If injury is seen, it will usually occur within hours following the application and will show tissue chlorosis and necrosis on the corn plant. The symptoms usually seen are the necrotic lesions and in more severe cases breakage of leaf midribs on some of the leaves. Symptoms usually do not persist over 30 days after application. Nodulation, the symbiotic relationship of bacteria on the soybean roots, can be seen shortly after emergence, but the plant is not actively fixing nitrogen until the V2 to V3 stages. The number and nodules formed on the soybean roots along with the amount of nitrogen fixed increases until the R5.5 stage.
Nodules actively fixing nitrogen for the plant are pink or red inside.
White, brown or green nodules indicate that nitrogen-fixation is not occurring. Soil nitrogen is utilized over fixed nitrogen, if available in large amounts. Check the health of your soybean nodules and check root proliferation. At V2, soybeans should be rooting down six inches into the soil and by V5 will completely reach between 30-inch rows, making any cultivation at V5 needing to be very shallow. Prolonged soil saturation affects crop growth and yield.