FIELD SLOPE EFFECTS ON UNIFORMITY OF CORN SEED SPACING FOR THREE PRECISION PLANTER METERING SYSTEMS

The effects of field slope on planter seed spacing uniformity were evaluated for three different seed metering units (cell plate, finger pick‐up, and flat plate) operating with medium round corn seed in a laboratory using the University of Nebraska planter test stand with an opto‐electronic seed spacing sensor system. The metering units included a John Deere MaxEmerge™ Plus VacuMeter row unit with the standard cell corn plate, a John Deere MaxEmerge™ Plus VacuMeter row unit with the flat plate, and a John Deere MaxEmerge™ Plus row unit with the finger pick‐up metering system. Planter seed spacing uniformity was measured using three parameters: ISO Miss index, ISO Multiples index, and Coefficient of Precision (CP3). Six replications for nine field slope treatments were conducted for each metering unit. The field slope treatments included: front‐up (front of planter unit), front‐down, right‐up (right side of planter unit), and left‐up (left side of the planter unit) each at field slope levels of 10% and 20%, and level. Slope and travel pattern had significant effects on the seed spacing uniformity for each of the three metering units tested. The finger pick‐up was the least affected by slope as only the treatment of front‐up at 20% slope had significantly worse seed spacing uniformity than the level treatment. For the cell plate metering unit, seed spacing uniformity was best with the planter on a level surface, or with the uphill‐downhill travel pattern on a 10% slope, and on a 20% slope the uphill‐downhill travel pattern had better seed spacing uniformity than the on‐the‐contour travel pattern. The finger pick‐up metering unit had equally good seed spacing uniformity on a level surface and with either travel pattern on the 10% slope. On a 20% slope, the finger pick‐up metering unit had better seed spacing uniformity with the on‐the‐contour travel pattern than with the uphill‐downhill travel pattern. The flat plate metering unit had its best seed spacing uniformity with the front up on a 10% slope, followed by equivalent seed spacing uniformity between right up on a 10% slope and on a level surface. The flat plate metering unit had equivalent seed spacing uniformity between the travel patterns on a 10% slope, while on a 20% slope the uphill‐downhill travel pattern had better seed spacing uniformity than the on‐the‐contour travel pattern