By: Brad Carlson, Extension educator If you’ve seen nitrogen (N) deficiency symptoms in corn popping up in fields across Minnesota, you’re not alone. Crops in the past couple weeks have begun to show substantial N deficiency symptoms around the R3-R4 stages. Challenging conditions during planting season led to less than ideal seedbeds, with compacted areas in many fields affecting crop rooting. Additionally, a widespread issue this year is compaction caused by manure applications when fields were too wet. In some locations, there was a lot of moisture early in the season that may have prevented deep rooting, and potentially led to N loss through denitrification. One final factor is that plants now have a big sink – the cob – causing N to mobilize within the plant. Between fertilizer and mineralization, the corn plant will have enough N to stay green under normal conditions. This makes it hard to detect deficiency either visually or with sensors, especially early in the season wh
