Question: I plant soybeans after corn that was grown with a covering of manure, 100# urea and 200# starter. I do not fertilize them and have been satisfied with the results. Would putting fertilizer in the row when planting soybeans be a good idea? If so, what kind and how much?
Answer: Soybeans are big users of potash and use a fair amount of phosphorus. Crop removal rates for soybeans can give you some indication of fertilizer needs; however, soil testing is very important. A 50 bu/a soybean crop removes 72.5 lb K20 which is equal to 121 lbs potash (0-0-60) per acre. A 50 bu/a soybean crop removes 42.5 lb P2O5 which is equal to 82 lbs of MAP (11-52-0). These values are just crop removal rates and do not take into consideration soil test values. The best thing to do is pull some soil samples and determine if your levels are low, medium or high. For example, if you have very high P levels from a history of manure application you may not need to apply any phosphorus for the soybeans. Soybean seed is very sensitive to injury from fertilizer, so I would be very cautious on applying much fertilizer with the planter. If you need high rates of potash you would want to apply broadcast applications. Contact your local extension office or university on soil testing instructions and finding a local lab.
Soil Fertility Resources For Soybeans
Fertilizer Helps The Bottomline
This blog is provided as an interactive way for you to have your questions answered by our Farm Journal Agronomists. E-mail your nitrogen, soil fertility, soil density, planter set-up, scouting, and other questions to: TestPlots@FarmJournal.com.
