IFAS Extension recently published a publication of interest to growers on the plant micronutrient nickel. This 5 page publication begins with an introduction to the 17th essential plant nutrient. It then explains the function of nickel in plants and what symptoms to look for when plants are deficient.
The publication explains that nickel is required by the urease enzyme in plants for the efficient conversion of urea to ammonia. When nickel is at an insufficient level in the plant, urea is not converted as efficiently and toxicity may develop.
Uptake, transport, bio-transport and soil testing are covered, as well as how to fertilize to avoid nickel deficiency. The publication is here: http://bit.ly/lv6jaF