Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/18/1998
Publication Date: N/A
Technical Abstract: Traditionally, it has been assumed that liquid water transport via seed- soil contact is the most important component of imbibition. Theoretically, liquid water is not necessary. Water vapor in equilibrium with soil as dry as 1 MPa is sufficient to germinate wheat seed. We compared the length of time required to germinate seed in contact with soil versus seed separated from soil by fiberglass cloth, which prevented liquid water from contacting the seed but allowed vapor movement. We examined germination under soil matric potentials from 0.8 to 0.1 MPa and temperatures between 3 and 28C. Germination of seed in contact with soil preceded that of seed without soil contact by less than 1 day. This demonstrates that vapor alone is nearly as effective as vapor plus soil contact. Decreasing emphasis on seed-soil contact in seeding equipment design may allow for improvements in other features. Designs which control vapor loss from the seed zone should produce good germination even without compaction of soil around the seed.