The bottleneck in the turnover of soil organic matter (SOM) is the conversion of large molecular compounds into smaller compounds that can be transported through a cell membrane of a microbe for processing. Once inside the cell, organic compounds can be converted into biomass or be respired. The microbial depolymerization...
Nitrification and denitrification are major biological processes transforming nitrogen (N) in soils to plant available N, highly leachable nitrate (NO₃⁻) and gaseous N oxides. Although many studies in the past have studied N cycling communities, the effect of increased N inputs on ammonia-oxidizer and denitrifier population dynamics is still under...
The principles of continuum mechanics provide a consistent
framework for the derivation of mathematical statements describing
transport of water and solute, and growth in plant tissue. These
derivations are based upon the explicit consideration of the tissue as
a mathematical continuum composed of a cell wall matrix, water, and
solute...
Field experiments were established in 1982 and 1983 on a Woodburn silt loam soil (Aquultic Argixeroll) to examine the effect of S fertilizer on dinitrogen fixation and dry matter yield of 10 week-old seedling alfalfa (Medicago sativa L. cv. 'Apollo'). Six levels of S fertilizer (0 to 67.2 kg S/ha)...
The influence of atmospheric humidity on three aspects of sporulation of
Sphaerotheca pannosa (Wallr.) Lev. var. rosae Wor., which causes rose powdery
mildew, was studied on leaf disks of susceptible Rosa cultivar Samantha.
To study conidiophore production, leaf disks were inoculated on the adaxial
(upper) surface with conidia of S....
The abundance of algal species and their parasites
was monitored weekly for two years in a sewage lagoon
at the Corvallis Airport, Oregon. During the cooler
months, Euglena species were dominant followed by a
Chlamydomonas assemblage in the spring and a
predominantly Scenedesmus assemblage in the summer and
fall. Parasites...
Fusarium spp. frequent conifer nursery soils yet are rarely recovered from coniferous forest soils. Experiments were performed to determine what influence humic-rich organic amendments and volatiles from soil, ectomycorrhizal fungi and ectomycorrhizae have on the populations of several physiologic and taxonomic microbial groups potentially related to this phenomenon. A comparative...
Growth of individual goosegrass (Eleusine indica (L) Gaertn.) plants of
three dinitroaniline-herbicide resistant (R) and three susceptible (S) biotypes from
North Carolina, South Carolina, and Mississippi was analyzed in greenhouse
experiments. Leaf area and biomass measurements, including root, shoot,
above-ground, and total dry weights were similar among the biotypes studied....