Issue No. 4, Article 7/April 17, 2009
Soybean Variety Selection
April brings the excitement and anxiety of planting at the start of a whole new crop year. So far, April '09 has brought below-average temperatures and above-average rainfall for most of Illinois. So if soggy soil has you inside, here are some thoughts to remember throughout the spring regarding what soybean varieties to plant.
It's likely you decided what to plant for all or most of your acres during the winter months. However, you might need to purchase a final few bags, or you may develop additional need for soybean seed as the spring progresses. If so, don't rush your final variety selections under the pressure of "I want to finish planting." Selecting appropriate genetics is always the first and best way to increase your yield and profits. This is particularly true with your soybean crop because maximum yields can be achieved from a wider planting timeline than with corn. Historically, maximum soybean yields can be achieved for planting dates between the third week of April and the third week of May, with the first two weeks of May being the likely best time. I will elaborate more on planting date studies in an upcoming article, but the point today is this: Continue to take the necessary time to select varieties with the appropriate maturity, soybean cyst nematode resistance, disease resistance, and overall agronomic characteristics to match the needs of your fields and farming operation.
In addition to getting details from your local seed supplier, utilize the yield and lodging information generated by the University of Illinois Variety Testing program. If you don't find the soybean varieties you use on your farm, nominate a variety to be tested in the future. Additional variety information, including SCN resistance data and disease ratings, is provided by the Varietal Information Program for Soybeans, funded by the Illinois Soybean Association. Yield data for all varieties and testing locations in 2008 ranged in bushels per acre from 39.9 to 73.2 (maturity group II), 45.9 to 73.6 (group III), and 54.3 to 77.4 (group IV). Proper seed selection, then, can easily have implications of 25 to 30 bushels an acre. These are also wider ranges in yield than are typically observed for soybean planting date experiments until planting dates extend into late June. A few good hours selecting the right seed is worth more than a few good hours planting a variety resulting from a poor or hasty choice.
Please remember one final and important guideline throughout the planting season. Your grain bin full of Roundup Ready soybean seeds from last fall's harvest is not a last-minute seed supply. The legal contract you signed when you bought the parent seeds of that harvest does not become void because you need a few more bags in a hurry. Besides, those seeds will be uncleaned and untreated and will have an unknown germination rate, making using them a questionable and risky agronomic practice.--Vince M. Davis