ABSTRACT
This chapter focuses on Nickle (Ni)-specific papers concerning arable soils, such as, unpolluted or polluted and field crops. It provides the evaluation of several methods for the determination of plant-available Ni in a wide variety of metal-polluted soils in order to predict toxicity in plants grown in those soils. Many single extraction methods, which have been used not only for the other four essential metal micronutrients for plants but also for macronutrients and non-essential trace elements, were widely employed in order to assess Ni availability for plant species grown in unpolluted or polluted soils. Application of simple extraction methods of Ni on unpolluted soils is not as commonly reported in the literature as those on polluted soils, probably because the role of Ni as a pollutant and not as an essential plant micronutrient was of major interest until recently. Apart from chemical extraction methods, ion exchange resin methods have also been employed for the assessment of soil-available Ni.
