Arguments for 1 foot row spacing: I would like to make the case for one foot rows and then for equal spacing of the seeds in the row. There have been many experiments to determine just how the row spacing affects the yield for wheat, barley, canola and other grains. It was found that row spacing can be increased to 14, 15 inches before the yield is adversely affected. There are many advantages to keep the row spacing as big as possible:
- More room to put the wheels of the implement without trampling the crop. With one foot spacing we could have an 8-inch tire, with 2 inch side clearance.
- Better ability to cope with trash with the seeder; the wider the row the easier the trash slips through.
- Less soil disturbance with seeding
- Easier to lock onto rows with a need for less accuracy required for GPS +/- 6” After making a turn in the headland, the tractor needs to hit the next pass before it can visually lock onto to the row of good plants. The wider the row, the easier it is to hit the right spot after the turn.
- Better chance for weed removal, with less chance for removing the good plants
- Fewer openers are needed for the seeder. This is important as the openers become more sophisticated and expensive.
So we want the row spacing to be as large as possible, but less than 15 inches, so I will suggest that a one-foot spacing is a good compromise. It happens to be the same spacing as current air seeders.
Arguments for consistent spacing within row. OK so we have settled on one foot spacing between rows; but what about spacing the seeds evenly in the row itself. Current seeders just let the seeds fall randomly down the chute. Let’s say we have set the seeding rate to have spacing of 2 inches. There will be seeds in the row that are touching each other all the way to over 4 inches; with an overall average of 2 inches. Why is this so bad? Because, to have the highest yielding crop, one must give each seed access to the maximum resources of water, nutrients and sunlight. We don’t want the plants competing with each other for these resources. This competition is mitigated by having as much distance as possible from its neighbor – that is with equal spacing. So, why aren’t seeders made such that there will be equal spacing? Because such seeders are more complicated. It is not that easy to plant the seeds with precise spacing. Is it worth it to have such a complicated seeder? I think so, for the following reasons:
- The crop should produce a higher yield if the resources are shared evenly.
- We would need less seed to produce the same density of crop. I would guess that maybe 10% of the seed could be saved.
- Anything that grows in the 2 inch spacing, not in the grid, would be considered a weed, and if we got really good at weed removal, we could even remove weeds that are in the row, between the good plants.
- When the plants are used for positioning, the 2” grid would provide a tighter more reliable lock.
- Inputs such as fertilizer and water could be applied in the row with precision as to not affect the good plants.
To plant seeds evenly in a row, a special seeder is needed, as will be explained in the next section – the sowing machine.