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Browsing Faculty Publications by Author "Acton, C. J., author"

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    Measurement of the polysaccharide content of soils
    (Colorado State University. Libraries, 1963-01) Acton, C. J., author; Paul, E. A., author; Rennie, D. A., author; Agricultural Institute of Canada, publisher
    The polysaccharide content of two soils, measured by precipitating and weighing the microbial gums from the fulvic acid fraction of soil organic matter, and by colorimetric analyses using anthrone, was increased appreciably during the incubation of samples with straw. Applications of nitrogen and phosphorus altered only slightly the amount of polysaccharides present. The polysaccharide content of the amended soils increased rapidly during the first week of incubation and then levelled off. Peptization of the soil with dilute alkali prior to acid hydrolysis substantially increased the carbohydrates measured with anthrone. The anthrone reagent which measures primarily hexoses indicated a soil carbohydrate content of 10–15 per cent occurring in a range of Saskatchewan soils. Thirty-five per cent more carbohydrate carbon was found using the less specific phenol-sulphuric acid reagent. The acetone precipitated fraction from the fulvic acids accounted for only 10 per cent of the soil carbohydrates and contained a large proportion of ash and other non-carbohydrate materials. The total acid-soluble base-soluble fraction, fulvic acids, contained 15–25 per cent; the remainder was distributed in the alkali insoluble humin — 55–70 per cent and the humic acid fraction 4–12 per cent.
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    The relationship of polysaccharides to soil aggregation
    (Colorado State University. Libraries, 1963-07) Acton, C. J., author; Rennie, D. A., author; Paul, E. A., author; Agricultural Institute of Canada, publisher
    Studies were conducted on two soil types to determine whether variations in level of aggregation, induced by adding wheat straw were accompanied by significant changes in the polysaccharide content of the soils. The addition of finely ground wheat straw to the soils, followed by varying periods of incubation, markedly improved the level of aggregation in both soils. Where nitrogen was added together with the straw, the percentage of aggregates > 0.5 and 0.1 mm. diameter was reduced significantly as compared to the straw treatment alone. The data indicate that maximal structural improvement due to straw additions can only be attained where N is maintained at a relatively low level. The level of aggregation of the variously treated soils was shown to be approximately 35 per cent dependent on the 'microbial gum' content of the soil samples. This low level of correlation was due m part to the fact that the maximum level of aggregation was attained at a different sampling period than maximum accumulation of 'microbial gum'. Also, appreciable contents of polysaccharides were found in the humin and humic acid as well as the fulvic acid fractions of the soil organic matter. It is concluded that level of aggregation is a function, not only of the microbial gum content of the soil, but also of the carbohydrate carbon content of the numic acid-humin fraction.