Plant-available species in agricultural crops

4 Extractants for functionally defined species 10.4.1 Plant-available species in agricultural crops 

The use of chemical extractants for the assessment or prediction of agricultural crop plant contents, plant growth or health and the estimation of the likelihood of plant or animal (consuming the fodder plant) deficiency or toxicity has been a major topic of study in agricultural laboratories for almost half a century, although 

2 Functionally defined species in hea vily polluted soils 

The use of chemical extractants for the determination of plant-available soil element contents of heavy metals in heavily polluted soils is less well established. 

While many of the procedures in Table 10.1 are applied in soils polluted, for example, from industrial sources they will not necessarily measure plant-available contents but rather the labile or mobile species contents or the more specific exchangeable species contents. These extracts indicate potentially plant-available contents rather than actual contents. 

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