Should Nitrogen Fertilizer be applied to “Tile Run” Soybeans?

Welcome rains have turned to downpours in some parts of Ontario.  In extreme cases, fields have received in excess of 12 inches of rain over a two week period.  Excess moisture has resulted in a tremendous number of fields turning yellow. This yellowing is not the result of root rots but largely a nitrogen deficiency. Although root rots are a significant problem in certain fields, the majority of yellow plants are a result of wet feet. The fact that tile runs are so evident in water-logged fields is clear evidence that that this is a nitrogen deficiency.

Another factor that has added to this N deficiency is that soybeans are in their rapid growth phase, attempting to quickly put on tri-foliates while flowering is in full swing. This rapid growth requires nitrogen. The early season dry conditions actually inhibited nodulation, so a number of factors have come together to cause these symptoms. A large demand for N, limited available soil N due to excess moisture, and insufficient biological N fixation have all added to this yellowing.