EFFECT OF SILAGING ON CHEMICAL COMPOSITION OF MAIZE SUBSTRATE FOR BIOGAS PRODUCTION

Maize (Zen mays L.) is one of the agricultural plants that is suitable substrate for biogas production. Fresh as well as ensiled maize can be used as biogas substrate. Practically, mainly maize silage is used because fresh maize is available only for short term during the vegetative period. The paper is aimed to determine the impact of ensiling on substrate composition of maize hybrids. A field trial was carried out in the Research and Study farm "Vecauce" of the Latvia University of Agriculture (LLU) in 2008 and 2009. Ten (in 2008) to eleven (2009) maize hybrids with different maturity rating according to FAO numbers (FAO 180-340) were harvested at three different times beginning on 5 September at fourteen-day intervals. Chopped maize samples of 1-3 kg were ensiled in plastic silos. Samples of fresh and ensiled (for at least 90 days) maize were analyzed detecting 14 parameters in the Scientific Laboratory of Agronomy Research of LLU using standard methods. Our results showed that ensilaging influence on organic dry matter and hemi-cellulose content was not substantial. High (p<0.05) correlation between organic dry matter content of fresh and ensiled samples was noted. The crude protein, crude fiber, ash and cellulose concentration was greater in the ensiled samples if compared with fresh maize samples in 2008 and 2009. After ensilaging process neutral detergent fiber (NDF) concentration was higher compared with fresh samples in 2009 but lower in 2008.