all sites. Key words: Zea mays L., N fertilization, year by N interaction

Description: Lateral variability in a variety of physical and chemical properties was studied in the surface 30 cm of mineral soil taken from beneath young (5–12 yr) Douglas-fir plantations established after clearcutting and slashburning, primarily in the Coastal Western Hemlock Zone in southwestern B.C. Of the 19 soil properties considered, pH was the least variable while available P and extractable Ca concentrations and quantities tended to be the most variable. However, the order of variability was not consistent among the five plots studied. Estimation of mean values with an allowable error of 10% at the 95% confidence level would require a very large number of samples for most of the properties studied. Even with an allowable error of 20% at the 90% confidence level, more than 100 samples would be required in some instances. Methods of overcoming this need for a large sample size are discussed. A comparison of within-plot variability to among-plot variability for three situations produced no consistent trends. However, the among-plot variability of high forest productivity plots was greater than that of low forest productivity plots for nearly all soil properties considered. Key words: British Columbia, forest soil, soil chemistry, soil variability

Description: The use of the universal soil loss equation in Canada to estimate soil loss potential for soil and water conservation planning purposes has been limited by the lack of published rainfall erosion indices and by the arduous procedure generally accepted for determination of these indices. This study was conducted to develop and test relatively simple methods to develop annual rainfall erosion indices and associated seasonal distribution patterns. An approach to the determination of a rainfall-runoff factor to accommodate the effect of winter conditions has also been included. The relatively simple techniques for estimating average annual rainfall erosion indices and seasonal distribution patterns of rainfall erosion have been found to yield comparable values to those determined by more tedious methods. These erosion indices and associated distribution patterns have proven useful for the development of a first approximation of rainfall erosion maps for Canadian locations east of the Rocky Mountains. Key words: Rainfall erosion indices, USLE

Description: The nature and distribution of carbonate minerals in the upper Qu’Appelle basin in south-central Saskatchewan were investigated. The equivalent carbonate content and calcite:dolomite ratios of the deposits reflect the mechanisms of glacial deposition and some differences in the sources of the original parent material. The particle size analysis shows that the Qu’Appelle Lake sediments are more clayey than the surrounding soils and till deposits. Mg-bearing calcites occur only in the fine-sized fraction of the carbonate accumulation horizons. However, most of the upper Qu’Appelle Lake sediments contain appreciable amounts of sand-sized Mg-bearing calcites. The marked increase in carbonate content of the sediments relative to the adjacent soils and deposits is partially due to direct precipitation of calcite from the supersaturated lake waters. In this respect, a good correlation exists between the lake water ionic activity products for CaCO3 and the relative equivalent carbonatic mineral contents of the sediments. Key words: Mg-bearing calcite, dolomite, IAP, erosion

Description: The carbonate mineralogy of the Blackstrap Lake sediments in central Saskatchewan indicates that the lake deposits are composed of carbonatic minerals similar to those found in surrounding soils and glacial deposits. Textural differences reflect the transport of finer materials (silts and clay) from the adjacent eroding landscapes. In particular the persistence of dolomite in the silt fractions of the lake sediment is a good indication that part of the calcite together with the dolomite are derived from surrounding soils. The sediment sand fraction contains appreciable Mg-bearing calcite and mollusk shells of pure calcite. Changes in the ionic concentrations of the lake water indicate that dissolution-precipitation processes have affected sediment composition. The increased calcium carbonate equivalent percentages and the presence of secondary magnesium-bearing calcites in the lake sediments suggest that this is so, particularly since erosional processes could not account entirely for the differences observed between the sediments and surrounding soils. The presence of gypsum and the nature of the secondary calcites in the Blackstrap Reservoir sediment tie in well with the known historical background of the Reservoir. The increased ionic concentration of the lake water over the last 15 yr or so since the original inception of the Reservoir is attributed to the influx of drainage waters, evaporation and possibly the effects of groundwater entry from below. Key words: Mg-bearing calcite, dolomite, IAP, erosion

Description: The formation of Podzols in the Rocky Mountain Region of Alberta has been related to the presence of an easily weatherable volcanic ash component within the upper solum of these soils. A silty surficial deposit, comprising a mixture of volcanic ash and locally derived aeolian detritus, is the parent material for the upper solum of pedons occurring in stable landscape positions. Source areas for this locally derived aeolian detritus comprise highly calcareous materials. Weathering of the carbonate component of the locally derived aeolian material releases considerable amounts of iron and aluminum, sufficient to produce a Bf horizon given an appropriate environment. The presence of a Bf horizon in this region is insufficient evidence to implicate volcanic ash as a parent material component in the genesis of the pedon. Key words: Genesis, Rocky Mountain region, weathering of CaCO3, volcanic ash, local aeolian materials, Podzolic soils

Description: This study assessed the lateral and vertical variability of the Atterberg indices within one soil map delineation and inferred the variability of two additional delineations of the Dalhousie association (Brandon series). The data showed that Atterberg indices were highly variable with the liquid limit varying from 33 to 51% for samples from one transect line. This variation was composed of spatial variation in both lateral and vertical directions. Much of the variation in liquid limit was related to the amount of fine material (

Description: One hundred and eighty-three soil samples from 60 pits were collected from a sequence of moraines located in front of the Robson Glacier, Mt. Robson, British Columbia. Univariate analysis of variance, oblique rotation factor analysis, and nonlinear regression were employed to ascertain the major processes operating on the moraines and to determine whether expected trends were masked by the variability of the parent material. Soil properties which varied significantly with depth and moraine age included organic carbon, nitrogen, and pH. Assumed to be functionally related, these properties were also identified with one of two significant factors from the factor analysis. The values for organic carbon and nitrogen were fitted to nonlinear equations involving an exponential term for depth and a logistic term for time; the resulting correlation coefficients were 0.89 and 0.88, respectively. Percent calcium carbonate equivalent, percent iron plus aluminum by citrate-bicarbonate-dithionite extraction, percent iron plus aluminum by pyrophosphate extraction, percent sand, and percent clay showed generally little or no relationship to depth and age. These properties were related to the second factor from the factor analysis, which was identified with water infiltration and abiotically induced carbonation. The absence of stronger depth and age trends for these properties was considered a result of a high degree of variability within the parent material. Key words: Chronosequence, chronofunction, pedogenesis, soil development, soil sequence, soil nitrogen

Description: Volumetric water content was measured by time domain reflectometry (TDR) and by a single-beam γ-ray attenuation at eight positions on each of three soil columns. Both methods measured equally well at single locations and both showed some position dependence, which was greater for γ-ray attenuation than for TDR. An error analysis showed the major contributor to variance in the γ-ray measurement was the unknown variability of bulk density which gave rise to uncertainty of ± 0.05 cm3∙cm−3 for three soils. For the TDR technique all sources of variance resulted in a total uncertainty of ± 0.02 cm3∙cm−3. The greater sampling volume of the TDR as used in this experiment was advantageous with the naturally structured heterogeneous soils. Key words: Soil structure, error analysis, γ-ray attenuation, time domain reflectometry.

Description: Effects of subsurface drainage on trafficability of farmland were assessed over a 2-yr period. When compared with undrained land, drainage by drains spaced at 30.5 m resulted in earlier trafficability by 2–4 wk in a silty clay loam and by up to 5 wk in a muck. Halving the spacing did not increase benefits. Drainage intensity exerted its greatest influence on trafficability when the intensity was low, that is, at large drain spacings. Prediction of trafficability by two procedures revealed close agreement with one another and compared extremely well with dates on which measured water table depth and soil water tension were considered by farmers to be adequate for trafficability. Key words: Trafficability prediction, subsurface drainage, drain spacing, drainage intensity

Description: A procedure is described by which the soil water desorption curve, modeled as a power curve, can be approximated from a limited number of measured water contents at specific tensions. Applicability of the model was tested on 90 soils. The results indicated that measurements at the two extremes were the most important, if only two water contents were measured. The best results were obtained when the curve was fitted through three measured water contents, respectively, at saturation, at an intermediate (5.0–35.0 kPa) tension and at a high (1500.0 kPa) tension. Key words: Soil water desorption curves, limited data, power curve

Description: A comparative investigation of the analytical features of organic matter fractions of acidic and calcium-saturated Vertisols (Ca-Vertisols) from the Caribbean was undertaken. The elemental composition and functional group content of the humic acids (HAs) and fulvic acids (FAs) were similar to previously reported values, except for the low yielding HAs of Ca-Vertisols which contained a greater proportion of O (35.82–47.17%). In addition, high values (8.38 meq/g–11.71 meq/g) for the COOH functional groups of the FAs emphasized the inherent high reactivity of the humic materials. Spectrophotometric analysis supported the view arrived at through chemical analysis that metal-organic (FA) complexes of Vertisols contained Al, Fe and Si with more soluble complexes in the Ca-Vertisols and in the presence of a basic cation (Ca). DTA analysis indicated that the organo-mineral complexes of Vertisols were regular and thermostable. Key words: Vertisols, humic materials, functional groups, infrared, DTA

Description: Reexamination of a "nontronitic" smectite from Mount Megantic indicates that it consists largely of a ferruginous (Fe3+ greater than Fe2+) smectite-like mineral with a small amount of a vermiculite-like mineral. The major component has a high substitution of Si by Al in the tetrahedral sheet and an excess charge in the octahedral sheet, as indicated by the overall chemical formula[Formula: see text]In many aspects, this mineral resembles so-called "cardenite." Key words: Di-trioctahedral minerals, gabbro saprolite, smectite, vermiculite

Description: The objective of this study was to verify and improve the accuracy of fertilizer recommendations for growing cole crops on mineral soils. To achieve this end, 21 field trials were conducted on 12 soils during 1978–1981; of these trials, 13 were performed with late cabbage and Brussels sprouts and eight early cabbage and brocoli. The test crops were fertilized at four rates of N, P and K, and yield responses were related to soil test values. The Cate-Nelson iteration method was used to partition soils into three different classes according to their yield response to fertilization. Furthermore, polynomial and Mitscherlich equations were fitted to yield versus soil K and P data. These procedures suggested that fertilizer recommendations would be more precise by classifying these crops into early- and late-maturing groups. Accordingly, the recommended fertilization rates for soils containing a deficient or medium P supply were 70 and 80 kg P/ha for early and late crops, respectively. A clear yield response by early cabbage to K fertilization was indicated for soils containing a medium K supply; on these soils maximum yields would be achieved with an application of about 180 kg K/ha. On the other hand late cabbage and Brussels sprouts apparently only needed about 120 kg K/ha to achieve maximum yields on the same class of soils. While an increase in yields attributable to K fertilization is unlikely on soils containing a low and high K supply, a rate of 120 kg K/ha is nonetheless recommended to ensure maximum yield and maintain soil fertility levels. As regards N-fertilization, maximum yields early and late crop were produced with 160 and 180 kg N/ha, respectively. Key words: Fertilizer, N, P, K, vegetables, cabbages

Description: not available

Description: Fine roots of tropical rain forests are sometimes associated with decomposing organic matter at the soil surface. This association is considered by some authors to be important in recovery of nutrients by the vegetation. In this paper, experimental evidence is presented to show that the association results from a dynamic process and is not a coincidental result of negative geotropism. The association appears to be the result of random encounters of growing roots with organic matter, followed by increased branching at that site. The concentration of absorbing tissue in such relatively nutrient-rich sites as decomposing organic matter implies more effective ion absorbtion than would result if roots were randomly distributed in the soil volume.

Description: Urea, gypsum-coated urea, and calcium nitrate fertilizers differentially affected indigenous rates of litter decomposition on the forest floor for coastal stands of western hemlock (Tsugaheterophylla (Raf.) Sarg.). These differences were most pronounced during the first 6 months after fertilization. Urea and gypsum-coated urea both stimulated the rates of litter decomposition, although the effect of gypsum-coated urea was more gradual. In contrast, calcium nitrate somewhat retarded existing decomposition rates during the first 6 months; after 12 months, it had little or no impact. The significant (P 〈 0.05) positive correlation of percentage of lignin in litter with time renders it an important qualitative measure of decomposition rates in studies utilizing litter bags.

Description: Soil from 10 slash burned and 3 unburned clear-cuts was tested for water repellency by the water drop penetration method and compared with naturally occurring soil water repellency in uncut mature forest. There was no difference in soil water repellency between unburned clear-cuts and the uncut forest control. Soil was more frequently water repellent in slash burned sites (35% of samples) than in the control sites (21% of samples), but differences were significant only for the first 2 years after burning. All humus samples were severely water repellent. At the 0- to 4-cm depth below the humus, burned samples were more frequently repellent than control samples, but there was no difference at the 8- to 10-cm and 15+ cm depths. Water repellence decreased with depth in both burned and control sites.

Description: Loblolly pine (Pinustaeda L.) seedlings, which set bud in fall, required exposure to chilling temperatures before growth could resume under a 10- or 12-h photoperiod; whereas a 14-h photoperiod partially substituted for the chilling requirement. A 10- to 14-h photoperiod, however, did not affect the rate of budbreak once the chilling requirement was satisfied. A broad temperature range (0 – 12 °C) was equally effective in satisfying the chilling requirement. In situations where subfreezing temperatures were sufficient to decrease the extent of shoot growth or result in seedling mortality, the rate of budbreak for surviving seedlings was not affected. Exposure to low but above freezing temperatures beyond that necessary to satisfy the chilling requirement for budbreak resulted in increased height growth. Chilling temperatures apparently were involved both in ameliorating bud dormancy and promoting vegetative growth.

Description: The average diameter used in power equations like Reineke's is neither the quadratic nor the arithmetic mean diameter. The diameter is a function of the equation's slope. As such it is a distinct stand variable which is not be to confused with other diameters.

Description: not available

Description: Cambial electrical resistance (CER) and periodic growth rate (PGR) of canopy balsam fir (Abiesbalsamea L.) trees were determined on 26 sites in Maine, New Hampshire, and Vermont, U.S.A., varying in level of spruce budworm defoliation. Determinations of water and potassium concentrations were made of the bark, wood, and vascular cambial zone (VCZ). Low CER was associated with high PGR and vice versa. A decline in PGR on all 26 sites was detected during early 1970's to late 1970's. It was not associated with, but may have been exacerbated by, spruce budworm defoliation. The most probable mechanism relating CER to PGR in balsam fir was variation in the thickness of VCZ and its correlation with potassium content. Thicker VCZ of faster growing trees released more potassium into the solution contacting electrodes than thinner VCZ of slower growing trees.

Description: The applicability of the rotatable second-order central composite design in forest fertilization studies was tested. The results indicated that the quadratic response equation specified by the central composite design was inadequate in approximating the response surface of white spruce (Piceaglauca (Moench) Voss) seedlings to fertilization with N, P, and K. Conventional factorial experiments arc useful not only in testing hypotheses of various effects but also in deriving an equation that adequately approximates the true response surface. Using the derived regression equation, seedling growth response to various rates of fertilizer application can be predicted and an optimal fertilizer regime can be determined.

Description: Live and dead conifer fine root (≤2 mm) and mycorrhizal root biomasses were determined in the forest floors of 16 stands of Douglas-fir (Pseudotsugamenziesii (Dougl.) Forbes) of low (IV) or high (II) productivity. The maximum biomass of both live conifer and mycorrhizal root biomass occurred at canopy closure in site II and IV stands. After crown closure this biomass decreased significantly in site II but not in site IV stands. During and following crown closure, site IV stands generally had a significantly higher live conifer root biomass than site II stands. Only in the 65- to 75- and 150- to 163-year age groupings of stands was a significantly higher live mycorrhizal root biomass measured in site IV than in site II stands. The proportion of dead to total conifer fine root biomass fluctuated from 13 to 56% in site II stands and from 26 to 76% in site IV stands. The percentage of total mycorrhizal roots that were dead fluctuated from 25 to 57% in site II stands and from 19 to 76% in site IV stands. Generally the highest percentage of live root tips infected by mycorrhizal fungi occurred in the 45- and 46-year-old site II stands and in the 33-, 49-, 67-, and 69-year-old site IV stands.