Ciência Rural (Feb 2009)
Fracionamento dos carboidratos de silagens de milho safrinha colhidas em diferentes alturas de corte Carbohydrates fractioning of late crop corn silages harvested at different cutting height
Abstract
Este trabalho teve como objetivo verificar se há alteração na composição dos carboidratos de silagens de milho safrinha quando colhidas nas alturas de corte (AC) de 20, 45, 70 e 95cm acima do solo. O experimento foi conduzido em delineamento completamente casualizado, com quatro unidades experimentais (minisilos) por tratamento. A matéria seca aumentou linearmente (MS=27,25+0,06928*AC, onde: R²=0,82 e PThe objective was to verify if there are changes in the carbohydrates composition of late crop corn silages harvested at 20, 45, 70 and 95cm of cutting height (CH). The research was conducted in a randomized entirely design with four replications (mini-silos) per treatment. The dry matter content increased linearly DM=27.25+0.06928*CH (R²=0.82 and P<0.01) with the CH elevation due to the larger grain proportion in the ensiled mass. The neutral detergent fiber corrected for ashes and protein (NDFap) and lignin (ADL) values lowered with the CH elevation, NDFap=43.75-0.08411*CH (R²=0.47 and P<0.01) and ADL=6.983-0.03156*CH (R²=0.49 and P<0.01), respectively. The carbohydrates B1=27.16+0.1239*CH (R²=0.66 and P<0.01) fraction and the non-fiber carbohydrates NFC=41.57+0.07861*CH (R²=0.54 and P<0.01) increased linearly with the CH elevation. The late corn cropping in the south region of Brazil lead to high quality silages, with high starch and low neutral detergent fiber values. The CH elevation in the corn plant changes the carbohydrates distribution, with higher starch and lower neutral detergent fiber and lignin values in the silage.
