Have questions on what soybean population to plant this year, given the potential for poorer seed quality and lower germination percentage? The chart below shows plants per acre based on various potential germination rates. Dr. Dunphy, Extension Soybean Specialist at N.C. State University, considers 75,000, 90,000. or 100,000 an adequate stand for maintaining yield when planted in May, June, or July respectively.
To adjust planting rate for a lower germination percentage, divide the seeds/acre at the current germination percent (in any column) by the seeds/acre typically used to get the adjustment factor to multiply with the planting rate usually used. Or increase the planting rate usually used by the percentage indicated by the two digits after the decimal in your adjustment factor. For example, 120,000/105,882 = 1.13 adjustment factor, or increase the usual rate by 13%, because there may be 75% germination this year instead of the typical 85%.
2016 N.C. Farmers Preferences on Planting Seed with Lower Germination
Recently, the NCSPA conducted a survey among growers about the impact of the tight seed supply on their variety selections. The survey asked farmers if it would impact the harvest of other crops if they cannot obtain seed for MG 6 or 7 soybeans in 2016 and they opt to plant an earlier maturity group (MG 5 or earlier).
- 78% responded they would experience low impact to no more than moderate impact, with 43% saying they would have the lowest level of impact.
The survey also asked farmers if they would prefer adjusting planting rates to planting an earlier maturity group if they were offered MG 6 or 7 soybeans AND the germination was specified at 65% to 70%.
- 63% of farmers said they would prefer to adjust planting rates.
- 37% said they would prefer planting an earlier maturity group.