| Abstract: | Upland rice is an important crop in Brazilian agriculture and phosphorus (P) deficiency is one of the most yield limiting factors for this crop. A greenhouse experiment was carried out with the objective of evaluating response of upland rice to P rate and sources. The treatment consisted five P rates: 0, 25, 50, 100, and 200 mg dm?3 supplied through four P sources: Araxa, Catalão, Irece, and Lagamar. The soil used in the experiment was a Typic Hapludox. Rice grain yield, shoot dry weight, and root dry weight was significantly increased with increasing resin extractable P in the soil. Maximum shoot dry weight and grain yield was achieved with resin extractable P of 30 mg P dm?3. However, root dry weight increased linearly with increasing P concentration in the range of 4 to 72 mg dm?3. Shoot dry weight, grain yield, and root dry weight increased significantly in a quadratic fashion with increasing P concentration in the shoot. Rice yield and P uptake were not affected significantly with P sources. Grain Cd concentration also was significantly affected by P rates but did not exceed the permissible concentration for human consumption, according to Brazilian food legislation. |
