The point where the two fertilizers intersect will get twice the rate. If the grass has a visual response or more growth, it means that a complete application may be warranted. Iron and nitrogen will almost always show up with a positive effect, so apply these in strips first if you see any symptoms as described. If you apply strips again later, choose another area of the green to apply the strips. This avoids responses from accumulated effects.
Potassium deficiencies can show up on greens, especially in late fall.
The edges of the leaves may shred, nick or tear easily. The pale color is usually yellow to light tan in color. However, the leaf will still remain alive. Use potassium sulphate as the source, since it has no N or P in it. Make sure you check the availability of the nitrogen source.