Which symptom indicates nitrogen deficiency in corn?

The symptom that indicates nitrogen deficiency in corn is characterized by V-shaped yellowing at the tips of the leaves. This specific pattern occurs because nitrogen is a mobile nutrient in plants, meaning it can move from older tissues to younger ones. As a result, when there is a deficiency, the older leaves tend to lose nitrogen first, leading to the distinct yellowing that appears in a "V" shape starting from the leaf tip and extending toward the base. This visual cue is crucial for diagnosing nitrogen deficiency, as it reflects the plant's struggle to obtain sufficient nitrogen needed for optimal growth and development.

Other symptoms, while they may also indicate nutrient deficiencies, are not as directly associated with nitrogen deficiency in corn. For instance, pale green color and yellowing beginning on older leaves can suggest other nutrient issues and are not specific to nitrogen. Stunted growth can occur due to various factors, including water stress or root issues, not solely nitrogen deficiency. Therefore, recognizing the V-shaped yellowing pattern is essential for accurately identifying nitrogen deficiency in corn.