Canopy height and N affect herbage accumulation and the relative contribution of leaf categories to photosynthesis of grazed brachiariagrass pastures

Autor(es)

Yasuoka, J. I. ^[1] ; Pedreira, C. G. S. ^[1] ; da Silva, V. J. ^[1] ; Alonso, M. P. ^[1] ; da Silva, L. S. ^[1] ; Gomes, F. J. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo ESALQ USP, Coll Agr, Dept Zootecnia Luiz de Queiroz, Piracicaba, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: GRASS AND FORAGE SCIENCE; v. 73, n. 1, p. 183-192, MAR 2018.
• Citações Web of Science: 7

Resumo

The effects of three canopy heights (10, 25 and 40cm) and two N rates (50 and 250kgha(-1)year(-1)) on herbage accumulation (HA), participation of leaf categories in the leaf area index (LAI) and photosynthesis of grazed Mulato II brachiariagrass (Brachiaria brizanthaxB.decumbensxB.ruziziensis) were investigated during two summer growing seasons in Piracicaba, SAo Paulo, Brazil. The HA and LAI increased linearly from 8560 to 13600kgDMha(-1)year(-1) and 2.3 to 5.5m(2)m(-2), respectively, as canopy height increased. Mulato II brachiariagrass maintained at 10cm canopy height showed greater proportion of young leaves, but was less productive than taller canopies. Taller canopies had greater proportion of mature leaves in the LAI as well as greater photosynthesis. The greater N rate contributed to increased LAI, leaf and canopy photosynthesis rates and HA but did not affect the LAI composition. The total leaf area is more important to HA than the proportion of young leaves in the LAI, as taller canopies were more productive, suggesting that maintaining Mulato II brachiariagrass at 25 or 40cm is advantageous for this grass. (AU)

• Processo FAPESP: 14/16717-4 - Assimilação de carbono e acúmulo de forragem do capim mulato II sob taxas contrastantes de crescimento e alturas do dossel mantida sob lotação contínua
• Beneficiário: Júnior Issamu Yasuoka
• Modalidade de apoio: Bolsas no Brasil - Mestrado