Effect of nitrogen and lime on Massai grass subjected to intensive cutting

Efeito de nitrogênio e calcário em capim-massai sob cortes intensivos

ABSTRACT

Soil acidity and lack of nitrogen fertilization limit the yield of forage grasses. This study aimed at evaluating the effects of lime (0 kg ha^-1; 2,000 kg ha^-1; 4,000 kg ha^-1; and 8,000 kg ha^-1) and nitrogen (0 kg ha^-1, 20 kg ha^-1, 40 kg ha^-1, 80 kg ha^-1 and 160 kg ha^-1) doses on forage accumulation, soil chemical properties and macronutrient concentrations in leaf blades of Massai grass (Panicum maximum cv. Massai). A randomized blocks design in a 4 x 5 factorial scheme, with four replications, was used. Lime and nitrogen doses positively affected the accumulation of green dry mass in the Massai grass as well as the base saturation in the soil. The maximum yield was obtained at nitrogen doses close to 587 kg ha^-1 year^-1 for nitrogen and 5,796 kg ha^-1 for lime, which produced the greatest accumulation of green dry mass (15,267 kg ha^-1 year^-1) in the first year of assessment. The demand for lime increased from the first to the second year. Lime increased the base saturation, whereas nitrogen reduced it. The nitrogen applied to the soil raised the nitrogen, magnesium and calcium contents (g kg^-1) in the leaf blades of Massai grass. Thus, Massai grass reacted positively to nitrogen and lime doses, with significant effects on the accumulation of green dry mass and soil characteristics assessed.

KEY-WORDS:
Panicum maximum cv. Massai; nitrogen fertilization; liming