Produ o e composi o qu赤mico-bromatol車gica de duas cultivares de braqui芍ria adubadas com nitrog那nio e sua rela o com o 赤ndice SPAD = Production and chemical-bromatological composition of two cultivars of brachiaria fertilized with nitrogen and its relationship with the SPAD index

作者：Camila Maida de Albuquerque Maranho; Cristina Cavalcante Felix da Silva; Paulo Bonomo; Aureliano Jose Vieira Pires

来源：Acta Scientiarum - Animal Sciences, 2009.

• Brachiaria brizantha
• Bachiaria decumbens
• clorofila
• raiz
• Brachiaria brizantha
• Bachiaria decumbens
• chlorophyll
• roots

O estudo foi conduzido com o objetivo de se avaliar a produ o de mat谷ria seca da parte a谷rea (PMSA) e da raiz (PMSR), a composi o bromatol車gica, o teor de clorofila (valor SPAD), assim como se realizar uma an芍lise de correla o entre o teor de clorofila(赤ndice SPAD) e o teor de nitrog那nio na planta e produ o de mat谷ria seca da parte a谷rea de duas cultivares de braqui芍ria. O ensaio foi conduzido em esquema fatorial 4 x 2, sendo quatro doses de N (0, 75, 150 e 225 mg dm-3 de N) e duas cultivares de braqui芍ria (Brachiaria brizantha cv. Marandu e Brachiaria decumbens cv. Basilisk) dispostos no delineamento em blocos casualizados com cinco repeti es. A PMSA foi incrementada com o aumento das doses de N, enquanto que com a PMSR aconteceu o inverso, reduzindo-se 角 medida que se aplicava N. 角 medida em que se aumentou a dose de N, houve incremento linear no teor de proteina bruta e tamb谷m melhorou a composi o qu赤mico-bromatol車gica da Brachiaria, pois aumentou o teor proteico e reduziram a FDN e a FDA. O teor de clorofila (赤ndice SPAD) pode ser utilizado como indicador do n赤vel de prote赤na da planta. The work was carried out in a green house, at the campus of Southwest Bahia State University-UESB, with the purpose of evaluating the production of dry matter in the external part (EPDM) and root (RDM) of Brachiaria brizantha＊s cv. Marandu and Brachiaria decumbens＊ cv. Basilisk, as well as their bromatologic composition and chlorophyll content (SPAD value), under different nitrogen doses (N). The experiment was conducted in a 4 x 2 factorial arrangement, using four N doses (0, 75, 150 and 225 mgdm-3 N) and two brachiaria species: Brachiaria brizantha＊s cv. Marandu and Brachiaria decumbens＊ cv. Basilisk, in five repetitions using a randomized blocks design. EPDM increased with the enlarging of the N doses, while the opposite happened with the RDM. There was no difference in the content of crude protein (CP) between the two brachiarias; there was a linear increment as the dose of N increased. neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents were reduced as the level of N in the soil increased. The chlorophyll content was also positively influenced by the N supply. The brachiaria generally presented betterdevelopment when supplied with N. Nitrogen fertilization improves the bromatologicchemical composition of Brachiaria, because it increases CP and reduces NDF and ADF. The chlorophyll content, (SPAD index) can be used as indicator of the level of protein of the plant, and also as an indicator of the expected production of cv. Marandu and cv. B