Bermudagrass shows typical iron deficiency symptoms primarily during the monsoon and in the early spring when the grass starts to grow out of dormancy. Scalping lawns at anytime of the year often causes an iron chlorosis condition. This problem can be solved by simply not scalping the turf. Iron deficiencies are often mistaken for nitrogen deficiencies in a lawn. Both deficiencies can make the lawn look yellow, but the actual leaf location where the yellowing occurs tells the story.
Nitrogen deficiency causes the lower leaves to turn yellow.
These are the leaves closest to the ground. Note that this is the exact opposite condition of what happens with iron deficiency. Normally, when the lower leaves are no longer useful, they slowly turn brown and wither away. When there is a severe shortage of nitrogen, the lower leaves actually turn yellow. This is because the extra nitrogen increases growth at a time or condition when the grass already cannot extract enough iron.