Soil dilution plate counts on selective media for bacteria, streptomycetes, and fungi were made at intervals before and after two prescribed burns on 10—acre jack pine tracts. Carbon dioxide determinations were also made. These tracts were compared with similar tracts cut and unburned and uncut and unburned. Three—year results are given. The number and activity of most microorganisms decreased immediately after fire but rose abruptly to a very high level after the first rainfall following burning. This increase is believed caused by the leaching of ash minerals. Depth and extent of the effects were influenced by intensity of fire and moisture conditions. Number and activity of organisms were generally lower in burned soil the second growing season after fire. Some effects were still noticeable the third growing season. Streptomycete populations were greatly increased the third growing season. Rainfall also caused a fluctuation of microbial populations on the unburned tracts.

Although microorganisms are often considered to be omnivorous and biochemically omnipotent, they seem unable to destroy at significant rates many synthetic chemicals that enter soil. This unexplained microbial fallibility recently has assumed prominence because of the long persistence of a variety of pesticides. With at least certain compounds, the chemical, physiological, or environmental basis of the biological failings can be established, as illustrated with substituted phenols and phenoxy herbicides. Microorganisms may detoxify pesticide-treated soil by metabolizing or degrading the added substance. The microflora may also be responsible for the generation of a toxic condition in soil by activation of the applied pest-control agent. The use of laboratory precedents as guides in investigations of natural transformations is considered, and instances of pesticide metabolism in soil are cited.

The effect of native and applied organic matter (straw) on sulfate reduction under anaerobic conditions in arid-zone soils was studied in the laboratory. Changes in the composition of dissolved and adsorbed ions as a consequence of SO₄ reduction was also studied. The results indicate that SO₄-reducing microorganisms are generally present in arid-zone soils. Appreciable reduction of any SO₄ present does not occur when arid-zone soils become anaerobic by waterlogging, however, unless undecomposed organic matter (plant residue) is present or the soil organic matter content is high (e.g., > 5%). Sulfate reduction results in the formation of equivalent amounts of carbonates which, upon reaction with soluble or exchangeable Ca and precipitation as CaCO₃, cause decreases in soil salinity and increases in the exchangeable sodium percentage.

Changes in the pH and in concentrations of ammonia, NO₂⁻, NO₃⁻, and K⁺ with distance from layers of decomposing leguminous plant material in Red Bay sandy loam soil were measured after 16 days' incubation. High concentrations of ammonia (2.7 meq/100 g) and of K⁺ (1.4 meq/100 g) were found near the plant material layer. Nitrification was inhibited and NO₂⁻ was found in this zone. Farther away, NO₃⁻ accumulated. A change in pH from 8.9, near the layer, to 5.6, about 4 cm away, was observed. Treatment with CaCO₃ decreased the pH range and increased nitrification. When the decomposing plant material layer was separated from the soil on one side by an air space, NH₃ diffused across the air space. This resulted in segregation of some of the NH₃ from the cations and other potentially toxic substances and lowered the overall toxicity to nitrification. Besides the toxicity observed, the availability of plant nutrients as well as growth of microorganisms and plant roots could be drastically affected by pH and cation concentration changes found near layers of decomposing plant material.

Biochemistry of the Amino Acids, Second Edition, Volume II focuses on the trends in research on amino acids and biochemistry. Given considerations are incorporation of amino acids into proteins, amino acid sequences, and discovery of amino acids. The first part of the book deals with intermediary metabolism of amino acids. Particularly noted are alanine, aspartic, adenylosuccinic, hydroxyaspartic acids, and asparagine. The book also has discussions on glutamic acid, glutamine, glycine, serine, and sarcosine. The processes and syntheses involved in these acids are noted. Another part of the book focuses on the formation, degradation, reactions, and conversion of acids. The processes and experiments discussed are supported by numerical analysis, and the biosynthesis of acids in microorganisms is also considered. The book also notes some disorders of amino acid metabolism in humans. These disorders include cystinuria, glycinuria, ammonemia, prolinemia, maple syrup urine disease, and homocystinuria. Discussions focus on how these diseases develop and the symptoms associated with them. The book is a vital source of data for readers interested in the study of amino acids. Annotation Published: January 2015.