A few weeks ago, I thought double-crop soybean planting would be delayed (in Virginia) due to a late wheat crop. However, the wheat seems to have caught up in most areas. So, we’re right on track to producing another good soybean crop. Virginia data estimates that every delay in planting past mid-June will cost you about 1/2 bushel per acre.
Using future prices (approximately $12/bushel), this translates into about $6 loss per day. The exact date when yield drops rapidly from delayed planting cannot be predicted; some years this may be June 10 and others this could be July 10. Yet, on average, the date is in the second or third week of June. Therefore, be sure that the planter is following close behind the combine.
Also, our data indicates that we need, on average of 180,000 plants per acre to economically maximize yield. Yes, this is double what is needed for full-season production, but it will usually pay. Note that I stated, “on average”, however. Like most things, averages rarely reflect the season. If we have plenty of rainfall early in the year that stimulates vegetative growth, then we won’t need as many plants.
Likewise, if you’re growing soybean on a field that consistently averages 50-60 bushels (rarely experiences severe water stress during the vegetative stages), then less seed is required. But, if you have poor vegetative growth followed by relative good conditions during pod and seed development, more plants will maximize yield. I can’t predict the season; therefore I use the average response. If you need more information, contact me.
What if soil moisture is lacking? My philosophy is to plant into moisture. By June and July, the soil is warm, therefore you can plant deeper to reach moisture and get adequate emergence. But, don’t plant deeper than 2 inches; I prefer 1 to 1.5 inches. Although many disagree with me, I don’t recommend planting into dry soils and waiting for a rain. Why? I don’t often see a entire field that is completely dry unless it is a tilled field. I’m not saying this is not possible; wheat and barley can extract nearly all of the moisture from the soil.
But, dry fields usually contain some wetter areas. And these wetter areas will sometimes contain enough moisture to germinate the seed but not enough for it to emerge. This results in re-planting, which can be expensive. Still, the soybean seed will usually wait for a rain; so planting into dry soils is an option, especially if you have large acreages.