Abstract

BORGES, Jorge A et al. Effect of the urea addition and type of fermentation in the sugarcane silage stability. Zootecnia Trop. [online]. 2011, vol.29, n.3, pp.283-292. ISSN 0798-7269.

The effect of the addition of 1%, 2% and 3% urea levels and two fermentations (FAe = aerobic and FAn = anaerobic) on fermentation and microbiological parameters were study in sugar cane microsilos, made in 3 kg black polyethylene bags capacity. Treatments were: sugarcane (control) and sugarcane added to the 3 levels of urea in fresh weight basis, subject to the 2 fermentations for 30 days. Variables evaluated were dry matter (DM), ammonia nitrogen (N-NH_3), pH and counting of fungal flora, the latter two at 0, 24 and 48 hours post-fermentation aerobic exposure. We used a factorial design 4 x 2 (4 treatments x 2 fermentation) with 3 replications. The data were processed through InfoStat program. Showed higher percentage of MS with the addition of urea to 1% in both fermentations (FAn = 23.02% and FAe= 26.45%), decreasing as increased the level of urea in the microsilos. As the percentage of N-NH₃ rise was observed as it increased the levels of urea, yielding the highest values for FAn (2.13%) and FAe (1.45%) to add 3% urea. pH values were found acceptable to the FAn (3.43, 4.38 and 4.54) after the silage mass to be subjected to aerobic conditions for 0, 24 and 48 hours respectively, while for FAe (3.26; 3.93 and 5.90) reached levels close to neutrality within 48 hours. With regard to fungal development, was corroborated fungistatic effect of urea from 1% concentration, even when the silo was exposed to air for 48 hours, with Aspergillus sp. the species most resistant to treatment. In conclusion, the addition of urea to 1% in sugarcane silage helps maintain the stability of the silo once exposed to aerobic post-fermentation conditions.

Keywords : Aerobic deterioration; silage; sugar cane; fungal development.

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