[en] The root-uptake of Np, Pu, Am, and Cm from three different artificially contaminated soils in grass, maize, spring wheat, and potatoes was investigated under greenhouse conditions in pots filled with 9 kg contaminated soil and in lysimeters with a surface area of 0,5 m² containing the soils in undisturbed profils up to a depth of 80 cm. Only the plough layer of 30 cm was contaminated with Np, Pu, Am, and Cm. Crop cultivation was done corresponding to usual practice in agriculture. Results of the 1st vegetation period are represented. Transfer factors obtained deviate considerably from those which are recommended for the estimation of long-term exposure of man in the Federal Republic of Germany. (orig.)