Soybean Scene - May 28

May 28

Here’s our soybean field. Things have changed, haven’t they? The crabgrass is nearly all gone and if you look closely you can see soybean seedlings that have emerged in rows. We need to look a little closer.

Here are three seedlings in various stages of emergence. The lower- left seedling’s cotyledons are starting to split apart; the top seedling’s cotyledons have separated; the middle seedling’s cotyledons have separated and we can see the next leaves that will unfold. You are probably wondering how important those two cotyledons are to the seedling, aren’t you? Well, the cotyledons’ function is to provide nutrients and food reserves for the seedling as new leaves develop, which means cotyledons are storage organs that are functional for about ten days. If both cotyledons are lost at this stage yields will be reduced by about 8 %. If one cotyledon is lost there is little or no yield reduction. So, I think these cotyledons are rather important for seedling development.

The upper-left seedling has the next leaves readily visible. (These leaves are called the unifoliolate leaves and we’ll get a better look at them as they unfold in a few days.) This area or part of the plant is called the epicotyl and it contains the growing point for the whole plant.

skips in rows where no plants have emerged

This is one thing that really bugs farmers .... skips in the row where no plants have emerged. You can see some seedlings on the left and right of the picture, but there’s about 36 inches between plants. Farmers don’t like this because they know that yields can be slightly reduced with large skips in the row and this gives weeds an opportunity to grow.