ALBERT

Beschreibung: The aim of this investigation was to suggest a mechanism whereby the basic ferric sulfates, which occur in acid sulfate soils as a result of the microbial oxidation of pyrite in the original sedimentary parent material, can be microbiologically transformed back to pyrite when the soils are flooded. Three basic ferric sulfates were tested and it was found that in the presence of lactate and Desulfovibrio desulfuricans, 10 g of each mineral were reduced within 12 wk to mackinawite (FeS). Additional incubation, to a total of 33 wk, resulted in no further sulfidation. However, in the presence of elemental sulfur, the sulfidation process resumed and mackinawite was soon transformed into greigite (Fe3S4) and then, following an aging process of increased temperature and pressure, pyrite (FeS2) was produced. Under simulated flooding conditions of sea water and decomposing seaweed, the sulfates were converted to a black X-ray amorphous sulfide which is known to change to mackinawite and/or greigite. The ability of H2S-oxidizing bacteria to form elemental sulfur in sedimentary pyrite-forming systems is reviewed and interpreted as a factor in producing the necessary sulfur. Basic aluminum sulfates were stable to microbial reduction. The X-ray pattern for ammoniojarosite was refined.

Beschreibung: Eight soils in Manitoba, varying in texture, Great Soil Group and Subgroup, and amount of clay movement were analyzed for concentration of HNO3 + HClO4-extractable Zn, Fe, Al and Mn and percent sand, silt and clay. Soils were categorized into three textural groups, coarse, medium to fine and very fine. Statistical analyses were conducted to investigate the inherent associations between concentration of native Zn and concentrations of Fe, Al and Mn as well as sand, silt and clay contents for each textural group independently. Native soil Zn concentration was highly correlated with HNO3 + HClO4-extractable concentrations of Fe (r = 0.80, 0.89 and 0.90 for coarse, medium to fine and very fine-textured soils, respectively) and Al (r = 0.68, 0.79 and 0.81 for coarse, medium to fine and very fine-textured soils, respectively) and with clay content (r = 0.69, 0.64 and 0.82 for coarse, medium to fine and very fine-textured soils, respectively). Significant correlation between Zn concentration and clay content likely resulted from Fe and Al oxides coatings on silicate clays and from a large proportion of free Fe and Al oxides being clay-size. Correlation between Zn and Mn concentration was not significant for medium to fine and very fine-textured soils and was significant at only 5% level for coarse-textured soils. Large quantities of Zn (45–71% of HNO3 + HClO4-extractable Zn) were extracted along with the amorphous and organic complexed Fe and Al from four other Manitoba soils indicating, once again, that Zn was in some manner associated with oxides of Fe and Al in Manitoba soils.

Beschreibung: The effluents and ochreous deposits in several partly blocked field drains in Ontario were microbiologically and chemically assayed. The effluents contained several million per milliliter of the iron-oxidizing bacterium Gallionella. Sphaerotilus, a sheath-forming bacterium, was also numerous. Both microorganisms were generally encrusted with amorphous ferric iron oxides. They were also found in the ochreous deposits inside the tiles and also in the deposits adjacent to plugged filters surrounding the tiles. The iron-oxidizing bacterium Thiobacillus ferrooxidans was not found. Filamentous structures resembling the iron-oxidizing bacterium Metallogenium were frequently observed but the experimental evidence indicated them to be aggregates of colloidal Fe(OH)3. Calcite, dolomite, quartz and feldspar were common constituents of the effluents and the ochreous deposits. In some cases, one or more of gypsum, plagioclase, chlorite and illite were present. The ochreous deposits were generally high in iron and contained elements normally found in soil. Occasionally the materials were found to contain traces of magnetite. Except for the iron in the silicates the remaining iron was non-crystalline, present as amorphous ferric oxyhydroxide. Amorphous manganese oxide was also found. It was recognized that chemical oxidation might be an important agent in oxidizing the FE+2; however, the results and a literature survey indicated that Gallionella plays a major role. It is theorized that following oxidation, a ferric hydroxide sol is produced, which in the presence of electrolytes forms aggregates of colloidal Fe(OH)3 that combine with microbes and ions in the tile water to produce an amorphous precipitate. In association with carbonates, quartz and clay minerals, the precipitate forms ochreous substances. The paucity of dissolved ferrous and ferric iron, the presence of organic matter and adsorbed anions inhibits crystallization of the amorphous ferric oxyhydroxide. Roots in conjunction with large numbers of Sphaerotilus formed effective plugs.

Beschreibung: A computerized soil information system has been established in Canada as a tool for making more efficient use of soil information. Its purpose is to characterize and quantify soil and land units, as a basis for providing decision makers with a better appreciation of the actual environment and the relationships between man and the land. The system is both national and provincial, consists of a collection of individual but mutually related, computer-oriented files, and handles site specific, geographic and evaluative data.

Beschreibung: The presence of magnesium-bearing calcites in secondary carbonate accumulation layers of soils is shown to be associated with soluble Mg++/Ca++ ratios of one or greater in the attendant or underlying layers. The dissolution of both calcite and dolomite within the solum and the precipitation of only calcite in the developing Cca leads to a buildup of Mg++ in the soil solution. If leaching depth is considerably below the Cca horizon, the secondary calcite is Mg free. If leaching is restricted to relatively shallow depths (2–4 m), the buildup of soluble salts and the increased soluble Mg++/Ca++ ratio which result are conducive to the precipitation of Mg-bearing calcites. Soluble salt distribution within a glacial till landscape suggests that surface runoff waters and snow accumulation in depressions are more important aspects of water distribution in such landscapes than is lateral movement within the soil itself. The accumulation of soluble salts in the 2 to 4-m zone of upland soils and the complete lack of salts to greater depths in depressions ties in well with the presence or absence of Mg-bearing calcites. The implications of the nature of the carbonates to soil salinization processes are indicated.

Beschreibung: Deep plowing was evaluated in the field and simulated in a greenhouse study in an attempt to isolate soil factors responsible for yield effects on a Duagh Solonetz soil. Generally, fertilization provided a more significant yield response than deep plowing in the field or horizon mixing in the greenhouse. In the field, however, deep plowing in combination with fertilization produced an additional 542 kg/ha of alfalfa-bromegrass forage over fertilization alone [Formula: see text]. Also, in fertilized greenhouse treatments, retaining the A horizon on the surface while mixing sub-horizons proved significantly beneficial over mixing all three horizons [Formula: see text]. The main factor responsible for yield effects appeared to be the Ca enrichment of surface and B horizon areas. An increase in the Ca:Na ratio improved water intake rates and reduced water-logging of the soil, thereby providing a more suitable medium for root development and a more efficient use of indigenous and applied N.

Beschreibung: not available

Beschreibung: A computer program that estimates changes in soil moisture was used to calculate fall soil moisture contents and possible deep drainage. Generally good agreement was obtained between the calculated and measured total moisture contents under continuous wheat and grass after each of four and six growing seasons, respectively. Estimates of soil moisture storage and deep drainage under summer fallow showed discrepancies because unsaturated moisture flow was not included in the model. However, a comparison of actual field and estimated moisture data indicated that in two of five growing seasons, 3.7–7.5 cm of water could have been lost from the root zone of fallowed land because of deep drainage.

Beschreibung: Paraquat (1,1′-dimethyl-4,4′-bipyridinium dichloride) and linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea] were applied to an organic soil, as spray treatments, at rates of 1.12 and 2.24 kg/ha, and 2.24 and 4.48 kg/ha, respectively. The persistence of the herbicides and their residues in lettuce (foliage), onions (root), and carrots (foliage and root) at harvest time were studied under field conditions. Proportionately more residues persisted in the soil from the higher rates of application of paraquat (2.24 kg/ha) and linuron (4.48 kg/ha). About 83–86% of the initial amounts of paraquat and 59–74% of the linuron remained in the soil 4 mo after application. Furthermore, about 50% of the paraquat was recovered from the treated soil 15 mo after application, whereas only about 20% of the linuron was recovered at the end of the same period. Carrots grown in this soil did not absorb detectable (〉0.005 ppm) amounts of linuron, while onions and lettuce grown 12 mo after application absorbed the herbicide in various amounts. At the lower rate of application (2.24 kg/ha) linuron residue in onions was 0.014 ppm and that from the higher application rate (4.48 kg/ha) was 0.046 ppm. Lettuce had about 0.009 ppm residue, irrespective of the rate of application. Onions and lettuce grown on paraquat-treated soil had low residue levels (0.001–0.011 ppm). The study demonstrates the potential of paraquat and linuron residues to persist in organic soil, and their uptake by vegetable crops.

Beschreibung: Barley was grown for 2 yr on Charlottetown fine sandy loam with various methods of application of fertilizers made from two nutrient source combinations. Grain yields were generally higher when fertilizer was placed 5 cm to the side of, and 5 cm below, the seed than when fertilizer was broadcast or drilled with the seed. Yields were higher with drilled than with broadcast fertilizer, except when urea and diammonium phosphate were used as N and P sources. High yields were obtained when P was drilled with the seed and N and K broadcast. Throughout the growing season, the uptake of P was lower from broadcast than from drilled or placed fertilizer. Low yields with broadcast fertilizer were attributed to the low availability of P. When N was broadcast and P drilled, yields were similar for broadcast and drilled K, although the uptake of K was lower when K was broadcast. Yield reduction where fertilizers containing urea and diammonium phosphate were drilled with the seed was attributed to damage from ammonia released by urea and diammonium phosphate.