The objective of this experiment was to compare the ability of soybean (Glycine max), corn (Zea mays), Brachiaria brizantha cv. Marandu and pearl millet (Pennisetum glaucum) for P-uptake, at different levels of the Alvorada natural rock phosphate, under controlled conditions. The soil used was a dystrophic Hapludalf (180 g kg-1 clay), which was limed and fertilized with N, K and micronutrients. The crops were grown in 18 dm³ pots for 50 days in a greenhouse, at different P2O5 rates (0, 100, 200, and 400 kg ha-1). The amount of rock phosphate was calculated based on the total P2O5 content. Contrasting to soybean, there was a positive response of maize to higher P2O5 doses. The dry matter production by Brachiaria brizantha cv. Marandu was lower than that observed for pearl millet, but it still was highly efficient in P uptake despite the low solubility of the rock phosphate. Pearl millet is an important cover crop because of the high dry matter production and the capacity for recycling P in a relatively short period (50 days).
Pennisetum glaucum; Brachiaria brizantha; tropical grasses; cover crops
