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Soil profiles under different cultivation/fallow status were examined in a village in the Thar Desert. Among the factors influencing plant productivity at three representative sites, the following were identified: (a) effective soil depth from the surface down to the calcrete layer, (b) clay content and (c) nutritive elements such as N, P, K, Ca and Mg. The distribution of available P was reflected from a history of landuse, i.e. cultivation and fallowing. The concentration of available P was higher in fallow than cultivated land and in the surface layer than in the lower layers. This was attributed to absorption of available P by plant roots and replenishment by return in the form of root litter. (C) 1997 Academic Press Limited.