Oklahoma State University

Contact Info

Josh Lofton, Assistant Professor
Cropping Systems Specialist
Oklahoma State University
376 AG Hall
Stillwater, OK 74078
Phone: 405-744-3389
FAX Number: 405-744-0354






Page Title

Soybean Planting Rate Test



Rick Kochenower, Panhandle Research and Extension Center, Goodwell; Ron Sholar, Dept. of Plant and Soil Sciences. Soybean Research at OSU 1999. p. 21. OSU/DASNR/OAES/OCES. P-976

Soybeans are a new crop of increasing interest from producers in the Oklahoma panhandle. Previous soybean research concentrated mostly on variety selection through variety trials at Oklahoma Panhandle Research and Extension Center (OPREC) Goodwell, OK. Research was started in 1999 to determine optimum planting rate for irrigated soybeans for the region. Plots were 5 feet by 20 feet long planted with a wheat drill on June 1, 1999 at selected seeding rates (Table 1).Asgrow AG4602RR, a Roundup Ready variety was selected for planting. Plots were harvested on October 14, with a Massey-Ferguson 8 plot combine to determine yield. Target populations, yield in bushels per acre, number of seeds per acre planted, and seed cost associated with planting rate are listed in (Table 1).

Table 12. Irrigated Soybean Planting Rate Test, OPREC, Goodwell, OK, 1999.

Target Population Plants/acre Yield bu/acrecre Seeds/acre Seed Cost Planted $/acre
100,000 54.3 125,000 16.79
125,000 52.8 156,250 20.98
150,000 55.5 187,500 25.19
175,000 51.4 218,750 29.38
200,000 52.1 250,000 33.57
225,000 53.6 281,250 37.76
250,000 50.9 312,500 41.95

The results of the first year of study show that a target population of 100,000 plants/acre produced a yield that was comparable to a target population of 250,000 plants/acre. No difference in yields existed between any of the seeding rates. Oklahoma State University generally recommends a seeding rate of 140,000 - 160,000 seeds/acre to insure an optimum plant population. Results of this research indicates this seeding rate is adequate for the panhandle. More research will be conducted at OPREC to evaluate proper planting rates for optimum yields.




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