The objective of this study was to evaluate grass responses to combined rates of nitrogen and calcium. Measured response variables included leaf number, tiller number, leaf area, and DM yield. Tanzaniagrass was grown in nutrient solution with ground quartz as substrate, in a greenhouse experiment. The experiment was carried out in randomized block design, with four replications. A fractionated 5² factorial was used, with combinations of five nitrogen rates (2, 9, 16, 23, and 30 mmol L-1) and five calcium rates (0.50, 1.75, 3.00, 4.25, and 5.50 mmol L-1). Three harvests were performed, the first one 39 days after seedlings transplanting, the second one 30 days after the first harvest, and the third one 28 days after the second harvest. Calcium rates did not interact with the nitrogen rates for the productive variables in the first growth of this grass. The number of tillers and leaves depended only on nitrogen rates. Combination of nitrogen and calcium rates was necessary for tanzaniagrass leaf area at the third growth, and for the shoot biomass at the second and third growths. Maximum productive responses of this forage were reached with the minimum supply of nitrogen of 23 mmol L-1. The use of calcium at rate not inferior to 2 mmol L-1 did not reduce productive variables of this grass, even with the supply of high nitrogen rate.
dry mass; leaf area; leaves; Panicum maximum; tillers
