Evaluating Planter Speed, Vacuum Pressure, and Seed Plate Effects On Plant Stand in Single Row Peanut.

Inadequate plant stand can greatly reduce yield and profitability of peanut seeded in a single row pattern.   Vacuum planters have increased the precision of seed placement but a poor plant stand is still possible if the equipment is not used optimally.  Planter speed, vacuum pressure, and hole-to-hole spacing on the seed plate are all factors that may affect seed placement and the resultant plant stand within a field.  Because of this, we designed an experiment to determine which of these factors play a significant role in determining plant stand and at what planter speed, vacuum pressure, and hole-to-hole spacing are plant stands adversely affected.  The trials took place in Tifton, GA and Plains, GA in 2010 and in Plains, GA and Attapulgus, GA in 2011.  Three gear settings (Low 2, Low 3, Low 4) were used in combination with two RPM settings (1700, 2000), resulting in six planting speeds (3.2, 3.9, 4.5, 5.1, 6.0, 6.6 KPH).  Two vacuum settings (138, 165 kPa) and two seed plates (40 hole, 48 hole) were also used to determine their effect on plant stand.  In three of four site-years, emergent plant stand decreased as ground speed of the tractor increased, with an average stand loss of 19.6% when planting in Low 4 gear versus Low 2.  In two of four site-years, as vacuum pressure increased, plant stand likewise increased, with an average gain of 12.3% at 165 kPa versus 138 kPa.  In one site-year plant stand increased as hole-to-hole spacing on the seed plate increased, resulting in 11.6% greater emergence when using a 40 hole versus a 48 hole plate.  All other site-years showed no significant difference between hole-to-hole spacing.   As the optimum window for peanut planting is time-limited, producers may be tempted to increase planter speed or utilize seed plates with reduced space between holes.  These results, however, highlight the effect that these variables can have on plant stand and potentially the resultant yield and profitability.