EFFECTS OF LIMING LEVELS AND PHOSPHORUS SOURCES ON TANZANIA GRASS YIELDS (Panicum maximum Jacq. cv. Tanzania)

Abstract

The phosphorus deficiency and the natural acidity of Brazilian savannah soils contribute to the low productivity of Brazilian livestock raising. This research evaluated the effects of liming levels and phosphorus sources and levels in dry matter production of Tanzania grass (Panicum maximum Jacq. cv. Tanzania). The treatments were divided into groups 1 (G1) and 2 (G2). G1 evaluated three liming levels - no liming and liming to reach 30% and 60% base saturation (0, 1.12, and 2.64 t/ha, respectively) – and three phosphorus sources – single superphosphate, Yoorin thermophosphate and Arad hyperphosphate. G2 evaluated the same liming levels and five phosphorus levels – 0, 30, 60, 120, and 240 kg/ha of P. In G1 no interactions were observed between phosphorus sources and liming, nor were liming effects. Significant differences were found for phosphorus sources: grass yield was higher under single superphosphate than under Yoorin thermophosphate or Arad hyperphosphate. Dry matter production in G2 didn't differ between liming levels and no interactions were observed between phosphorus and liming levels. However, there were significant differences among phosphorus levels, with maximum dry matter production for 172.8 kg/ha of P. This result confirms the importance of phosphorus fertilization to achieve high yields in Brazilian soils.

KEY-WORDS: Phosphorus; liming; forages; tanzania grass.