Agronomy (Sep 2021)

Intensive Production and Management of Marandu Palisadegrass (<i>Urochloa brizantha</i> ‘Marandu’) Accelerates Leaf Turnover but Does Not Change Herbage Mass

  • Fernando Ongaratto,
  • Marcia Helena Machado da Rocha Fernandes,
  • Erick Escobar Dallantonia,
  • Lais de Oliveira Lima,
  • Guilherme Alves do Val,
  • Abmael da Silva Cardoso,
  • Izabela Larosa Rigobello,
  • Jorge Augusto Americo Campos,
  • Ricardo Andrade Reis,
  • Ana Claudia Ruggieri,
  • Euclides Braga Malheiros

DOI
https://doi.org/10.3390/agronomy11091846
Journal volume & issue
Vol. 11, no. 9
p. 1846

Abstract

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Pasture intensification through higher stocking rates, nitrogen fertilization and intensified grazing management in beef cattle production optimizes pasture use by increasing the forage harvested. We aimed to assess its effects on the morphogenesis and canopy structure of Urochloa brizantha ‘Marandu’ (marandu palisadegrass) pastures. The treatments consisted of marandu palisadegrass pastures managed under continuous stocking and a canopy height of 25 cm, with different levels of intensification: extensive, semi-intensive, and intensive systems N-fertilized with 0 kg, 75 kg, and 150 kg N ha−1 year−1, respectively, as ammonium nitrate (32% of N), with four replicates (paddocks) in a completely randomized design. Phyllochron (9.8 days) and leaf lifespan (34.7 days) were shorter in intensified pastures, whereas herbage mass was similar among treatments. Extensive pastures had a higher proportion of senescent material; thus, more intensive systems showed higher proportions of leaves and stems, although the leaves-to-stem ratio remained similar across production systems. The defoliation interval was lower in intensive (14.4 days) and higher in extensive (18.7 days) treatments. Thus, pasture intensification accelerates leaf appearance, decreases leaf lifespan, shortens the tiller defoliation interval and increased herbage accumulation rate but does not change herbage mass. The extensive system produces excessive forage losses due to dead material.

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