Browse on keywords: organic matter microbial activity
Search results on 10/15/18
7095. Vandecaveye, S.C. and B.R. Villanueva. 1934. Morphological relationships of soil microbes.. J. Bacteriology 27:257-269.
Looked at microbial groups active in a soil with annual application of 12 T/ac manure for 27 yr, with annual winter wheat vs. soil with no fertilizer and wheat-fallow for 27 yr. Manured soil had a marked increase in numbers of both authochthonous and zymogenic organisms. Soil amendments in the lab elicited different CO2 responses that were not consistent with the bacterial numbers.
7112. Vandecaveye, S.C. and G.O. Baker. 1938. Microbial activities in soil. III. Activity of speicific groups of microbes in different soils.. Soil Sci. 45:315-333.
Studied different decomposition of different plant materials in a soil from western WA and eastern WA. Native microflora was distinct for the two soils. Palouse soil (4.4% OM) had about 5 times as many microbes as Melbourne soil (8.1% OM), with more bacteria and actinomycetes than fungi in the Palouse. Studied decomposition of wheat straw and sweetclover residue. Rate of CO2 evolution and NO3 accumulation was not proportional to microbial population. Soils became slightly more acid with time. A small decrease in total N occurred in all samples, not due to ammonia.
7121. Vandecaveye, S.C. and H. Katznelson. 1940. Microbial activity in soil. VI. Microbial numbers and nature of organic matter in various genetic soil types.. Soil Sci. 50:295-311.
Attempted to correlate microbial activity with variations in the amount and chemical composition of the soil humus. Larger bacterial populations corresponded broadly with the greater rate of nitrification in, and the narrower carbon-nitrogen ratios of the humified organic matter and organic matter fractions of, the grassland soils. Under the experimental conditions, the majority of the soils supported a larger microbial population in the B rather than the A horizon.
7131. Vandecaveye, S.C. and H. Katznelson. 1938. Microbial activities in soil. V. Microbial activity and organic matter transformations in Palouse and Helmer soils.. Soil Sci. 46:139-167.
Treated each soil with residue from the other and measured microbial changes. Larger amounts of nitrate N accumulated in the Palouse soils than in the Helmer soils. The ammonia N content of the soils decreased rapidly as their nitrate content increased, and this was associated with a gradual decrease in pH.
7141. Vandecaveye, S.C. and H. Katznelson. 1938. Microbial activities in soil. IV. Microflora of different zonal soil types developed under similar climatic conditions.. Soil Sci. 46:57-73.
Studied virgin areas with Palouse and Helmer soils over time. Measured microbial levels, pH, redox potential, and soil moisture. Microbial peaks were in spring (April) and late fall. Numbers of microbes decreased sharply with depth. Helmer soil had smallest total microbial population, smallest number of bacteria, largest number of fungi. Weight of dry roots in top 10" soil was 7 T/ac (grass) for Palouse and 4.7 T/ac (forest) Helmer. For plant residue, Helmer received about 1.4 T/ac/yr, Palouse about 0.7 T/ac/yr.
7151. Vandecaveye, S.C. and M.C. Allen. 1935. Microbial activities in soil. II. Activity of specific groups of microbes in relation to organic matter transformation in Palouse silt loam.. Soil Sci. 40:331-343.
Studied decomposition of wheat straw with and without N fertilizer. Bacteria were fastest to respond to amendments. Activity of cellulose decomposers and Azotobacter were never large.