Replanting Soybeans

Soybean emergence has less than desirable in some areas of fields. Wetter areas or soils with higher clay content and cool conditions have been responsible for thin stands. Much of the replanting going on at this point is the no-brainer type of decision,if there are no plants there is no yield potential. Areas that have stands become somewhat questionable as to whether we patch in or take what we have.

Generally if we have 75,000 plants per acre we can expect near maximum yields. For a 30 inch row we need 5 plants per foot of row, 15 inch rows we need 3 plants per foot, 10 inch rows need 2 plants per foot and 7 inch rows 1 plant per foot to meet this threshold plant number. These type of stands will not suffer yield losses, but weed control maybe more of a challenge which will be a problem for most fields this year given the calendar date and sizes of plants.

Stand of less than 50,000 start to loss 5-7 bushels per acre. While this loss is real it is also a given teat soybeans planted in mid June to early July will not have as great a yield potential as earlier planting dates. So likely the decision to replant even stands at 50,000 is a wash economically.

A couple of good references on the soybean replant decision can be found from Iowa State University and Purdue University for further reading.