The availability of phosphorus (P) from " Patos de Minas" phosphate rock (PR) can be improved if it is applied mixed with a water-soluble P source. The objective of this study was to evaluate 32P as a tracer to quantify the effect of the ratio of mixtures of triple superphosphate (TSP) with PR and the rates of application on P availability from PR. Two experiments were conducted in a greenhouse utilizing corn (Zea mays L.) plants as test crop. In the first experiment, the P sources were applied at the rate of 90 mg P kg-1 soil either separately or as compacted mixtures in several TSP:PR ratios (100:0, 80:20, 60:40, 50:50, 40:60, 20:80 and 0:100 calculated on the basis of the total P content). In the second experiment, the TSP was applied alone or as 50:50... |