Características fenológicas e valor nutritivo das silagens de híbridos de girassol (Helianthus annuus, L.)

Content Provider	Semantic Scholar
Author	Mello, Renius De Oliveira
Copyright Year	2005
Abstract	MELLO, Renius de Oliveira, M.S., Universidade Federal de Viçosa, February, 2005. Phenological traits and nutritive value of the silages of sunflower hybrids (Helianthus annuus, L.). Adviser: Augusto César de Queiroz. Co-adviser: José Laerte Nörnberg. Committee member: José Carlos Pereira. The objective was to evaluate the phenological, productive and nutritional traits of the silages of four sunflower hybrids: Rumbosol-91 (forage), M-734 (double purpose), C-11 (double purpose) and BRS-191 (grain) sowed in three dates: October (early), November (normal) and December (delayed). A randomized block experimental design in a 4 x 3 factorial arrangement (four hybrids x three seeding dates) with four replicates was used. The interaction effect between sunflower hybrids and seeding dates was significant for most of the analyzed variables. The seeding in October showed longer cycle, higher plant height, and lower head diameter and contribution, due to lower temperature, insolation and photoperiod (day's length) in this date. The Rumbosol-91 and BRS-191 hybrids sowed in November showed larger lodging plus stalk breaking rate, being 49.6 and 65.7%, respectively. The BRS-191 and M-734 hybrids sowed in December showed higher biomass yields, with 39.71 and 43.76 t ha of fresh matter and 11.31 and 11.41 t ha of dry matter, respectively. In the plant parts, the CP values increased and the NDF, ADF and ADL decreased, respectively, for the stem, leaves and head. In the whole plant, the DM values ranged from 23.2% for the Rumbosol-91 hybrid sowed in November to 47.9% for the C-11 hybrid sowed in December, indicating that the hybrids had differentiated capacity of humidity retention in similar physiologic maturity of the culture (R-9 phase). The CP values ranged from 7.0 to 15.7%, demonstrating the high protein content of the culture. The ADL values of the whole plant ranged among 6.5 to 12.4%, and the M-734 hybrid sowed in December and C-11 hybrid sowed in October showed the smallest values. In the silage, the dry matter values ranged from 23.2 to 43.0%; pH from 4.0 to 5.1 and ammonia nitrogen as percentage of the total nitrogen from 5.3 to 16.8%, demonstrating the diversity of results in the same maturity phase of the culture. In relation to mineral composition, the values ranged among 6.8 to 8.8% for mineral matter; 0.61 to 0.93% for calcium; 0.28 to 0.53% for phosphorus; 0.52 to 0.76% for magnesium; 1.37 to 3.16% for potassium and 0.010 to 0.033% for sodium, and the values increased from seeding in October to December. The silage of the Rumbosol-91 hybrid showed smallest ether extract and highest N in
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