Nitrogen deficiency

General light green colour and sparse canopy, compared with N-fertilized crop behind (J. O'Sullivan).

Yellowing, wilting and drying up of oldest leaves, and purple veins on young leaves are common symptoms (J. Low).

- overall pale, dull appearance and small leaf size.

- slow establishment and ground cover.

- some older leaves may turn yellow and slightly wilted, then drop off.

- increased purple pigmentation of young leaves, especially veins, and sometimes apparent only on the undersurface.

Common on soils with low organic matter, or soils which have been cropped for some time without adequate fertilisation or manuring.

Applying urea to a test area (such as one row within the crop) should make it visibly greener.