Record Details
Soil physical conditions and nitrogen fixation of soybeans (Glycine max. Merrill, var. Chippewa 64)
ScholarsArchive at Oregon State University
| Field | Value |
|---|---|
| Title | Soil physical conditions and nitrogen fixation of soybeans (Glycine max. Merrill, var. Chippewa 64) |
| Names |
Kuo, Tsungmin
(creator) Boersma, L. (advisor) |
| Date Issued | 1969-08-25 (iso8601) |
| Note | Graduation date: 1970 |
| Abstract | The effect of soil water suction and soil temperature on rates of transpiration, photosynthesis, respiration and nitrogen fixation of soybean (Glycine max. Merrill, var. Chippewa 64) seedlings was studied. A special apparatus was developed in which the soil water suction of several cells with soybeans growing in them could be maintained independently at a selected temperature. Transpiration was determined by a constant-water level device which recorded the amount of water used over a period of time. Photosynthesis and respiration were measured using an infra-red gas analyzer. The total nitrogen content of plants was measured by the micro-Kjeldahl method at the beginning and end of a ten-day experimental period. Leaf surface areas were determined with an air flow planimeter. In general with increasing soil temperature rates of transpiration, photosynthesis, and nitrogen fixation increased slowly at first and then rapidly until a certain optimum range was reached and decreased at higher temperatures. Maximum rates occurred around soil temperatures, of 30, 27 and 27°C, respectively. The rate of respiration also increased with increasing soil temperature until an optimum range around 27°C was reached and then dropped rapidly as the soil temperature further increased. Rates of photosynthesis, respiration, transpiration and N-fixation decreased steadily with increasing soil water suction. The decrease in the rate of these metabolic processes with increased soil water suction was attributed to effects of changes in viscosity and root cell permeability, stomatal movement and translocation of metabolic substrates. At low soil temperatures the dry matter accumulation seemed to be controlled by the water supply. At higher than optimum soil temperatures the dry dry matter accumulation was very sensitive-to temperature changes and less soil water dependent. When the nitrogen supply from the soil is limiting, the nitrogen fixation may possibly be a most important factor in the metabolic processes and thus the growth of leguminous plants. It is obvious that for such a plant, soil water availability, soil temperature and nodule rhyzobium organism-plant relationships are important. |
| Genre | Thesis/Dissertation |
| Topic | Soybean |
| Identifier | http://hdl.handle.net/1957/46207 |
