Soybean Seeding Rate Effect on Yield, Agronomic and
Quality Traits in Northeastern
Bryan Hanson, North
Dakota State University
� Langdon Research
Soybeans seeding rate studies were embedded in the Roundup
Ready Soybean variety trials at Devils
Lake, Cavalier and Park
River, ND.� The number of seeding rates at each location
was determined by the number of entries needed to fill a square lattice experimental
plot design for the trial.� Target plant
populations ranged from 100,000 to 250,000 pure live seeds/acre in 25,000
increments.� All locations had adequate
nitrogen and phosphorus levels and granular inoculum was also applied.� The plots were 3.5 x 16 feet in length and
the row spacing was six inches.� Planting
and harvest dates and previous crop are given in Table 1.� ��The
variety used was NK Brand S00-J4 with 00.4 maturity grouping.
The summer was much colder than normal with above average
precipitation.� A light frost occurred
across the region on August 20.� No major
frost damage was noted in any of the trials.�
The first killing frost occurred on October 1.� The variety S00-J4 matured before the killing
frost at all locations.
Plant heights average from 23 to 25 inches across the three
locations (Fig. 1).� Differences within
each location were greatest at Park River
where the 250,000 seeding rate had the shortest height.�� Days to mature ranged from 116 to 118 with
the greatest difference occurring at Park
River (Fig. 2). ��Oil percentages for the seeding rates were
very similar to one another (Fig. 3).�
Only the Park River
location had significant differences in oil levels with the 225,000 seeding
having the highest percentage.� Protein
levels generally decreased with increasing seeding rates (Fig. 4).� This was more evident at the Devils
Lake and Park
River locations.� Difference is test weight were generally less
than 0.5 lbs/bu at all locations (Fig. 5)�� Yield levels at all locations peaked at
either 200,000 or 225,000 pls/a (Fig. 6).� The 100,000 seeding rate, when average across
all locations, yielded three bushels less then the next highest seeding
rate.� A seven bushel yield difference
occurred between the 100,000 and 200,000 seeding rate at Cavalier.
Table 1.� Soybean planting, harvest dates and previous
Figure 1.� Soybean
seeding rate effects on plant height, 2004.
Figure 2.� Soybean
seeding rate effect on days to mature, 2004.
Figure 3.� Soybeans
seeding rate effect on percent oil, 2004.
Figure 4.� Soybean
seeding rate effect on percent protein, 2004.
Figure 5.� Soybean
seeding rate effect on test weight, 2004.
Figure 6.� Soybean
seeding rate effect on yield, 2004.