A physically based model describing the mechanism of surface sealing of soil was evaluated in the context of aggregate stability. The intent of the model study was to better understand the effect of mixing fine-textured mineral subsoil with organic surface soil on structural stability and surface seal formation. The mixing results from tillage and harvesting operations, and management practices such as levelling. The index derived from the model showed that sealing of the shallow organic soil increased with an increase of mineral matter content. The mathematical formulation of the model was based on the principle of conservation of mass and Darcy's law for flow of water through a layered soil column. Assuming convective flow, it was shown theoretically that the rate of surface seal formation is proportional to the flux density of the filtrate, as assumed by Scheidegger (1974). In the model it was further assumed that the pore necks at the soil surface clog first before the seal develops. The assumption that convective flow alone was responsible for the movement of the suspension is likely incorrect for suspensions derived from medium or coarse textured soils, since sedimentation does influence the movement of larger particles. However, introducing a constant sedimentation parameter into the convective flow model did not improve the model. Therefore, it is likely a non-constant sedimentation parameter could improve the model considerably. The model showed that for sufficiently large times the flux density of a filtrate flowing through a soil column at a constant hydraulic head is proportional to inverse square root of time. Testing the model experimentally showed a good agreement between theory and experiment. A highly significant correlation between the soil stability factor derived from the model and aggregate stability suggests that the index is a soil structural attribute. The soil stability factor was exponentially related with aggregate stability and mineral matter content. However, whereas the relationship between the soil stability factor and aggregate stability gave a positive exponent, a negative exponent was obtained with mineral matter content. Further studies showed that structural stability and saturated hydraulic conductivity of the aggregate beds were positively and significantly correlated exponentially. However, saturated hydraulic conductivity and mineral matter content were negatively and significantly correlated exponentially. Collateral to the results of the model, the strong negative correlation between wet-sieved aggregate stability and mineral matter content confirmed the deleterious effect of mixing fine-textured mineral soil on the structure of the shallow organic soil. It was theorized that aggregates stabilized through clay-organic complexing are likely to be much stronger than aggregates stabilized through other mechanisms. This implies that whenever the mineral matter content is much higher than the organic matter content, the surplus mineral matter that does not interact with organic matter will be most dispersible. The high silt content of the mineral matter fraction is likely to be an important factor contributing to the decrease in structural stability with increasing mineral matter content. Once the clay and the organic colloids have interacted, the silt that remains is not capable of forming stable aggregates without colloids (Baver et al. 1972). From measurements of the air to water permeability ratio, the decrease in saturated hydraulic conductivity of the aggregate beds with increasing mineral matter content was attributed to slaking of the mineral matter fraction. However, it is possible for the soil with high mineral matter content to be stable if the mineral matter is allowed to be in contact with the organic matter for a long period of time. / Land and Food Systems, Faculty of / Graduate

A mineralogical and chemical study was conducted on the clay fractions of lower Fraser River alluvial sediments. The major objectives of the study were to characterize the mineralogy of these sediments and to evaluate the influence of a marine environment and sedimentary phases of deposition on their mineralogical content. Twenty-one sampling sites representing the four major soil series developed on these sediments and six sea bottom samples were collected. Surface and subsurface samples were taken for the soil series. X-ray diffraction analyses were conducted on the coarse and fine clay fractions of all samples and the total K, Mg and Ca contents of the clay fractions were also investigated. With the exception of samples from the Pitt Meadows area, there was a marked similarity in the clay mineral suite present in these sediments. The major clay mineral components of the coarse clay fraction were montmorillonoid and chlorite. Lesser amounts of micaceous material and several interstratified clay minerals were also present. The interstratified clay minerals identified included a randomly interstratified chlorite-montmorillonoid and chlorite-mica and in a limited number of cases regularly interstratified chlorite-montmorillonoid. The identification of a regularly interstratified chlorite-mica was quite questionable. Positive identification of kaolin was prevented in most instances by a heat unstable chlorite. However, kaolin was identified in a sample from the Pitt Meadows area and there was strong evidence to suggest its presence in other samples. Quartz, feldspars and amphiboles were the only non-phyllosilicates identified. The fine clay fractions were dominated by montmorillonoid and much lesser amounts of chlorite. Micaceous material, inter-stratified clay minerals and quartz were present in only questionable amounts and in some instances appeared to be absent. The chlorite was identified as an iron rich variety possessing thermally unstable higher order reflections. A progressive decrease in the relative intensity of these reflections was observed on heating from 4OO to 450°C. Further heating to 500°C resulted in the disappearance of the peaks. The montmorillonoid component identified appeared to be of two types: An octahedrally substituted member and a tetrahedrally substituted member. The presence of the latter mineral prevented identification of vermiculite. The results support the findings of other workers that marine deposited sediments are highly detrital in nature, dominantly reflect their source area and are influenced by sea water to only a minor extent. Diagenesis of 14+ A° material of the marine sediments was indicated by X-ray diffraction analyses. Chemical analyses were also indicative of the minor influence of a marine environment. Mineralogical variations within and among soil series were largely quantitative in nature. These variations tended to be minimized within a particular soil series. Mineralogical differences between the two clay fractions were observed, however these were to be expected. The variations noted in the mineralogy of the clay fractions of these sediments were attributed to sedimentary processes, seasonal variations in the detrital components carried by rivers, yearly variations in particular source areas and the local influence of sediments carried by several tributaries of the lower Fraser River that flow out of the Coast Mountains. The X-ray and chemical analyses indicated that there was a valid basis for continued mapping of the Pitt soil series separate from the Monroe and Fairfield series. The two sampling sites from the Pitt Meadows were considerably higher in randomly interstratified chlorite-montmorillonoid and lower in micaceous material than those of the other sediments. Chemical analyses were also indicative of these differences. The variability noted in soils from the Pitt Meadows area may be related to the influence of sediments carried by the Alouette River. / Land and Food Systems, Faculty of / Graduate

Some of the physical and chemical properties of the stony marine clays recently described by Armstrong and Brown in the Lower Fraser Valley area of British Columbia were investigated. Mechanical analysis of samples taken from four depths from the Murrayville, Jackman and Lehman sites showed that the amount of clay material less than 2 microns in diameter increased from a range of 4 to 18 per cent in the surface foot to 20 to 40 per cent at a depth of 18 feet. The silt and fine sand material varied conversely, the surface foot containing from 77 to 96 per cent while the material from; 18 feet contained from 61 to 68 per cent. The textural classification of the samples ranged from sandy loam to silt loam in the surface, and from loam to clay loam at depth. The material collected from the fourth site, Haney, had a somewhat higher content of clay material, 42 to 46 per cent, and a smaller percentage of coarse skeleton, fine sand and silt. Samples from the surface were not available, but the textural classification at depth was clay to silty clay. The mechanical analysis and other physical and chemical information support the suggestion that the material at the Haney site differs significantly from that at the others. The apparent and real densities of the material at all four sites increased with depth, the range in apparent density being from about 1.1 to 1.4 at the surface to 1.4 to 1.8 at 18 feet. In the case of the real density the range was from about 2.69 on the surface to 2.74 to 2.82 at depth. There was a corresponding reduction in total porosity from about 60 per cent of the soil volume at the surface to 35 per cent at depth. The moisture tension determinations showed that to a large extent this reduction was at the expense of large or macro pores. Hydraulic conductivity determinations with soil cores showed that close to the surface the material is reasonably permeable to water, but that it decreases to a very low value at depth. The cation exchange capacity of the material was found to vary considerably ranging from 7 to 23 milli-equivalents per 100 gm. In general the deeper samples gave somewhat lower and more constant values than the surface, ranging from 10.2 to 16.5 milli-equivalents per 100 gm. Reaction and exchangeable cation determinations showed that at the one-foot depth the material is acid, pH 5.0 to 5.8, and from 40 to 73 per cent base saturated. However, the reaction and degree of base saturation was found to increase with depth until in the deeper samples the reaction ranged from pH 7.4 to 9.4> and the clay material was completely base saturated. Highly significant quantities of exchangeable sodium and free lime were found in all the deep samples. Material with effective diameter less than 2 microns was separated from all samples, and from the 18-foot samples less than .5 micron material as well. The free-oxide content of the less than 2 micron material was found to range from about 8.7 per cent at the surface to 3.9 per cent at depth. Sodium carbonate fusion analysis showed the fine material to contain from 50 to 60 per cent silica, and have a high silica-sesquioxide ratio ranging from 3.02 to 6.41. The fine material was found to contain significantly more total magnesium and potassium at depth. These results, together with the high exchange capacity and dehydration values obtained suggest that the fraction smaller than .5 microns contains a significant amount of clay material of the montmorillonite, illite, or hydrous mica types, and that the proportion of this material is somewhat higher at the surface. / Land and Food Systems, Faculty of / Graduate

The study included field, greenhouse and laboratory experiments with sawdust used as mulch and incorporated with soil. The field experiments were conducted with hemlock sawdust mulches on Lynden silt loam at Abbotsford and on Everett sandy loam at Aldergrove. In both cases the crop was strawberries. Two depths of sawdust were used, two and four inches, and these were compared with clean cultivation, with and without sprinkler irrigation. Soil samples were taken in triplicate from three depths at intervals throughout the 1951 growing season and used for the determination of soil moisture. The 1951 season was one of the driest recorded and both depths of sawdust were very effective in conserving soil moisture. On the Lynden silt loam the sawdust maintained soil moisture at a satisfactory level for growth throughout the growing period and was as effective as sprinkler irrigation for this purpose. However, on Everett sandy loam, sprinkler irrigation maintained soil moisture in a more satisfactory manner. Samples taken from the Lynden soil after the mulches had been down a year, indicated a reduction in Humin I nitrogen and nitrate nitrogen had occured as a result of mulching. However, the differences were not great and a more significant reduction of total nitrogen and nitrate nitrogen was noted on the irrigated plots. In the greenhouse experiment, two sizes of cedar and hemlock sawdust were incorporated at two rates with Alderwood sandy loam, fertilized at two rates and planted with lettuce. After one year it was found that hemlock sawdust had increased the moisture equivalent and wilting percentage more than cedar had, but that the cedar mixtures gave a higher yield of lettuce. In all cases the differences were small but significant. Sawdust, when incorporated with the acidic soil, raised the pH slightly and increased the moisture equivalent, permanent wilting percentage and cation exchange capacity of the soil, the effect being greater for the higher rate of incorporation. Sawdust had the opposite effect on available moisture and lettuce yield. Apparent specific gravity of the soil was noticeably decreased as a result of the sawdust additions and a very large increase in non-capillary pore space occured. This was associated with a large increase in percolation rate. Capillary porosity was affected to a very small extent by the sawdust. Nitrogen fertilization (NH₄NO₃) increased soil acidity in the control soil and in the soil sawdust mixtures. Tests were conducted to determine the absorptic capacity of sawdust for water and ammonia. Size of sawdust affected the amount of water absorbed but not the amount of ammonia absorbed. / Land and Food Systems, Faculty of / Graduate

This study examines the economic and social aspects of part-time farming in two municipalities in the Fraser Valley region of British Columbia. The study was undertaken in 1970 under the auspices of the British Columbia Department of Agriculture and the Department of Agricultural Economics at the University of British Columbia. The primary purpose of the study was to provide descriptive information about part-time farmers and to provide some framework within which policy decisions could be made. The study examines the physical characteristics of the part-time farm, the socio-economic characteristics of the part-time farm operator and his family, and the financial aspects of part-time farming. Some analysis is undertaken with respect to the findings of the survey and, where possible, these are related to census data for comparison between part-time farms and all census farms for the same area. The main conclusions drawn from these analyses were that part-time farmers were only distinguishable from the census population farmers on the basis of direct financial aspects of their farms. This was reflected in the much lower levels of farm sales and expenses experienced by part-time farmers. Several characteristics of both census farms and part-time farms were significantly different between the two municipalities. There were strong indications that neither of the two groups are homogeneous between regions. Consequently, it is difficult to envisage a single definition of farming, much less part-time farming, being formulated which will have application in such a diversified agricultural mosaic as is found in British Columbia. The study concludes by questioning the validity of a policy which segments the farm community on the basis of the farm operator having an off-farm job. The study suggests that the only meaningful indicator as to whether or not farm land resources are being effectively utilized is productivity as measured by the usual economic criteria of gross and net dollar receipts. / Land and Food Systems, Faculty of / Graduate

The northerly trending Hozameen, Yale and Hope faults transect the northwesterly trending Custer Gneiss and Hozameen, Ladner and Jackass Mountain Groups. Yale Fault separates gneisses of the Hozameen Group to the east from Custer Gneiss to the west. The Custer Gneiss, as herein restricted, is compositionally distinct from the Hozameen Group and shows a period of early deformation not present in the Hozameen Group. During the Cretaceous, regional deformation and greenschist facies metamorphism of the biotite zone affected rocks between the Yale and Hozameen faults. These rocks grade into gneisses of the hornblende hornfels facies within a few hundred yards of the Spuzzum Quartz Diorite and Yale Intrusions. This restricted contact metamorphism contrasts with the widespread, high temperature and pressure metamorphism found in this and other areas around the Spuzzum Quartz Diorite on the west side of the Hope fault. / Science, Faculty of / Earth, Ocean and Atmospheric Sciences, Department of / Graduate

This study analyses the adoption and rejection of some dairy farm innovations by Lower Fraser Valley dairymen. It also analyses use of information sources, length of time spent in the adoption process, reasons for delay in proceeding through the adoption process, reasons for rejection and discontinuance of innovations, and dairyman-district agriculturist contact. Data for the analysis were collected by interviewing a representative sample of the Lower Fraser Valley dairymen. There was a distinct tendency for the earlier adopters to have large farms, a high production per cow, less than 20 years farming experience, a high farm plus off-farm employment income, large numbers of dairy young stock, office visits with the district agriculturist, agriculture courses at vocational schools, and enjoyment from dairying. There were no significant differences between the earlier and later adopters regarding age, years of school completed, social participation, tenure, specialization, use of hired labour and place of birth. A number of the respondents had had no contact of any type with the district agriculturist in the year previous to the interview but on the average each respondent used 2.53 types of contact. When classified by the nature of the activity, the most used sources of information were personal, followed by individual instructional, mass and instructional group. When classified by origin, the most to least used sources were personal, commercial, government and farm organization. The proportions in which the information sources were used for the two groups of innovations differed. On the average each respondent was unaware of 2.19 of the 10 innovations and continuing in the adoption process for 1.57. Rejection had occurred for an average of 4.38, adoption for 1.66 and discontinuance for 0.20 of the 10 innovations. Almost half the decisions to reject innovations were made at the awareness stage in the adoption process. From the laggard to the early adopter-innovator category, unawareness and rejection decreased while continuation in the adoption process, adoption and discontinuance increased. Situational factors made up more than two-thirds the reasons for delay in proceeding through the adoption process but characteristics of the innovations made up more than two-thirds the reasons for rejection and discontinuance of innovations. The rate of rejection and discontinuance was higher and adoption lower when less than one year was spent than when one or more years was spent in the adoption process. An adoption tendency score was derived and compared with the adoption score but it could not be determined that use of one or the other was a more useful way of identifying differences among the respondents. / Land and Food Systems, Faculty of / Graduate

A study was undertaken to determine the manganese status of some Lower Fraser Valley soils developed from alluvial and marine deposits. Mn fractions in six soils and in their particle size separates were determined by atomic absorption spectrophotometry. Water soluble Mn ranged from 0.5 to 1.4 ppm; Exchangeable Mn from 0.5 to 15.0 ppm; Hydroquinone reducible from 0.7 to 119.5 ppm; Total Mn from 82.0 to 957.5 ppm; and "Active Mn" from 3.2 to 129.8 ppm. These ranges were similar to reported values, except that.the study failed to find the high levels of total Mn reported by Baker on some soils from the same area. Generally water soluble and exchangeable Mn showed little variation within profile or between soils. In four out of the six profiles reducible and total Mn were higher in the parent material than in the surface horizons. However, there was no satisfactory fit for a number of the profiles to the four distribution patterns suggested by Leeper. Values for EDTA extractable and "active" Mn in two profiles suggest that both fractions of Mn represent the same chemical form. However, further results suggest that the two Mn fractions are different. In nearly all samples with high organic matter content EDTA extracted more Mn after removing "active Mn" than direct extraction with EDTA, supporting suggestions that EDTA extracts chelated Mn and also causes some dispersion of soil particles. Sonic dispersion led to increased recovery of all forms of Mn, more especially reducible and total Mn. The results suggest that until more is known about sonic dispersion it is unwise to assume that no modification of soil constituents takes place. Statistical techniques were used to examine the relationship between Mn distribution and parent materials, pH, organic matter content and cation exchange capacity. These analyses showed that the level of Mn fractions in the soil cannot be predicted by any single factor, but only by a number of soil factors in combination. The possibility of building up a computer model to predict Mn distribution is suggested. The significance of soil Mn distribution in terms of plant requirements is discussed. Plant available Mn in these soils, estimated by 0.02 M CaCl₂ extraction, ranged from 0.5 to 10.7 ppm. This was very similar to that for exchangeable. Based on data in the literature these soils were classified into manganese-deficient and-sufficient categories. Using extraction techniques only, various Mn pools were established for these soils according to the chemical pool concept proposed by Viets. These pools and their possible relation to Mn availability are discussed. It was suggested that a further study was necessary to establish a correlation between these Mn pools and plant Mn requirements and also to reveal the equilibria and rates of interconversion existing between the established pools as found under the soil conditions of the Lower Fraser Valley. / Land and Food Systems, Faculty of / Graduate

Near the earth's surface, ozone is a highly toxic and reactive pollutant. In order to avoid potentially hazardous concentrations near densely populated areas, accurate forecasts of the temporal variability of ozone are necessary. Several statistical models which may be used to understand the temporal variability of ozone as well as to forecast short-term ozone fluctuations are developed. The models may be divided into two distinct categories: (1) those which forecast daily maximum one-hour average ozone concentrations and (2) those which forecast the diurnal behavior of one-hour average ozone concentrations. To assess the relative utility of each model, their forecast ability is evaluated by statistical comparison with data not used in model development. Most of the developed models appear to perform reasonably well; however, the utility of any forecast model is dependent upon the needs of the user. It is believed that the limits of the "pure time series" method (i.e., mathematical decomposition of time series into various elements) have been approached. Future investigations with these data should attempt to answer specific questions regarding the physical mechanisms governing ozone variability. / Arts, Faculty of / Geography, Department of / Graduate

A two year field study located in Delta Municipality, British Columbia, was conducted to investigate the possible improvement of nitrogen (N) fertilizer recommendations for arable crops in the Lower Fraser Valley (LFV). After reviewing current N fertilizer recommendation systems in other humid regions, the approach taken in the study was to determine the applicability of a spring soil test and/or a N Index system for the LFV region. The project, which used sweet corn (Zea Mays saccharata) as the trial crop, consisted of two interconnected parts: 1) A 'Replicated Fertilizer Response Trial' which aimed to; a) Monitor soil N0₃-N and NH₄-N during spring to a depth of 80cm, using intervals of 0-20, 20-50, and 50-80cm. b) Investigate yield response and N uptake efficiency at four different rates of sidedress applied urea, 0, 50, 100 and 200 kg ha⁻¹ N. c) Compare the effectiveness of urea applied broadcast preplant, and applied by sidedressing, when the crop was approximately 30cm tall. 2) A 'Multifarm Survey' at 28 locations, comparing plots sidedressed with 135 kg ha⁻¹ N, to control plots containing only starter N. The aim of this survey vas to establish the range of N supplying capacities in some LFV soils and relate these capacities to other soil properties and site history. Monitoring mineral N in the soil demonstrated that soil N0₃-N increased during the spring, reaching a peak 5-6 weeks after planting. Maximum N0₃-N levels in the 0-80cm profile were 90 and 135 kg ha⁻¹ in 1984 and 1985 respectively. NH₄-N levels tended to be low compared to NO₃-N. As a proportion of total mineral N, NH₄-N decreased from approximately 25% at the beginning of May, to between 10 and 15% by mid June. Large amounts of spatial and temporal variability in both N0₃-N and NH₄-N were observed on the two sites studied. The difference in magnitude of mineral N between the years was due to a large number of site and weather factors which could not be separated. No significant differences in corn yield or crop N content were found between any of the four fertilizer treatments in the Replicated Response Trial. Similarly, no significant differences were found in the comparison of urea N applied by broadcasting before planting and urea N applied by sidedressing. Two reasons for this lack of response were suggested, one, that the soil plus starter N provided sufficient N for the crop's needs, and two, that the fertilizing techniques were inefficient considering the soil and weather conditions. The Multifarm Survey provided the greatest amount of information relevant to the project's objectives. It showed that the range of soil types and cropping regimes on corn fields in Delta Municipality was too narrow to have a direct influence on N supplied by the soil. Soil N supplying capacity was shown to be weakly related to organic matter, the study results suggested that a knowledge of site history was necessary before this relationship could be assumed to be positive. Such findings favoured the implementation of a spring soil test rather than a N Index system. Various approaches to estimating N fertilizer requirements using a spring soil sample were examined. In conclusion, the project showed that substantial amounts of N vere made available by the soil and that these should be taken into consideration when fertilizer recommendations are made. The study suggested that in a small agricultural region such as Delta Municipality, spring soil N0₃-N appeared to be sufficiently well correlated with total soil plus crop nitrogen to warrant the further investigation of a soil test for N. This test, for corn, should be as close as possible to sidedress time and the ideal sampling depth would be to 80cm. Anomalous sites with adverse soil conditions, such as poor drainage, marine influences, low pH or compaction should not be included in the test. / Land and Food Systems, Faculty of / Graduate