A pot experiment technique was developed for rapid identification of the nutrients which are in short supply in soils. The principle is that young plants can take up nutrients simultaneously from the soil to be investigated and from a nutrient solution. When a nutrient is omitted from solution, plants can take it up from the soil only. The difference in growth between plants on a deficient and on a complete solution, expressed as the so-called 'sufficiency quotient', is an estimate of the availability of the relevant nutrient in the soil. Some experiences with different nutrients and with different crops are discussed.