In order to properly utilize organic amendments as nitrogen sources, reliable methods
to estimate plant-available nitrogen (PAN) are needed. The objectives of this study
were to (1) evaluate the use of crop and soil responses in fertilizer N equivalence
(FNE) calculations, (2) examine the relationships between the C/N ratio, total...
The effect of different soil moisture levels on the amount and
location of NO₃ -N accumulation in the soil profile were studied.
The cultivars used in this study were Mcdermid, a soft white
winter wheat, and Hudson, a medium early winter barley.
Moisture treatments simulating dry, normal and wet fallow...
The effects of different fallow moisture levels and tillage
systems on the amount of nitrate-nitrogen accumulation in the 0-30 cm
soil profile were studied.
Fallow moisture treatments simulating typical dry, normal and
wet precipitation cycles were established on trial plots.
Data were obtained for nitrate-nitrogen, soil moisture and
nitrogen mineralization...
A mechanistic simulation model of nitrogen fixation in dead wood was developed to help synthesize knowledge, develop hypotheses, and estimate rates of nitrogen fixation in the Pacific Northwest. In this model nitrogen fixation is directly controlled by log substrate, temperature, moisture, and oxygen content. Respiration and diffusion of
oxygen indirectly...
A study was made to evaluate the effect of different rates of N
fertilization on Nugaines wheat. The variable N treatments provided
different N regimes as a basis for evaluating potential diagnostic
tests for assessing the N status of the wheat plant. The crop was
grown in Lane county during...
Although legumes have been widely studied for their nitrogen-fixing ability, it is uncertain to what extent legume cover crops achieve their nitrogen-fixing potential under the climatic conditions encountered in western Oregon. Furthermore, it is unknown what factors control the proportions of legume cover crop N that are either sequestered into...
A better understanding of grass seed crop and soil fertility is necessary to
improve fertilizer practices and preserving water quality in Willamette Valley,
Oregon, where 55% of land-use is in grass seed production that directly impacts
adjacent waterways containing native protected fish species. I determined tillage
effects on soil N...
Effects of different tillage systems on nitrate-nitrogen
accumulation in a 120 cm profile and on soil structure in the top 30 cm
of the profile were studied under a fallow-wheat rotation.
Treatment effects on nitrate-nitrogen, soil moisture and soil
aggregation were measured.
Fallow tillage treatments consisting of bare fallow, stubble-mulch...
