In slightly acidic soils the effect of two rates of PARP (60 and 120 kg P2O5 per hectare) was compared to that of single superphosphate and of the original ground Araxá rock phosphate (ARP), both supplied to give 90 kg P2O5/ha. Testcrops were: upland rice, corn and soybeans. Main conclusions, based on yield data, and soil and leaf analyses were the following: (1) there was no statistical diferrence between yields obtained with PARP and SS which, however, were ussuallu higher than those provided for by ARP; (2) results from chemical analyses show that the PARP, as well as the SS, were a source of P, Ca and S to the three crops; (3) under the experimental conditions, there fore, the effect of the PARP was close to that of the SS rather than to the effect due to the ARP.