ALBERT

Beschreibung: not available

Beschreibung: not available

Beschreibung: not available

Beschreibung: Atomic absorption spectrophotometric measurements of Al in plant digests and neutral salt extracts of soils were studied. Using a new lamp (Westinghouse design) and 5 × scale expansion, 1.0 ± 0.08 ppm Al was measured. Lanthanum (2000 ppm) suppressed enhancements from Na, K, Sr, Fe and a mixture of a large number of constituents. The measurements in plant digests were independent of dilution, gave complete recovery of added Al and showed excellent agreement with the 8-quinolinolate colorimetric values. Similarly, there was complete recovery from soil extracts, but the measurements by atomic absorption were larger than by 8-quinolinolate or Aluminon. It was concluded that the new lamp provides adequate sensitivity, stability and freedom from interferences so that atomic absorption can be used for routine measurements of Al in plant digests and neutral salt extracts of soils.

Beschreibung: Copper, in the form of Cu-polyflavonoid, was applied at 50 or 100 ppm to surface samples of nine Wisconsin soils varying from 0.8 to 12.5% organic matter. The effects on yield and on plant uptake of Cu, Zn and Mn were evaluated using oats (Avena sativa L. cv. Lodi). Complexed Cu additions increased extractable Cu, had little effect on extractable Zn, but also increased extractable Mn. Complexed Cu decreased plant uptake of Zn, but increased uptake of Mn. Interactive effects of organic matter, clay, available phosphorus and Zn appeared to occur with respect to plant yield and Cu, Zn, and Mn uptake.

Beschreibung: In a soil incubation experiment with different rates of Zn, the amounts of Zn extracted with 0.005 M DTPA, 1 M MgCl2, and 0.01 M CaCl2 increased with an increase in the organic matter content of a neutral sandy loam soil and with alfalfa added as an organic amendment. Addition of muck and peat increased the amount of Zn exchanged with 1 M MgCl2 but decreased the amount soluble in 0.01 M CaCl2, whereas addition of clay increased the amount of exchangeable Zn but decreased the amounts in the DTPA and 0.01 M CaCl2 extracts. Liming of an acid sandy loam soil (pH 4.9) to about the neutral point reduced the amounts of extractable Zn markedly. A pretreatment of the soils with phosphate almost invariably increased the amounts of extractable Zn. In a corresponding pot experiment, the highest rate of Zn (250 ppm) reduced the yield of corn slightly, prevented the growth of lettuce, and reduced the yield of alfalfa markedly when these crops were grown successively in the acid soil. The concentration of Zn reached levels of 792 ppm in the corn and 702 ppm in the alfalfa. Addition of 50 ppm Zn to the acid soil restricted the growth of lettuce and increased the concentration of Zn to 523 ppm. Despite discrepancies, the concentrations of Zn in the plants as influenced by soil organic matter, organic amendments and liming were usually in accord with the amounts of Zn extracted from the soils. But the P pretreatment tended to decrease the concentration of Zn in corn and lettuce. The mean weight concentrations of Zn in the three species were correlated significantly with the amounts of Zn extracted with 0.005 M DTPA (r = +0.73), 1 M MgCl2 (r = +0.93) and 0.01 M CaCl2 (r = +0.90).

Beschreibung: The results of two studies are reported: (1) a comparison of colorimetric and atomic absorption measurements of Fe and Al in dithionite, oxalate, and pyrophosphate extracts of soils; and (2) a comparison among nine Canadian laboratories of measurements of dithionite-, oxalate-, and pyrophosphate-extractable Fe and Al in six soils. Colorimetric and atomic absorption analyses gave the same measurements of Fe and Al in dithionite, oxalate, and pyrophosphate extracts of soils. Data reported by six Canadian laboratories showed close agreement; data reported by three laboratories showed poor agreement, indicating a need for reference soil samples containing known amounts of extractable Fe and Al to standardize laboratory procedures. Atomic absorption analysis of the extracts is much more rapid than colorimetric analysis and details of the atomic absorption methods are appended.

Beschreibung: The effects of cultivation on the net mineralization of carbon and nitrogen in a lacustrine Brown clay (Sceptre) and two Orthic Black soils on glacial till (Oxbow) were assessed with the aid of fractionation and radiocarbon dating techniques. Fractionation of the soil organic matter of comparative virgin and cultivated soils by acid hydrolysis and peptization in dilute NaOH showed that the distribution of carbon and nitrogen among fractions of these soils was similar. There was no measurable alteration in the mean residence time (MRT) of the soil during the first 15 to 20 yr of cultivation, during which time the Sceptre soil had lost 19% of its carbon and the Oxbow, 35%. However, the MRT increased from 250 yr before present (BP) to 710 years BP after 60 yr of cultivation of the Oxbow soil. The losses for nitrogen were 10% lower than for carbon in the Oxbow soil due to the recycling of nitrogen in the soil. The rate of loss of carbon from the Oxbow soil during the cultivation period was simulated by expressing it as the sum of two first order reactions using fractionation and carbon dating data as the variables.

Beschreibung: Wood Mountain loam was wetted with water or (NH4)2SO4 solution to provide a factorial combination among three moisture and three NH4-N levels. Samples in polyethylene bags were incubated at 2.5-cm depths in fallow, and in an incubator that simulated the diurnal patterns of temperature fluctuation recorded in the field. During the growing season, treatments were sampled regularly for moisture, NO3− and exchangeable NH4-N. Similar determinations were made on in situ samples taken in fallow Wood Mountain loam. The incubator simulated the effects of growing season temperatures on soil N transformations satisfactorily. Pronounced increases or decreases in temperature led to flushes in N mineralization. However, in the 1972 growing season, temperature was suboptimal and temperature changes were generally small. Consequently, when a stepwise multiple regression technique was used to analyze the data, neither ammonification nor nitrification showed a quantitative relationship to temperature. Comparison of the nitrification occurring in laboratory-incubated soils with that occurring in situ led to the conclusion that 70 to 90% of the NO3-N produced in surface soil resulted from wetting and drying. Estimates of potentially ammonifiable soil N(No) and its rate of mineralization (k) were derived from cumulative ammonification by assuming that the laws of first-order kinetics were applicable. In the 10, 15, and 20% moisture treatments the average No was 27, 41, and 82 ppm, respectively. Under the conditions of this study, the time required to mineralize half of No was about 7 wk.

Beschreibung: The distribution of selenium (Se) in 54 Canadian soil profiles was examined according to horizon in the profile, and to soil properties. Apart from the organic surface layers, the Podzolic B horizons had the highest Se values (0.52 ppm), and so displayed a marked accumulation. The Luvisolic and Gleysolic B horizons also showed some accumulation. The Se content of parent materials was generally low (0.10 ppm). Simple correlation analyses of the combined data (irrespective of horizon) indicated that Se distribution was closely associated with both organic carbon and NH4-oxalate extractable Fe and Al. When the data were arranged according to genetic groupings, this association remained true only for Podzolic B horizons. Multiple regression analyses revealed that the predominant factors involved in the Se distribution were the Se content of parent materials, and the organic carbon content of the upper horizons, in that order, except for Podzolic soils. Clay had little or no influence on the Se distribution. In spite of the relationship of Se to parent materials, the contribution by atmospheric contaminants to the Se enrichment of soils could remain important.

Beschreibung: Soil respiration during the growing season was calculated from CO2 profiles in a heavy clay soil under native grass and on cultivated plots. Soil respiration of the native grass plots was correlated with moisture content and temperature of the surface soil. However, the correlation accounted for only ⅓ of the observed variation in soil respiration and could not explain the large difference between two growing seasons. Addition of mineral N decreased soil respiration and irrigation increased it. Total soil respiration on the cultivated plots was higher than on the native grassland. On the wheat plots, soil respiration was significantly correlated with soil moisture but not with temperature; the reverse was true for the fallowed plots. Soil respiration between 1 May and 1 September on the native grassland was highly correlated with rainfall and the number of days with rain in excess of 5 mm. It was concluded that the number of wetting and drying cycles in the soil was mainly responsible for the annual variation in soil respiration. From comparison with data on shoot production, it appears that soil respiration exceeds net production in wet years and that the opposite is true in dry years.

Beschreibung: Potassium mine refinery dust at rates from 1.12 to 11.2 ton/ha (½ to 5 ton per, acre) was applied to a Dark Brown Chernozemic silt loam and to a Black Chernozemic loam. Under dryland farming conditions, no significant effects on yields of cereal grains have been recorded. After 5 years there is no indication that any K has moved deeper than 46 cm (18 inches). The chlorides have been removed from the surface soil and about 50% have leached to below 213 cm (7 ft). The K replaced some of the exchangeable Ca and Mg which were subsequently leached to lower depths. Much of the added K is now in the exchangeable form; some may have become fixed in the clay lattice.

Beschreibung: A study was made of the effects of temperature and different microorganisms, or mixtures of microorganisms, on the changes in the nitrogenous constituents of mixed forest litters (mixed pine, oak, maple) during decomposition periods of up to 4 yr at 1, 4, 10, and 27 C. The percentage of total-N in the decomposing materials increased with time, the increase being related to loss in weight of sample. The percentage of amino-N/total-N was higher with the soil-extract-treated leaf mixture than with the fungi-inoculated material; it increased to a maximum at some intermediate period, then decreased, and was highest with the 930 day 27 C material. Most of the individual amino acids increased in amount up to 930 days; then decreased, the amounts being, in general, higher with higher temperatures. Much of this increase was related to loss in weight of sample, but there appeared to be some net synthesis of amino acid. Lysine and, to a lesser extent, histidine were exceptions to this generalization. The amounts of hexosamines increased with decomposition: with the soil-extract-treated materials the increase of galactosamine was relatively greater than that of glucosamine, but little or no galactosamine was found in any of the fungi-inoculated materials. The amino acid ratios, i.e., the proportion of one relative to another, did not change in any consistent fashion, except for lysine. With the fungi-inoculated material, autoclaving reduced the amount of lysine to less than one-half and a ninhydrin-reacting material appeared before arginine on the amino acid chromatograms; its amount was not changed during decomposition. It may be similar to lysine derivatives found in acid hydrolyzates of heated milk.

Beschreibung: Growth chamber and laboratory studies of four selected soils differing in C:N:S ratios and the percentage of total S present as HI-reducible S in the soil organic matter showed that: (1) the yield response of alfalfa to applied S occurred when the 0.01 M CaCl2-extractable soil SO4—S was less than 3.3 μg/g, (2) mineralization of soil organic S was unaffected by the addition of 25 μg S/g to the soils, and (3) the amount of S mineralized was not directly related to the quantity of total S, HI-S or the percentage of total S present as Hi-reducible S. It was noted that the largest amount of S mineralized occurred from the soil with the lowest C:N:S ratios.

Beschreibung: About 250,000 acres of soil with fragipan have been mapped in Nova Scotia. The fragipan horizons of two soils (Tormentine and Debert) reported in this paper are typical for the province. They have high bulk densities and low saturated hydraulic conductivity. They are also low in organic carbon and free oxides. They are high in fine sand and silt but low in clay, and the fragments of fragipan are readily slaked in water. Mica, chlorite, vermiculite, and kaolinite were found in the clay fractions of both soils throughout the two profiles. A moderate amount of smectite was found in the clay fractions of the Ae horizon of Debert but not in the Tormentine profile. A significant amount of clay increase in both fine and total clay fraction was found in the Bf horizon of the Tormentine soil and the Bmgj and Btx horizons of the Debert soil, and results from translocation or lessivage. The brittleness and other associated properties of the fragipans were attributed to clay bridges linking coarser particles, which were shown in the scanning electron microscope pictures.

Beschreibung: The soil had a thick, dark brown, highly porous Podzolic B horizon with a high content of amorphous Fe, Al- organic matter complex material and a low bulk density, underlain abruptly by a dense, gray fragipan with a bulk density of nearly 2 g/cm3. Mean pore diameters of subhorizons within the Podzolic B ranged from about 25 to 120 μm and those of the fragipan were about 0.5 μm. The marked contrast in porosity was consistent both with hydraulic conductivity values of about 20 cm/h in the Podzolic B and 0.2 cm/h in the fragipan, and with the micromorphology. Strongly oriented argillans in the fragipan indicated some clay translocation. The clay mineralogy indicated weak weathering of phyllosilicates, but appreciable weathering of primary minerals must have occurred to produce the amorphous Fe and Al- rich amorphous material in the Podzolic B. Seepage along the surface of the fragipan, and the absence of roots in this layer indicated the significance of this horizon with respect to plant growth and to the water regime of the soil.

Beschreibung: An extraction-fractionation method was developed with which it is possible to isolate 60–67% of the humus of Chernozemic and Luvisolic soils. Two humic acid fractions were obtained: (1) a conventional alkali-pyrophosphate extractable HA-A; (2) a clay-associated HA-B fraction isolated after ultrasonic dispersion, in water, of the residue of the alkali-pyrophosphate extraction. As compared to the HA-A, the HA-B fractions had lower C contents but greater N contents, narrower C:H ratios, higher molecular weights, and less resistance to hydrolysis in 6 N HCl. It was concluded that the HA-B is a weakly humified, potentially labile humic constituent stabilized by adsorption to clay. Spectral measurements on low-ash (

Beschreibung: The addition of ammonium salts increased the hydraulic conductivity of samples taken from the Bnt horizon of a Solonetz soil. The improved conductivity was caused by an increase in the salt concentration in the soil solution and by the ammonium adsorbed on the clay particles. Since the dominant clay mineral in this soil type is montmorillonite, purified bentonite was used for comparative studies. Mobility studies of montmorillonite systems indicated that the adsorbed NH4 ions are tightly bound to the clay particles. The size of the NH4-tactoids was found to be larger than that of the Na-tactoids but less than half that of the Ca-tactoids. It was concluded that the beneficial effect of ammonium on water movement in Solonetz soils will be less than that of calcium, but the transformation of the adsorbed ammonium in the field, followed by replacement of sodium by hydrogen, may result in further improvement of these soils.

Beschreibung: Conditional stability constants of some metal fulvate complexes have been determined at 25 C using specific ion electrodes. In aqueous 0.1 M NaNO3, solution, the log K values are: 4.86 and 5.08 at pH 3 and 4 for mercury complexes; 3.04 and 3.64 at pH 4.9 and 5.95 for cadmium complexes; and 3.22, 3.72, and 4.35 at pH 3, 4, and 5 for copper complexes. In 0.04 M NaNO3 solution, the log K value for mercury–fulvic acid system is 5.12 at pH 3.1. The order of metal affinity toward fulvic acid Hg 〉 Cu 〉 Cd is in general agreement with the literature for complexing of these metals with similar type donors.

Beschreibung: Water contents and bulk densities were measured in a soil pedon with a gamma-ray transmission technique utilizing 137Cs and 241Am. By alternating the sources for each scan down the soil profile, both bulk density and water content were determined in 1-cm increments in the top 10 cm of the pedon. Bulk density decreased to a depth of 6 cm about 30 min after 4 cm of water was ponded on the soil surface. As soon as the water drained from the surface, bulk density values increased and approached pre-irrigation levels. Water content increased rapidly corresponding to the decrease in bulk density. Assuming that the bulk density remains constant during ponding, calculated water contents may be in error by as much as 0.25 gcm−3.

Beschreibung: not available

Beschreibung: not available

Beschreibung: not available

Beschreibung: Monocalcium phosphate was broadcast at 0, 50, 100, and 200 kg P/ha to a calcareous soil, very low in NaHCO3-extractable P. Wheat (Triticum aestivum cv. Selkirk) and flax (Linum usitatissimum cv. Marine) were seeded in the 1st yr and barley (Hordeum vulgare cv. Montcalm) and flax were alternated in 3 subsequent yr. Subplot treatments consisted of 0, 5, 10, 20 and 40 kg P/ha applied as monoammonium phosphate with the seed. Wheat and barley responded well to broadcast or seed-drilled P. The latter was the most effective method of application; this was apparent even on plots receiving large amounts of broadcast P. In contrast, flax was not responsive to newly applied P, and yields decreased with application of seed-drilled P in combination with large amounts broadcast. The solubility of P in the untreated soil was between that of octacalcium phosphate (OCP) and hydroxyapatite (HA). The solubility of P in the treated soils was greater than in the untreated soils for the duration of the sampling period (3 yr) and was slightly less than that of OCP for the 50 kg/ha treatments, about that of OCP for the 100 kg P/ha treatment and greater than that of OCP for the 200 kg P/ha treatment. These studies indicate that the reaction product most likely governing the solution concentration of P was OCP.

Beschreibung: not available

Beschreibung: not available

Beschreibung: not available

Beschreibung: Two well-drained soils formed in the subalpine zone of the Washington Cascades from the same complex parent material and environment exhibit contrasting morphologies due to the vegetation. One of the soils, presently unforested, exhibits in its morphology the influence of three ash falls and a complex vegetational history. The horizon sequence and properties fit the Lithic Regosol criteria of the Canadian classification system. The second soil, formed on the same parent materials but under forest vegetation, exhibits properties of an orthic Ferro-Humic Podzol. These pedons exemplify the complex nature of soils whose classification has previously been oversimplified as steep, rocky soils or lithosols.

Beschreibung: Recent surveys in the Canadian subarctic have shown the wide distribution of cryogenic earth-hummock soils with permafrost. A study of chemical, physical, mineralogical and micromorphological features revealed quite acidic, partially unsaturated surface horizons, large amounts of amorphous sesquioxides and fulvic acids, and fluctuating redox conditions. It appears that the permafrost table and the surface organic layer play a governing role in most pedological processes. It is suggested that the occurrence of fires contributes a cyclical aspect to these processes, which appears to be an integral part of soil development in the subarctic. A consideration of fire history helps to explain many of the physical and environmental variations found in the field.

Beschreibung: Greenhouse studies were conducted in which various amounts of phosphorus were added to calcareous and noncalcareous soils, and the iron, manganese, zinc and copper utilization by wheat were determined. Wheat yields were significantly increased by phosphorus fertilization; mean yields on the noncalcareous soils were greater than on the calcareous soils. Plant micro-element concentration and uptake were reduced in many instances when large amounts of phosphorus were applied. Plants grown on the calcareous and noncalcareous soils had similar concentrations of iron, manganese and copper. However, plants grown on the calcareous soils tended to contain lower amounts of zinc than plants grown on the noncalcareous soils. Concentration of micro-elements in soil-water extracts of phosphated soils, particularly for the noncalcareous soils treated with large amounts of phosphorus, tended to be greater than for nonphosphated soils. Yields were usually not affected when phosphorus at 2–100 ppm was added to nutrient solutions. Zinc and copper concentration and uptake were usually greater for plants grown in a 2-ppm phosphorus solution than for plants grown in solutions of higher concentration. In several instances, plant iron concentration and uptake were also reduced by high phosphorus concentration. Manganese uptake appeared not to be affected by phosphorus concentration. Increasing the micro-element concentration of nutrient solutions at various phosphorus concentrations did not affect yields but increased plant micro-element concentration and uptake, indicating that ion antagonism was mainly responsible for the lower utilization of microelements in high phosphorus media.

Beschreibung: Properties of soils along the 3% slope were affected both by water table levels and by the nature of the parent sedimentary rock. All of the soils had upper sola of medium to fine texture, due largely to the disintegration of the underlying shaly gravel. Relatively impermeable shaly bedrock at depths of 1–2 m from the surface maintained generally high water tables. Redox potentials, gley colors and mottling were closely associated with proximity to the surface of the water table. Evidence of podzolisation and of clay weathering and translocation were obscured by the release of bases and clay from the disintegrating gravel. Hydraulic conductivities of the surficial layers were generally much lower than those of the gravelly subsoil layers, but the data were highly variable due to soil variability, seasonal changes in soil structure and problems with methodology. The data suggest that surface ridging might be more effective than tiles for draining soils such as these.

Beschreibung: Thatcher wheat was grown in tank-type lysimeters over a 7-yr period to determine the effect of fertilizer, two levels of available water and two cropping systems on the yield and nutrient content of grain and on some soil nutrients. Fertilizer did not change the yield of grain materially under natural rainfall. Added water only increased the yield by one-half and three-quarters of continuous wheat and fallow, respectively. Fertilizer with added water nearly doubled the yield of continuous wheat and increased by one-third the yield from the wheat-fallow rotation. The P content of the grain was not affected by fertilization, but was higher in the treatments to which additional water was applied than in those receiving natural rainfall only. It was also higher in continuous wheat than in fallow wheat. There was an interaction between the N and P uptake ratio and the N content of the grain. Fertilizer or additional water or both increased or decreased the N content, depending upon which way the N or P balance was shifted. Surplus available N not utilized by the crop grown with natural rainfall accumulated as nitrates at lower soil depths, particularly under the wheat-fallow system. All the NO3-N produced where supplemental water or water and fertilizer were applied was utilized and none accumulated. The organic N content of the surface soil increased along with a reduced loss in organic C where water and fertilizer were applied, as compared to the other treatments. Fertilizer application resulted in a sharp increase in NaHCO3 soluble P, particularly following the supplemental water plus fertilizer treatments where an excess of P was supplied with the fertilizer over that removed by the crop. There was an increased demand on soil P where water only was applied, and the soluble P content was appreciably reduced.

Beschreibung: Brown heart sometimes occurs in rutabagas (Brassica napobrassica Mill.) grown on some southern Ontario soils even though a recommended quantity of B fertilizer has been applied. Fourteen field experiments were conducted on growers' fields over a 4-yr period to determine the cause of this phenomenon. Brown heart occurred when the hot-water-soluble B content of the soil decreased below approximately 1.3 ppm although there were a few exceptions. An application of 4.5 kg B/ha as borax did not completely overcome the brown-heart condition in a majority of the experiments. The B concentration in the third or fourth leaf from the centre of the whorl was not related to brown-heart incidence. However, it was found that a B concentration of less than 18 ppm in the roots was generally associated with brown-heart incidence. Although there was no clear relationship between the Ca/B ratio in the leaf blades and brown-heart incidence, there was an increase in brown-heart incidence as the Ca/B ratio in the roots increased above 170. In three experiments, an application of 224 kg Na/ha as NaCl significantly increased brown-heart incidence, whereas in a fourth experiment there was a significant decrease. There was some evidence that the Na may slightly decrease the B concentration. Also the Ca concentration increased as the Na concentration increased in rutabaga tissues thereby affecting the Ca/B ratio and possibly brown-heart incidence. There was also evidence that, in the root tissues, the Ca/B ratio was inversely related to the K concentration. It was concluded that the effectiveness of B in decreasing brown-heart incidence was related to the Ca concentration in rutabaga plants.

Beschreibung: The adsorption of acid and dimethylamine salts of 2,4-D and dicamba was studied on Canadian prairie soils and various other adsorbents, using slurry-type adsorption experiments. The amount of adsorption of both the acid and dimethylamine forms of the two herbicides was minimal. The results were explained on the basis of dissociation of the acidic and dimethylamine salts to the respective anionic forms in the near-neutral prairie soils. This conclusion was supported by (1) the strong adsorption of these herbicides to the anion-exchange resin but not to the cation-exchange resin; (2) the strong adsorption of the 14C-dimethylamine cation to these soils; and (3) the leaching patterns of the 14C-dimethylamine salts of both herbicides from soils and resins. Only the anionic species were eluted from columns containing soils and cation-exchange resin whereas only the 14C-dimethylamine cation eluted from columns containing anion-exchange resin. Both forms of 2,4-D and dicamba were strongly adsorbed to activated charcoal, cellulose triacetate, and peat. There was little or no adsorption of these herbicides to montmorillonite and kaolinitic clays, cellulose powder, or wheat straw.

Beschreibung: In a series of 11 surface burns in old fields at two locations in southern Ontario the environmental factors having the greatest effect on fire severity were fuel moisture content, windspeed and fuel energy. Other environmental factors were of less significance. Changes in soil chemistry were restricted to the surface litter and were transitory. Changes at mineral soil depths may have gone undetected because of the highly buffered soils involved. As much as 30% of the loss of nutrients from the biomass during burning was recovered in downwind deposits of fly-ash adjacent to the burned areas. Recovery estimates are considered approximate and minimal but indicate the importance of nutrient losses in fly-ash during low temperature burns.

Beschreibung: Ecological studies on soil nematodes, enchytraeids, collembolans and mites in a 1948 Pseudotsuga menziesii plantation at Shawnigan, British Columbia were made from March 1971 to March 1972. The plantation was thinned to 1,900 stems/ha and urea was applied at 0, 224 and 448 kg N/ha just before faunal sampling. Monthly samples were extracted in high-gradient apparatus, Murphy split funnels and simple wet funnels. Fifty-two and 53% of collembolans and mites, respectively, occurred in the top 5.3 cm of the 17.5-cm soil profile studied. The Pearson and Hartley power function test indicated that for intramonth sampling to show statistical significance of treatment, at least 10 samples per treatment would be required for any of the groups under experimental conditions similar to the one reported here. Collembolans and mites exhibited significant downward seasonal distribution, and urea treatment accentuated this phenomenon for all four groups, suggesting that sampling below 6 cm would be required to observe the full impact of urea fertilization on the soil fauna. Except for enchytraeids, seasonal population fluctuation contrasted with the generally observed pattern in temperate regions of spring and fall peaks and showed increases through the spring, culminating in summer and autumn maxima. Urea fertilization increased annual mean population of nematodes by 1.41 and 2.51 times the control for 224 and 448 kg N/ha, respectively, and decreased enchytraeids by 0.52 and 0.28 times the control for the same two fertilizer rates; collembolans and mites were not significantly affected.

Beschreibung: A computer program was written to estimate from sequential data the parameters for a Markov chain probability model. The program was applied to the analysis of field workday probabilities at 10 selected locations across Canada. The suitability of the first-order Markov chain model was tested and the locations across Canada were compared as to the probability and conditional probabilities of workdays. These probabilities estimated by the program also provide data which should be of interest in farm machinery selection.

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Beschreibung: not available

Beschreibung: Yield of white beans increased markedly (250, 1,090 and 1,545 kg/ha) when grown in field plots at soil temperatures of 11.6 (T1), 19.7 (T2), and 29.7 C (T3) (20-cm depth 0830 h). This represents a change in yield of 71.1 kg/ha per 1 C change in the seasonal temperature (T2) of the soil from 23 June to 21 August. The number of degree-day units for the soil (〉 5 C) corresponding to these temperatures (20-cm depth) were 268, 602, and 1,004. A decrease in the Soil Moisture Index (SMI) from 0.69 to 0.10 and an increase from 0.69 to 1.00 lowered yield by 35% and 6%, respectively (T2), for the seasonal temperature. Loss in yield from plants infected with bacterial blight (Xanthomonas phaseoli E.F. Sm. Dows.) by spraying the organism onto leaves of 21-day-old seedlings was negligible. However, loss in yield from plants infected by injecting the organism into stems was 9.0, 43 and 52% for plants grown at cool (T1), seasonal (T2), and warm (T3) soil temperatures, respectively. Percent of pods infected by spraying was increased, whereas percent of pods infected by injection was decreased at the higher soil temperatures. In general under cool seasonal temperatures, protein content of the infected and noninfected beans decreased with higher moisture that coincided with only a small change in yield. The protein content, however, remained fairly constant under large yield increases resulting from higher soil tempratures. The data are interpreted in relation to spread of the disease in fields from seedborne infection and subsequent spread of the disease to adjacent healthy plants.

Beschreibung: The potential application of a computer soil data file to the study of soil concepts is discussed. This method aids the pedologist to analyze, summarize and correlate large quantities of data. For applied objectives the data file allows the prediction of soil properties for interpretive purposes. The computerized soil data file was used to explore its usefulness in studying the concept of the modal profile, confirmation of definitions of the Podzolic and Gleysolic Great Groups, derivation of equations for estimating soil drainage and cation-exchange capacity, and studying some interrelationships among soil properties. Soil parameters used to define soils at the Order and Great Group levels did trend toward normal distributions for Gleysolic but less for Podzolic soils. The prediction equations for cation-exchange capacity accounted for a higher percentage of the variation than did equations for soil drainage. Many soil property interrelationships were confirmed. The study illustrates some of the weaknesses of using routine soil survey data collected over a 10-yr period.

Beschreibung: Soil samples from virgin profiles of Solonetzic and geographically associated Chernozemic series along with Ap horizons of Solonetzic and Chernozemic soils were taken. Soil pH, organic C, oxalate-extractable Al and Fe, inorganic P forms, organic and total P, and extractable P by NH4F + H3SO4 and NaHCO3 methods were determined. On the average, Solonetzic sola had higher contents of oxalate-extractable Al and Fe, Fe-P, and lower levels of Ca-P than do their associated Chernozemic sola. There was not a clear difference in Al-P contents between the sola of the two Orders. Ap samples from Solonetzic soils had twice the amount of NH4F + H2SO4- and NaHCO3-extractable P found in the Chernozemic ones. The higher levels of extractable P in the Solonetzic than in the Chernozemic Ap samples could be explained by the higher contents of Al-P and Fe-P in the former. The high acidity in the upper sola of Solonetzic soils, indicative of intense weathering conditions, apparently has resulted in relatively high contents of oxalate-extractable Al and Fe, and these probably account for the higher levels of Al-P and Fe-P and lower levels of Ca-P in the Solonetzic than in the Chernozemic soils.

Beschreibung: Total Zn and seven measures of extractable Zn in horizons of seven soil profiles declined with increasing depth of sampling within the profile. Although not invariabily found, some extractants removed more Zn from the deepest horizons of some profiles than from the horizon sampled immediately above. This distribution pattern was more pronounced for extractable than total Zn. From 27 horizon samples containing an average of 108 ppm total Zn, 2 N MgCl2, DTPA, North Carolina, Morgan, N KCl, acidic NH4Ac, and 0.01 M CaCl2 extractants solubilized an average of 4.14, 3.77, 3.37, 1.99, 1.82, 1.64, and 0.69 ppm Zn, respectively. Extractable Zn values were positively correlated with total Zn, organic matter, percentage clay, and cation-exchange capacity, but inversely related to soil pH, base saturation, and percentage sand. Zinc concentrations in corn and in oats grown on the horizon samples were best correlated with amounts extracted by 2 N MgCl2, acidic NH4Ac, and N KCl. Regressions on extractable Zn and soil pH accounted for as much as 74 and 55% of variations in Zn content of corn and oats, respectively.

Beschreibung: not available

Beschreibung: Many soil mapping units (MU) have not been adequately sampled to provide a true measure of their variability; therefore, their descriptions must be regarded as incomplete, and valid statistical comparisons cannot be made with other closely related MU. The number of samples required to detect the differences in means of 18 soil properties between Brantford and Beverly Silt Loam MU were calculated and they ranged from 4 at the 80% probability level (10 at the 95% probability level) for organic matter content of the Ap horizon to several thousand for pH of the Ap horizon. Calculation of required sample numbers indicated that sufficient samples had been collected to make valid statistical comparisons between seven of the soil properties. All seven properties were found to be significantly different between the two MU at the 95% probability level. However, only two of the properties, hue and organic matter content of the Ap horizon, had distinctly different modal values between the two MU and neither of these properties is easily measured in the field. Therefore, it was concluded that the 18 soil properties examined were impractical and unreliable criteria for separating the MU in the field. But, the MU separations can be readily and validly made on the basis of landscape position.

Beschreibung: not available

Beschreibung: Lettuce grown in a pot test using the surface soil layer of three golf course sites contaminated with mercurial fungicides contained up to 317 ng Hg/g as compared with no more than 36 ng Hg in plants grown in corresponding deeper soil layers containing much less Hg. In another experiment with 10 crop species, addition of phenylmercuric acetate to a loam soil at the rate of 5,000 ng Hg/g increased the Hg content of several of the species slightly over that found in the controls. The highest amount found was about 440 ng Hg/g in soybean vines and potato tops. The concentration tended to be lower in the edible portion (fruit, grain or roots) than in the remainder of the plants. In an incubation experiment where phenylmercuric acetate was added to seven soils and two clay-sand mixtures at the rate of 5,000 ng Hg/g, the retention of added Hg against volatilization varied from 41% in a sandy subsoil to 97% in a peat. Addition of flowers of sulfur was effective in preventing volatilization of Hg from the soils, but not from the clay-sand mixtures. Subsequent equilibration of the Hg-treated samples in 0.01 M CaCl2 removed only a minimal amount of Hg from one soil, but removed appreciable amounts from the clay–sand mixtures.

Beschreibung: The acid neutralization method and manometric procedures, using several acid-reducing agent combinations, were compared to determine their suitability for carbonate determination in organic soils. The soil–acid reaction observed with the acid neutralization procedure was significantly influenced by the acid concentration and soil type. Mean soil–acid reactions were 0.394 and 0.412 meq/g with the 0.3 and 0.6 M HCl, respectively. Moreover, it ranged from 0.023 to 0.694 meq/g soil for different soil types. The comparison of manometric procedures that were made used different acid-reducing agent combinations of HCl, CCl3COOH, HClO4, and SnCl2, and FeCl2. Of these, the HClO4–SnCl2 combination gave the lowest mean blank reading and standard deviation that remained stable (0.05 ± 0.009 ml). Though the perchloric acid alone is adequate for calcitic determinations, using the SnCl2 reducing agent with longer reaction times is recommended.

Beschreibung: The clay fraction from various horizons of two Podzols sampled in the Appalachian Highlands was analyzed by X-ray diffraction and by a quantitative mineralogical procedure. Different cation saturation and heat treatments made it possible to detect differences in the mineralogical properties of the clays of the Ae horizon, but did not cause appreciable differences in the spectra of B and C horizon samples. In the Ae horizon, the clays were shown to have properties of both vermiculites and smectites. The paragonite-like structure induced by Na-saturation and moderate heat treatment is characteristic of minerals in the early stages of weathering from dioctahedral illites.

Beschreibung: The Ah horizons of a Brown–Dark Brown–Black–Dark Gray–Gray Luvisolic sequence of Canadian grassland and forest soils were studied. Clay-associated humus was present in greater proportions in the grassland than in forest soils, particularly in the grassland soils of the more arid regions. Amounts of alkali-pyrophosphate-extractable humus increased in the Brown to Gray Luvisolic sequence. Alkali-pyrophosphate-extractable humic acid (HA-A) contents were greatest in the Black and Dark Gray soils. C:H ratios, extinction coefficients at 280 nm (E280), and resistance to acid hydrolysis of the HA-A and clay-associated HA-B increased in the Brown to Gray Luvisolic sequence. Free radical concentrations were least for the Brown and Dark Brown soils, moderate for the Black and greatest for the Gray Luvisolic soils. The data suggest an increase in the proportion of aromatic components in the humic acids in going from the Brown to the Gray Luvisolic soils. An objective, multivariate similarity analysis based on 22 humus characteristics showed a relationship between soil zone or soil environment and the nature of the soil's humus.

Beschreibung: not available

Beschreibung: The oxidation-reduction potentials of the upper 50 cm of a waterlogged, floating, Sphagnum peat mat were reduced an average of 47 mv by heavy rainfall, while expected small but insignificant changes occurred in acidity. Changes of this magnitude in redox potential will significantly alter valence states of some ions and may produce concentrations of the reduced forms that will detrimentally affect normal plant development.

Beschreibung: not available

Beschreibung: Nitrogen, supplied as NH4NO3 to timothy (Phleum pratense L.) and bromegrass (Bromus inermis L.) or as N derived from alfalfa (Medicago sativa L.) growing in association with timothy, enhanced the utilization of surface applications of pelleted, 32P-labelled calcium phosphate. The proportion of the P in timothy derived from a single application of 60 kg P/ha increased from a range of 16% to 21% without N to a range of 38% to 43% with an application of 60 kg N/ha before spring growth and repeated after the first and second harvests. At the first two harvests, growing timothy in association with alfalfa further increased the proportion. The increase was greater at the second harvest and at the lower rates of N, amounting to an increase of one-third at applications of 15 and 30 kg N/ha. The proportion of P in the first harvest of bromegrass which was derived from a surface application was increased 17% to 26% as the rate of P was increased from 40 to 120 kg P/ha; however, N fertilizer as NH4NO3 increased fertilizer P utilization from 17% to 32% as the rate of N was increased from zero to 120 kg N/ha at the 40 kg P/ha rate, and from 26% to 57% with increasing N at the 120 kg P/ha rate. Similar data were obtained when the rates of N application were repeated for the second and third harvests. A relationship, developed between the N concentration in the grass species and the percent utilization of fertilizer P, would suggest that enhancement in utilization of P was, in part, the result of an increase in the assimilated N in the plant. The experiments illustrate that it is imperative to provide adequate N for efficient utilization of surface-applied P by perennial forage grasses.

Beschreibung: Subjecting barley at four stages of development to short-term periods of 2–7 days flooding of a Gleizolic soil reduced the dry weight of the plants from that of non-flooded plants in proportion to the duration of flooding. Barley 14 days old at flooding was injured more than barley 35 days old at flooding, although the injury was more permanent with the older plants. Delayed head emergence and up to 55% reduction in grain yields were measured. Eh values of 289 mv, or less, were measured below the 5-cm depth although there was no flooding-induced increase in the concentration of water-soluble or exchangeable Mn in the soil. The concentration of Mn in the barley was not altered by flooding. Short-term flooding reduced the concentration of N, P and K in the barley. The greatest decrease was measured in the youngest plants; at the end of 7 days' flooding the concentration of N, P and K was reduced by 51, 60 and 58%, respectively. Two wk after drainage, N, P and K levels in the youngest plants recovered to levels equal to non-flooded barley, whereas more mature plants were subject to continued depressed levels. Under the conditions of this experiment, the reduced growth and yield of barley resulting from short-term flooding was not due to Mn toxicity, but may be due to reduced ion uptake resulting from O2 deficiency brought about by the reducing conditions in the soil or other unknown factors.

Beschreibung: The status of native and applied selenium (Se) in various soils and plants was assessed while the level of phosphorus (P) and humic compounds varied in the growth medium. The addition of 1.5 ppm of selenite-Se was found adequate to maintain a suitable Se content in alfalfa plants grown on a loam and a clay soil. Under greenhouse conditions, the lasting effect of the treatment would extend much beyond a 15-mo period of cropping. Although the incorporation of fulvic acid (FA) into the soil increased the water-soluble fraction of total Se, FA had a depressing effect on the Se content of the alfalfa plants. The effect of P addition on the uptake of native Se by alfalfa and corn plants was generally positive; for lettuce, however, P reduced the uptake markedly. The water-soluble Se was found to be of doubtful value as an index of Se availability for Se-deficient soils; but it was a useful criterion for assessing the behavior of Se applied to soil. Se in soils was closely assocated with organic matter and/or with organic matter-iron complexes; this association influenced the behavior of Se in the root zone, and its uptake by plants. It was concluded that, in the temperate eastern zone of North America, Se addition to Se-deficient soils would be a practical method of correcting Se deficiency. Se adequacy in plants grown on certain soils could be obtained through ordinary fertilization; but it is necessary, for a better control of Se in plants and soils, to clarify further the interactions of Se with P, organic matter, and other soil constituents.

Beschreibung: not available

Beschreibung: The survival and decomposing ability of the four dominant fungi found in low-temperature decomposing leaf litter was studied over a 46-mo period, at temperatures ranging from 1 C to room temperature. A Rhizoctonia sp. by itself and in association with the three other fungi disappeared. When alone it brought about no decomposition. Over the temperature range a Penicillium sp. that appeared to be a member of the Penicillium terrestre series showed strong survival properties in association with the other fungi, and by itself decomposed about the same amount of litter as the natural microbial flora of the unaltered litter, indicating that under natural conditions and at temperatures above 1 C this fungus is an important colonizer and decomposer of organic matter. Mucor spinescens alone and in association survived at room temperature and 10 C, but was absent at 4 and 1 C. By itself it decomposed a small amount of litter. The most abundant species, Chrysosporium pannorum (50% of all isolates at cold temperatures), a cellulolytic fungus, was not able to survive in litter in the absence of the other fungi. In their presence, it not only survived but increased in number as temperature decreased. The facts that pH changes and litter extract did not affect its growth suggest that C. pannorum does not possess the ability to be a pioneer colonist, and it is only after associated fungi begin the initial breakdown and perhaps supply easily available energy sources or growth factors that C. pannorum is able to take part in the decomposition process and survive. Thus, as temperature decreases, there is perhaps less competition for this cold-tolerant fungus, and its role in the decomposition process increases.

Beschreibung: Samples of 10 Organic soils, 1 with a humic surface layer and 9 with mesic surface layers, but representing a wide range of Humisol and Mesisol soil profiles, all of the euic reaction class, were collected for growth room fertilizer trials and subsampled for chemical analyses. Reed canary grass responded markedly to N, P and K applications on all soils, but to lime only on the humic surface layer which had the lowest extractable-Ca value. Soil-nutrient sufficiencies based on dry matter yields ranged between 6 and 44% for N, between 4 and 24% for P, and between 10 and 17% for K. Sufficiencies based on nutrient uptake ranged between 4 and 31% for N, between 1 and 13% for P, and between 3 and 21% for K. Correlations between N response measurements and degree of soil decomposition, as measured by bulk density, Na4P2O7-extractable organic matter, and water holding capacity, gave the highest significant [Formula: see text] values which averaged 0.86, 0.82 and −0.63, respectively. Linear regression equations show an increasing dependence of dry matter yield on soil bulk density with successive cuts for the treatment that received only P and K fertilizer. Bulk density would therefore be a good indicator for N requirement of Organic soils. Rubbed fibre (volume basis) was also negatively correlated with N response measurements (r = 0.77, [Formula: see text]) when the data for the humic surface layer were omitted and when all cuts were considered. Irreversibly dried granules in this layer adversely affected fibre determinations. Extractable P and K values were correlated positively, though not all were significant, with certain yield response measurements. Since reed canary grass grown on all soils responded to applications of P and K, the extractable P and K values were considered to be in the deficiency range and would serve as a basis for evaluating field situations.

Beschreibung: Continuous cropping of eight Manitoba soils to alfalfa in the greenhouse decreased the exchangeable potassium of the soils to low equilibrium levels. Non-exchangeable potassium was removed from the soils by the alfalfa. The rate of decrease of exchangeable potassium and the quantity of non-exchangeable potassium mobilized was significantly influenced by the addition of ammonium nitrate or urea to the soils. However, there were no significant differences between the soils treated with ammonium nitrate and those treated with urea. There was considerable variation among soils in the rate of decrease of exchangeable potassium and the quantity of non-exchangeable potassium mobilized. The total yield of soil potassium was related to the initial exchangeable potassium levels of the soils. Addition of NH4NO3 increased the percentage of total N in the plant material harvested prior to the eighth harvest. After this eighth harvest the added nitrogen had no effect on the nitrogen content of the harvested material. In general, fine-textured soils yielded more plant material and total potassium, and maintained a higher level of exchangeable potassium than coarse-textured soils.

Beschreibung: not available

Beschreibung: Deficiency of N could be an important limitation to the establishment of sugar maple (Acer saccharum Marsh.) on former agricultural soils. Consequently a study of the seasonal pattern in N and C mineralization was conducted with calcareous soils from four similar segments of a land unit that supported maple woodlot, old field, red pine (Pinus resinosa Ait.), planted old field, and pasture, respectively. Net N mineralized was determined after incubation in situ; rate of C mineralization was measured in situ; and both net N and C mineralized were determined after incubation (perfusion) in the laboratory. All soils showed marked seasonal variation in both their content of exchangeable ionic N and the rate at which N was mineralized. The results from in situ and laboratory determinations were similar. Maxima in May-June and in September were separated by a minimum in July. Winter minima occurred in November and late April. The direction of seasonal change was little affected by short-term changes in temperature and soil moisture, and appeared to be explicable as a response to phenological changes in the vegetation. The rate at which C was mineralized in situ reached a maximum in late July and minima in May and September; it was closely correlated with soil temperature (P = 0.001). In the laboratory the rate reached a maximum in June, and a minimum in July, followed by a slow recovery thereafter until the end of November. Both in situ and in the laboratory, N was mineralized most rapidly from the maple woodlot soil. While there were large differences among soils in the rate at which N was mineralized, there were only small differences in the rate of C mineralization. Thus, per unit of C mineralized, the net amounts of N mineralized in the laboratory from pine stand, pasture, and old-field soils were only 0.29, 0.27, and 0.22, respectively, of the amount mineralized from maple woodlot soil; comparable figures from in situ measurement were 0.24, 0.59, and 0.30. These results indicate that a diminished rate of mineralization of N on former agricultural soils vis-à-vis that on uncleared forest soils is associated with little diminution in their level of biological activity. Forest trees grown on such soils can, therefore, be expected to suffer a degree of N deficiency.

Beschreibung: Laboratory procedures for estimating plant-available Al and Mn in soils were compared on 33 Canadian surface soils having a pH range of 3.65 to 4.98 (measured in 0.01 M CaCl2). Barley, rapeseed and buckwheat were grown on the soils in the greenhouse, and correlation coefficients were calculated between laboratory soil measurements and the percent yields (yield unlimed × 100/yield limed) of barley, Al contents of rapeseed, and Mn contents of rapeseed and buckwheat. The quantities of soil Al soluble in 0.01 M and 0.02 M CaCl2 were highly correlated with the Al contents of rapeseed and percent yields of barley. Levels of soil Mn soluble in the same reagents were highly correlated with the Mn contents of rapeseed and buckwheat. The CaCl2-soluble Al was better correlated with the crop data than was exchangeable Al (2 N NaCl). The CaCl2-soluble Mn was better correlated with the crop data than was 0.1 N H3PO4-soluble, H2O-soluble, reducible or exchangeable Mn. The following method is recommended for determining plant-available Al and Mn in acid soils: Shake the soil at a 1:2 (w/v) ratio with 0.01 M CaCl2 for 5 min and measure Al and Mn in the supernatant solution by atomic absorption spectrophotometry.

Beschreibung: Twenty-two samples of till representing Ck horizons of soils with very similar morphologies were investigated in west-central Alberta in order to determine the validity for their separation into four separate soil series on the basis of parent material characteristics. Physical, chemical and mineralogical analyses were conducted in order to characterize the tills and determine differences in their lithology, texture and geochemistry. The data were statistically evaluated using Duncan's new multiple range test. The data indicate that the four tills investigated are statistically separable on the basis of their analytical differences. The Lobley till is characterized by a higher limestone content and higher calcium carbonate equivalent than the other three tills. Amphibole minerals and high grade metamorphic and igneous pebbles were absent in the Lobley till. A greater quantity of total sand, coarse sand and amphiboles permits the separation of the Cooking Lake till from the other three tills. The Hubalta and Breton tills were found to be somewhat similar in many of their characteristics. However, the Breton till is coarser in texture and contains a greater montmorillonitic component in the clay fraction.

Beschreibung: Two barley (Hordeum vulgare L.) cultivars, Charlottetown 80 and Herta, were grown on plots of Tormentine sandy loam soil which had been limed to a range of pH levels (4.8, 5.1, 5.8, 6.6 and 7.1) for 10 years previous to this experiment. The pH areas were subdivided for a factorial arrangement of N fertilizer at 30, 60, 90 and 120 kg/ha with P-K fertilizer at 10–19, 30–56, 59–112 and 88–168 kg/ha. Yield of each cultivar increased when the soil pH was increased from 4.8 to 5.8. The Charlottetown cultivar exceeded Herta in yield at the low pH levels. The greatest response from N fertilizer was at the 60 and 90 kg rate in combination with P-K at 59–112 and 88–168 kg per ha, for the mean of the two cultivars. Percent N in barley tissue varied with pH and decreased with increasing rate of P-K fertilization. Percent total N and protein nitrogen in barley grain increased as pH increased. Percent P and K in tissue also increased as the pH increased. In vitro digestibility of barley grain was not affected by P-K, but decreased slightly as N fertility increased.

Beschreibung: Most of the 14C measurements reported here were made between October 1972 and October 1973. Equipment, measurement, and treatment of samples are the same as reported previously (R, 1968, v 10, p 36–37; 1970, v 12, p 534).

Beschreibung: The radiocarbon dating facility is part of the UM Geochronology laboratory housed in the Department of Geology, University of Miami, Main Campus. The laboratory was established to carry out and support research in Pleistocene marine geology, particularly in the Caribbean, and to act as a specialized teaching facility of geochronologic research using radiometric age dating techniques.

Beschreibung: A radiocarbon facility has been installed at the University of California, Riverside (UCR) to support interdisciplinary studies including archaeologic, archaeometric, geophysical, and geologic research. The laboratory was built between 1970 and 1973. Initially, a sample pretreatment and combustion system designed for a proportional CO2 counting system was installed. It was designed after concepts developed at the University of California Los Angeles (UCLA) and New Zealand (Institute of Nuclear Sciences) Laboratories, and began processing samples in November 1972.

Beschreibung: The following list of dates contains all measurements made during 1973, ie, since our last list (R, 1973, v 15, p 451–468). We have installed this year a Nuclear Enterprises NIM system to be used with our 2.5L Oeschger-type proportional counter (Philips), in addition to our 6L and 1L proportional counters which have worked consistently with Beckman Lowbeta electronics. The Philips counter has been calibrated relative to the Beckman electronics and we are now calibrating it relative to the NIM system.

Beschreibung: The following list includes samples dated in 1973. Benzene is used as the carrier of natural 14C activity as previously described (Punning et al, 1973). We used both 1-channel and 2-channel scintillation devices. The detector shield comprises 10cm lead. Around the detector we put 16 Geiger-Mueller type counters in anticoincidence circuit with output signals from detector. It decreased the average background ca 20 to 40%.

Beschreibung: Measurements have continued with the same proportional counter system, pretreatment procedure, methane preparation and measurement, and calculation using a half-life of 5568 ± 30 years, as described previously (R, 1970, v 12, p 298–318). Uncertainties quoted are single standard deviations originating from standard, sample, background counting rates and half-life. No 13C/12C ratios were measured.

Beschreibung: The dating equipment and operating conditions remain essentially as previously described. All samples are from Ireland unless specified.

Beschreibung: This date list includes most of the archaeologic and geologic samples dated in this laboratory since publication of our last date list (R, v 13, p 367–381), as well as some samples dated previously, which lacked adequate sample information. Known-age samples are reported in Univ of Pennsylvania Radiocarbon Dates XVI, this issue. The bp ages are based on ad 1950, and have been calculated with the half-life value of 5568 yr. All samples were counted at least twice for periods of not less than 1000 min each. Errors quoted for each sample are derived from the measurement of the sample, the background, and several counts of our mid- 19th century standard Oak sample, but do not include the half-life error. All samples were pretreated with 3N HCL, and some, where noted, were given additional pretreatment with 2% NaOH for the removal of possible humic acid contaminants.

Beschreibung: On two previous occasions we have published lists of 14C results of precisely dated wood samples in Radiocarbon as per mil deviations (R, 1965, v 7, p 179–186; R, 1969, v 11, no. 2, p 469–481). We have also published a list of 14C dates, consolidating all dated wood samples processed in our lab to July 1969 (Ralph and Michael, 1970).

Beschreibung: In September 1970, the laboratory moved into new premises on the ground floor of a new building. The measuring room is constructed of low radioactive limestone concrete and is lined with grounded copper plate. Air conditioning insures a working temperature of 20 ± 1°C and a relative humidity of 40%.

Beschreibung: The Radioisotopes Laboratory was established in January 1972, in order to supply radiocarbon measurements of various samples to several institutions. Active analyses commenced in June following the testing and evaluation of equipment and known samples for accuracy and reproducibility. During this time, data was accumulated for the statistical establishment of counting accuracy, particularly for background activity.

Beschreibung: 14C dates listed in this report on geochemical, geologic, and archaeologic samples were obtained mainly from the beginning of 1971 to the middle of 1973. Techniques of measurement used are the same as described previously (Yang, 1972). Sample descriptions and comments for archaeologic samples were prepared in collaboration with collectors and submitters. For age calculation, 95% activity of NBS oxalic acid is used as the modern standard and the value of 5568 ± 40 years is used for the half-life of 14C. Dates are expressed in years bp (before ad 1950). The error (1σ) quoted is calculated from the uncertainty involved in counting background, NBS oxalic acid standard, and sample.

Beschreibung: Radiocarbon measurements, mainly on soil and water samples are being continued. Benzene samples are prepared as described earlier (Scharpenseel and Pietig, 1969; 1970). Radioactivity is measured in a single quartz vial, and also with 13 specially manufactured, low background Teflon/Duraluminium vials, similar to the system described by Polach (1971, pers commun).

Beschreibung: The following list of dates is of archaeologic samples submitted in 1971–2, using the counting equipment described in R, 1971, v 13, p 468. Ages are quoted with a 1σ counting error which includes statistical variation of the sample, background, and standard count. The reference year is ad 1950 and 0.95% NBS oxalic acid for 14C dating is the standard. The half-life used is 5570 years.

Beschreibung: The following date list consists of samples prepared mainly during 1970 and 1971. Some old measurements, not included in previous lists are added. Ages reported here are calculated using the conventional half-life of 14C: 5568 years and NBS oxalic acid as recent standard.

Beschreibung: The 14C dates given below are continued from our previous list (R, 1972, v 14, p 223–238), and results obtained mainly during 1971–2 are described. A 2.7L stainless steel counter and a 3.3L copper counter are used as previously, yielding background counting rates of 6.9 and 6.0 cpm, respectively, when filled with dead CO2 at ca 1.8 atm. Dates have been calculated on the basis of the 14C half-life of 5568 yr and 95% of NBS oxalic acid is modern standard. No correction has been made for any of the samples in this list.

Beschreibung: This list includes results of measurements made from 1969 to 1972 in the Natural Radiocarbon Laboratory of the Centre de Recherches Radiogéologiques de Nancy (CRR).

Beschreibung: Most of the 14C measurements reported here were made between August 1970 and August 1972. Chemical treatment of samples and counting technique remain as described previously (R, 1968, v 10, p 144–148; 1971, v 13, p 97–102). We have added Houtermans-Oeschger type multi-anode anticoincidence gas proportional counter, manufactured by Tokyo Atomic, Japan. The central counter tube, which has several small holes, 5mm diam, is made of aluminized polyethylene foil, 0.06mm thick, with 72mm inside diam and 300mm sensitive length. The external counter tube is made of stainless steel 4mm thick, with 93mm inside diam and 350mm length. The anode wires of both counters are also made of stainless steel 0.05mm diam. The counters are surrounded by a paraffin shield 50mm thick and encased in a 250mm shield of steel on all sides. Acetylene is used as the counting gas at 753.3mm Hg (22 ± 1°C). Counting rates of background and 95% activity of NBS oxalic acid standard were 1.25 ± 0.02cpm and 14.39 ± 0.12cpm, respectively.

Beschreibung: The SMU Radiocarbon Laboratory is operated by the Department of Geological Sciences within the Institute for the Study of Earth and Man. One laboratory room contains the benzene synthesis system where samples are pretreated and converted to CO2 in a standard way and gas is purified after the procedures of Broecker (1957) by passage through hot CuO, 10% AgNO3 solution, chromic acid, hot copper, and P2O5 via cryogenic pumping with liquid nitrogen. Purified CO2 is then converted to Li2C2 which is hydrolized to C2H2 and converted to C6H6 catalytically following the procedures of Noakes et al (1966). Carbon dioxide and benzene yields are routinely in excess of 90% in both cases.

Beschreibung: This date list was compiled by the Institute of Geological Sciences (UK) incorporating data supplied under contract by E Welin, Radioactive Dating Laboratory, Stockholm. Unless otherwise stated, age figures are in 14C years before ad 1950. The half-life of 14C is taken as 5568 years and the error, based on counting statistics of sample, background, and modern, is given as one standard deviation. Correction for 13C/12C fractionation has been made.

Beschreibung: The Dublin radiocarbon dating laboratory was operational in 1958 to 1960 and the scintillation counter system used at that time has previously been described (Delaney and McAulay, 1959). The system is now operational again and has been modified to date samples after conversion to benzene. The electronic equipment differs from that previously used only insofar as more compact and drift-free transistorized units are now employed. With these modifications, considerable improvements in sensitivity and accuracy are obtained. 5ml benzene, diluted with a commercial toluene based scintillant is used in a 12.5ml silica cell for the detection of 14C disintegrations. The background count-rate varies inversely with the barometric pressure (ca 2.6% cm–1Hg). The background is ca 3.4cpm, and the detection efficiency is ca 60% and excludes the tritium spectrum.

Beschreibung: This list comprises age measurements carried out from October 1972 to July 1973. Samples dated are all of archaeologic interest and come from Italian territory. Pretreatment of samples, production of purest CO2 and counting techniques have been described elsewhere (Azzi, 1972; Azzi et al, 1973).

Beschreibung: The Organisation of Egyptian Antiquities believes that Egypt should play an important role in current international research in the field of radiocarbon dating of archaeologic samples. Thus, such a laboratory was established within the Center of Research and Conservation of Antiquities, CRCA, Cairo.