inches tall and leaning slightly to one side due to wind damage. Under these

conditions thinning with the electronic thinner was far from satisfactory. It

was observed again that tall plants are almost impossible to thin properly and

that failures can occur when inclement weather delays thinning too long. A

comparison of plant spacing was made using a John Deere plateless seeder and an

International Harvester 400 cyclone seeder. The cyclone seeder was adjusted to

give a 2.5-inch seed spacing in the row at a 2 mph planting speed. The plateless

seeder was adjusted to give a 3.5-inch seed spacing at a 1.5 mph planting speed.

This was the closest distance permitted by this planter with the sprockets avail-

able. Thinning was performed at a 1.2 mph travel rate and a 1500 rpm tractor

engine speed. Table 3 gives the data for the 4 tests.

Table 3. Number of EES 279 corn plants in 30-foot plots planted with the plate-
 less and cyclone planters and thinned with the John Deere electronic
 thinner.

 Plateless Cyclone
 Before thinning 90 99*
 Doubles before thinning 8 15*

 Test 1
 After thinning 38 40
 Doubles after thinning 2.5 3

 Test 2
 After thinning 33 33
 Doubles after thinning 2.5 2.6

 Test 3
 After thinning 32 34
 Doubles after thinning 2.5 3

 Test 4 1/
 After thinning 42 41
 Doubles after thinning 2.5 2.5

 / After adjusting delayed action mechanism.
 Significant at 0.05 level.


 For the intent of these tests, the plateless and the cyclone seeders are

excellent planters and no major differences were noted in the final stand of

EES 279 corn plants using either planter.