Two field plots in the Ladner area, one supporting pasture species and the other inter-tilled crops, were irrigated by sprinkler with water containing more than 13,000 parts per million of ocean salts. Eight acre inches of water were applied annually, in three equal applications, the trial being conducted for a period of two to three years. Soil samples, obtained at appropriate intervals during the course of the irrigation trials, were studied in the laboratory to determine the effects of the treatment on their physical and chemical properties. Plant yields were recorded and tissues chemically analysed to reveal alterations, if any, in the uptake of mineral elements. Analyses revealed that, as a result of irrigation, marked increases occurred in respect to salt content of the soil and osmotic pressures in the soil solution. Subsequent dormant-season rains were observed to remove a large portion of the accumulated salt, but sufficient salt residue remained in the cultivated soil after two year's irrigations to affect injuriously the growth of a non-irrigated silage crop. The exchangeable sodium percentage of the soil was increased only slightly in the pasture field, but to a dangerous level in the cultivated field. Exchangeable magnesium was increased and calcium decreased in both soils. The effects on soil calcium are considered to be important, since the soils are already low in available calcium, and a further deficiency of this element for plant growth is therefore threatened. Studies of soil structure revealed no destructive changes which could be definitely ascribed to irrigation with saline water. Calcium uptake by the plants was generally depressed by the treatment, and of the tissues studied, all, with the exception of the grasses, showed accumulation of sodium Pea and silage corn yields were reduced by irrigation, sugar beet yield was unaffected, and pasture grass yield was increased eight-fold. The quality of all crops was impaired by the treatment. The author is convinced that the continued use of this highly saline water, except in very special circumstances, will cause reduced crop yields and lead ultimately to serious and permanent impairment in the physical and chemical properties of the soils. / Land and Food Systems, Faculty of / Graduate

Brown’s Method was found to be a very satisfactory technique for determining the exchange capacity of soils. It was simple, rapid and gave comparable results with Shollenberger’s technique for thirty soils from Vancouver Island. The Puri Method gave comparable results to Brown’s but was too lengthy. Considerable variation occurred at high percent base saturation levels when determined by Schollenberger, Brown and Purl Methods for these soils. It was concluded, however, that Brown’s Method as well as being rapid and simple gave satisfactory results. As much as twenty percent variation in percent base saturation was noted for soils having the same pH value. The percent base saturation of a soil cannot be estimated from its pH with a high degree of accuracy. The total titration curves produced by adding increments of calcium to hydrogen saturated soils showed that the exchange capacity and base saturation could be determined by this method. It was also concluded the position and shape of the curves, indicated the buffer capacity of the soil. In a greenhouse experiment where Virginian Stock was grown as the indicator crop on five levels of percent base and calcium saturation, the following conclusions were made: (1) That a relationship exists between calcium and base saturation of the soil and plant growth. (2) That the flex point for the growth saturation curves occurred at 30% calcium saturation and 60% base saturation for both soil types. (3) That response to lime in the greenhouse coincided with known response in the field. (4) That a relationship exists between base saturation in the soil and calcium content of the plant. (5) That 1200 gm. samples of soil were better suited for saturation studies than 300 gm. samples. (6) That below a certain percent base saturation calcium is not available to plants. (7) That base saturation studies should form a sound basis for estimating the lime requirement of soils. The lime requirement of six soil types was estimated by three methods: (1) Percent Base Saturation expressed on a Volume Weight Basis. (2) Percent Base Saturation expressed on a weight basis. (3) Titration Curves on a weight basis. It was concluded that the Percent Base Saturation Method expressed on a volume weight basis gave a good indication of the lime requirement for the six soil types studied. The latter two methods indicated that very large quantities of lime were required for soils with low apparent specific gravities. This may result in overliming of the surface horizons / Land and Food Systems, Faculty of / Graduate

The distribution of trace elements in bedrock, soils and plants, was studied in twelve areas of British Columbia where mineralization was known to occur below different kinds and depths of overburden. Samples were taken from two soil profiles and the bedrock at each location, and second and third year twigs of the principal vegetation found within a radius of fifty feet of each profile were also collected. The bedrock, soil and plant samples were analysed. The soil samples were used for the determination of pH, organic matter content, percentage of material <80 mesh, cation exchange capacity, exchangeable heavy metals, and content of Cu, Mo, Zn, Pb, As, Co, Ni, Fe and Hg. The same elements were determined in the bedrock and vegetation samples. The results were examined graphically for relationships between elemental contents of the bedrock, soil horizons and vegetation. The data were then statistically analysed.(a) soil horizons and plant relationship with bedrock. (b) inter-elemental relationship of individual horizons of soils and of plants, as well as all horizon relationships. (c) multiple correlation study of cation exchange capacity, percentage of organic material and -80 mesh of element content of individual and all soil horizons. These studies showed that, although most of the soil horizons were developed from transported materials, (glacial, alluvial, etc.), there was a highly significant correlation with B and C horizons and bedrock that confirmed the value of soil sampling in prospecting, since horizon development includes the upwards migration of the elements from bedrock. The secondary dispersion of the halo elements (Mo, Zn, Pb, As, Co, Ni, Hg) proved useful as pathfinders where major economic elements may have been masked during the upward migration process. Secondary dispersion may also be in some degree, helpful in identifying the origin of soils and plants. A great divergence in the affinity of various plants for different elements, and of the same species at different locations, was noted. It was also observed that plants have a closer relationship to the soils than to the bedrock itself, but even so, indicate mineralization. The important relationships between elemental distributions in soil horizons and in plants with bedrock, indicated a logarithmic relationship. The multiple correlation study indicated that some of the major factors of influencing the level of element content in soils developed on transported material-covered areas, are the size of the soil particles and frequently the pH of the soil. In general, the study indicated that the distribution of trace elements is highly complex and that bedrock, soils, and plants, should all be combined into one study; since the study of one of these alone would be incomplete without the others. / Land and Food Systems, Faculty of / Graduate

Forest road building and timber harvesting operations have been recognized as principal causes of forest soil degradation. These activities can result in accelerated soil erosion, excessive scarification, and/or increased soil density, which may adversely affect site productivity. A study of landing areas emphasize the deficiencies in current rehabilitation guidelines Increased soil density on both summer and winter landings was still evident at 30 cm and the soil nutrient quality was poor. Two field tests of a green fallow system on subsoil materials exposed by erosion and landing construction proved successful in building site nutrient capital to acceptable levels. Seedling growth response to green fallow crop establishment in the coastal study verified these findings. A benefit-cost analysis of several forest soil rehabilitation scenarios demonstrated the importance of including secondary and intangible factors. From a pecuniary standpoint, based on primary benefits and costs, rehabilitation was economically feasible only when a low social discount rate (2%) and an optimistic stumpage increase projection (3% per year), were used. A discussion of some secondary and intangible benefits (i.e., harvesting rates, employment, government revenues, erosion control, and industry image) stresses the need for effective forest soil rehabilitation. / Forestry, Faculty of / Graduate

Four papers are presented in this thesis each one reporting on studies relating to volcanic ash with special reference to soils. The first paper reviews a) some of the phenomena relating to the ejection and deposition of ash that are important in interpreting the significance of its occurrence, b) the significance of ash layers to workers in the Quaternary, c) the techniques available for the characterization and recognition of tephra, d) the literature on ash deposits in western Canada and compiles the noted occurrences. In addition this paper presents the data from a study to determine the amount of ash retained by soils within and beyond the major areas of deposition indicated in the literature. The presence of ash in soils was found to be widespread though the amounts present may be limited for identification purposes, in some cases. The second paper describes two soils derived from Bridge River volcanic ash and their underlying paleosols and presents selected physical and chemical analyses. The analyses indicate that in the youthful soils studied the physical properties of the ash soils are inherited from the parent material. The colloidal and chemical properties are initially imparted by organic matter with some influence from ash weathering products especially aluminum. Shallow surface additions of volcanic ash to soils influence soil properties to varying degrees depending on pedogenic environment and depth of material. The third paper evaluates a number of methods that have been used to identify podzolic B horizons and the influence of surface additions of volcanic ash on the podzolic characteristics of soils. Pyrophosphate, pyrophosphate dithionite, citrate dithionite bicarbonate extractions, phosphate sorption capacity and pH-dependent cation exchange capacity determinations all highlighted the podzol B horizons while acid ammonium oxalate extractions and pH determined in NaF did not. The presence of surface additions of Bridge River ash may influence acid ammonium Oxalate or NaF criteria but it was not found to reduce the value of the other diagnostic criteria examined in this study. The final paper studies the amorphous material and clay mineral characteristics of the two aforementioned soils and examines some of the methods of extraction and isolation of clay materials in soils. All of the chemical treatments applied to the soils were found to result in some dissolution of secondary and primary soil materials. The treatments used to extract amorphous materials indicated that the Si to Al ratios of extracted materials was greater than 2. As this value approaches 2 the formation of allophane and imogolite will take place. This situation is indicated as having taken place in isolated capillaries as evidenced by the limited occurrence of imogolite-like material. Chlorite is the dominant clay mineral in the ash soils and is believed to be the weathering product of primary biotite, horneblende and pyroxene. / Land and Food Systems, Faculty of / Graduate

Site preparation treatments are often used prior to the planting of clearcut forest lands to improve planter access and to increase the number and quality of planting spots. Most mechanical site preparation treatments alter the configuration and material composition of surface soil materials, and can have marked effects on soil properties important to seedling survival and growth. Effects of some of these treatments on soil moisture, soil temperature, rates of nitrogen mineralization, and the establishment of Picea glauca x engelmannii seedlings were examined on fresh, moist, and wet sites in the moist cold subzone of the Sub-boreal Spruce Zone in west-central British Columbia. Four types of microsite alteration were investigated: forest floor removal (spot scalping), soil mounds over inverted sections of forest floor (inverted mounds), mineral soil mounds over a mineral soil surface, and inversion of the forest floor and mineral soil in place. Soil temperature was monitored continuously and soil moisture weekly at the 10-cm depth in 16 combinations of site and microsite treatment during two growing seasons. The response of seedling height and diameter growth was monitored for three growing seasons. Effects of altering soil temperatures through mechanical treatments on rates of nitrogen mineralization were examined by incubating a standard soil material in a range of microsites created by six combinations of site and mechanical treatment. Effects of substrate quality and soil temperature on rates of nitrogen mineralization were examined in paired mounded and untreated spots in fresh, moist, and wet sites. In all sites, early growing season soil temperatures in the seedling rooting zone were substantially warmer in inverted mounds than in other treatments. Spot scalping increased temperatures slightly relative to controls in the fresh site, but had little or no warming effect on moist and wet sites. Inverted mounds became substantially drier than other treatments during periods of low rainfall, particularly in the fresh site. After three growing seasons, seedling height growth was greatest in inverted mounds, irrespective of site. Amounts of nitrogen mineralized in a standard soil material during incubation for 77 days in the field were significantly greater for samples placed in inverted mounds than for those placed in other microsite treatments. There was a significant positive correlation between amounts of nitrogen mineralized during field incubations and degree hour sums calculated for associated microsite treatments and sites. Both substrate quality and soil thermal regime affected rates of N mineralization in samples from paired mounded and untreated spots, and an interaction was observed between the two factors. / Graduation date: 1991

The body of work presented in this Thesis document provides a comprehensive examination of final cover design for municipal solid waste landfills. Accompanying general design principals is the investigation and resulting recommendations for issues specific to the closure of the Vancouver Landfill. The first objective of the Thesis was to develop a set of physical characteristics for soil materials, which would allow for the construction of a lowpermeability barrier layer meeting British Columbia guidelines. The second objective was to then use the developed soil criteria to evaluate the suitability of Lower Mainland soils. The physical characteristic of soil material, originating from trench excavations in Vancouver, was closely examined and the material evaluated for use in all layers of final cover design. The last objective of the Thesis was to investigate the use of alternative cover materials, including geosynthetics, in final cover design. The combination of a comprehensive literature review and the implementation of a program of soil sample collection and analysis allowed for the completion of the above objectives. Testing of soil samples included the determination of the grain size distribution to the clay fraction level. The major findings of the work are that soil sources in the City of Vancouver are not suitable for use in the construction of a low-permeability barrier layer. Suitable soil sources however, can be found in areas of Surrey and Langley. Trench excavation soil is recommended for use in the foundation layer of the final cover. Lastly, geosynthetic materials are a viable alternative to the use of soil in final cover design. A polyvinyl chloride (PVC) geomembrane would be the most suitable geosynthetic based barrier layer for the requirements of the Vancouver Landfill.

An understanding of runoff generation is a requirement for efficient erosion control and land management practices. This research is designed to investigate the processes by which runoff occurs on a Whatcom soil at an upland site in the Lower Fraser Valley. The objectives of this study are to summarize water erosion measurements, to determine soil hydraulic properties, to predict infiltration for typical rainstorms and to determine the mechanism of runoff generation. Rill, interrill and rainsplash measurements, and previous erosion measurements made at the study site are used to qualitatively assess the magnitude of water erosion. Soil loss is dominated by rill erosion and erosion rates are greatest from November to January. Runoff coefficients are relatively low (<26%), but erosion rates are anticipated to be in excess of 35-45 t ha⁻¹yr⁻¹. Soil hydraulic properties are measured using a low tension absorption technique described by Clothier and White (1981). The sorptivity tube device provides a simple method for obtaining S, λ* and K₋₂ Measured values of i and x* depend on t¹′² as expected from the constant-concentration absorption theory. Soil hydraulic variables and constant-concentration absorption theory are used to determine the soil-water diffusivity characteristics. Measured D(θ) functions for the field varied widely in a and b, especially for the lower horizons. The Van Genuchten (1980) θ(h) expression provides a good fit to the water retention data. D(θ) functions predicted from the soil-water retention curves and the conductivity at satiation are at least 1-2 orders of magnitude greater than the measured functions. Hysteresis effects may account for a 1 order of magnitude increase in D(θ), but the predictions are poor without matching at D(θ₅). The measured hydraulic properties are used to predict infiltration, runoff and drainage. Constant-flux infiltration theory is used to model soil moisture profiles for various rainfall events. High field moisture contents necessitate the inclusion of gravity effects during infiltration. Rainfall, runoff and soil loss measurements at the Mahal farm indicate that rainfall intensities <10 mm h⁻¹ cause considerable runoff and erosion. For rainfall intensities known to cause runoff and erosion, runoff is not predicted for most Ap horizon cores. Infiltration may be restricted at some sites by the lower horizon but runoff is not predicted at many sites. To evaluated soil moisture conditions between rainfall events, drainage is estimated from a unit gradient model. A rapid decrease in θ between rainfall events predicted by the unit gradient model, but θ measured at the Mahal farm suggests limited drainage between rainfall events. Rainfall, runoff and soil loss measurements suggest that factors other than those measured are contributing to the runoff observed in the field. Compaction, surface sealing and subsurface seepage may be factors influencing runoff and moisture conditions in the field. The high moisture contents observed in the field suggest the water table is perching on a layer of lower conductivity which in consistent with Dunne runoff. However, the measured infiltrabilities suggest Hortonian runoff and the resultes of the thesis are not conclusive with respect to the mechanism of runoff generation. / Land and Food Systems, Faculty of / Graduate

The body of work presented in this Thesis document provides a comprehensive examination of final cover design for municipal solid waste landfills. Accompanying general design principals is the investigation and resulting recommendations for issues specific to the closure of the Vancouver Landfill. The first objective of the Thesis was to develop a set of physical characteristics for soil materials, which would allow for the construction of a lowpermeability barrier layer meeting British Columbia guidelines. The second objective was to then use the developed soil criteria to evaluate the suitability of Lower Mainland soils. The physical characteristic of soil material, originating from trench excavations in Vancouver, was closely examined and the material evaluated for use in all layers of final cover design. The last objective of the Thesis was to investigate the use of alternative cover materials, including geosynthetics, in final cover design. The combination of a comprehensive literature review and the implementation of a program of soil sample collection and analysis allowed for the completion of the above objectives. Testing of soil samples included the determination of the grain size distribution to the clay fraction level. The major findings of the work are that soil sources in the City of Vancouver are not suitable for use in the construction of a low-permeability barrier layer. Suitable soil sources however, can be found in areas of Surrey and Langley. Trench excavation soil is recommended for use in the foundation layer of the final cover. Lastly, geosynthetic materials are a viable alternative to the use of soil in final cover design. A polyvinyl chloride (PVC) geomembrane would be the most suitable geosynthetic based barrier layer for the requirements of the Vancouver Landfill. / Applied Science, Faculty of / Civil Engineering, Department of / Graduate

It is generally accepted in British Columbia that Canada Land Inventory Class 1 to 4 lands are arable, yet in many instances commercial farms exist on lands of lower capability. A case study was done for an area (1.6 km * 2.9 km) southeast of Nanaimo, B.C. to determine if Canada Land Inventory Class 4 and 5 soils are biophysically suitable for Pyrus (pear) and Mai us (apple) orchards, and if such a development would be socioeconomically feasible. The critical biophysical conditions governing orchard development identified were climate (freeze free period, effective growing degree days, dormancy period and minimum winter temperature); soils (depth, drainage, texture/% coarse fragment content and topography); and groundwater availability for irrigation. The critical economic conditions were land tenure (Tree Farms and parcel size); current land use; and fruit yields and prices. While all biophysical conditions were favourable to apple orchards, the soils were found to be too coarse textured for pear orchards. Maps outlining the critical biophysical and socioeconomic conditions were prepared and overlayed. The composite map identified one area with realistic development potential for apple orchards. Although soils, land tenure, parcel size and current land use decreased the area available for orchards, the lack of groundwater for irrigation was found to be the most limiting factor to orchard development. Estimates of costs and returns for a 3.3 ha apple orchard over a 25 year period were done. Using these estimates, the net present value of the orchard was determined for three discount rates: 5%, 8% and 10%; and for five prices per kilogram: $0.15, $0.22, $0.33, $0.44 and $0.66. At prices of $0.15, $0.22, $0.33 and $0.44 (at discount rates of 10% and 8%), orchard establishment was not feasible. However, at prices of $0.44 (and discount rate of 5%) and $0.66, orchard establishment was feasible. / Science, Faculty of / Resources, Environment and Sustainability (IRES), Institute for / Graduate