EFFECTS OF SEEDING TREATMENT AND SOIL MOISTURE CONTENT ON THE EMERGENCE OF LETTUCE
Lettuce seeds (Lactuca sativa L. ’Boston Dark Green’) were sown by fluid drill and as dry seed into soils at 25%, 50%, 75% and 100% field capacity (FC). Fluid drilling reduced the time to initial emergence and 50% emergence at soil moisture levels between 50% and 100% FC. At 25% FC, neither seeding method performed well with fluid drilled seed being entrapped inside the carrier gel after it had dehydrated. After 2 wk, no significant difference in final percent emergence was noted between seeding treatments at any soil moisture level. In a second experiment, fluid drilled lettuce seeds emerged earlier and reached 50% emergence sooner than dry seed, germinated seed sown without gel and dry-seed in gel at 40%, 50% and 75% FC. Gel-seeded treatments were not significantly affected by soil moisture whereas the emergence of seeding treatments without gel application was markedly improved as soil moisture content increased. After 2 wk, the percent emergence of dry seeded lettuce at 40% FC was significantly lower than the other seeding treatments. No differences were noted among treatments at 50% FC whereas at 75% FC, the emergence of dry seed in gel was significantly reduced.Key words: Lettuce, fluid drilling