Seeding Rate and Row Width Recommendations for Ohio Soybeans.

As soybean seed costs increase, there is a need to re-evaluate seeding rate recommendations.  Previously established seeding rate recommendations do not account for new plant varieties, improving cultural practices, and precision planting equipment.  Based on survey data, farmers in Ohio plant on average 172,000 seeds per acre. The objectives of this research are to 1.)  evaluate soybean seeding rate in on-farm strip trials, and 2.) evaluate the effect of row width and seeding rate in small-plot research trials  The on-farm strip trials consisted of 4-5 seeding rates ranging from 60,000 to 235,000 seeds/acre with 3 to 4 replications of treatments. There were five on-farm strip trials conducted in 2014 in Fulton and Darke County, Ohio. The experimental design for the small-plot research was a split-plot, randomized complete block with four replications of treatments.  The main plot factor was row width and the subplot factor was seeding rate.  Soybean stand counts were conducted shortly after planting and just prior to harvest.  A quadratic model was fit to the yield data and indicated that 90% relative yield was achieved when there were 101,900 soybean plants/acre at harvest.  Preliminary results indicate that farmers in Ohio are planting more soybeans that necessary to maximize yield.