Along with V4 corn, the soil temps have jumped above 60 degrees and that’s when the soil microbes explode and start doing their thing. Microbial population will double for every ten degrees the soil temp rises. The large increase in microbes will consume a lot of nitrogen and sulfur. This will cause some temporary yellowing in the corn if we don’t have enough surface nitrogen to offset it. Corn on corn will be worse as well as any place you have residue buildup (like bathtub rings around low areas or poor distribution of residue out of the back of the combine). Fields with surface applied N that has received large amounts of rain may have leached the nitrates below corn roots. It will show symptoms until the roots catch up with the nitrogen.
Remember, while these fields will eventually green back up, the patterns you see now is how it will pollinate. Keep that in mind when scouting later.[/vc_column_text][/vc_column][/vc_row][vc_row][vc_column width=”1/1″][vc_single_image image=”5068″ alignment=”center” style=”vc_box_shadow_3d” border_color=”grey” img_link_target=”_self” img_size=”full”][/vc_column][/vc_row]
[vc_row][vc_column width=”1/1″][vc_column_text]This week was the start of ugly corn week for the earlier planted corn. This happens when the corn reaches V4 and the seed roots hand off to the true crown roots. If anything slows this process, it will show up in height and color. Any wheel tracks or compaction will show up in streaks across the field. The thermal and regular images shot at or before planting that showed the wheel tracks and wet areas are now the same areas that are affected. The change in soil density is enough to change root growth and soil microbial activity.