We got two threads going on the SAYA drills. We have a 505 thread and a 507 thread. I forgot about this.....and have posted what I think is an improvement at the 507 thread. What I did was to fashion an assembly that will drop the seeds from the rear box BEHIND the double disc openers.....which is how Great Plains small seed box is configured. Most people are happy with the GP drills ....so this is an inexpensive means to use their method.......or alternately use the current method of dropping these small seeds in the slot provided by the openers. Your choice.
I have not yet put seed down with this suggestion......but I will in a week or two. From my perspective.....I think this will be a great solution to burying those little seeds too deep. Last fall I seeded some small seeds all in the same trench with the front seed box. I did not get great germination from these small seeds as I feel they are buried too deep.
A point I will make is.....why would you have two seed boxes if you were going to put all the seed in the same (deep) trench??? Makes no sense to me. I think I have a good and affordable solution.
EDIT: The below is from an Article by Penn State that is posted in another thread.....and it confirms what I am trying to say here.
Drill Adjustment to Ensure Consistent Plant Establishment
Depth should be checked several times, especially when beginning the planting operation until proper depth is achieved, and then periodically during seeding. When operating in no-till conditions, depth adjustments may need to be made as amounts of residues from previous crops change across the field. Be careful not to plant small-seeded species--particularly small-seeded legumes--too deep, especially during the spring, in cold soils. Seeding depth should be roughly 3.5 times seed diameter. Use no more down pressure on the drill and closing wheels than necessary to provide consistent seed-to-soil contact. Too much down pressure, especially in wet soils, provides a very poor environment for emerging seedlings. Pay particular attention to the drive wheel, if it is not also a transport wheel, to ensure that it continuously rides on the soil surface to ensure consistent seed metering.
Drill Performance
Many drills with a small seed box have tubes that drop the seed behind the double disk openers, just before the press wheel. In some cases this may mean a significant portion of seed is not in close contact with the soil. Some farmers have found it beneficial to run a cultipacker through the field after drilling to increase seed-to-soil contact. Drill wear also needs to be taken into consideration when calibrating the drill. When changing the opening setting on older drills, not all openings may be affected in the same manner. If this becomes extreme, the drill may be in need of maintenance.
Prepared by Sjoerd W. Duiker, Ronald J. Hoover, and Joel C. Myers.