Throughout the 2017 growing season, we’ve seen a few trends in nutrient management that stand out. By taking a look back at our observations, we’re better able to plan for the future, observing what worked and what didn’t. Here’s a look at the stand out trends of 2017.
Iron Deficiency Chlorosis
2017 has been a banner year for iron deficiency chlorosis (IDC) issues. IDC is greatly impacted by the weather. Cool and wet soils can increase issues, but not all soils prone to IDC will produce it in soybean plants.
The best option for managing IDC is with an in-furrow application of an ortho-ortho EDDHA Fe product. Once symptoms are present, it may be too late to effectively treat areas of the field that are severely affected by IDC, so planting a tolerant variety is a must in fields where IDC is present.
In the winter of 2016-2017, while we saw tile flow occurring late into the winter like previous winters, the risk for N loss should still have been low. We saw N loss across the state, but the N lost through winter tile flow likely would have been lost in April or May when we typically have N loss.
In research trials this year, we’ve seen less deficiency for treatments that showed clear deficiencies this time last year. Some of the difference may be attributed to better mineralization, but rainfall patterns have also been less favorable to June N losses across Minnesota. While there are some areas where some N loss is expected yet this season, 2017 has been a better year for nitrogen than 2015 and 2016.
Sulfur deficiencies have become more prevalent in Minnesota the last five years and 2017 was no exception. Corn, alfalfa, canola, and wheat all can benefit from some application of sulfur. Soybean, dry edible bean, and sugarbeet have not demonstrated a consistent response to sulfur for most soils in the state. These crops can benefit but research shows that concentrating on more responsive crops is more economically viable.
For example, a current AFREC study is evaluating how sulfur cycles in a two-year corn-soybean rotation. In that study, we found a yield increase for soybean in soils when the sulfur is only applied before the corn year.