Composição mineral da cana-de-açúcar in natura hidrolisada com cal virgem (CaO)

Abstract

The aim of this study was to evaluate the mineral composition of “in natura” sugarcane hydrolyzed with increasing doses of quicklime and different periods of exposure to air. The levels of quicklime (CaO) used were 0.0 (control); 0.5; 1.0; 1.5 to 2.0% based on natural matter of cane and the time of exposure to air at 0; 24; 48; 72 and 96 hours. The mineral composition was assessed through the concentrations of calcium (Ca), phosphorus (P), potassium (K), magnesium (Mg), zinc (Zn), copper (Cu), manganese (Mn), chromium (Cr), lead (Pb) and cadmium (Cd). We used a completely randomized design. Data were analyzed using analysis of variance with repeated measures for comparison of means by Tukey test at 5% probability was used. The Ca concentration changes (P<0,05) caused a modification of the Ca:P ratio in the hydrolyzed sugarcane that reached 36.46:1 at the highest dose of lime (2.0%). The levels of P, K, Mg, Zn and Cu decreased with increasing levels of quicklime (P<0,05). Regarding to the period of exposure to air, there was an increase in the concentration of K, Mg, and Mn (P<0,05). The treatment of sugarcane with microprocessed quicklime (CaO) increases the Ca content of the forage. Pb is present in the quicklime but in a concentration well below the toxic concentration for ruminants.